Tesi sul tema "Rights of Cattle pasture"

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Foram realizados quatro experimentos distribuídos durante a época de seca e águas, com o objetivo de avaliar a inclusão de glicerina bruta (80% de glicerol) no suplemento de bovinos Nelore criados em pastagem tropical, sobre o consumo, digestibilidade, fermentação ruminal, perfil de microrganismo no rumem, desempenho, emissões de metano, qualidade de carne e características de carcaça. Os tratamentos consistiram de suplementos com níveis crescentes (0, 70, 140, 210, e 280 g/kg MS do suplemento) de glicerina bruta, fornecidos aos animais em uma relação de 700 g/100kg de peso corporal da época da seca, e 300 g/100kg de peso corporal durante a época das águas. Na estação da seca, cinquenta tourinhos Nelore (279.52 ± 16.31 kg peso corporal inicial) foram usados para avaliação de performance animal, e dez novilhos Nelore canulados (408.8 ± 38.5 kg) foram usados para investigar a digestibilidade, fermentação ruminal e perfil de microrganismos do rumem. Na estação das águas, os experimentos foram repetidos com os mesmos animais utilizados na fase anterior. Inclusão de glicerina bruta no suplemento de bovinos Nelore castrados, criados a pasto na época da seca, não afeta o consumo e digestibilidade aparente. No entanto, altera a fermentação ruminal, aumentando a proporção de butirato e valerato enquanto reduz acetato e ácidos graxos voláteis totais, sem apresentar efeito negativo sobre a população relativa de bactéria celulolíticas e protozoários no rúmen. Contudo, a inclusão de glicerina até o nível de 28% da matéria seca do suplemento de tourinhos Nelore em crescimento criados em pastagens tropicais na época da seca, melhora o ganho de peso e a eficiência alimentar. A inclusão de glicerina bruta até a concentração de 28% da matéria seca do suplemento não altera consumo, as características de carcaça e qualidade de carne, e emissão de metano. No entanto, promove ...
Four experiments were conducted during the dry and rainy season, in order to assess the increasing concentrations of crude glycerin (80% glycerol) in the supplement of young Nellore grazing tropical grass, on intake, digestibility, ruminal fermentation, rumen microorganism profile, performance, methane emission, and carcass and meat quality traits. The treatment consist of supplements with increasing concentrations (0, 70, 140, 210, and 280 g/kg DM basis of supplement) of crude glycerin, fed to the animals in a ratio of 700 g/ 100kg of body weight in the dry season and 300 g/100kg of body weight in the rainy season. In the dry season, fifty young Nellore bulls (279.52 ± 16.31 kg initial body weight) were used for animal performance evaluation, and ten ruminal cannulated Nellore steers (408.8 ± 38.5 kg) were used to investigate the digestibility, ruminal fermentation and rumen microorganism profile, in the two experimental phases. In the rainy season, the experiments were replicated with the same animals used in the previous phase. Inclusion of crude glycerin in the supplement of young Nellore steers grazing tropical grass in the dry season, does not affect intake and apparent total tract digestibility. However, alters rumen fermentation whereas increases butyrate and valerate while reducing acetate and total VFA, showed no negative effect on relative proportion of cellulolytic bacteria and protozoa population. Nevertheless, inclusion concentration of glycerin at up to 28% DM in the supplement of growing Nellore bulls raising tropical grass in the dry season, improved BW gain and feed efficiency. Inclusion of crude glycerin up to the level of 28% of dry matter in the supplement does not alter the carcass characteristics, the meat quality and methane emission. However, glycerin supplementation promotes additional daily gain with potential ...

Orientador: Telma Teresinha Berchielli
Banca: Ana Claudia Ruggieri
Banca: Juliana Duarte Messana
Banca: André Soares de Oliveira
Banca: Mateus Pies Gionbelli
Resumo: Foram realizados quatro experimentos distribuídos durante a época de seca e águas, com o objetivo de avaliar a inclusão de glicerina bruta (80% de glicerol) no suplemento de bovinos Nelore criados em pastagem tropical, sobre o consumo, digestibilidade, fermentação ruminal, perfil de microrganismo no rumem, desempenho, emissões de metano, qualidade de carne e características de carcaça. Os tratamentos consistiram de suplementos com níveis crescentes (0, 70, 140, 210, e 280 g/kg MS do suplemento) de glicerina bruta, fornecidos aos animais em uma relação de 700 g/100kg de peso corporal da época da seca, e 300 g/100kg de peso corporal durante a época das águas. Na estação da seca, cinquenta tourinhos Nelore (279.52 ± 16.31 kg peso corporal inicial) foram usados para avaliação de performance animal, e dez novilhos Nelore canulados (408.8 ± 38.5 kg) foram usados para investigar a digestibilidade, fermentação ruminal e perfil de microrganismos do rumem. Na estação das águas, os experimentos foram repetidos com os mesmos animais utilizados na fase anterior. Inclusão de glicerina bruta no suplemento de bovinos Nelore castrados, criados a pasto na época da seca, não afeta o consumo e digestibilidade aparente. No entanto, altera a fermentação ruminal, aumentando a proporção de butirato e valerato enquanto reduz acetato e ácidos graxos voláteis totais, sem apresentar efeito negativo sobre a população relativa de bactéria celulolíticas e protozoários no rúmen. Contudo, a inclusão de glicerina até o nível de 28% da matéria seca do suplemento de tourinhos Nelore em crescimento criados em pastagens tropicais na época da seca, melhora o ganho de peso e a eficiência alimentar. A inclusão de glicerina bruta até a concentração de 28% da matéria seca do suplemento não altera consumo, as características de carcaça e qualidade de carne, e emissão de metano. No entanto, promove ...
Abstract: Four experiments were conducted during the dry and rainy season, in order to assess the increasing concentrations of crude glycerin (80% glycerol) in the supplement of young Nellore grazing tropical grass, on intake, digestibility, ruminal fermentation, rumen microorganism profile, performance, methane emission, and carcass and meat quality traits. The treatment consist of supplements with increasing concentrations (0, 70, 140, 210, and 280 g/kg DM basis of supplement) of crude glycerin, fed to the animals in a ratio of 700 g/ 100kg of body weight in the dry season and 300 g/100kg of body weight in the rainy season. In the dry season, fifty young Nellore bulls (279.52 ± 16.31 kg initial body weight) were used for animal performance evaluation, and ten ruminal cannulated Nellore steers (408.8 ± 38.5 kg) were used to investigate the digestibility, ruminal fermentation and rumen microorganism profile, in the two experimental phases. In the rainy season, the experiments were replicated with the same animals used in the previous phase. Inclusion of crude glycerin in the supplement of young Nellore steers grazing tropical grass in the dry season, does not affect intake and apparent total tract digestibility. However, alters rumen fermentation whereas increases butyrate and valerate while reducing acetate and total VFA, showed no negative effect on relative proportion of cellulolytic bacteria and protozoa population. Nevertheless, inclusion concentration of glycerin at up to 28% DM in the supplement of growing Nellore bulls raising tropical grass in the dry season, improved BW gain and feed efficiency. Inclusion of crude glycerin up to the level of 28% of dry matter in the supplement does not alter the carcass characteristics, the meat quality and methane emission. However, glycerin supplementation promotes additional daily gain with potential ...
Doutor

Thesis (M.S.)--West Virginia University, 2003.
Title from document title page. Document formatted into pages; contains vi, 163 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 132-136).

Manure production and nutrient management in pasture-based dairy production systems by Walter Svinurai The effect of dietary treatments on nutrient excretion was determined and an attempt to improving the retention of excreted nitrogen in stored manure using Aloe ferox leaf gel (AFLG) and pine bark was conducted at a pasture-based dairy farm. The animal mass-balance method was used to determine nutrient excretion by cows fed on three dietary treatments, Lolium perrene-based treatment (LP), Lolium multiforium-based treatment (LM) and Lolium perenne- Trifolium repens -based treatment (LTF). In separate experiments, slurry from dairy cows fed LM was amended with AFLG and pine bark at concentrations of 25, 50, 75 and 100 g/l and stored under anaerobic conditions for 16 days. The highest and lowest excretions of N, P and K were observed in LM and LP treatments, respectively. Increasing dietary N improved K and N retention in milk and, consequently increased milk urea nitrogen (MUN) and N excretion (P < 0.05). The concentrations of AFLG affected N and P retention in manure (P < 0.05). The highest retention in total Kjeldahl nitrogen (TKN) of the initial was 42% AFLG at 25g/l inclusion rate. Ammonium nitrogen (AMN) concentration increased significantly due to the interactive effect of AFLG inclusion rate and time. Pine bark powder significantly improved N and P retention in manure at all concentrations. The retention in TKN was higher (P < 0.05) at 25g/l pine bark powder than other concentrations. The interaction effect of inclusion rate and time increased iii AMN (P < 0.05). Dietary treatments significantly affected nutrient excretion, and AFLG and pine bark considerably improved N retention in stored slurry. Findings from the filed trial suggest the need for more attention on managing dietary nutrients in the post-rainy and cool-dry season when growth of pasture influenced choice of dietary treatments that led to high nutrient excretion. Field simulation of the additives to determine their efficacy and environmental hazards was recommended.

The objective of the current study was to compare tick loads, growth, carcass characteristics and meat quality of Nguni, Bonsmara and Angus steers raised on natural pasture. A total of 30, 7-month old steers each of Bonsmara and Angus, and 40 Nguni steers were kept at the University of Fort Hare Farm till slaughter at 18 months. Monthly weights of the steers were recorded. Carcasses were electrically stimulated. The m. longissimus thoracis et lumborum was sampled for the measurement of meat colour, pH, drip loss, sarcomere length (SL), water holding capacity (WHC), cooking losses, myofibrillar fragmentation length (MFL), Warner Bratzler shear force (WBSF), fatty acid profiles and sensory characteristics of the steers. Urine samples were collected at the slaughter line for the determination of stress hormone concentrations. The Nguni had the lowest tick load (P < 0.05) while the Angus had the highest tick load (P < 0.05). Tick load did not affect the growth rate and carcass characteristics of the steers. Bonsmara and Angus steers had higher (P < 0.05) carcass weight and dressing percentage than the Nguni steers. Meat quality characteristics were similar (P > 0.05) among all the breeds, except that Nguni meat was darker (L*) (P < 0.05) than meat from the other two breeds. The Bonsmara had the highest (P > 0.05) concentrations while the Nguni had the lowest (P > 0.05) concentrations of stress hormones. There were significant (P < 0.05) correlations between WB values of meat aged for two and 21 days in Nguni and Bonsmara, but not in Angus. The correlations among stress responsiveness hormones and meat quality were breed-dependent. Except monounsaturated fatty acids (MUFA) and the n-6/n-3 ratio, fatty acid profiles among the breeds were similar (P > 0.05). Cholesterol levels among the breeds were similar (P > 0.05). The Nguni had the best (P < 0.05) sensory characteristics, such as flavour and tenderness. It can be concluded that while the Nguni is a small framed breed, its meat quality is similar to that of Bonsmara and Angus and has the best meat taste when raised on natural pasture.

Thesis (M.S.)--West Virginia University, 2005.
Title from document title page. Document formatted into pages; contains ix, 64 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 49-60).

The aim of the first study was to determine if barley could replace maize as an energy source in concentrates fed to dairy cows grazing on kikuyu/ryegrass pasture without affecting the milk production, milk composition, or cause metabolic disorders. Sixty Jersey cows, in early to mid lactation were randomly allocated to one of five treatments (n = 12) based on feeding concentrates with different ratios of maize to barley, ranging from 100:0, 75:25, 50:50, 25:75 and 0:100, respectively. Concentrates contained 12 MJ ME kg -1 and 130g CP kg-1 DM and cows were fed 3 kg (as-is) concentrate after each milking for a period of 42 days (14-day adaptation and 28-day measurement). Cows strip-grazed the irrigated kikuyu/ryegrass pastures (15.7 ± 1.8 percent DM; 20.2 ± 4.3 percent CP; 44.7 ± 3.5 percent NDF). Milk weights were recorded daily and milk samples collected weekly and analyzed for milk fat and protein content. Body condition score and live weight were recorded at the start and end of the experimental period. Data of all the studies were subjected to a one-way ANOVA. Daily milk yield, FCM, MUN, milk fat yield, milk fat percent, protein yield, protein percent, live weight change, or body condition score change were not affected by treatment and values were 15.8 kg, 17.2 kg, 14.9 mg dl-1, 0.72 kg, 4.56 percent, 0.59 kg, 3.77 percent, 6.67 kg, and 0.15 BCS; 15.6 kg, 17.4 kg, 15.2 mg dl-1, 0.73 kg, 4.3 percent, 0.57 kg, 3.71 percent, 1.33 kg and 0.04 BCS; 17.2 kg, 17.9 kg, 15.2 mg dl-1, 0.74 kg, 4.36 percent, 0.63 kg, 3.71 percent, 0.33 kg and 0.08 BCS; 15.6 kg, 16.4 kg, 15.5 mg dl-1, 0.67 kg, 4.33 percent, 0.60 kg, 3.83 percent, -1.46 kg and 0.11 BCS; and 15.0 kg, 16.0 kg, 15.5 mg dl-1, 0.67 kg, 4.57 percent, 0.57 kg, 3.85 percent, 8.86 kg, and 0.05 BCS, respectively for the cows fed 100:0, 75:25, 50:50, 25:75 and 0:100 maize to barley ratio concentrate. According to these results, barley can replace maize without significantly affecting the milk production or milk composition. None of the cows presented any visible symptoms of acidosis. As it was clear from the results in the first study that maize could replace barley the aim of study 2A was therefore focused on determining the effect of feeding different levels of such a barley-based (2.4, 4.8 or 7.2 kg cow-1day-1) concentrate, on milk production, milk composition and live weight change of Jersey cows on kikuyu/ryegrass pasture (23.1 ± 2.95 percent DM, 11.1 ± 0.11 percent CP, 60.8 ± 0.58 percent NDF). Forty-five Jersey cows (early- to mid lactation), were randomly allocated to one of three treatments (n = 15) involving different levels of concentrate (12 MJ ME and 130g CP kg-1 DM) feeding for a period of 42 days (14-day adaptation and 28-day measurement). Milk weights were also recorded daily, and milk samples collected weekly, and analyzed for milk fat and protein. Body condition score and live weight were recorded at the start and end of the experimental period. The results of this study indicated that increasing the concentrate level from 2.4 to 4.8 and 7.2kg cow-1day-1 did not increase the milk yield (14.0 kg, 15.2 kg, 14.4 kg; P = 0.19). The FCM production increased from 15.8 to 17.5kg (P = 0.04) as the concentrate level increased from 2.4 to 4.8kg cow-1day-1. Increasing the concentrate from 4.8 to 7.2kg cow-1day-1 did not result in a significant increase in FCM. The milk protein percent increased significantly from 3.4 - 3.6 percent when the concentrate feeding level was increased from 2.4 to 7.2kg cow-1day-1. The MUN levels were 17.09 mg dl-1, 16.03 5 mg dl-1, and 16.36 mg dl-1 for the 2.4, 4.8 and 7.2kg cow-1day-1 concentrate levels, respectively. This is well within the recommended MUN levels (12 – 18 mg dl-1) indicating that sufficient protein was fed to cows. Increasing the concentrate level from 4.8 to 7.2 kg cow-1day-1 did not increase production, probably due to a higher pasture substitution rate. Supplementing large quantities of rapidly fermentable grains, such as barley, can suppress rumen pH and may have a negative effect on the rate and extent of fibre digestion in the rumen. Therefore the aim of study 2B was not only to determine the effect of feeding different levels of a barley-based concentrate, on milk production, milk composition and live weight change, but was also to determine the effect of a low (4.8 kg cow-1day-1) versus a high (7.2 kg cow-1day-1) level of barley-based concentrate supplementation on ruminal DM and NDF degradability of Westerworld ryegrass sampled from the pastures that these cows were grazing on. Sixty Jersey cows (early- to mid lactation), were randomly allocated to one of three treatments (n = 20) involving different levels of concentrate feeding. Concentrate (12 MJ ME, 130g CP kg-1 DM) was fed at 2.4, 4.8 or 7.2 kg cow-1day-1 for a period of 74 days (14-day adaptation and 60-day measurement). These cows stripgrazed irrigated kikuyu/ryegrass pastures (14.7 ± 4.37 percent DM, 25.1 ± 1.53 percent CP, and 44.4 ± 2.58 percent NDF) at a daily pasture allocation of 10 kg DM cow-1. Milk weights were recorded daily and milk samples collected weekly and analyzed for milk fat and protein. Body condition score and live weight were recorded at the start and end of the experimental period. Twelve Jersey cows, fitted with ruminal cannulae, were randomly allocated to two of the three treatments in the production study and received either 2.4 or 7.2 kg cow-1 day-1, of the same barley-based concentrate, in a two-period crossover design. These cows strip-grazed the same irrigated kikuyu/ryegrass pastures as the sixty cows in the production study. Each period consisted of 21 days for adaptation and seven days for data collection. Rumen liquor samples were collected every 4 hours within a 24-hour cycle and repeated once. Rumen pH was measured immediately, recorded, and the supernatant fluid preserved and frozen, pending VFA analysis. The in situ nylon bag technique was used to determine DM and NDF degradation and dried samples of Westerworld ryegrass pasture were incubated for 0, 4, 8, 12, 20, 30, 48, 72 and 96 hours. The data were fitted in the non-linear model p = a + b (1-exp-ct) (Ørskov & McDonald, 1979). Daily milk production, fat corrected milk, milk fat yield and milk fat percent were not affected by treatment and values were 17.3 kg, 18.4 kg, 0.76 kg and 4.42 percent; 19.0 kg, 20.0 kg, 0.82 kg and 4.35 percent; and 18.1 kg, 19.1 kg, 0.79 kg and 4.37 percent for the 2.4, 4.8 and 7.2 kg cow-1 day-1 concentrate treatments, respectively. Milk protein percentage of cows on the 7.2 kg concentrate cow-1 day-1 was significantly higher than that of cows on 4.2 kg concentrate cow-1 day-1 feeding level. Live weight increased significantly as the level of concentrate feeding increased and values were 17.9 kg; and 28.9 kg on the 2.4 and 7.2kg concentrate treatment, respectively. There was a significant increase in the live weight of cows that were fed 7.2 kg cow-1 day-1 (as-is) in comparison to those cows that were fed 2.4 kg concentrate cow-1 day-1 (as-is). This may have resulted from more nutrients being partitioned to live weight gain rather than milk production. No further response in milk production was observed when concentrate daily feeding was increased from 4.8 to 7.2 kg cow-1 day-1. It is postulated that the higher concentrate allowance resulted in a higher substitution rate and lower DMI intake from pasture. 6 There was no significant decline in the rumen pH (6.2 ± 0.4 and 6.2 ± 0.5) when the concentrate level was increased from 2.4 to 7.2 kg cow-1 day-1 (as-is). The total VFA (118.1 ± 45.9 and 139.4 ± 45.6 mmol L-1) and isovalerate (0.009 ± 0.07 and 0.248 ± 0.52 mmol L-1) increased significantly when the concentrate was increased from 2.4 to 7.2 kg cow-1day-1. No other rumen parameters were affected by treatment. Ruminal DM and NDF degradability of the Kikuyu/ryegrass pature were not affected by the level of concentrate supplementation. An increase in the concentrate level from 2.4 to 7.2 kg cow-1day-1 did not reduce degradability of either DM (94.67 ± 5.97, 94.49 ± 5.09; P = 0.919) or NDF (92.15 ± 8.69, 94.4 ± 11.73; P = 0.451), respectively. Results of rumen parameters and PD values were within the range reported by Bargo et al., (2003), viz. pH 5.76 – 6.29, NH3-N concentration 8.7 – 32.2 mg dl-1, total VFA concentration 90.3 - 151.4 mmol L-1 and PD values 89.5 – 93.5 % reported by Bargo et al. (2003). According to these authors, there is no simple relationship between any amount of the concentrate supplemented, and the ruminal pH and concentrate feeding only affects the in situ ruminal digestion of pasture when it is fed, at quantities higher than 8 kg DM cow-1day-1 (Bargo et al., 2003).

Today, dairy farmers in the U.S. are faced with the challenge of reducing the cost of producing milk. Milk prices have risen very little in the past decade, while the cost of producing milk has risen steadily. In North Carolina alone, dairy farm numbers have dropped more than 30% in the last ten years, and the trend is expected to continue. Dairy farmers have been forced to increase their profitability to stay in business. In addition, farmers have been forced to comply with stricter environmental regulations. Over the past few years, interest has been shown in intensive management rotational grazing systems. This four-year comparison trial was designed to compare the milk production, herd health, reproductive performance, and environmental impacts of pasture-based and confinement feeding systems using Holstein and Jersey cattle for the Mid-Atlantic region. The project had both Spring and Fall calving herds with breeding via artificial insemination in 75-day periods. Each seasonal herd replicate had 36 cows on pasture and 36 cows in the confinement group. Similar numbers of Holsteins and Jerseys were included in each year. Paddocks grazed comprised 29 ha of cool and warm season pasture species in 37 paddocks for year-round grazing. Pasture-fed cows received variable amounts of grain and baled silage as needed depending upon pasture availability. Confinement cows were housed in a covered freestall barn with access to an exercise lot and received a total mixed ration with corn silage as the primary forage. Confinement cows produced significantly more milk than pasture-fed cows, both for total lactation and average daily production. Reproductive performance of the two treatments did not differ with an overall 75-day pregnancy rate of 68%. Jerseys in both systems did have higher percentages of cows inseminated (96.5%), conception rate (59.6%), and 75-day pregnancy rate (78%) compared to Holsteins (86%, 49%, 57.9% respectively). The percentage of cows infected with at least one case of clinical mastitis was higher in the confinement herd than the pasture-fed herd (43% vs. 24%) with Holsteins higher than Jerseys (41% vs. 26%). Interactions of breed and feeding system and average somatic cell count scores were not significantly different. Pasture-fed cows had lower average body condition scores than confinement cows, ranging from 0.2 to 0.6 points lower on a 5-point scale.In a short-term trial, intake measurements were taken from pasture-fed Holsteins and Jerseys consuming a grain supplement. This supplement was similar to those that were fed to the pasture-fed cows during the four-year trial. It was determined that Jerseys could consume as much as Holsteins at three different feeding levels (6.8, 4.5, and 2.3 kg/cow per feeding). This experiment showed that in certain time frames, Jersey cattle can consume equal amounts of supplements compared to Holsteins. Therefore in mixed groups Jerseys can consume relatively more supplemental energy relative to body size and milk production compared the Holsteins. In another short-term trial using cows from a spring season replicate, milk samples were obtained from pasture-fed and confinement-fed cattle and analyzed for fatty acid composition. The pasture grazed was a warm-season pasture, while the confinement-fed cattle consumed a corn-silage based TMR. The major fatty acid of interest was conjugated linoleic acid (CLA), which has been shown to be a potent anticarcinogen. Concentrations of CLA were 80% higher in pasture-fed cattle compared to the confinement-fed cattle. In addition concentrations of CLA were higher in Holsteins compared to Jerseys. To study the distribution of manure in a pasture-based system, pastured cows were observed for several 24-h periods. Data included: (1) times and location of all feces and urine events from eight cows, observed while in the pasture, feed area, milking parlor or in transit; and (2) all urine and feces events on pasture for all 36 cows each grazing period. The locations of urine and feces events were surveyed, mapped and analyzed. Percentages of the manure events in each area were highly correlated with time spent in each area (r= .99). Feces and urine (estimated at .12 m2 and .36 m2, respectively) from six observational periods covered 10% of the total paddock. Within 30 m2 of the portable waterer and gate, concentrations of feces and urine from the warm season observations were significantly greater than concentrations during the cool season observations. Manure on pasture was relatively evenly distributed over multiple grazing periods with the exception of the area around the water tank during summer grazings. These experiments showed that when compared to confinement-fed cattle, pasture-fed cattle produced less milk, produced more conjugated linoleic acid, had less mastitis and had lower body condition scores, while reproductive performance did not differ between the two groups. Jerseys had less mastitis, produced less conjugated linoleic acid, and performed better reproductively when compared to Holstein cattle. In addition, pasture-fed Jersey cattle can consume as much supplemental grain in certain time frames as pasture-fed Holstein cattle. Manure distribution on a pasture-based system is highly correlated with time spent in an area and is fairly evenly distributed over the paddock area over multiple grazing periods except for the area around the water tank during heat stress temperatures.

Orientador: Ana Cláudia Ruggieri
Banca: Carlos Eduardo Pellegrino Cerri
Banca: Patrícia Perondi Anchão de Oliveira
Banca: Ricardo Andrade Reis
Banca: Mara Cristina Pessoa da Cruz
Resumo: Metano (CH4) e óxido nitroso (N2O) são dois dos mais importantes gases de efeito estufa emitidos pela pecuária. Eles são produzidos pelas excretas dos animais e fertilizantes. No Brasil, a quantidade emitida destes gases e opções para mitigação foram pouco exploradas. Uma sequência de 4 experimentos foram realizados em campo (em duas estações chuvosas e duas secas, 106 dias de duração cada) com o objetivo de quantificar as emissões de N2O e CH4, volatilização de NH3 e o fator de emissão (FE) quando aplicadas fezes, urina, fezes + urina e fertilizante ureia em Latossolo Vermelho cultivado com capim-marandu. Investigou-se o efeito da umidade do solo e compactação, composição da urina, volume urinário, e adição de fezes sobre as emissões de N2O em um Latossolo recebendo urina manipulada em condições controladas, bem como nas emissões de CH4. Como opção para mitigar as emissões de gases de efeito estufa (GEE) foram estudadas as variáveis como as alturas de pastejo que afetam a magnitude das emissões de GEE; a influência estacional na produção e consumo dos GEE; quais são as variáveis chaves associadas com as emissões de GEE em pastagens de capim-marandu. Adicionalmente, investigou se o efeito dietético dos níveis do sal mineral na concentração de N na urina, o volume urinário, a proporção dos compostos nitrogenados na urina e a concentração de N nas fezes em condições de campo. Os FEs de N2O quantificados diferiram de acordo com a excreta e estação do ano. O FEs foram 2,34%, 4.26% e 3,95% na estação chuvosa e 3.00%, 1.35% e 1.59% na estação seca, respectivamente, para fezes, urina e fezes + urina. O FE do fertilizante ureia foi 0,37%. As emissões médias do CH4 acumuladas foram 99,72, 7,82 e 28,64 (mg C-CH4 m2) para fezes, urina e fezes + urina nesta sequência. Quando manipuladas as condições do solo como umidade, compactação e adição de...
Abstract: CH4 and N2O are two of the most important greenhouse gas emitted by livestock. They are produced from animal excretes and the fertilizer. In Brazil the amount and options to mitigate these gases are little explored. We carried out a sequence of 4 field-trials (two rainy and two dry season, 106 days each) aimed to quantify the N2O and CH4 emissions, NH3 volatilization and emission factor (EF) after application of dung, urine, dung + urine and urea fertilizer on a Ferralsol of a marandu palisade-grass pastureland of Brazil. We aimed to investigate the effects of soil moisture, soil compaction, urine composition, urine volume, and dung addition on N2O emission from a urine-treated tropical Ferralsol under controlled conditions as well on CH4 emission. As option to mitigate greenhouse gas (GHG) emissions we studied how grazing heights affect the magnitude of GHG emissions; how season influence GHG production and consumption; what are the key driving variables associated with GHG emissions. Additionally, we investigated the effect of dietary mineral salt levels on urine-N concentration, urine volume, the proportion of N compounds in the urine and faeces-N concentration under field conditions. The emissions factor (EF) calculated differed according excretes and season. The EFs were 2.34%, 4.26% and 3.95% in the rainy season and 3.00%, 1.35% and 1.59% in the dry season, respectively, for the dung patches, urine patches and dung + urine. The N2O EF from urea was 0.37%. The averages of CH4 accumulated emissions were 99.72, 7.82 and 28.64 (mg CH4-C m2) for dung, urine and dung + urine in this sequence. The manipulated soil conditions moisture content, compaction, and dung addition affected N2O emissions when varying quantities of urine-N were applied (in equal urine volumes) being higher when added dung and did not affect when varying urine volumes were applied (containing equal quantities of urine-N) ...
Doutor

Thesis (MScAgric)--Stellenbosch University, 2012.
ENGLISH ABSTRACT: Kikuyu over-sown with ryegrass is the most widely used pasture system in the Southern Cape of South Africa. During the winter months the kikuyu component remains dormant and cows are solely dependent on the ryegrass component of the pasture. Ryegrass has a low growth rate (25 - 30 kg DM ha-1 day-1) during the winter and early spring months (June - September), resulting in roughage shortages. There are various strategies that can be adopted to overcome these shortages. Most commonly, lucerne hay is bought in. The cost (R 1800 - R 2400 ton-1), however, is high and all farms do not have the capacity to store hay in large quantities. Significant wastages occur when feeding lucerne in ring feeders or feed troughs. Silage made of surplus grass, maize or cereal crops can also be fed. Many farms do not have the implements required for ensiling and due to financial pressure, most farms are at full capacity and as such no surplus pasture is available for ensiling. The purpose of this study was to determine whether a high fibre concentrate supplement and restricted pasture intake strategy could be followed to overcome roughage shortages during the winter months. Forty eight lactating Jersey cows were blocked according to 4 % fat corrected milk yield (19.1 ± 2.2 kg day-1 (±s.d.)), days in milk (104 ± 62.7) and lactation number (4.4 ± 1.8). Cows within blocks were then randomly allocated to one of the three treatments. Treatments were defined according to the amount of a high fibre concentrate supplement that was allocated as well as the level of pasture allocated: Treatment 1 - Low concentrate treatment (LC) received 4 kg concentrate cow-1 day-1 and 10 kg DM pasture cow-1 day-1; Treatment 2 - Medium concentrate treatment (MC) received 7 kg concentrate cow-1 day-1 and 7 kg DM pasture cow-1 day-1; Treatment 3 - High concentrate treatment (HC) received 10 kg concentrate cow-1 day-1 and 5 kg DM pasture cow-1 day-1. Eight ruminally cannulated Jersey cows were used in the rumen study portion of the trial. These cows were divided into two groups of four and were allocated to the MC and LC treatments. They were used in a cross-over design, where all cows were subjected to both treatments. The metabolisable energy, crude protein and neutral detergent fibre contents of the high fibre concentrate supplement was 10.9 MJ kg-1, 145 g kg-1 and 231 g kg-1, respectively. Cows of the three treatments grazed separately, allowing for the restriction of pasture intake according to treatments specifications. The average daily milk yield and milk fat content of treatments LC, MC and HC was 16.2a, 17.3ab and 18.1b kg day-1 (P < 0.05) and 4.91a, 4.96a and 4.58b % (P < 0.05), respectively. The average stocking rate for treatment LC, MC and HC was 5.07a, 6.07b and 7.64c cows ha-1 respectively. Thirty seven percent of pasture was saved on the HC treatment strategy compared to the LC treatment. Cows gained body weight during the study at a rate of 0.62a, 0.28b and 0.27b kg day-1 (P < 0.05) for the LC, MC and HC treatments, respectively. None of the hourly rumen pH values differed between treatments LC and HC. The rumen pH of cows on treatment LC did, however, spend a longer time below pH 6.0 and pH 5.8 compared to the rumen pH of cows on treatment HC (P < 0.05). The digestibility of dry matter and neutral detergent fibre of pasture of cows on treatment LC and treatment HC at 30 hours of incubation was 82.3 and 73.5 % (P < 0.05) and 43.5 and 39.2 % (P < 0.05), respectively. The results show that winter roughage shortages can be managed by feeding higher levels of a high fibre concentrate supplement and restricting pasture intake, although a decrease in milk fat content can be expected.
AFRIKAANSE OPSOMMING: Kikoejoe, oorgesaai met raaigras, is die mees algemene weidingstelsel in die Suid-Kaap van Suid-Afrika. Tydens die wintermaande is die kikoejoe-komponent dormant en diere is afhanklik van die raaigras-komponent. Raaigras het ‘n lae groeitempo (25 - 30 kg DM ha-1 dag-1) gedurende die winter- en vroeë lentemaande (Junie - September) en dit lei tot ruvoertekorte. Daar is verskeie strategieë wat toegepas kan word om die ruvoertekorte te oorkom. Die gewildste is die aankoop van lusern hooi, alhoewel die prys (R 1800 - R 2400 ton-1) die gebruik daarvan beperk. Boere het ook nie altyd die kapasiteit om groot hoeveelhede lusern te stoor nie en baie hooi word vermors as koeie dit uit hooivoerders en voerbakke vreet. Kuilvoer wat gemaak word van surplus weiding, mielies of graangewasse kan ook gebruik word. Baie boere het nie die implemente om kuilvoer te maak nie en as gevolg van finansiële druk, funksioneer die meeste plase reeds op vol kapasiteit en is daar dus nie altyd voldoende surplus ruvoer waarvan kuilvoer gemaak kan word nie. Die doel van hierdie studie was om te bepaal of ‘n hoë-vesel kragvoer en beperkte weiding-inname gebruik kan word om ruvoertekorte gedurende die wintermaande te oorkom. Agt-en-veertig lakterende Jerseykoeie is geblok volgens 4 % vet-gekorrigeerde melkopbrengs (19.1 ± 2.2 kg dag-1(±s.d.)), dae in melk (104 ± 62.7) en laktasie nommer (4.4 ± 1.8). Koeie binne blokke is vervolgens ewekansig aan een van drie behandelingsgroepe toegeken. Die groepe is gedefinieer volgens die hoeveelheid hoë-vesel kragvoer en weiding wat toegeken is: Behandelingsgroep 1 - Lae-vesel kragvoergroep (LC) het 4 kg kragvoer koei-1 dag-1 en 10 kg DM weiding koei-1 dag-1 ontvang; Behandelingsgroep 2 - Medium-vesel kragvoergroep (MC) het 7 kg kragvoer koei-1 dag-1 en 7 kg DM weiding koei-1 dag-1 ontvang; Behandelingsgroep 3 - Hoë-vesel kragvoergroep (HC) het 10 kg kragvoer koei-1 dag-1 en 5 kg DM weiding koei-1 dag-1 ontvang. Agt rumen gekanuleerde Jerseykoeie was gebruik in die rumen studie gedeelte van die proef. Die koeie was verdeel in twee groepe wat dan aan die LC en HC behandelings groepe toegeken is in ’n omslag ontwerp met twee behandelings en twee periodes. Die metaboliseerbare energie, ruproteïen en neutraal bestande veselinhoud van die hoë-vesel kragvoer was 10.9 MJ kg-1, 145 g kg-1 en 231 g kg-1 onderskeidelik. Die drie behandelingsgroepe het apart gewei, sodat weidingtoekenning beperk kon word en weidinginname bepaal kon word. Die gemiddelde daaglikse melkopbrengs en melk vet % van behandelingsgroepe LC, MC en HC was 16.2a, 17.3ab en 18.1b kg dag-1 (P < 0.05) en 4.92a, 4.96a en 4.58b% (P < 0.05) onderskeidelik. Die gemiddelde veelading van behandelingsgroepe LC, MC en HC was 5.07, 6.07 en 7.64 koeie ha-1 onderskeidelik. Volgens die strategie van die HC behandelingsgroep strategie is sewe-en-dertig persent weiding bespaar, in vergelyking met die LC behandelingsgroep. Koeie in behandelingsgroepe LC, MC en HC het in massa toegeneem gedurende die studie teen ‘n tempo van 0.62, 0.28 en 0.27 kg day-1 (P < 0.05), onderskeidelik. Rumen pH-waardes het nie tussen behandelingsgroepe LC en HC verskil nie. Behandelingsgroep LC se rumen pH was vir ’n langer periode onder pH 6.0 en pH 5.8 as in die geval van behandeling HC. Die verteerbaarheid van droëmateriaal en neutraalbestande vesel van wieding van koeieop behandelingsgroepe LC en HC na 30 ure van inkubasie was 82.3 en 73.5 % (P < 0.05) en 43.5 en 39.2 % (P < 0.05), onderskeidelik. Die resultate dui daarop dat winter ruvoertekorte bestuur kan word deur die voeding van hoër vlakke hoë-vesel kragvoer en die beperking van weidinginname, hoewel ‘n afname in melk vet % verwag kan word.

Should justice rule in close personal relationships, for example in the giving and taking between the sexes? Orare these relationships beyond justice? This paper defends the feminist call for justice (even) in close personal relationships against a common objection raised, among others, by Hugh LaFollette in 1996. According to this objection the call for justice undermines love; it tums close personal relationships into self-interested exchange relationships.
¿Debería gobernar la justicia en las relaciones personales cercanas, como por ejemplo en el dar y recibir entre hombres y mujeres? ¿O es que estas relaciones se hallan más allá de la justicia? El presente artículo defiende, basándose en Aristóteles, el llamado feminista por la justicia sexual, (aun) en las relaciones personales cercanas, en oposición, entre otras, a la objeción de perversión de Hugh LaFollette planteada en 1996. De acuerdo a esta objeción, el llamado por la justicia en relaciones personales cercanas socava o pervierte el amor y la amistad, dando Jugar a relaciones de intercambio interesadas.

Measurements of runoff quantity and quality from three cattle stocking treatments applied to pastureland in southwestern Virginia indicate the need for further research to determine treatment effects. Three cattle stocking treatments (1) Continuous, 2) Rotational, and 3) Mob) were applied to three pastures at the Virginia Tech Prices Fork Research Farm. Rainfall simulations were performed over replicated plots in each treatment to induce runoff for collection of runoff quantity and quality data during the 2012 grazing season. Additionally, rainfall simulations were performed prior to applying the grazing treatments to establish initial conditions. Monitored runoff quantity and quality response variables included runoff depth, mean nutrient concentrations, and nutrient mass loss. Response variables were compared among the three pastures for initial conditions and among treatments for post-treatment conditions. Additionally, the trends in response variables within the 2012 season were compared among treatments. Plot and rainfall conditions that were expected to influence responses were also collected and analyzed in relation to response variables. Analyses of the response variables suggested that the variability within treatments likely muted any treatment effect on the response variables. Therefore, we concluded that further research is needed to determine treatment effects on runoff quantity and quality.
Master of Science

Thesis (Ph. D.)--University of Sydney, 2009.
Title from title screen (viewed December, 2009) Submitted in fulfilment of the requirements for the degree of Master of Veterinary Science to the Faculty of Veterinary Science. Degree awarded 2009 ; thesis submitted 2008. Includes bibliographical references. Also available in print form.

Time budgets, avoidance distance scores-related behaviour and milk yield of pasture-based Jersey, Friesland and crossbred cows. by Madodana Sunson Dodzi The study was conducted at the University of Fort Hare farm to determine the time budgets, the avoidance-related behaviour variables and their relationship with milk yield in three pasturebased dairy genotypes: Jersey, Friesland and crossbreed. Twenty one clinically health dairy cows aged between 52 and 55 months, in mid lactation and comprising of seven cows from each genotype were used in the study. The time spent on different activities (grazing, lying down, standing and others) at pasture was recorded using stop watches across four seasons. The behavioural responses of the three genotypes to humans were determined by recording their avoidance distance scores (AD), exit speed (ES), pen scores (PS), pen behaviour scores (PBS), plat form scores (PLS) and the occurrence of kicking (KCK) and stepping (SPG) during milking on four consecutive days in four seasons. Time spent standing was higher (P < 0.05) for Friesland compared to Jersey and crossbred during the hot-wet season. In the cool-dry season the Jersey spent more time (P < 0.05) grazing than the other breeds. The Friesland and crossbred on the other hand devoted most of their time lying down compared to Jersey in the cool- dry season (P < 0.05). There were season differences in time spent on all activities (P < 0.05). Time spent on grazing was longest in post-rainy seasonal and lowest in hot- wet season (P < 0.05). The longest lying down period was observed in the hot-dry season and lowest in hot-wet season (P < 0.05). iii Daily milk yield Varied (P < 0.05) with genotype with the Friesland and Jersey producing higher yield than the crossbred. The highest amount was produced in hot-dry and the least in hot-wet season. Milk yield was positively correlated (P < 0.05) with lying down. Standing was negatively correlated with milk yield (P < 0.05). The Friesland had the highest avoidance distance scores (P < 0.05) and the Jersey had the lowest avoidance distance scores in all seasons. There was an association (P < 0.05) between genotype and exit speed scores, pen scores and stepping behaviour scores. The Friesland exhibited the highest exit speed scores than the other breeds. The Jersey had the lowest (P < 0.05) kicking behaviour scores. There was a relationship (r = 0.64) between avoidance distance scores and exit speed. Exit speed scores were correlated with pen score(r= 0.23). Milk yield was significant related (r= 0.17) to the occurrence of kicking behaviour. The genotypes showed different levels of sensitivity to season and milk yield was influenced by breed and season. It can be concluded that time budgets vary with season and farmers need to adopt measures that buffer the effect of season on welfare of dairy cows. It can also be concluded that avoidance distance scores differs according to genotype with Jersey being more confident to humans than other two breeds. It is therefore recommended that provision of shades or cooling mechanism should be adopted to buffer the effects of hot-wet season. Improving quality of feed during the cool-dry season may be critical for Jersey cows. Finally positive handling of the dairy cows is recommended in order to improve the welfare and milk yield of pasture based dairy cows.

In the Australian dairy industry, and in particular Victoria, there has been a shift away from seasonally concentrated calving patterns. Reasons for such a shift stem largely from improved feeding of cows with year round feed supplies, and the introduction of new germplasm from North American Holstein Friesian animals into some Australian dairy herds. Such impacts have resulted in an increase in the phenotypic and genetic potential of cows to produce more milk and be milked for longer than the standard 305 days under seasonal calving systems. The increase in high output cows has come at an associated cost with a national decrease in reproductive performance and many highly productive cows being prematurely culled for failing to get in calf. One strategy of interest to the dairy industry is for high-producing cows being mated out of season and then carried over and milked for an extra 6 months (18 month calving interval). In Australia this is regarded as the most optimal and economical method on pasture-based systems. Limited information was available about the potential for genetic improvement of extended lactation under the Australian dairy system, which led to the objectives of this thesis. A very large amount of data with over 158 million test-day records was available to examine the scope for genetic improvement in extended lactation in the Australian dairy industry. A data handling pipeline was developed to assist in analysing and editing large scale industry test day records. Variation in Australian dairy cattle in respect to their lactation curves over an extended lactation was explored and derived traits obtained that were then used in the genetic analysis using mixed model methodology. The Wood model was fitted to milk yield records divided into 8 random subsets of 1 million pure Holstein cows with 20 million test-day records. Two traits of interest, namely persistency and extended lactation, were quantified and relevant descriptive traits derived. Variation among cows in their ability to maintain high production over a longer period of time was evident and a representation of the shape of average lactation curves in Australian dairy cows was presented. Findings showed that milk production during the extended lactation phase (from day 305 to day 610 of lactation) was on average equivalent to 40% of the production of the first 305 days of lactation (standard lactation) with an average milk yield of 8,887 L over the extended lactation. In terms of lactation persistency, 50% of peak production is maintained up to day 305. Estimates of heritability for milk, fat and protein yield under extended lactation (0.09-0.06±0.004) and lactation persistency (0.06-0.1±0.004) were low, while the cows’ repeatability for extended lactation and lactation persistency milk traits (0.20) was higher by comparison. Such findings indicate the potential for early cow performance to be used as an indicator for a cow’s successive lactation performance. Extended lactation and lactation persistency were found to be highly correlated to each other (genetic 0.60-0.98 and phenotypic 0.68-0.93), but not with the other economically important traits of milk, fat and protein yield (-0.05-0.1). This suggests that selection for increased extended lactation will not adversely impact on economically important and highly selected traits, namely cumulative 305 day yields and the Australian Selection Index (ASI). Extended lactation measured as a standardised ratio trait automatically adjusts for high peak yield. Producers selecting on this trait do not favour selecting cows with higher peak yields yet maintaining peak production over another 300 days in milk. In addition, extended lactation can be incorporated with cumulative 305 day milk yields and lactation persistency in a selection index in a designed breeding program. Estimated breeding values (EBVs) were generated for extended lactation and lactation persistency for milk, fat and protein yields, to assist with the selection of cows and bulls. Genetic trends showed no change till early 1990, followed by a steady increase (1genetic SD) in EBVs for extended lactation characteristics in the last 20 years. This increase is potentially a reflection of the increased selection for milk production and introduction of new germplasm from North American Holstein Friesian cattle into Australian herds. The research presented in this thesis will provide the Australian dairy industry with the breeding tools to enable selection of bulls to produce cows that are best suited to extended lactation in pasture-based systems. It has also contributed to the understanding of the genetics of extended lactation and lactation persistency that can be applied to other breeds in the Australian herd, and opened avenues for genomic predictions for these traits.

An experiment was conducted to evaluate the effects of pasture finishing versus high-concentrate finishing, over time, on fatty acid metabolism in Angus crossbred (n = 24) beef steers. Ruminal fluid, serum, and adipose tissue biposies were obtained on d 0, 28, 84, and 140. Pasture forages and diet ingredient samples were obtained at 14 d intervals to determine nutritive value and fatty acid composition. The high-concentrate diet consisted of corn silage, cracked corn, soybean meal, and a vitamin and mineral supplement. The pasture-finished steers grazed sequentially on triticale (Triticale hexaploide)/annual ryegrass (Lolium multiflorum), alfalfa (Medicago sativa)/orchardgrass (Dactylis glomerata), and a cool-season grass/legume mixture. The high-concentrate diet consisted of 57 % linoleic acid and 7 % linolenic acid (of total fatty acids). The pasture forages contained an average 9 % linoleic acid and 66 % linolenic acid (of total fatty acids). Adipose tissue concentrations of 18:2 cis-9, trans-11 CLA were higher (P < 0.05) in the pasture-finished steers than high-concentrate finished steers. Concentrations of 18:2 cis-9, trans-11 CLA declined in the high-concentrate finished steers (P < 0.05) from d 0 to 28 and d 28 to 84. In the pasture-finished steers concentrations peaked (P < 0.10) on d 28, and remained high throughout the duration of the study. Concentrations of linolenic acid were higher (P < 0.05) in adipose tissue, ruminal fluid, and serum of the pasture-finished steers, compared to the high-concentrate finished steers. In the pasture-finished steers linolenic acid concentrations peaked (P < 0.05) on d 28, and remained high throughout the study. Concentrations of linolenic acid gradually decreased (P < 0.05) over time within the high-concentrate finished steers. Thus, it appears that only a short time is needed to alter the omega-3 and CLA composition of adipose tissue in cattle finished on pasture.
Ph. D.

Sustainable animal production on pasture planted on rehabilitated mine land will only be possible if the optimal stocking rate for animal and pasture production is determined. A grazing trial was conducted on tall fescue, established on rehabilitated mine land and irrigated with mine waste water. The aims of this study were to quantify: a) animal performance and nutritive value at different levels of nitrogen (N) fertilization during pasture establishment, and b) intake, animal performance (defined as average daily gain; ADG) and nutritive value when different stocking rates were applied. This study was done during two seasons: season one in winter (6 June -16 July 2008) and season two in spring (28 Aug – 6 Nov 2008). In terms of post mining land use this study supplied valuable information on potential livestock production. The higher level of N fertilization applied during the winter of 2007 at pasture establishment resulted in a significantly (P < 0.05) higher crude protein (CP) concentration a year later compared to the lower levels of N fertilization. During the winter grazing season the pasture contained an average of 83.4 g CP kg-1 dry matter (DM), 601.9 g NDF kg-1 DM, 6.2 g Ca kg-1 DM and 1.7 g P kg-1 DM, the average in vitro organic matter digestibility (IVOMD) was 642.2 g kg-1 OM and the average leaf: stem ratio was 88:12. The ADG of crossbred weaner calves grazing the low N fertilization (LN), low stocking rate (LS) paddock (229.1 g day-1) was significantly (P < 0.05) lower than the ADG of weaner calves grazing the LN, high stocking rate (HS) and the high N (HN), LS respectively. The ADG of the animals in the HN, LS paddock was 482.7 g day-1 and in the LN, HS paddock was 310.6 g day-1. The low ADG for the LS treatment was due to the low CP concentration of this paddock, with values as low as 55.1 g CP kg-1 DM recorded during the winter grazing period. Low pasture nutritive value during winter can potentially limit animal production.spring grazing season the pasture contained an average of 101.0 g CP kg-1 DM, 639.1 g NDF kg-1 DM, 8.9 g Ca kg-1 DM and 2.1 g P kg-1 DM. The average leaf: stem ratio was 85:15, IVOMD was 717.5 g kg-1 OM and effective DM degradability (in situ) was 56.1 %. The average OM digestibility estimated with the alkane method varied between 720.8 to 768.3 g kg-1 depending on the alkane used and weather a correction was made for the faecal recovery of the alkane used. On average the forage available in the paddock with the LS had a significantly (P < 0.05) higher CP concentration, leaf: stem ratio and IVOMD, with a significantly (P < 0.05) lower NDF concentration than the HS paddock. This is probably due to the fact that in the HS paddock forage with a high nutritive value was removed at a higher rate. Irrespective of the calculation used, digestibility calculated by the alkane method did not differ significantly (P > 0.05) between paddocks at any time period. The average intake in the paddock with medium grazing stocking rate (MS) was significantly (P < 0.05) higher than the average for the other paddocks. The paddock with the MS was managed to supply a pasture DM allowance of 2.5 % body weight (BW). The DM intake over the spring season was 2.2 % BW. The MS treatment supplied sufficient plant material without resulting in large accumulation of plant material. The ADG for the spring season was 110.5 g day-1 and averages for each paddock did not differ significantly (P > 0.05) from each other. During the
Dissertation (MSc Agric)--University of Pretoria, 2013.
gm2014
Animal and Wildlife Sciences
unrestricted

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb. 12, 2010 ). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dr. Robert L. Kallenbach, Thesis Supervisor. Includes bibliographical references.

This thesis describes a series of four experiments designed to evaluate the role of the supply of protein in livestock grazing high quality pasture during mating and during pregnancy. The first two studies investigated the effects of high crude protein content of spring or autumn re-growth pasture on the reproductive performance of dairy cows and of ewes at mating. The last two studies investigated how the dietary supply of protein, body condition and their interactions contribute to the breakdown of immunity during the peri-parturient period in ewes and investigated underlying endocrine mechanisms. In the first study (Chapter 3) cows were blood sampled via the tail vein during the breeding period in spring. Plasma was then analysed for urea concentration. Cows with high plasma urea (HPU) or low plasma urea (LPU) were defined as those with plasma urea concentrations of ≥ or < 44.9 mg/dl respectively. Lactating cows (n = 200) were also categorized into high milk producers (HMP) or low milk producers (LPM) relative to an average daily yield of 26.6 l/d. Pasture clipping showed an average pasture CP (crude protein) content of 223 g/kg DM. Concentrations of plasma urea ranged from 26.6 to 64.4 mg/dl. No correlation was observed between plasma urea concentration and either reproductive indicators or milk parameters. Mean blood urea concentration of HPU cows was 50.8 compared to 38.5 mg/dl in LPU cows. There was a trend for more animals (P = 0.09) in the HPU group than in the LPU group not to return to oestrus. Cumulative pregnancy rate in HPU and LPU was similar except at week 6 after the start of mating when more (P < 0.01) HPU than LPU cows were pregnant. Calving to conception interval, calving interval and interval between conception and first service were similar (P > 0.05) between HPU and LPU cows. Gestation length, calving rate, milk yield and milk components were also similar (P > 0.05) between LPU and HPU cows. There was no difference (P > 0.05) in plasma urea concentrations between HMP and LMP milk producers. However, calving to conception interval, interval between calving and first service and calving interval were longer (P < 0.001), submission rate higher (P < 0.001) and NRR (Non-return rate) higher (P < 0.05) in LMP than HMP. The number of services, the interval between first and second service, gestation length and CR (calving rate) were similar (P > 0.05) between HMP and LMP cows. HMP had lower (P < 0.001) milk protein and fat concentrations than LMP cows. This information indicates that, despite the fact that plasma urea was consistently higher than levels in the literature which have been associated with reduced fertility in dairy cows; no impairment of reproductive performance was observed. In the second experiment (Chapter 4) mature and dry Coopworth ewes were blocked by weight, body condition and previous prolificacy (high, HP vs low twinning frequency, LP) into two groups and thereafter randomly allocated to diet which were designed to provided either 1) high protein (163 g/kg DM, ryegrass/red clover pasture, HPP) or low protein (119 g/kg DM, hay and barley grain, HB) supply at joining. These were designed to provide high and low plasma urea concentration. Over a period of 17 days, ewes recorded as mated were examined by laparoscopy, at which time there was no difference in blood urea concentration (58.6 vs 56.1 mg/dl) between HPP and HB groups. Fifty days after the start of joining the number of foetuses present was counted using ultrasonography. As a consequence of lack of difference in the plasma urea concentration, irrespective of treatment group, individual animals were categorized into high (HU) and low plasma urea (LU) status based on whether plasma urea concentration was higher or lower than the sample mean of 51.5 mg urea/dl. Lambs which weighed greater than the mean plus one standard deviation for their litter size were classified as oversize. Ovulation rate and conception rate were similar (P > 0.05) between HPP and BH and between HU and LU ewes. Ewes with previous high reproductive performance (HP) as would be expected had higher ovulation rate (P < 0.001) and conception rate (P < 0.01) than LP ewes. Embryo losses was not (P = 0.06) different between HB and HPP ewes. Urea category (HU vs LU) did not (P > 0.05) influence embryo mortality. Foetal loss, neonatal loss, total reproductive loss and mean lamb birth weight was were not affected by diet, nor urea category (P > 0.05). Single ovulations had tended (P = 0.08) to contribute to higher embryo loss compared to multiple ovulations, and, single foetuses suffered higher (P<0.001) losses compared to multiples. While the study did not achieve large differences in plasma urea concentrations between diets, the levels of plasma urea operating were high yet reproductive wastage rates were similar to those recorded in the literature. Together with similar apparent lack of effect on a high plasma urea environment, the data suggest either that previous findings from controlled studies have a more complex aetiology or that pastoral animals can adapt to high tissue ammonia/urea status. The third trial (Chapter 5) was designed to provide information on the supply of amino acids to the abomasum from protein supplementation which have previously been found to overcome dietary scarcity associated with limitation of peri-parturient increase in FEC. Twin-suckling ewes were fitted with rumen and abomasal cannulae and grazed a ryegrass/clover sward (C) or the same sward but with a 500 g/h/d protein supplement (S). The trial was designed as a cross-over with two 14 day adaptation periods followed by two five-day digesta-sampling periods. All ewes were treated with anthelmintic 14 days after lambing. Weekly analysis of blood glucose was carried on whole blood and analysis of amino acids in plasma. The flows of amino acids (AA) and dry matter (DM) at the abomasum were measured during both sampling periods using intra-ruminally infused markers. Live weight and faecal egg count (FEC) were recorded weekly. Diurnal variation in AA flow at the abomasum peaked between 12:00 and 15:00 h and was greatest in S ewes. Flows of AA, including DAPA, were increased by supplementation by 16%, while sulphur amino acids (SAA) were the most enhanced (by 21%) and flows of leucine, lysine, glutamine and aspartate were increased by about 20%. There were significant time effects in rumen and abomasal pH (P < 0.01; in both cases in both periods) reflecting increase in pH after 09.00 h. During Period II, rumen pH in digesta of C ewes was significantly higher (P < 0.001) than that of S ewes (6.7 ± 0.05 vs 6.4 ± 0.05 for C and S ewes, respectively). Plasma AA concentrations (P < 0.01) were lower in S ewes 21 days after parturition, but similar (P > 0.05) to those of C ewes at other times. Forty-three days after lambing (after cross over), the order was reversed as plasma methionine and cysteine concentrations of C ewes became low (P < 0.05). These changes in plasma AA were accompanied by changes in body condition score between day 23 and 70 post-partum whereby C ewes lost more body condition than S ewes. There was evidence for a lower FEC in S ewes, being 46 vs. 670 epg, respectively for S and C groups (P = 0.08) 21 days after anthelmintic treatment. There were higher (P < 0.05) blood glucose levels in C compared to S ewes at day +35 relative to lambing which was reversed and significantly higher (P < 0.01) for S ewes by day +56 from lambing (after treatments were reversed). There was no significant effect of treatment on live weight and lamb performance. There are limited data in amino acid supply on lactating ewes on pasture and the present study contributes additional information on the supply of amino acids at the abomasum. The prediction that flow rates that sulphur amino acids may have been enhanced to the greatest degree could be significant since sulphur amino acids are needed for the synthesis of glutathione for immune response. It can be calculated that supplementation to supply the quantities of S-amino acid at pasture would be needed, since it would not be possible for sheep to increase pasture intake to achieve similar S-amino acid flow. Increase in bypass amino acids in S ewes at certain times in the day probably suggests influence by protein supplementation at certain times of the grazing cycle. Reduced plasma free amino acids at day +21 relative to lambing, may indicate sparing of body protein breakdown by protein supplementation. However, the difference in blood glucose on day 35 and day 56 may indicate re-adjustment of hormonal settings, responsible for nutrient partitioning. The last study (Chapter 6) used ewes during the peri-parturient period on pasture. Eighty pregnant ewes were allocated into four groups balanced for anticipated number of lambs. Group 1 had a high body condition score (BCS) of 4.0 which was maintained throughout pregnancy by pasture allowance (HM; n = 20). Group 2 (n= 40) had medium body condition (BCS 3.0) and were split into two subgroups; one was offered pasture to allow gain of condition (MH; n = 20) and the second allowed to lose condition by offering a low grazing allowance (ML; n = 20). Group 3 were thin ewes (BCS 2.4) and pasture allowance was designed to maintain this condition (LM; n = 20). These feeding regimes were maintained for 3 weeks from week -8 of pregnancy. During week -5 to -4 all ewes were acclimatized to a protein supplement (60 g/d). A glucose tolerance test (GTT) was conducted during week -4 after which half of the ewes in each group were offered a protein supplement at the rate of 500 g/d, creating –S and –NS groups. During wk -2, a second GTT was carried out. Animals were treated with an anthelmintic 3 wks before lambing, and were then challenged with a dose of 10 000 Teladorsagia circumcincta larvae on weeks -2 and -1 relative to lambing. Weekly recording of FEC, live weight and body condition was carried out. Lambs were weighed within 24 h of birth and again at 44 and 65 d of age. Computed tomography body scanning was carried out on ewes at weeks -8, -3 and +8 relative to lambing. There were no differences (P > 0.05) in lamb performance due to body condition or protein supplementation. FEC of all groups was low (≈ 9 peg) and there was no (P > 0.05) significant difference between ewes of different body condition or due to effects of protein supplementation. Ewes bearing/bearing multiple lambs had the highest FEC at day -32 and +12 relative to lambing, which was significant (P < 0.05) on the latter date. There were no significant effects of supplementation on parasite status. There were differences in basal plasma glucose concentration between groups (P < 0.001), being highest in HM/S and least in ML/NS ewes and was generally higher (P <0.001) during GTT 2 than GTT 1. Ewes carrying a single foetus had higher (P <0.001) basal glucose than those carrying multiple lambs (2.2 vs. 1.7 mmol/L, respectively). Other plasma glucose response indexes were similar (P <0.05) between groups. There were differences in insulin responsiveness between groups (P < 0.001), being highest in MH/S and least in ML/S ewes. Insulin responsiveness tended (P = 0.06) to be lower during GTT 1 than GTT 2, but was higher (P < 0.01) in ewes carrying singles than multiples. There was tendency for higher though non-significant, basal insulin concentrations in HM ewes. Insulin trends over time after glucose infusion suggest greater insulin response at GTT 1. Basal insulin was not correlated with CT muscle weight. Despite differences in body muscle mass at the start of the trial and differences induced by nutrition during late pregnancy, positive gains in muscle mass occurred during early pregnancy and muscle mass was similar in all groups by day 56 of lactation. Animals with greatest fat content at parturition (HM) mobilised the greatest amount and those with least fat (LM) deposited fat during lactation. Further experimentation may consider the use of the hyperinsulinemic-euglycemic clamp approach to more precisely estimate whether hormonal re-setting through insulin resistance may be involved in relaxation of immunity during the peri-parturient period.

Thesis (MScAgric)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Genetic selection for high milk production, type and appearance for the last 50 years has suppressed secondary traits such as reproductive performance, productive life, health and survivability in the pure milk breeds. The economic importance of these secondary traits in dairy production systems is the basis for the interest seen in crossbreeding. The problem of growth rate of heifers, cow fertility, reduced disease resistance and small body frame for beef production in Jerseys can be improved by crossing Jerseys with dual purpose breeds, such as Fleckviehs which possess a more beef potential. Against this background, this study aimed at comparing the production and reproduction of Jersey and Fleckvieh × Jersey cows in a pasture-based system. Milk recording was done according to standard milk recording procedures. Milk production (milk, fat, and protein yield) was adjusted to 305 days of lactation and corrected for age at calving. Effects of breed, parity, month and year were estimated for milk, fat and protein yield as well as fat and protein percentage using general linear models procedure. The fixed effects identified as having significant effects on milk, fat and protein yield were breed, parity and year. F×J cows produced significantly more milk than J cows (6141 ± 102 vs. 5398 ± 95 kg milk). Protein and fat yield were significantly higher in F×J (201 ± 3 and 272 ± 4 kg, respectively) than in J cows (194 ± 2 and 246 ± 3 kg, respectively). There percentages of fat and protein differed slightly between the two breeds with the Jersey recording slightly higher percentages (4.61 ± 0.04 and 3.62 ± 0.03 %, respectively) compared to the F×J cows’ percentages, which were, respectively, 4.47 ± 0.04 and 3.51 ± 0.03 %. It was concluded that F×J crossbred cows were more productive than purebred J cows probably owing to heterotic effects. Heifers were inseminated at 13 months of age and cows 40 days post-calving. Using insemination records and pregnancy check results, fertility traits were analyzed and compared between the two breeds, using analysis of variance for continuous records. Conception age was the same for both breeds resulting in a similar age at first calving. For cows, the interval from calving to first insemination was significantly shorter (P <0.001) in crossbred cows being 76.7 ± 2.2 days compared to 82.4 ± 2.5 days for purebreds. A larger proportion (P < 0.001) of 0.70 for crossbred cows was inseminated within 80 days after calving compared to 0.54 for J cows. Although the absolute number of days between calving and conception (DO) was lower for F×J cows in comparison to J cows (104.8 ± 6.8 vs. 114.8 ± 8.1days, respectively), the difference was not significant. However, the proportion of F×J cows confirmed pregnant by 100 days in milk was 0.79, which was higher (P < 0.001) than the 0.66 for J cows. Results indicate the potential of improving reproductive performance of J cows through crossing with dual-purpose breeds. The beef production of purebred J and Fleckvieh x Jersey (F×J) bull calves was compared, where bull calves were reared similarly for veal, i.e. carcass weight not exceeding 100 kg, or as steers for beef to 21 months of age. In both the veal and steer production systems, the mean birth weight were higher (P < 0.001) for crossbred in comparison to J calves and steers (33.5 ± 1.2 kg vs. 27.9 ± 1.2 kg for veal) and (33.4 ± 0.9 kg vs. 26.9 ± 0.9 kg for steers) respectively. The live weight at 6 months of age was 163.5 ± 3.9 kg for J bull calves, which was lower (P < 0.001) than that for F×J bull calves (180.6 ± 4.0 kg). The F×J bull calves had a significantly higher average daily gain (ADG) of 0.82 ± 0.02 kg/day compared to 0.73 ± 0.02 kg/day for J bulls. Marketing age differed (P < 0.001) in the veal production system with F×J and J bull calves marketed at 7.1 ± 0.1 and 6.3 ± 0.1 months, respectively. End live weight at 21 months of age was significantly higher (P < 0.001) in F×J bulls (441.4 ± 14.9 kg) than the 322.6 ± 13.4 kg in J bulls; while ADG differed (P < 0.001) between the two breeds being 0.64 ± 0.02 and 0.46 ± 0.0 kg/day in F×J and J bull calves, respectively. Crossbred steers had a significantly higher carcass of 206.5 ± 8.9 kg compared to 157.9 ± 8.6 kg for J steers. Results indicate the potential of improving beef production characteristics of the J cattle through crossbreeding.
AFRIKAANSE OPSOMMING: Genetiese seleksie vir hoë melkproduksie, tipe en voorkoms die afgelope 50 jaar het sekondêre eienskappe soos reproduksie, produktiewe lewe, gesondheid en oorlewing onderdruk in die suiwer melk rasse. Die ekonomiese belangrikheid van hierdie sekondêre eienskappe in melkproduksie stelsels is die basis vir kruisteling. Probleme soos groei tempo van verse, koei vrugbaarheid, verlaagde weerstandbiedenheid teen siektes en klein liggaam raam vir vleisproduksie in Jerseys kan verbeter word deur die kruising van Jerseys met ' n dubbele doel rasse, soos Fleckviehs wat beskik oor beter vleis potensiaal. Teen hierdie agtergrond, is hierdie studie daarop gemik om produksie en reproduksie van Jersey en Fleckvieh x Jersey koeie in 'n weiveld - gebaseerde stelsel te vergelyk. Melk opname is gedoen volgens standaard melkaantekening prosedures. Melkproduksie (melk-, veten proteïen opbrengs) was aangepas vir 305 dae van laktasie en gekorrigeer vir kalf ouderdom. ‘n Algemene lineêre model was gebruik om die effekte van ras, pariteit , maand en jaar op melk-, vet- en proteïen opbrengs sowel as vet- en proteïen persentasie te bepaal. Die vaste effekte geïdentifiseer met 'n beduidende effek op melk-, vet- en proteïen opbrengs was ras, pariteit en jaar. F × J koeie het aansienlik meer melk as J koeie (6141 ± 102 teen 5398 ± 95 kg melk) produseer . Vet opbrengs was aansienlik hoër in F × J koeie as in J koeie (272 ± 4 246 teen ± 3 kg vet). Proteïen opbrengs was ook aansienlik hoër in F × J koeie as J koeie (201 ± 3 vs 194 ± 2 kg proteïen). Vet en proteïen persentasies het geneig om effens te verskil met 'n klein effek (4.61 ± 0.04 % vet en 3.62 ± 0.03 % proteïen) vir J koeie en (4.47 ± 0.04 % vet en 3.51 ± 0.03 % proteïen) vir F × J koeie. Daar is tot die gevolgtrekking gekom dat F × J gekruisde koeie kan meer produktief wees as suiwer J koeie weens heterotiese effekte. Verse kunsmatig geïnsemineer was op 13 maande ouderdom en koeie 40 dae na- kalwing aangehou was. Met behulp van bevrugting en swangerskap rekords, is vrugbaarheid eienskappe ontleed en vergelyk tussen die twee rasse, met behulp van ontleding van variansie vir deurlopende rekords. Ouderdom van bevrugting was dieselfde vir beide rasse wat in 'n soortgelyke ouderdomsgroep was by eerste kalwing. Vir koeie was die interval van kalf tot eerste inseminasie aansienlik korter (P < 0.001) vir kruisgeteelde koeie wat 76.7 ± 2.2 dae in vergelyking met 82.4 ± 2.5 dae suiwerrasse is. ‘n Groter proporsie ( P < 0.001) van 0.70 vir gekruisteelde koeie is binne 80 dae na kalwing geïnsemineer in vergelyking met 0.54 vir J koeie. Alhoewel die absolute aantal dae tussen kalwing en opvatting (DO) laer was vir F × J koeie in vergelyking met J koeie (104.8 ± 6.8 teen 114.8 ± 8.1dae, onderskeidelik), is die verskil nie betekenisvol nie. Maar die verhouding van F × J koeie wat swanger bevestig is met 100 dae in melk was 0.79, wat hoër was (P < 0.001) is as die 0.66 vir J koeie. Resultate dui daarop dat daar potensiaal is reproduktiewe prestasie te verbeter van J koeie deur kruisteling met 'n dubbel- doel rasse. Die vleisproduksie van suiwer J en Fleckvieh x Jersey (F × J) bulkalwers vergelyk. Die bul kalwers is soortgelyk grootgemaak vir kalfsvleis, d.w.s karkas gewig mag nie 100 kg oorskry as bulkalwers nie, en as osse vir vleis tot 21 maande oud. In die kalwers- en os produksie stelsels, was die gemiddelde geboorte gewig hoër (P < 0.001) vir die kruise in vergelyking met J kalwers en osse (33.5 ± 1.2 kg teen 27.9 ± 1.2 kg vir kalwers) en (33.4 ± 0.9 kg vs . 26.9 ± 0.9 kg vir osse) onderskeidelik . Die lewendige gewig op 6 maande ouderdom was 163.5 ± 3.9 kg vir J bulkalwers en was hoër (P < 0.001) vir F × J bulkalwers 180.6 ± 4.0 kg. Die F × J bul kalwers het 'n aansienlik ‘n hoër gemiddelde daaglikse toename (GDT) van 0.82 ± 0.02 kg/dag in vergelyking met 0.73 ± 0.02 kg/dag vir J bulle. Bemarkingsouderdom verskil (P < 0.001) in die kalf produksie stelsel met F × J en J bulkalwers bemark op 7.1 ± 0.1 en 6.3 ± 0.1 maande , onderskeidelik. Finale lewendige gewig van 21 maande oud was aansienlik hoër 441.4 ± 14.9 kg in F × J bulle as 322.6 ± 13.4 kg in J bulle , terwyl GDT hoër was (P < 0.001), met 0.64 ± 0.02 kg/dag en 0.46 ± 0.0 kg/dag in F × J en J bulkalwers, onderskeidelik. Gekruisde osse het 'n aansienlik hoër karkasgewig 206.5 ± 8.9 kg in vergelyking met 157.9 ± 8.6 kg van J osse. Resultate dui daarop dat daar potensiaal is om die beesvleis produksie-eienskappe van die J beeste te verbeter d.m.v. kruisteling.

Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Monensin was approved in the 1970’s as a feed additive to ruminant diets. Since then, many studies on the effects of Monensin were done. Its mode of action includes the improvement of feed conversion by altering rumen fermentation. This alteration results in a change in the rumen microbial population. Some processes that benefit from the manipulation of rumen microbial population are volatile fatty acid production, peptide degradation and amino acid deamination. The use of ionophores as an antibacterial product in animal feeds were banned by the European union ( EU) in 2006 because of chemical residues found in the edible product making it potentially unhealthy for human consumption and it is also socially unacceptable. Thus, alternative sources need to be identified to help improve the rumen microbial population. Such an alternative could be plant based EO. Oregano (Origanum vulgare) is a natural anti-bacterial compound affecting a variety of gram positive and gram negative bacteria. It has been reported to improve the overall health and production of lactating dairy cows by enhancing rumen fermentation. The aim of this study was to determine the effect of an essential oil extracted from oregano on production and rumen fermentation of Jersey cows grazing ryegrass pasture during spring. Effects were determined on milk yield, milk composition, live weight body condition, rumen pH, Ammonia-nitrogen (NH3-N) and volatile fatty acid (VFA) composition, organic material (OM) and neutral detergent fibre (NDF) digestibility of pasture in the rumen. Fifty four early lactation Jersey cows were blocked, according to days in milk (DIM), 4% fat corrected milk (FCM) and lactation number. Cows within blocks were randomly allocated to one of the three treatments. The three treatments were as follows: Control (CON; maize based concentrate with no feed additives), an ionophore treatment, (MON; a maize based concentrate with monensin provided a daily dose at 300 mg per cow), and an essential oil treatment (EO; a maize based concentrate with oregano extract provided at a daily dose of 1.15 g per cow. Cows received 6 kg of concentrate in the milking parlour and were allocated 10 kg dry matter (DM) of ryegrass pasture, divided into two grazing periods after each milking. Before milking, cows were separated into their respective treatment groups for milking and the consumption of their specific concentrate treatments. Milk yield was recorded on a daily basis. Composite milk samples were collected per cow on a bi-weekly basis. Live weight and body condition score (BCS) were determined before and after the study. Six rumen cannulated cows were used in the rumen study. Two cows were randomly allocated to each of the three treatments in a 3 x 3 Latin square design (three treatments and three periods) thus all the cows were subjected to all three treatments over the experimental period. Ruminal pH, volatile fatty acids (VFA) concentration, ruminal ammonia-nitrogen (NH3-N), and in sacco degradability were determined. The daily average milk yield and milk fat content did not differ among treatments (P > 0.05) and were 20.5, 20.3 and 20.4 kg per cow and 4.5, 4.5 and 4.6 % for cows receiving the CON, MON and EO concentrates respectively. Milk protein and milk lactose content increased (P < 0.05) for the two additive treatments in comparison to control and were 3.39b, 3.55a and 3.60a % for milk protein and 4.50b, 4.80a and 4.80a % for milk lactose where cows received the CON, MON and EO treatments, respectively. Ruminal pH values did not differ among treatments, however, the average overall pH over the 24 hour profile was higher for the two additive treatments. There were no differences in total volatile fatty acid concentrations among the three treatments. With regards to individual VFA, propionate was decreased in the MON treatment when compared to the CON treatment. The ruminal ammonia nitrogen concentration did not differ among treatments. There were no differences in DM and NDF degradability (DMd and NDFd) on the 6 h incubation period but monensin increased the DMd at 30 h incubation and both monensin and oregano increased NDFd after 30 h incubation. To conclude the use of monensin and oregano oil extract have shown to be beneficial with regards to increasing the milk protein and milk lactose content as well as the NDFd. The average overall pH from the pH profile resulted in the two additive treatments being higher when compared to the control treatment. This could be beneficial to rumen fermentation and have a positive effect on the microbial population. As monensin and oregano oil extract showed similar results, oregano oil extract can be considered as an alternative natural feed additive to monensin.
AFRIKAANSE OPSOMMING: Monensin is in die 1970's goedgekeur as 'n voerbymiddel in herkouerdiëte. Sedertdien het navorsing met betrekking tot die invloed van monensin vinnig toegeneem. Die werking van monensin sluit die verbetering van voeromsetting in deur die verbetering van rumenfermentasie. Die verandering in rumenfermentasie het ‘n invloed op die rumenmikrobiese bevolking. Sommige prosesse wat voordeel trek uit die manipulasie van die rumenmikrobiese bevolking is onder andere vlugtige vetsuurproduksie, peptiedafbraak en aminosuurdeaminering. Die gebruik van ionofore as 'n antibakteriese produk in veevoere is gedurende 2006 deur die Europese Unie verbied as gevolg van chemiese residue wat in die eetbare produk gevind is. Die residue maak dit moontlik ongesond vir menslike verbruik en dit is ook nie sosiaal aanvaarbaar nie. Alternatiewe produkte wat help om die rumenmikrobiese bevolking te verbeter en manipuleer moet geïdentifiseer word. Een alternatiewe produk is plantgebasseerde essensiële olies. Origanum (Origanum vulgare) is 'n natuurlike anti-bakteriële produk wat 'n verskeidenheid van gram-positiewe en gram-negatiewe bakterieë in die rumen beïnvloed. Daar is gevind dat die algemene gesondheid en produksie van 'n lakterende melkkoeie verbeter deur die verbetering van rumen fermentasie. Die doel van hierdie studie was om die invloed van 'n essensiele olie-ekstrak uit oreganum op die produksie en rumenfermentasie van Jerseykoeie wat raaigras gedurende die lente bewei, te bepaal. Effekte is ondersoek op melkproduksie, melksamestelling, lewende massa, liggaamskondisie, rumen pH, ammoniak stikstof konsentrasie (NH3-N) en vlugtige vetsuursamestelling (VFA) asook ruminale droeë materiaal (DMd)- en vesel-verteerbaarheid (NDFd) van die weiding. Vier en vyftig Jersey koeie in vroeë laktasie is geblok volgens dae in melk (DIM), 4% vet gekorigeerde melk (VGM) en laktasie nommer. Koeie binne blokke is ewekansig aan een van die drie behandelings toegeken. Die drie behandelings was as volg: Kontrole (CON, mielie-gebaseerde konsentraat met geen voer-bymiddel nie), ‘n ionofoor-behandeling (MON; mielie-gebaseerde konsentraat met monensin teen 300 mg / koei per dag), essensiële olie-behandeling (EO; mielie-gebaseerde konsentraat met oreganum ekstrak teen 1.15 g / koei per dag). Koeie het 3 kg konsentraat in die melkstal ontvang met elke melking en 10 kg droeë material (DM) raaigras-weiding is per koei toegeken. Weidingsessies is verdeel in twee periodes, naamlik na elke melking. Voor melking is die koeie geskei om te verseker dat hulle die regte behandeling in die melkstal ontvang. Melkproduksie is daagliks aangeteken. Saamgestelde melk monsters is tweeweekliks per koei versamel. Lewende massa (LW) en liggaamskondisie (BCS) is aan die begin en teen die einde van die studie bepaal. Ses rumen-gekannuleerde koeie is in die rumen studie gebruik. Twee koeie is toegeken aan elk van die drie behandelings in 'n 3 x 3 Latynse vierkant ontwerp (drie behandelings en drie periodes) en al die koeie het gevolglik al drie behandelings gedurende die eksperimentele periode ontvang. Ruminale pH, VFA konsentrasie, ruminale NH3-N, en in sacco degradeerbaarhede; DMd en NDFd is bepaal. Die daaglikse gemiddelde melkproduksie en melkvetinhoud het nie beduidend tussen behandelings verskil nie (P > 0.05) en was 20.5, 20.3 en 20.4 kg/koei per dag en 4.5, 4.5 en 4.6% vir koeie op die drie behandelings (CON, MON, EO), onderskeidelik. Melk proteïen en melk laktose het aansienlik toegeneem (P < 0.05) vir die twee behandelings met die supplemente in vergelyking met die CON behandeling met waardes van 3.4, 3.6 en 3.6% vir melk proteïen en 4.5, 4.8 en 4.8% vir koeie op die CON, MON en EO behandelings, onderskeidelik. Die rumen pH oor 24 uur het nie verkil tussen die drie behandelings nie en die totale VFA konsentrasie het ook nie verskil nie. Die propionaatkonsentrasie het wel afgeneem op die MON behandeling in vergelyking met die CON. Die rumen NH3-N het nie tussen die drie behandelings verskil nie. Die DMd en NDFd verteerbaarhede van die raaigras in die rumen het nie verskil na ‘n 6 h inkubasieperiode nie. Na 30 h inkubasie het monensin ‘n hoër DM verteerbaarheid getoon en in beide die MON en EO-behandelings het die NDF-verteerbaarheid verhoog wanneer dit vergelyk word met die CON. Om saam te vat; die gebruik van monensin en oregano olie ekstrak het getoon dat dit voordelig kan wees met betrekking tot die verhoging van die melk proteïen en melk laktose inhoud, sowel as die NDFd. Die gemiddelde pH van die pH profiel het gelei tot hoër gemiddeldes vir die twee voerbyvoegsel behandelings in vergelyking met die kontrole behandeling. Dit kan voordelig wees om rumen fermentasie te verbeter en dus ‘n positiewe uitwerking te hê op die mikrobiese bevolking. Monensin en oregano olie ekstrak het soortgelyke resultate getoon en daarom kan oregano olie ekstrak beskou word as 'n alternatiewe natuurlike voerbyvoegsel.

Virtual fence technology has the potential to alleviate labour and cost associated with current physical fencing in pasture-based dairy systems. However, there is limited knowledge regarding the effects of management practices and associated cow motivators on cattle learning and response to VF stimuli. This thesis aimed to evaluate how dairy cattle learn and respond to a virtual fence at the individual and herd level using a pre-commercial VF prototype (eShepherd®, Agersens, Melbourne, VIC) and determine the effect of feed restrictions and social motivators on these responses. The first experiment revealed that dairy cows learn at different rates when exposed to VF stimuli for the first time in a group setting vs as individuals, which has implications for the training requirements. Individual variation in learning and response, and feed and social motivation were identified as factors requiring further research. The effect of a restricted diet and associated hunger levels on the response of trained dairy cows to a VF, when contained from additional feed, was evaluated in the second experiment. Cows fed restricted ration received more stimuli and performed more VF breakthroughs in the test paddock context. To understand how these findings would translate in a commercial pasture-based system, a third experiment evaluated feed restriction on pasture. Dairy cows were successfully contained by a VF across a 10-day strip grazing setting, even when restricted to the previous day’s residual for two 24 h periods. The focus of the final experiment was to evaluate the social motivation identified across the experimental chapters and identified a minimum distance between two VF to inform the future VF requirements of group management. This thesis builds upon the application of a VF technology in pasture-based dairy systems, through understanding the role feed and social motivation has on VF response and containment.

Thesis (Ph. D.)--University of Oregon, 2003.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 459-492). Also available for download via the World Wide Web; free to University of Oregon users.

The effect of stage of lactation on milk yield, somatic cell counts, mineral and fatty acid profiles in pasture-based Friesian, Jersey and Friesian × Jersey cows was investigated. Twenty Friesian, twenty Jersey and twenty Friesian × Jersey cows were randomly selected from a dairy herd. A total of 202 milk samples were collected and analysed in three stages of lactation. Genotypic differences were observed in milk yield and fat content. Friesian cows produced the highest yield and lowest fat content whereas the opposite was true for Jersey cows (P<0.01). No significant differences were observed in SCC in the different genotypes, but SCC levels were higher in mid and late lactation (P<0.001). There was no effect (P<0.005) of genotype and stage of lactation interaction on Ca, P, Mg, Na, Mn and Bo concentration. Jersey cows had the least concentration of Fe and Cu in all stages of lactation. Strong positive correlations were observed among Ca and P, Mg and Zn. Aluminium had a strong positive relationship with Bo, Fe, Mn and Zn (P<0.001). Generally, SCC had a weak positive relationship with macro elements but a significant negative relationship with microelements. Yield levels were negatively correlated with Mg, Na, Al, Mn and SCC. Pasture ALA, SFA, n-3, n-6/n-3 and PUFA/MUFA concentration did not differ across the study period. Linoleic acid was highest in the second phase which coincides with mid lactation in cows (P<0.001). Highest moisture content coincided with the least fat free dry matter content in early lactation (P<0.001). Significantly high fat content was observed in late lactation than in early lactation. Highest butyric, caproic, linoleic, n-6 and PUFA were observed for Friesian cows. All other fatty acids ratios were not significantly different among different genotypes. Highest CLA, ALA, LA, SFA, PUFA, n-6, and n-3 and atherogenicity index were observed in early lactation whereas desaturase activity indices were highest in late lactation. Strong positive correlations were observed among milk vaccenic, ALA, LA and CLA concentrations. Inverse relationships were observed between SFA and long chain fatty acids. It can be concluded, it may be of advantage to consume milk from early stage of lactation poses a lower risk to coronary diseases and are much safer to consume.

A pecuária de corte extensiva se mostra incapaz de competir em termos de resultados econômicos com outras alternativas de uso da terra em regiões de terras valorizadas, fato que pode ser comprovado pela substituição gradativa de áreas de pastagens por culturas agrícolas. Nessas regiões, a adubação intensiva de pastagens tem se tornado a opção freqüentemente utilizada para o incremento da produtividade animal que é imprescindível para a viabilização econômica da pecuária frente a demais alternativas de uso da terra. A irrigação aliada à adubação de pastagens cresceu muito desde o final da década de 90 no Brasil Central, crescimento motivado pela expectativa de resultados produtivos elevados como os divulgados por revistas técnicas especializadas. Com o intuito de comparar os resultados produtivos e econômicos de pastagens adubadas intensivamente com e sem o uso da irrigação, foram conduzidos dois experimentos ao longo de um ano em pastagens de Panicum maximum cv tanzânia. Foram avaliados desempenho animal, taxa de lotação e produtividade nos experimentos. A avaliação econômica foi efetuada com a determinação dos indicadores lucro líquido, taxa de retorno sobre o ativo e taxa interna de retorno, por meio de simulações determinísticas e estocásticas. Enquanto no experimento em sequeiro os valores de desempenho animal e de taxa de lotação médios obtidos foram de 0,615 kg GPD e 5,6 UA/ha, respectivamente, no experimento irrigado foram obtidos 0,492 kg GPD e 5,9 UA/ha. A irrigação só foi efetiva no incremento da taxa de lotação na transição entre os períodos de “seca” e “águas”, não confirmando o potencial da irrigação de pastagens no incremento da taxa de lotação. A diferença de produtividade animal entre os experimentos foi minimizada pelo maior desempenho animal do experimento sem irrigação em alguns períodos. Foram obtidas produtividades de 1.628 kg PV/ha no experimento irrigado e 1.672 kg PV/ha no em sequeiro, corroborando o potencial de produtividade de pastagens adubadas intensivamente. A análise de viabilidade sem a consideração de risco apresentou resultados de lucro líquido, taxa de retorno sobre o ativo e taxa interna de retorno, respectivamente de R$ - 164,91 por hectare, - 1,0% e – 6,1%, para o sistema irrigado e R$ 574,90 por hectare, 4,4% e 17,2% para o em sequeiro. Contudo, essa análise subestimou os resultados dos indicadores de viabilidade econômica em ambos sistemas. A análise de risco apontou o sistema irrigado como inviável economicamente, enquanto para o sistema sem irrigação a probabilidade de um resultado econômico que apontasse inviabilidade foi baixa.
Extensive beef production cannot compete with others uses of land for agricultural productions, mainly where land costs are high, therefore a gradual substitution of pasture areas for agricultural crops is occurring. High levels of fertilizer application to pastures have been used for improving beef productivity and, consequently, improve the economic profitability of this activity. Irrigation of pasture increased since 90’s in Central Brazil, motivated by the expectation of high productivities as presented in technical magazines. The objective of this research was to compare the productivity and economic results of highly fertilized pasture, with and without irrigation. Two experiments were conducted for a year in Panicum maximum cv tanzânia pastures. Weight gain, stocking rate and beef productivity were evaluated. In the economic evaluation was determined net margin, simple rate of return and internal rate of return, using deterministic and stochastic simulations. In the non-irrigated experiment the weight gain was 0,615 kg/day and the stocking rate 5,6 AU/ha, and in the irrigated one, 0,492 kg/day and 5,9 AU/ha, respectively. The irrigation only increased the stocking rate in the season transition between dry and rainy period, not confirming the potential for pasture irrigation in the Central South part of Brazil by increasing stocking rate. Productivity difference in irrigated and non-irrigated pastures was minimized by the high weight gain of non-irrigated area in some periods. The animal live weigh gain was 1.628 kg/ha in irrigated experiment, and 1.678 kg/ha in non-irrigated one, indicating high potential for productivity of highly fertilized pasture. The analysis without risk consideration showed results of net margin, simple rate of return and internal rate of return, respectively of R$ -164,91 per hectare, - 1,0% and -6,1% for irrigated system, and R$ 574,90 per hectare, 4,4% and 17,2% for non-irrigated one. Deterministic analysis sub estimated the results of economic viability indicators. Risk analysis showed weak probability of economic viability for irrigated system. Non-irrigated system with high levels of fertilizer application indicated weak probability for not been an economic activity.

Flavor lexicons are used in sensory evaluation to determine the flavor profile of a food product. The objective of this study was to develop a flavor lexicon for cooked beef, which can then be used in various projects relating to beef quality such as studies investigating animal diet, marinating, ageing, or other enhancements. A descriptive panel of 10 people was used to develop a flavor lexicon of 18 attributes, including astringent, barny, bloody, brothy, browned, gamey, grassy, juicy, fatty, livery, metallic, oxidized, roast beef, and the five basic tastes (bitter, salty, sour, sweet, and umami). In contrast to other studies on beef, this lexicon was developed to include both positive and negative attributes. The lexicon was able to show that rib eye steaks from the Longissimus dorsi muscle in grass-fed animals were significantly (p<0.05) higher in barny, bitter, gamey, and grassy flavors, and lower in juicy and umami flavors. The steaks were also rated by consumers, who showed a preference for grain-fed beef over grass-fed beef. The ratings of the descriptive panel were related to the consumer panel scores to equate the lexicon terms with a positive or negative consumer degree of liking score. Those terms that were considered positive in this study due to their positive correlation with consumer liking include brothy, umami, roast beef, juicy, browned, fatty, and salty. The terms that were inversely associated with consumer liking were barny, bitter, gamey and grassy, among others. A separate descriptive panel was conducted on the Spinalis dorsi (or “cap” muscle) of the rib eye steak, with similar results. Additionally, descriptive and consumer evaluations found no difference between two types of grass diets, namely alfalfa and sainfoin. Different mixtures of beef and chicken were also evaluated to determine flavor differences between the two meats. Chicken was found to be more closely correlated to brothy, juicy, sweet, and umami, among others, while beef was found to be more closely correlated to terms such as gamey, bloody, oxidized, metallic, roast beef, and astringent. Throughout these tests, the newly developed lexicon was shown to be an effective tool for profiling fresh meat samples.

Beef cattle production is highly criticized because of the high use of land and water resources, and by the pollution (e.g., the gas methane in a cow’s breath and nitrogen in urine) produced by cows fed in feedlots. In contrast to feedlots diets and grasses, some plants (e.g., legumes) contain bioactive compounds (condensed tannins) that reduce pollution and enhance animal nutrition. In my research, I observed that cows grazing a tannin-containing legume (birdsfoot trefoil; BFT) had methane emissions similar to cows fed a feedlot ration with comparable weight gains. Cows in the BFT treatment gained more weight than cows grazing grass (meadow brome) or a legume without tannins (cicer milkvetch). Additionally, I estimated the potential areas in the state of Utah than can sustain birdsfoot trefoil production, with 412,250 ha distributed mostly in the Box elder, Cache, Millard and Sanpete counties. Thus, feeding tannin-containing legumes to cows is a viable alternative to feedlot rations, with greater levels of productivity than other pasture-based systems, which can lead to a more sustainable production of beef.

In Quebec, 62% of agricultural land is devoted to forage production and 20% of this is pasture. Pasture management provides the opportunity for farmers to maintain and improve the productivity of agricultural land, and to engage in sustainable ruminant production. An experiment was conducted on 42 hectares of pasture land to study the impact of management intensive grazing (MIG) on cow-calf productivity. The pasture area was divided into 18 paddocks and the experiment was conducted as a randomized complete block design with two blocks. The treatments were arranged as a 3 x 3 factorial of stocking rate and rotational frequency. The stocking rates (SR) were 0.5, 0.7, and 0.9 hectares per cow (HSR, MSR and LSR respectively); the rotation frequencies (RF) were two days, six days and continuous grazing (2d, 6d and C). Sixty-one purebred Angus cow-calf pairs were randomly assigned to each of the nine treatments, and the animals were grazed during two consecutive grazing seasons (1997 and 1998). Hay harvested early in the season was used for pasture supplementation late in the season. Increasing RF had no effect (P > 0.05) on forage mass available. Increasing SR from 0.9 to 0.5 cow-calf pairs ha -1 resulted in a linear reduction (P < 0.01) in individual cow gain, but increasing the SR caused a linear increase in cow gains ha-1. Calf gain ha-1 increased linearly (P < 0.01) in response to SR, but was unaffected (P > 0.05) by RF. A system of 6d rotation and high SR generated the greatest net revenue. The study showed little benefit of MIG on animal performance, but substantial benefits on efficiency of land use and economic performance.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
O objetivo deste trabalho foi avaliar o desempenho de bovinos de corte manejados organicamente, em três sistemas de manejo. A área experimental foi dividida em 3 módulos de pastejo rotacionado com 6 piquetes de áreas iguais cada. Os sistemas 1 e 2 possuíam áreas iguais a 20,64 ha e o sistema 3 uma área total de 12,96 ha. O período experimental teve 16 ciclos de 42 dias, com sete dias de ocupação e 35 dias de descanso por piquete. O delineamento adotado foi o inteiramente casualizado sendo os tratamentos T1 pastejo intermitente de capim-Marandu com banco de proteína de 30% da área do piquete na seca, T2 pastejo intermitente de capim-Marandu com suplementação protéica de 0,5% do peso vivo na seca e T3 mantidos em pastejo intermitente de capim-Marandu. Na avaliação da forragem a unidade experimental foi piquete e para os dados de desempenho foi animal. Foram utilizados inicialmente 170 bezerros Nelore castrados, com idade média de 10 meses e peso vivo médio inicial de 188 kg distribuídos aleatoriamente pelos tratamentos. Amostras dos piquetes foram coletadas para determinação da massa de forragem e avaliações quantitativas e qualitativas da gramínea. No primeiro ano de avaliação os animais com acesso ao banco de proteína tiveram melhor desempenho que os demais tratamentos. No segundo ano os animais suplementados no cocho apresentaram desempenho superior aos animais com acesso ao banco de proteína, proporcionado a esses dois tratamentos atingirem o peso vivo médio para abate (487,7 kg, sistema 1 e 470,1kg sistema 2) no décimo quinto ciclo de pastejo. Os animais do grupo controle permaneceram mais um ciclo para atingir o peso de abate (476,1 kg).
The objective of this work was to evaluate the performance of beef cattle, in organic handling, in three handling systems. The experimental area had three modules of rotational pasture with 6 paddocks each. The systems 1 and 2 possessed areas of 20,64 ha and the system 3 a total area of 12,96 ha. The experimental period had 16 cycles of 42 days, being in each cycle seven days of occupation and 35 days of rest for each paddocks. The treatments adopted was T1 intermittent pasture of Marandu-grass with bank of protein of 30% of the area of the paddocks during the drought, T2 intermittent pasture of Marandu-grass with protein supplement in the amount of 0,5% of the live weight during the drought and T3 maintained in intermittent pasture of Marandu-grass. In the evaluation of the forage the experimental unit went paddock and for the performance was animal. At the beginning of the experiment 170 Nelore calves was used, with the average age of 10 months and average live weight initial of 188 kg distributed in the treatments. Samples of the paddocks were collected for determination of the forage mass and for quantitative and qualitative evaluations of the grasses. In the first year of evaluation the animals with access to the protein bank had better performance than the animals with protein supplement and the animals of the control group, already in the second year of evaluation the feeders supplemented animals presented better performance than the animals with access to the protein bank, what provided to those two treatments they reach the live weight for slaughter (487.7 kg, system 1 and 470.1kg system 2) in the fifteenth pasture cycle. The animals of the control group they needed to stay one more cycle to reach the slaughter weight (476,1 kg).

Thesis submitted in fulfilment of the requirements for the degree of Magister Technologiae: Agriculture in the Faculty of Applied Sciences at the Cape Peninsula University of Technology
Conjugated linoleic acid (CLA), a fatty acid (FA) present in the meat and milk of ruminant animals, is considered a functional nutrient for humans. The interest in CLA is attributed to its many health benefits, such as having anti-carcinogenic, anti-atherogenic, anti-diabetic and anti-adipogenic effects. Dairy products are a rich natural source of CLA, and preliminary research indicates that the levels in milk can vary based on cattle breed and feeding system. The Fleckvieh is a popular dual-purpose breed recently introduced to the Western Cape. It is used in crossbreeding programs with Holstein and Jersey herds to increase fertility and beef production. Holstein and Jersey cattle are the two most common South African dairy breeds, but little information is available on the effect of crossbreeding on FA content and CLA levels in the milk. The primary objective of this study was to compare milk FA composition and CLA content of these two dairy breeds and their respective Fleckvieh crosses. A second objective was to investigate the effect of lactation stage on CLA levels. Jersey (J) and Fleckvieh x Jersey (F×J) cows were kept in a pasture-based system (PBS) for the duration of the study. Holstein (H) and Fleckvieh x Holstein (F×H) cows were housed in a feedlot system and fed a total mixed ration (TMR) for the duration of the study. The FA and CLA content of feeds from these two feeding systems were also analysed and compared. All cows used in the study were housed at the Elsenburg Research Farm of the Western Cape Department of Agriculture. Milk samples were collected every 35 days from the cows in each feeding group, starting 10 days after calving. Samples were kept in a freezer at -20 °C until laboratory analyses. The total number of milk samples collected was 1044. The milk FA composition and CLA in particular were determined by gas chromatography. Differences between groups were statistically analysed by two-way repeated measures of analysis of variance (ANOVA). Results show that milk CLA levels are higher in Fleckvieh-crossbred cows when compared to purebred cows. The higher CLA content of milk from Fleckvieh crossbred cows demonstrates the feasibility of using Fleckvieh bulls in South African crossbreeding programs, and are also an indication that genetic selection for increased CLA content is possible. The analysis of lactation stage showed that milk CLA is higher during late lactation. A comparison of feed samples from the two feeding systems revealed that pasture feeding resulted in higher omega-3 FA in milk. Key words: Conjugated linoleic acid, milk fatty acids profile, diet, breed, health benefits, Fleckvieh, Holstein, Jersey, diet, pasture based system, total mixed ration system,

Thesis (MSc)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: A survey to assess the sustainability and marketing opportunities for smallholder cattle production systems was conducted by consulting with a total of 95 smallholder cattle producers in Ncorha and Gxwalibomvu communities in the Eastern Cape Province (ECP) of South Africa. In addition, a total of 18 surrounding beef retailers, 5 abattoirs that supplied beef to these retailers and 155 beef consumers who bought beef from these retailers between February 2013 and February 2014 were also interviewed using pretested structured questionnaires. The surveys established the perception of beef traders and consumers on the development of a Natural beef (NB) brand and indicated the willingness of participants to support the development of a NB brand. The results indicated that a smallholder beef cattle production system was socially and environmentally conditionally sustainable but economically not sustainable. Overall, the system was conditionally sustainable. Cattle herd size was bigger in Ncorha than in Gxwalibomvu (13.7±1.9 vs. 11.3 ± 1.9 heads of cattle, respectively). Smallholder producers from both sites sold an average of two cattle per year. Young farmers (<40 years old), Christians and small households (<5 members) had a greater potential to sell cattle than adults (>40 years old), traditionalists and larger households (>5 members). Similarly, households with access to extension services, owners of smaller cattle herds (<10 cattle) and from a lower income bracket (AFRIKAANSE OPSOMMING:'n Opname om die volhoubaarheid en bemarkingsgeleenthede vir kleinboer vleisbeesproduksiestelsels te evalueer, is deur middel van konsultasie met 'n totaal van 95 kleinboere vee produsente in Ncorha en Gxwalibomvu gemeenskappe in die Oos-Kaap Provinsie van Suid-Afrika, uitgevoer. Daarbenewens is altesame 18 omliggende vleis kleinhandelaars, 5 abattoirs wat beesvleis verskaf aan hierdie kleinhandelaars en 155 beesvleis verbruikers wat vleis gekoop het van die kleinhandelaars tussen Februarie 2013 en Februarie 2014, met behulp van vooraf-getoetste gestruktureerde vraelyste ondervra. Die opnames het die mening van beesvleis handelaars en -verbruikers oor die ontwikkeling van 'n natuurlike weiding-geproduseerde beesvleis (NPB) handelsmerk ingewin en ook die bereidwilligheid van die deelnemers om die ontwikkeling van 'n NPB handelsmerk te ondersteun, aangedui. Die bevindinge dui daarop dat 'n kleinskaalse vleisbees produksiestelsel sosiaal en omgewingsvriendelik voorwaardelik volhoubaar is, maar nie ekonomies volhoubaar is nie. In geheel is hierdie tipe produksiestelsel as voorwaardelik volhoubaar beskou. Beestrop grootte was groter in die Ncorha as in die Gxwalibomvu gemeenskappe (13.7 ± 1.9 beeste vs. 11.3 ± 1.9 beeste, onderskeidelik). Kleinboer produsente van beide areas het 'n gemiddeld van twee beeste per jaar verkoop. Jong boere (<40 jaar oud), Christene en klein huishoudings (<5 lede) het 'n beter potensiaal gehad om beeste te verkoop as volwassenes (> 40 jaar oud), tradisionele boere en groter huishoudings (> 5 lede). Net so het huishoudings met toegang tot voorligtingsdienste, eienaars van klein troppe (<10 beeste) en boere wat aan die laer inkomstegroep behoort het (