Littérature scientifique sur le sujet « Hay-based diets »

This study aimed to evaluate the performance of feedlot lambs fed diets formulated with hay of different genotypes of Cynodon spp. and to compare the dry matter digestibility of diets using different evaluation methods (total fecal collection and chromium oxide). Suffolk crossbred neutered male lambs (n=30), with an average age of 90 days and average body weight of 21.5 kg ± 1.6. Diets were formulated using a standard concentrate and hay of the following genotypes of Cynodon dactylon: Jiggs, Vaquero, Tifton 68, Coast-Cross, Tifton 85 and Russell, in a 60:40 forage concentrate ratio, composing the treatments distributed in a randomized block design in a factorial 5 x 2 arrangement of 5 diets and 2 digestibility evaluation methods. Animals receiving Vaquero hay showed dry matter intake of 18.3; 16.9; 25.6; 20.7 and 24.2% higher than those fed hay of Jiggs, Tifton 68, Coast Cross, Tifton 85 and Russell, respectively. There was no difference between diets for digestibility using total fecal collection, chromium oxide and final weight of animals. Jiggs hay based diets allowed greater daily weight gain and better feed conversion.

The metabolisable energy (ME) content of a range of oats-based diets, encompassing a wide range in dry matter digestibility of oat grain, was measured at maintenance in sheep. Dry matter digestibility was 66-82% and ME content was 11.4-15.9 MJ/kg DM for the range of oats-based diets studied. Chaffed lucerne hay, used as a control diet, had a dry matter digestibility of 61% and ME content of 9.7 MJ/kg DM. The ratio of ME to digestible energy content of oats diets was 0.88, compared with 0.81 for chaffed lucerne hay. The difference between the diets based on oats grain and chaffed lucerne hay was accounted for by increased urine energy and nitrogen loss on the lucerne diet and not by reduced methane output on oats-based diets. Cell wall organic matter and lignin content of the oats-based diets were strongly correlated with diet digestibility (r2 = 0.79-0.90).

This study aimed to evaluate animal performance and economic performance of feedlot crossbred lambs (½ Santa Inês+ ½ Suffolk) fed different diets based on hay from Cynodon dactylon genotypes, through the use of financial measures considering only the period of confinement, without relating it to the complete management cycle. A total of 30 intact crossbred Suffolk lambs, identified with earrings, with an average age of 90 days and an average body weight of 21.5 kg were used in this study. Diets were formulated using as treatments a standard concentrate and hay of the Cynodon dactylon genotypes Jiggs, Vaquero, Tifton 68, Coast-Cross, Tifton 85 and Russell in a 60:40 forage-to-concentrate ratio. The treatments were distributed in a randomized complete block design with five replicates. There were significant differences between diets in terms of total expenditure on food, and the highest values were obtained for the Jiggs genotype (BRL 48.96/animal). The animals fed diets based on Tifton 68 hay had a higher rate of return (2.16%) and profitability (34.63%) compared to the other diets. The use of diets based on Tifton 68 hay for feedlot lambs in the finishing phase brings higher economic returns compared to the remaining diets.

This study aimed to evaluate the microbiological composition of cactus pear-based diets with increasing levels of buffel grass hay, and its effect on the blood and physiological parameters and occurrence of diarrhea in feedlot sheep. Four diets containing different percentages of buffel grass hay were tested. Diets were composed of forage cactus, buffel grass hay and concentrate, and the treatments were represented by different levels of hay in the dry matter of the feed: 7.5% buffel grass hay; 15% buffel grass hay; 30% buffel grass hay; and 45% buffel grass hay on a dry matter basis. There was a significant effect (p = 0.0034) of inclusion levels of buffel grass hay on fecal score. Only at the 45% inclusion level diarrhea was not observed, showing that the level of buffel grass affected more the animals than the collection period, although the collection period has affected the microbial counts. Probably there was a physiological adaptation of animals over time. There were significant changes (p < 0.0001) in the blood parameters of sheep. The reduction of the proportion of cactus and the inclusion of greater than 15% buffel grass hay, on a dry matter basis, provides less contamination of the diet and animal feces by enterobacteria, such as E. coli.

Beef steers of liveweight (LW) 277kg were offered a basal ration of hay, untreated silage, or enzyme-treated silage supplemented with a barley + lupin + mineral (67:30: 3) concentrate at 0.5, 1.0, and 1.5% of LW for a maximum of 120 days. The quality of silage was significantly (P<0.001) higher than hay (in vitro DMD: 673.0 v. 609.2 g/kg DM), primarily due to a shorter ungrazed growing period before harvest. The enzyme additive did not improve the quality of the silage compared with untreated silage, as indicated by pH, lactic acid, and in vitro dry matter digestibility. Intake of silage was significantly (P<0.001) higher than that of hay (4.10 v. 3.68 kg DM/day). Final LW and LW gain of cattle fed silage were significantly (P<0.001) higher than of those fed hay (370 v. 345 kg; 1.03 v. 0.61 kg/day). As the level of grain increased there was a significant (P<0.001) increase in daily LW gain across all diets (0.63, 0.94, and 1.10 kg/day at 0.5, 1.0, and 1.5%). At slaughter, carcass weight was significantly (P<0.001) higher for cattle fed silage-based diets (207 v. 194 kg). When cattle were fed a higher quality conserved forage (silage), less grain (1.5 v. 4.5 kg/day) was required to achieve similar LW than with more traditional, forage (hay) based diets.

AbstractExperiments were carried out in Nepal and Costa Rica to compare voluntary dry-matter intake (DMI) by oxen of diets based on poor quality hay (Costa Rica) and rice straw (Nepal) supplemented with different levels of concentrate foods when the animals were working and not working. Values for the apparent digestibility of the diets, rates of passage of solid and liquid phases ofdigesta and nitrogen balance are also reported.Amounts of work calculated to raise daily energy expenditure to 1·3 to 1·6 × maintenance were associated with the following effects. (1) A depression of proportionately 0·11 and 0·14 in the DMI of oxen given a diet based on rice straw plus 18 and 27 g/kg live weight of concentrate respectively during work. No depression of DMI was seen with the hay diets which had slightly higher metabolizable energy but less nitrogen than the rice straw diets. (2) An increase in intake in the weeks following work on both the hay and rice straw diets. (3) Variable effects on apparent digestibility of food probably related more to the changes in DMI. (4) A tendency for gastro-intestinal mean retention time to be increased in working weeks particularly on the more fibrous diets.

Abstract Data from experiments conducted at the University of Nebraska-Lincoln were pooled to compare predicted and observed dry matter intake (DMI) of growing cattle consuming foraged-based diets (corn silage, grass, alfalfa, or sorghum-hay) to determine the accuracy of current modeling systems. Experiments (n = 22) were a minimum of 84 days and included individually fed calves using the Calan gate system with 8 to 12 calves per treatment mean or pen-fed calves with 8 to 12 head per pen. Average body weight (BW) of calves ranged from 235 to 397 kg with average daily gain (ADG) between 0.16 and 1.65 kg. Cattle were fed ad libitum and mid-point BW and ADG were entered into the Beef Cattle Nutrient Requirements Model (2016) to determine predicted DMI. Simple regression was used to compare predicted and observed DMI to determine the accuracy of the prediction model. Ninety-three treatment means were evaluated and were separated into three categories: hay-based diets (n = 24), hay-based diets with distillers grains (n = 31), and corn silage-based diets (n =38). The model for observed versus predicted DMI was significant (P &lt; 0.05; R2 = 0.09) when comparing all means but had a poor R2. The model was the best at predicting DMI for forage-based diets (P &lt; 0.08; R2 = 0.22). Observed and predicted DMI were regressed along TDN values, calculated using book values and digestion studies. As TDN increased, observed DMI increased linearly (P &lt; 0.01) and predicted DMI had a quadratic response (P &lt; 0.01), increasing up to 63% and then decreasing with increasing TDN. The model over predicted DMI intake for TDN &lt; 63% and under predicted DMI in forage-based diets greater than 63% TDN. Further development of the current modeling system through addition of intake data from forage fed growing cattle is needed

Extensive research has been conducted to decrease the environmental impacts of dairy farming by using forages containing condensed tannins (CT). In this study, it was hypothesized that feeding CT-containing birdsfoot trefoil (Lotus corniculatus, BFT) to lactating dairy cows would result in a decrease in N degradation in the rumen, causing a shift in N partitioning into milk and manure outputs, compared with alfalfa hay. Urine N is more volatile and harmful to the environment compared with fecal N. By reducing urine N, overall N utilization efficiency can improve. It was our goal to verify how the changes in N partitioning would affect the overall N utilization efficiency by dairy cows fed BFT hay-based high-forage diet. The results in this report showed that feeding BFT-hay diet reduced protein degradation in the rumen, decreased N excreted to milk and urine, and increased N excretion into feces, resulting in decreased urinary-N:fecal-N ratio due to feeding BFT-hay diet. However, the change in the N excretion routes was not associated with N utilization efficiency, which may have resulted from poor nutritive quality of BFT hay. Although the BFT hay fed in the current study was in a very mature condition and was of poor quality, DM intake and milk yield were similar in both treatments. Therefore, it is implied that BFT hay can replace alfalfa hay in dairy rations, because even poor quality BFT hay compared with alfalfa hay led to similar lactational performance and a beneficial shift in N excretion into environment.

The livestock sector is facing different challenges, and the demand for higher sustainability seems to be one of the most urgent. This PhD project debated, in particular, the environmental impacts related to ruminant nutrition, focusing on dairy cows, since nutrition is bound tightly to two of the most important sources of impact: enteric CH4 emission and land use change (LUC). Enteric CH4 emission from ruminants represents 29-38% of the total (anthropic + natural) emission of this powerful (21 CO2 equivalent) greenhouse gas. The production of CH4 is a physiological process used by ruminants to discharge the [H] resulting from rumen fermentation. Different strategies can be implemented to mitigate this impact, and they can be roughly grouped into three main categories: animal and feed management, diet formulation, and rumen manipulation. The second issue investigated in the project is the high reliance of European livestock on soybean meal as a protein source for diet formulation. A total of 30 million tonnes of this feedstuff was imported into Europe in 2020. The main countries of origin are in South America (65% of total import), where 20% of soybean meal production was linked with deforestation (and consequently LUC) in the last decades. Clearing these areas means loss of carbon sink and emission of CO2 in the atmosphere. Other feedstuffs, like grain legumes, oilseed meals alternative to soybean, and high quality forages could be considered to provide protein feed with a lower environmental cost. In this context, the PhD project was developed as follows:  To address the problem of CH4 emission, plant essential oils, as modulators of rumen fermentation, were evaluated (Experiment 1). Furthermore, the effect on CH4 emission of different forages in the diet of dairy cows was investigated (Experiment 2). For validation of mitigation strategies and inventory computation of emissions at a national scale, country-specific equations to quantify CH4 emission were evaluated (Experiment 3).  To address the problem of soybean meal environmental impact, soybean silage and responsible soybean meal (not connected with land use change) were evaluated as protein source alternatives to soybean meal in the diet of lactating cows (Experiments 4 and 5). Enteric methane direct emission In the first experiment, Achille moschata essential oil and its main pure components, namely bornyl acetate, camphor, and eucalyptol, were evaluated in an in vitro experiment. The trial comprehended a short-term in vitro incubation (48 h), with 200 mg of compound per L of inoculum, and a long-term one by continuous fermenter (9 d), with 100 mg/L for each compound. In the first incubation, no differences due to the treatments were found for in vitro gas production (on average, 30.4 mL/200 mg DM, P = 0.772 at 24 h and 45.2 mL/200 mg DM, P = 0.545 at 48 h). Camphor and eucalyptol reduced CH4 production when expressed as % of gas production at 48 h (P < 0.05): -7.4% and -7% compared to control. In the second incubation, CH4 was reduced by eucalyptol (-18%, P < 0.05). Regarding volatile fatty acids, the main effects were a decrease of total production for camphor (-19.5%, P < 0.05) and an increase in acetate production at 9 d with bornyl acetate and camphor (+13% and 7.6%, respectively, P < 0.05) compared to control. Total protozoa count was increased compared to the control (on average: +37%, P = 0.006, at 48 h and +48%, P < 0.001, at 9 d) with all the pure compounds tested. In the short-term incubation, all the treatments reduced Bacteroidetes (30.3%, on average, vs. 37.1% of control, P = 0.014) and Firmicutes (26.3%, on average, vs. 30.7% of control, P = 0.031) abundances but increased Proteobacteria (36.0%, on average, vs. 22.5% of control, P = 0.014). In the long-term incubation, eucalyptol increased the genus Ruminococcus abundance (2.60% vs. 1.18% of control, P = 0.011). An adaptation at long time incubation was observed. In particular, considering eucalyptol addition at 9 d incubation, VFA production was reduced (26.8 vs. 33.3 mmol of control, P < 0.05) contrary to the 48 h incubation (P = 0.189). Furthermore, the treatments affected protozoa genera relative abundances at 24 h (increased abundance for Entodinium with all the treatments, P < 0.001, and reduced for Diplodinium, P = 0.001); at 9 d, instead, protozoa genera relative abundances were not affected by the treatment. The additives tested showed potential in reducing CH4 production without compromising the overall fermentation efficiency. A meta-analysis (Experiment 2) investigated the effects on lactation performance and enteric CH4 of the main forage included in the diet. In the dataset, composed of in vivo experiments, four main forage bases were evaluated: corn silage, alfalfa silage, grass silage, and green forage. Cows fed corn, and alfalfa silages had the highest DMI (21.9 and 22.0 kg/d, P < 0.05) and milk yield (29.7 and 30.4 kg/d, P < 0.05). On the opposite, NDF digestibility was highest for grass silage and green forage (67.6% and 73.1%, P < 0.05) than corn and alfalfa silages (51.8% on average). CH4 production was lower (P < 0.05) for green forage (332 g/d) than the silage diets (on average 438 g/d). Instead, corn silage and alfalfa silage gave the lowest CH4 per kg of milk yield (14.2 g/kg and 14.9 g/kg, P < 0.05). Considering CH4 per kg of DMI, the only difference was between corn silage and grass silage (19.7 g/kg vs. 21.3 g/kg respectively for corn and grass silage, P < 0.05). Finally, prediction models for CH4 production were obtained through a step-wise multi regression. In particular, the models for the prediction of: CH4 in g/d (CH4 = - 65.3(±63.7) + 11.6(±1.67) × DMI - 4.47(±1.09) × CP - 0.86(±0.33) × Starch + 2.62(±0.78) × OM digestibility + 30.8(±9.45) × Milk fat) and for CH4 in g/kg of milk yield (CH4/milk yield = - 55.5(±20.1) - 0.37(±0.13) × DMI + 0.18(±0.05) × Total forage inclusion on diet DM - 0.10(±0.04) × Inclusion of the main forage on diet DM + 0.48(±0.21) × OM + 0.14(±0.06) × NDF + 1.98(±0.86) × Milk fat +4.34(±1.66) × Milk protein) showed high precision (R2 = 95.4% and 88.6%, respectively), but the best AIC value (320) was found for the model predicting CH4 in g/kg DMI: CH4/kg DMI = 6.16(±3.89) - 0.36(±0.03) × CP + 0.12(±0.05) ×OM digestibility + 3.77(±0.56) × Milk fat - 3.94(±1.07) × Milk fat yield. A dataset (66 observations in total) of three in vivo experiments conducted in Italy on lactating cows in respiration chambers was built to evaluate IPCC Tier 2 equations to estimate enteric CH4 production (Experiment 3). In the dataset, the CH4 conversion factor (conversion of gross energy intake into enteric CH4 energy) was lowest for a diet based on grass and alfalfa silages (5.05%, P < 0.05), while the others values ranged between 5.41 and 5.92%. On average, energy digestibility was 69.0% across the dataset, but the diet based on hays had a lower value (64.8%, P < 0.05). The IPCC (2019) Tier 2 (conversion factor = 5.7% or 6.1% for diet with NDF concentration < 35% or >35%, respectively; digestible energy = 70%) gave, on average, a value of CH4 production not statistically different from the ones measured in vivo (382 vs. 388 g/d in vivo, P > 0.05). The IPCC (2006) Tier 2 (conversion factor = 6.5%, digestible energy = 70%) over-predicted CH4 emission (428 vs. 388 g/d in vivo, P < 0.05; μ = -1.05). The most precise models were the two considering digestible energy equal to 70% and average values of conversion factor for IPCC (2006) and IPCC (2019) (R = 0.630); the most accurate models was the one considering a conversion factor equal to 5.7% and energy digestibility measured in vivo (Cb = 0.995). Overall, the best performance among the predicting models tested was for the one based on a conversion factor equal to 5.7% and energy digestibility of 70% (CCC = 0.579 and RMPSE = 9.10%). Use of alternative protein source to conventional soybean meal The dietary inclusion of soybean silage in partial replacement of soybean meal for dairy cows was evaluated in vivo in lactating cow diets (Experiment 4). Cows were fed two diets, one with 12.4% of DM from soybean silage in substitution of 35% of the soybean meal of the control diet. The treatment did not affect DMI and milk yield (on average, 23.7 kg/d, P = 0.659, and 33.0 kg/d, P = 0.377, respectively). Cows fed the soybean silage diet had lower milk protein concentration (3.43% vs. 3.55% of the control, P < 0.001) and higher milk urea (30.5 vs. 28.7 mg/dL, P = 0.002). The soybean silage had lower nutrient digestibility than the control: DMD 65.2% vs. 68.6%, OMD 66.4% vs. 69.8%, NDFD 31.5% vs. 38.8% (respectively for soybean silage and control diet; P < 0.001 for all of them). Regarding N balance, cows fed soybean silage excreted more nitrogen in the urines (32.3 % of N intake vs. 28.9%, P = 0.005) and less in the milk (31.3% vs. 32.7%, P =0.003) than the control. When used as a protein source alternative to soybean meal, soybean silage sustained comparable milk production, but NDF digestibility and N use efficiency should be improved. The environmental impact of the use of soybean silage in comparison to a control diet with soybean meal as the main protein source was evaluated through an LCA approach (Experiment 5). In addition, two scenarios were included in the study, considering the two diets mentioned before, but with soybean meal not connected to LUC (responsible soybean meal). Regarding the single forages, soybean silage had higher global warming potential than alfalfa hay (477 vs. 201 kg CO2eq/ton DM), also when this was expressed per tonnes of protein production (2439 and 1034 kg CO2eq/ton CP, respectively), probably due to the lower contribution of the cultivation phase for alfalfa, being a multi-year crop. The scenario with soybean silage reduced the global warming potential per kg of fat and protein corrected milk (1.17 kg CO2eq) compared to the control (1.38 kg CO2eq). Responsible soybean meal reduced the global warming potential per kg of fat and protein corrected milk (1.13 kg CO2eq/kg vs. 1.38 of the scenario with the control diet). Overall, the best result per kg of fat and protein corrected milk was obtained when responsible soybean meal and soybean silage were used in combination (1.01 kg CO2eq). Also, when global warming potential was evaluated per daily fed TMR, the impact was lowest for the scenario with responsible soybean meal (13.4 kg CO2eq/d) due to the lower contribution of soybean meal to the total impact (11% vs. 43% of the control). Therefore, the two alternative protein sources tested should be preferred when considering environmental impact compared to conventional soybean meals.

Thesis (MSc. (Animal Production)) -- University of Limpopo, 2018
A study was done to determine the effect of Acacia (A.) karroo, A. tortilis or A. nilotica leaf meal inclusion in a diet on methane emission and productivity of yearling male Boer goats fed a basal diet of Avena sativa hay. The first part of the study was conducted to determine and compare nutrient contents and tannin levels of A. karroo, A. tortilis and A. nilotica leaf meals and Avena sativa hay in a completely randomised design. The diets means were compared using Fisher’s least significant difference at the 5 % level of probability. The three Acacia species had higher (P<0.05) crude protein contents compared to Avena sativa hay, ranging from 12.42 to 14.49 %. No tannins were detected in Avena sativa hay. Among Acacia species, A. nilotica leaves had higher (P<0.05) total phenolic and total tannin contents than A. karroo and A. tortilis leaves, the latter being similar (P>0.05). All three Acacia species had similar (P>0.05) contents of condensed tannins, ranging from 1.49 to 1.76 %. However, only A. nilotica leaves had hydrolysable tannins of 128 mg/g. The second part of the study was conducted to determine the effect of A. karroo, A. tortilis or A. nilotica leaf meal inclusion level on diet intake and digestibility, methane emission, productivity and blood profiles of yearling male Boer goats. A total of three experiments were conducted and different goats were used in each experiment. A grand total of thirty six (twelve per experiment) yearling male Boer goats with initial mean live weights of 23 ± 2 kg (experiment 1), 23 ± 2 kg (experiment 2) and 23 ± 2 kg (experiment 3) were used in 21-day experiments. The goats were randomly assigned to four dietary treatments, each containing A. karroo, A. tortilis or A. nilotica leaf meal inclusion levels at 10, 15, 20 and 30 % with Avena sativa hay as a basal diet. Each goat was housed in well-ventilated individual metabolic pen. The diets were replicated three times. The data collected were subjected to analysis of covariance and analysis of variance in a completely randomized design using SAS. Differences were separated at 5 % level of probability. Additionally, regression equations were used to determine the relationships and responses in optimal diet intake and digestibility, methane emission, productivity and blood profiles of yearling male Boer goats to differing inclusion levels of A. karroo, A. tortilis and A. nilotica leaf meal. v Experiment 1 involved feeding different levels of A. karroo leaf meal inclusion to yearling male Boer goats fed Avena sativa hay as a basal diet. Results of methane emission before and during the experiment indicated that inclusion of A. karroo leaf meal in the diets of goats reduced (P<0.05) methane emission. Similarly, some of the blood parameters before and after experiment were affected (P<0.05) by inclusion of A. karroo leaf meal. However, A. karroo leaf meal inclusion level had no effect (P>0.05) on diet intake, methane emission, live weight changes and digestibility, except (P<0.05) for digestibility of crude fibre. Feed conversion ratio improved linearly with increased A. karroo leaf meal inclusion level. In the case of experiment 2, results of methane emission before and during the experiment indicated that inclusion of A. tortilis leaf meal in the diets of goats reduced (P<0.05) methane emission. Similarly, some of the blood parameters before and after the experiment were affected (P<0.05) by inclusion of A. tortilis leaf meal. However, variation in A. tortilis leaf meal inclusion level had comparable effect (P>0.05) on methane emission, live weight changes and digestibility, except (P<0.05) for digestibility of crude protein and acid detergent fibre. Diet intake and feed conversion ratio were affected (P<0.05) by A. tortilis leaf meal inclusion level. A positive relationship was observed between A. tortilis leaf meal inclusion level and diet intake. In experiment 3, results of methane emission before and during the experiment indicated that inclusion of A. nilotica leaf meal in the diets of goats reduced (P<0.05) methane emission. Similarly, some of the blood parameters before and the after experiment were affected (P<0.05) by inclusion of A. nilotica leaf meal. Apart from diet fat digestibility and feed conversion ratio, no statistical differences (P>0.05) were observed on diet intake, digestibility and live weight changes of goats fed A. nilotica leaf meal inclusion level. Positive relationships were observed between A. nilotica leaf meal inclusion level, diet fat digestibility and feed conversion ratio in male Boer goats. The high crude protein and low tannin contents in A. karroo, A. tortilis and A. nilotica leaves indicate that these Acacia species can be safe to use as a source of protein in animal nutrition if used sparingly. It was noted that nutrient intake, digestibility, vi feed conversion ratio and blood profiles of Boer goats in the present study were optimised at different inclusion levels for all the three Acacia species. This may imply that inclusion levels of A. karroo, A. tortilis and A. nilotica leaf meals for optimal productivity will depend on the Acacia species used and, also, on particular productivity parameters in question. Although, A. karroo, A. tortilis and A. nilotica leaf meal reduced methane emission, optimal reduction in methane emission was not determined. Further validation is required to determine Acacia inclusion levels for optimal methane production and emission by goats.
NRF (National Research Foundation), AGRISETA (Agricultural Sector and Education Training Authority) and NSFAS (National Students Financial Aid Scheme)