Dissertations / Theses on the topic 'Suckling'

In their first days of life, dairy calves in artificial rearing systems often have difficulty using an artificial teat for feeding. I examined the age at which calves are able to stand up and suckle without lifting assistance, as well as their suckling behavior when presented with a plain dry teat versus a dry teat modified with a presumably attractive odor or taste substance. Single-housed newborn dairy calves (n = 51) were presented for ten consecutive days with a two-minute two-choice test, in which suckling time was recorded for 1) a plain (control) teat vs. a glucose-coated teat (taste test) and 2) a plain teat vs. a teat with a "Freshly Cut Grass" odor (odor test). On average, the calves were able to suckle without lifting assistance from the second or third day of age on. The "Freshly Cut Grass" odor had no significant effect on their suckling behavior. The calves showed a significant preference for suckling the glucose-coated teat and displayed a significantly longer total suckling time in the taste test compared to the odor test. There were no significant differences between sexes regarding suckling preference. The results of the present study show that glucose had a significant effect on the calves' teat preference and significantly increased total suckling time with a dry artificial teat. As such, glucose may increase suckling motivation in non-efficient drinkers or ill calves with low motivation to suckle.

Five experiments were designed to investigate factors affecting the creep feeding of suckling piglets and a preliminary method to monitor the creep feeding of suckling piglets was developed. In experiment 1, neonatal viability and creep feeding behaviour on d 14-15 were monitored. Birth weight rather than birth order affected the neonatal viability in terms of cumulative suck number (P< 0.01). The lighter piglets at birth went to contact the feeder faster (P< 0.10), but tended to touch the food slower (P< 0.10) on dl4 when creep food was introduced. Neither birth weight or birth order affected the creep feeding behaviour over 24 hours on d 14-15. The relationship between neonatal viability and creep feeding behaviour was not consistent and clear. In Experiment 2 and 3 the effect of hunger was studied after piglets were made hungry by preventing nursing twice. The hungry piglets showed more foraging behaviour (P< 0.05) and more general activity (P< 0.05) when they first encountered creep food in the test pen on dl7. More of the hungry piglets in Experiment 2 ate creep food in the test pen than those not hungry (P< 0.05). However these effects were not repeated on the following day. Food type did not affect any foraging behaviour and general activity in Experiment 3. In the Experiments 2 and 3, after the test until the weaning day on d28, creep food intake varied between litters but neither feeding time nor growth of piglets varied amongst treatments. There was no clear correlation between the foraging behaviour in the test pen and the creep feeding behaviour in the home pen.

Changes in follicular dynamics were monitored in forty-four Brahman multiparous (n=30) and primiparous (n=14) cows randomly assigned to control (n=22) and once-daily suckling (n=22) treatments. Daily transrectal ultrasonography images were taken from d 21 through 88 post-calving or detection of first estrus. Suckling treatment was introduced on d 28 post-calving. Follicular waves were profiled and characterized by development and regression of a variable number of small and medium sized (2-9 mm) follicles before one of the follicles differentiated and became the dominant follicle. Primiparous cows had 34% more (P<0.04) follicular waves (4.8 + 0.6) than did the multiparous cows (3.1 + 0.4) prior to first ovulation (FO). Once-daily suckled multiparous cows had 37% fewer (P<0.03) follicular waves (2.4 + 0.5) prior to FO than controls. Interval from calving to FO was reduced (P < 0.05) by an average of 12 d by once-daily suckling in multiparous cows. Primiparous cows developed 30% more (P<0.02) dominant follicles (6.3 + 0.6) from d 21 to estrus than did the multiparous cows (4.3 + 0.4). Ovulation before d 88 occurred in 42 of 44 (95%) cows. Behavioral estrus was not detected in 40 of 42 (95%) cows at FO. The length of the subsequent estrous cycle was short (<17 days) in 39 of 42 (93%) cows. We can conclude from these data that ovarian function is resumed shortly after parturition and ovulation of a dominant follicle ends postpartum anestrous. Primiparous cows experienced more follicular waves and therefore grew more dominant follicles prior to first estrus. Once-daily suckling hastened return to estrus and reduced the number of follicular waves prior to first post-partum estrus in multiparous cows. The incidence of first ovulation being associated with behavioral estrus was low. Short cycles followed first ovulation. It appears obligatory that postpartum Brahman cows experience a silent ovulation with formation of functional luteal tissue prior to resumption of normal estrous cyclicity.

The series of experiments described in this thesis were designed to investigate the role of suckling or late weaning in the response of young lambs to nematode infection. All experiments were conducted outdoors with grazing animals and no supplementation but for suckled groups of lambs whose counterparts were weaned to ryegrass – white clover swards. The parasite of interest was mainly Teladorsagia circumcincta solely but with mixed infection of Trichostrongylus colubriformis in one instance. In Chapter 3 (first experiment), the hypothesis that milk per se may have a direct effect on nematode development, rather than an indirect effect through enhancement of host immunity by superior nutrient supply was tested. Sixty, twinborn lambs were used, allocated to one of eight groups formed by either dosing lambs from 42 days of age or not with the equivalent of 1000 or 250 L₃ T. circumcincta larvae d⁻¹ until five days before necropsy, while a twin was either weaned at 39 days of age, suckled as single or twin until necropsy on day 84. The possibility that weaning one of a twin set onto pasture in close proximity to the ewe would cause abnormal ewe and lamb behaviour was tested by replicating the work in twins maintained as twins but in which one twin received equivalent of 250 and the other 1000 L₃ T. circumcincta larvae d⁻¹. This showed no abnormal ewe nursing or lamb suckling behaviour as a result of weaning a twin in a set. Relatively low faecal egg counts (FEC) and a two to three fold lower worm burdens suggest suckling could reduce larval establishment. Inability to detect peripheral titres of immunoglobulins supports this conclusion. An intra worm-population regulation of T. circumcincta, indicated by a pattern of greater egg-laying by a numerically smaller but physiologically better developed nematode population in suckled lambs measured in eggs 'in utero' and worm length made interpretation of FEC difficult. Suckling significantly improved weight gain and carcass weights, but early weaning did not reduce resilience to infection. In Chapter 4 (second experiment), 40 pairs of twin lambs, average age of 39 days, were either infected with the equivalent of 1000 L₃ T. circumcincta larvae d⁻¹ or not, while one twin was weaned and the other allowed to continue suckling. Necropsy was carried out on groups of five and six lambs from each of the uninfected and infected treatments, respectively, at mean age of 84, 112, and on six lambs from each group at 140 days of age. This serial slaughter allowed further confirmation of the hypothesis in Chapter 3 but also investigated the long-term effect of suckling on resistance or resilience of lambs at the trial when immune responses were anticipated to be developing. An in vitro direct larval challenge (IVDC) study, to monitor larval establishment, was carried out on tissue explants from necropsied lambs. Suckled lambs consistently showed lower FEC (P < 0.05) and worm burdens (P < 0.05) at every phase of the trial. Within the infected groups, % in vitro larval rejection suggested earlier immune responses in the weaned lambs by day 84, which was not consistent with lower worm burdens in suckled lambs but appeared similar in the subsequent necropsies. Lambs continued to show better growth due to suckling while weaning did not reduce the resilience of lambs confirming observations in Chapter 3. The immunoglobulin profile suggested the commencement of immune responses in lambs from the period after the 84th day necropsy, with significantly greater (P < 0.01) IgA titre in the infected groups, and the suckled lambs towards the end of the trial on day 140. A vaccinating effect of early exposure to parasites was coincidentally revealed as a result of unintentional pasture larval contamination, seen in suckled non-infected lambs shedding fewer eggs and harbouring fewer worms during the later necropsies compared with their weaned non-infected counterparts. In Chapter 5 (third trial), 93 pairs of twin lambs, 47 pairs of which received a vaccinating mixed infection of T. circumcincta and T. colubriformis larvae (60 L₃ / kg W / d) at ratio 40:60, respectively during the period 36 – 103 days of age, were either weaned early on day 51 or later on day 108. All lambs were drenched on day 108 and groups received challenge infections from day 116, at same rate with the vaccinating infection, or not, which ceased five days before respective necropsies. Necropsies were carried out on selected lambs on days 108, 184 and 218. The direct effect of milk on larval establishment appeared to feature only in the T. circumcincta populations on slaughter day 108. The long-term benefit of late weaning for development of resistance was conditional on lambs receiving the vaccinating infection, and appeared to be more pronounced in the small intestine, reflected by a greater reduction of T. colubriformis populations in that organ than of T. circumcincta populations in the abomasum. A negative consequence of enhanced immune response was the suggestion of an increased metabolic cost in reduced performance of lambs. In conclusion, the work provides support to the hypotheses that: (a.) suckling may reduce the establishment of nematode larvae through the direct effect of milk, (b.) may enhance rapid development of host immunity to infection, and (c.) it further suggests that lack of larval experience during suckling may have long term negative implications for host resistance. Finally, it suggests that milk may play little role in the enhancement of host resilience to infection and, on the contrary, that additional metabolic cost may be associated with a more rapid development of immunity resulting from larval challenge while suckling.

The objectives of these two studies were to characterize normal growth and resultant changes in conformation and walk kinematics of warmblood foals. The first study quantified linear and angular conformation changes of 13 warmblood foals during the first 9 mo of growth. An objective photographic method of evaluating conformation was used to obtain all data. All linear measurements increased significantly over the investigated ages and growth rates were highest in the first 2 mo of growth. Total percentage of growth during the study was greatest for neck and back length. Distal limb growth was minimal over the investigated ages. Metacarpal growth slowed earlier than many other traits. Length of the metatarsus increased minimally during the studied ages with significant growth occurring only between 23 wk and post-weaning measurements. Increasing wither heights were positively associated with increases in scapula, humerus, radius, ilium, femur, tibia and metatarsal and metacarpal lengths. Angular conformation also changed significantly during growth. Trends in angular changes were generally less clear than those for linear variables. Scapula, femur and hock angles significantly increased and humerus angle decreased with age. Utilizing a plumb line from the hock upward, the distance of the hindlimb behind the body was quantified. The distance out behind decreased significantly between 1 and 15 wk. Distance out behind was positively correlated with tibia angle at all ages. The second study quantified linear and temporal kinematics of the walk in growing foals. Nine warmblood foals from the first study were filmed as they walked over a uniform concrete surface covered in 13mm thick rubber matting. Speed was controlled through the use of a uniform handler with a metronome. Trait means at ages 3, 11, 21 wk and post-weaning were compared. Length variables were standardized to percent of total stride length. Temporal variables were standardized to percent of stride duration. Stride length and duration increased significantly with age. Step lengths, stance duration and protraction and retraction durations did not change across ages. Over-stride decreased significantly with age, potentially due to increased back length in older foals. Linear distance between diagonal hooves during stance increased with age, and was negatively correlated to the decrease in over-stride. While older foals appeared to display a more regular, 4-beat walk rhythm, timing between lateral and diagonal footfalls remained significantly different at all ages. Both conformation and kinematics changed during growth. Characterizing conformational changes due to growth can allow a better understanding of how foal conformation and gait change during growth and may predict these traits in adults, thus allowing selection of top performance prospects at a younger age.
Master of Science

Infant formula companies began fortifying formulas with long-chain polyunsaturated fatty acids (PUFA) in 2002, including arachidonic acid (AA) at ~ 0.5% of total fatty acids. This study is the first in a series that will examine effects of supra-physiological supplementation of AA on intestinal health. The objective was to determine the time specific effects of dietary AA on fatty acid composition of enterocyte phospholipids and on the mRNA abundance of hepatic ∆6- and ∆5-desaturases. One d old pigs (N=96) were fed a milk-based formula for 4, 8, or 16 d. Diets contained either no PUFA (0%AA, negative control), 0.5%AA, 2.5%AA, 5%AA, or 5% eicosapentaenoic acid (EPA) of total fatty acids. Growth (299 +/- 21 g/d) was unaffected by treatment (P>0.1). By day 16, ileal enterocyte phospholipid concentrations of AA were enriched 176%, 280%, and 355% in pigs fed the 0.5%AA, 2.5%AA, and 5%AA diets, respectively, compared with the 0%AA control (P<0.05). Concentration of AA within enterocytes of the 5% EPA fed group was similar to that of the 0%AA fed pigs, while EPA concentration increased by >8 fold. As pigs aged from birth to 16 d of age, there were no differences in the desaturase mRNA abundance (P>0.1), measured in pigs fed 0.5% or 5%AA. Abundance also was similar among AA-supplemented pigs, but was elevated by 60-80% in the 0%AA-fed pigs compared to those fed 2.5% (P<0.05). These data demonstrate a dose-dependent response in enterocyte AA concentration to dietary AA and show that supra-physiologic supplementation of AA is not detrimental to growth or desaturase gene expression.

Suckling rats show a low level of synthesis of epidermal growth factor (EGF) and obtain this important polypeptide from maternal milk. Thus, this study was performed to characterize how and where in the gastrointestinal tract the absorption of rat-EGF (rEGF) occurs and to which organs it is delivered. Although radiolabeled EGF transferred to the liver by the ileum was significantly higher than that by the jejunum, the total amounts of immunoreactive and receptor-binding active ¹²⁵I-rEGF in the liver were significantly higher from jejunal than from ileal absorption. These results indicate that the ileum degrades most of the ¹²⁵I-rEGF during absorption, whereas the jejunum absorbs more intact ¹²⁵I-rEGF. Higher numbers of EGF receptors were found in the brush border membranes of jejunum than that of the ileum, suggesting that the larger amounts of intact EGF delivered by the jejunum to the liver may be due to a higher capacity of EGF receptors in the jejunum. Liver and intestine were the main organs taking up the radioactivity after intrafemoral vein ¹²⁵I-rEGF administration. The degradation rates of EGF in the liver, intestine and pancreas were significantly lower in suckling as opposed to adult rats. In suckling rats intact rEGF was secreted by the liver into the bile and by the enterocytes into the lumen of the intestine. The competitive effects of unlabeled rEGF were found at both sides of the small intestine and at the circulatory side of the liver, submandibular glands, pancreas, and other organs, indicating a receptor-related uptake of EGF from the lumen and circulation of these organs in suckling rats. The results indicate that after absorption maternal milk-EGF stays mainly in the digestive system during the suckling period. The amount of EGF in each organ may remain relatively stable on a daily basis since EGF is absorbed continuously from the jejunum in suckling rats and is distributed and circulated in the digestive system by hepatico-enteric, entero-enteric, and perhaps pancreatico-enteric circulations; in this way, EGF accelerates the growth of the digestive system.

This thesis examines inter-relationships between the feeding, health, and growth of infants (aged 0-24 months) in low-income households in Addis Ababa, Ethiopia. Mixed-longitudinal data were collected from a sample of 113 infants and their mothers in Kebele 11, Keftegna 24 from November 1987 to April 1988. Breastfeeding is the culturally esteemed mode of infant feeding. The culture-specific concept of weaning places the emphasis on the termination of breastfeeding, with little consideration of the quality and quantity of weaning foods. As a result, weaning foods are basic and monotonous. Survival data analysis shows that weaning is commenced at the mean age of 9.2 months, and completed at the median age of 20 months. A probabilistic model is proposed that includes a set of inter-related 'infant-centred', 'mother-centred', and other factors such as the seasonal availability of weaning foods influencing the process of weaning. Culturally-prescribed norms appear to play little or no part in the timing of weaning, in particular, the infant's age is of secondary importance. Direct observations of suckling behaviour and infant care reveal that 'on demand' breastfeeding was practised, and the mean duration of suckling sessions was 10.96 minutes. The duration of breastfeeding was influenced significantly by maternal body-mass index. Seasonal patterns were detected in the prevalence of fever, coughing, and vomiting in the infants. Associations between morbidity and other data using log-linear models suggest that infant's diarrhoea is closely linked to the level of household hygiene, maternal education, and mother's morale. Infant's ilnesses caused appreciable deficits in weight, but not in stature. Processes of 'catch-up' and 'catch-down' growth are demonstrated by the seasonal effect of diarrhoeal illness on weight. Avenues for further research and policy reform suggested by the findings of this study are discussed.

Doctor of Philosophy
Department of Animal Sciences and Industry
Duane L. Davis
Jim L. Nelssen
A total of 188 sows and their litters were used in 2 experiments to evaluate methods to induce estrus and ovulation in lactating sows and effects on pig growth. In Exp. 1, an altered suckling method (ALT) was designed to combine split-weaning and intermittent suckling as a means to reduce the suckling stimulus in primi- and multiparous sows during the last week of lactation (d 18 to 25). The ALT sows were also removed for daily boar exposure. The ALT treatment produced lactational estrus in 75% and 95% of primiparous and multiparous sows, respectively. The ALT sows were in estrus earlier (P < 0.01) than controls post-farrowing, with no effect on subsequent reproductive performance. From d 18 to 32, the ALT treatment benefited (P < 0.01) growth of lightweight pigs but decreased (P < 0.01) BW gain of heavyweight pigs, resulting in overall similar growth. However, variation in BW was reduced (P < 0.01) by 50% for ALT litters. In Exp. 2, varying suckling reduction strategies were applied to boar-exposed lactating sows. Overall, 76% of sows in suckling reduction treatments expressed estrus in lactation. Split-weaned and ALT sows performed reproductively similar to controls, whereas sows with daily litter separation or a single 24 h litter removal tended (P < 0.10) to have reduced conception rates versus controls or split-weaned sows. Reduced suckling treatments differed in their ability to induce lactational estrus and impact on pig BW gain immediately post-weaning. However, no evidence was found of benefit for pig growth to market weight or litter BW variation. Four additional experiments using 902 nursery pigs were conducted to test the efficacy of potential detoxifying agents against deoxynivalenol (DON) in swine diets. The effects of DON were not offset by adding an algae-modified montmorillonite clay nor by a proprietary blend of preservatives and clays. However, hydrothermally treating DON-contaminated diets with sodium metabisulfite modified the structure of DON to a non-toxic DON-sulfonate adduct and restored nursery pig growth via improved (P < 0.05) ADG, ADFI and G:F.

Breast milk contains many biologically active substances, including epidermal growth factor (EGF), that are absent from artificial milk formulas. Previous studies have shown dramatic growth and maturation effects of milk-borne EGF on the intestine. This raises the question as to whether artificial milk formulas should be supplemented with biologically active substances, such as EGF. As a result, this dissertation examined whether feeding suckling rats artificial milk formula supplemented with EGF modulates liver development. The normal development of hepatic cells in suckling and weanling rats also was characterized. Additionally, this dissertation examined whether gut-derived endotoxin and tumor necrosis factor alpha (TNFα) play a role in liver development. Dam-fed suckling and weanlings showed increases in the reorganization of hepatocellular plates, numbers of binucleated hepatocytes, and a tendency for sinusoidal endothelial cell fenestrae density and porosity to increase with age. Monocytic derived cells increased at days 8-12 and decreased at day 16. Hepatic stellate cells decreased with age. Colon microbial flora and portal venous endotoxin were present from day 8 onward. Compared to artificial milk formula feeding alone, EGF in the artificial formula elicited increased numbers of binucleated hepatocytes, changes in colon microbial flora, and a tendency for increased numbers of Kupffer cells and portal venous endotoxin. Compared to breast milk, the artificial diet caused decreases in binucleated hepatocytes, increases in monocytic derived cells, Kupffer cells, hepatic stellate cells, portal venous endotoxin and changes in the composition of the colon microbial flora. These increases in cells may be due to colonization of the colon with microbial flora which increased portal venous endotoxin. Increased endotoxin may provide a stimulus for the recruitment of monocytic derived cells to the liver and differentiation into Kupffer cells, which then stimulates hepatic stellate cell proliferation. However, the increases in portal venous endotoxin were not sufficient to elicit hepatic TNFα, mRNA production. In conclusion, milk-borne EGF is involved in differentiation of hepatocytes and changes colon microbial flora that occur in suckling rats. Whether accelerating maturation of hepatocyte is beneficial or detrimental to the suckling rats remains to be determined. Therefore, the supplementation of artificial milk formula with EGF warrants further consideration and research.

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The challenge of keeping the properly development in the Holstein breeders of reposition (HPB) in the initial stages of creation, depends on both the feed management as well the health condition. The management of heifer s creation, during suckling in collective stalls, with automatic feeders enables the search for new nutritional protocols associated to the transfer of the passive immunity (TIP) which are both determining factors to the success of the livestock. Aiming the evaluation of the influence of the IgG serum in the weight gain of heifers during suckling and after their first year of life, it was conducted an experiment with 45 Holstein heifers distributed in three collective stalls equipped with automatic feeders where the heifers were undergone to three different suckling protocols. These protocols were denominated as: treatment one, with the daily provision of 4 liters of milk replacer at ease; treatment two, with the daily provision of 6 liters of milk replacer at ease; and treatment three with the daily provision of milk replacer at ease. All the heifers began the experiment on their fifth day of life and the concentration of serum immunoglobulin G (IgG), was at least 10 mg/dL, with a variation around 13,4 and 43,7 mg/dL. The experimental period of suckling, in all the treatments was fixed in 55 days and all the animals were weaned on their sixth day of life. The heifers had their weight gain checked weekly. After weaned, all the heifers were conducted to a single collective lot and handled under the same feeding conditions until their first year of life. The feeding management in the post-weaning had a daily ingestion of 2kg of supplement divided in 2 meals during the period of 10 months. During this period, they also had Tifton straw at ease and free access to pickets with Tifton grass. After the weaning, the measurement of the body weight of the heifers was taken in monthly intermissions. The experimental design used was totally randomized (DIC). All the data were evaluated by statistics analysis of the linear correlation of Pearson, analysis of variance ANOVA and submitted to the Tukey's average test at 5% and a paired t-test at 5% of significance. Regarding to the performance in the weight gain, there was no influence of the IgG concentration in the weight gain to the weaning and neither in the weight gain after the heifers were one year old. The evaluation of the weight gain occurred between the treatments and disregarding treatments. When dealing with the performance and taking only the suckling protocol, it has been found that the treatments 2 and 3 have shown a higher weight gain at weaning , but the efficiency in weight gain after the heifer's first year was higher in treatments 1 and 3. It was concluded that since the minimum serum concentration of IgG is 10mg/dL, there is no interference of this parameter about the weight gain at weaning and during the first year of life of the heifer. The milk consumption at ease ensures a better weight gain of animals compared to the animals with controlled milk consumption
O manejo de criação de bezerras na fase de aleitamento em baias coletivas equipadas com alimentadores automáticos possibilita a busca por novos protocolos nutricionais que, associados à transferência da imunidade passiva (TIP), representam fatores determinantes para o sucesso da criação. Com o objetivo de se avaliar a influência da concentração sérica de IgG no desempenho ponderal de bezerras em fase de aleitamento e após um ano de vida, 45 bezerras da raça Holandesa foram distribuídas em três baias coletivas equipadas com alimentadores automáticos e submetidas a três diferentes protocolos de aleitamento (Tratamentos experimentais) denominados de 4L, tratamento que teve o fornecimento de quatro litros diários de sucedâneo lácteo; 6L, tratamento com o fornecimento de seis litros diários de sucedâneo lácteo; e AL, tratamento com fornecimento ad libitum de sucedâneo lácteo. O fornecimento de concentrado para todos os animais foi a vontade. As bezerras entraram no experimento com cinco dias de idade e concentração de imunoglobulina G sérica (IgG), variou entre 13,4 e 43,7 mg/dL. O período experimental de aleitamento em todos os tratamentos foi fixado em 55 dias sendo que os animais foram desmamados aos 60 dias de idade. As bezerras tiveram seu ganho de peso aferido semanalmente. Após o desmame todas as bezerras foram conduzidas para um único lote coletivo e manejadas sob as mesmas condições alimentares até completarem um ano de vida. O manejo alimentar dos 65 dias aos 12 meses de vida contou com a ingestão de 2 Kg de concentrado diário divido em duas refeições, feno de Tifton à vontade, e, acesso contínuo à piquetes de pastoreio com grama Tifton. Após o desmame, a mensuração do peso corporal das bezerras foi feita em intervalos mensais. Utilizou-se o delineamento inteiramente casualizado (DIC), os dados foram avaliados através da análise estatística de correlação linear de Pearson, análise de variância ANOVA e submetidas ao teste de média de Tukey a 5%, e teste t pareado a 5% de significância. Com relação ao desempenho em ganho de peso, não houve influência da concentração de IgG no ganho de peso ao desmame e também no ganho de peso após um ano de vida. As avaliações de ganho de peso aconteceram entre os tratamentos e desconsiderando-se os tratamentos, com o objetivo de encontrar o efeito apenas da concentração de IgG sobre o ganho de peso, porém, o resultado foi o mesmo para ambas as avaliações. Quanto ao desempenho e o protocolo de aleitamento, verificou-se que os tratamentos 6L e AL foram superiores no ganho de peso ao desmame, porém a eficiência em ganho de peso após um ano de vida foi maior nos tratamentos 4L e AL. Conclui-se que desde que a concentração sérica mínima de IgG seja de 10 mg/dL, não há interferência deste parâmetro sobre o ganho de peso no desmame e durante o primeiro ano de vida da novilha. O fornecimento de leite a vontade garante melhor ganho de peso aos animais em relação ao fornecimento controlado

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Fundação de Apoio ao Desenvolvimento do Ensino, Ciência e Tecnologia do Estado de Mato Grosso do Sul (FUNDECT)
Universidade Estadual Paulista (UNESP)
O objetivo desta pesquisa foi avaliar a influência do grupo genético do bezerro no comportamento de mães e suas crias. Usaram-se 24 vacas Nelore paridas e seus bezerros, dos quais oito eram Nelores, oito ½Simental ½Nelore, e oito ½Red Angus ½Nelore. Avaliaram-se as medidas de freqüência e duração das mamadas, tempo de pastejo e ruminação dos bezerros e vacas. Os bezerros puros mamaram mais freqüentemente que os mestiços (3,51 vs. 3,17 vezes/dia), porém com menor duração de mamada (7,37 vs 7,80 minutos). A freqüência de mamadas, duração de cada mamada e tempo total de mamadas diminuíram com o aumento na idade do bezerro. Nos bezerros, pastejo e ruminação aumentaram com a idade; porém, nas vacas, aumentou o tempo de pastejo e diminuiu o de ruminação com o passar dos dias. Os bezerros mestiços pastaram, em média, 18 minutos a mais que os puros, e os machos, 16 minutos a mais que as fêmeas. Os bezerros machos ruminaram, aos 40 dias de idade, 25 minutos a mais que as fêmeas, mas esta diferença diminuiu com a idade e desapareceu por volta dos 220 dias. As mães de mestiços ruminaram, em média, 10 minutos a mais que as mães dos puros. O comportamento da mãe e de sua cria é influenciado pelo grupo genético desta última.
The objective was to evaluate the effect of a calf's genetic group on the behavior of dam and calf. We used 24 Nellore dams and their calves, of which eight were Nellore, eight were ½Simmental ½Nelore and eight ½Red Angus ½Nellore. Grazing and rumination times, as well as suckling frequency and time, were measured. The straightbred calves suckled more often than the crossbreds (3.51 vs. 3.17 times/day), but their suckling lasted less time (7.37 vs 7.80 minutes). Suckling frequency, suckling length and total time spent suckling decreased as calf age increased. Calf grazing and rumination time increased with age; however, the cows’ grazing time increased and rumination time decreased as the days postpartum went by. The crossbred calves grazed, on the average, 18 minutes longer than the crossbreds, and the males grazed 16 minutes longer than the females. The male calves grazed, at 40 days of age, 25 minutes longer than the females, but this difference decreased as they grew up and disappeared around 220 days. The dams of crossbreds ruminated, on the average, 10 minutes longer than the dams of straightbreds. In conclusion, dam and calf behavior are influenced by the calf's genetic group.

In most mammals, nutritive suckling is critical during the early neonatal period. The genioglossus (GG) muscle in rat plays an important role in protruding the tongue for efficient suckling. The purpose of this study was to examine the contractile properties and myosin heavy chain (MHC) phenotype of the GG following an early period of artificial rearing, which reduced nutritive suckling. Beginning at three days of age Sprague-Dawley rats were fed via implanted gastric cannula until postnatal day 14 (P14). At P14, artificially reared (AR) rat pups were either placed with a lactating dam until the end of the weaning period and allowed to mature until postnatal day 42 (P42), or anesthetized and prepared for physiological experimentation. GG contractile properties at P14 and P42 in AR and dam reared (DR) rats were obtained with a force transducer and digital recording system through stimulation of the medial branch of the hypoglossal nerve. Following physiological experimentation, muscle samples were removed and stored for MHC analysis. Comparisons were made between AR and DR groups at P14 and P42. At P14 maximum tetanic tension and fatigue index were lower in the AR group than the DR group and no differences were found in MHC distribution. By day 42, AR rats had a higher fatigue index that DR rats and DR rats had a higher percentage of MHCIIa than AR rats. The artificial rearing technique employed in this study was adequate to produce chronic changes in fatigue resistance and MHC distribution in GG muscle. GG muscle of premature human infants requiring early artificial feedings may develop similar changes in their contractile characteristics and MHC phenotype.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
A reprodução é o principal fator limitante na eficiência da produção de carne, e a baixa taxa de concepção observada no rebanho brasileiro reflete a baixa taxa de fertilidade das vacas e a idade tardia à puberdade das novilhas de substituição. A fim de fornecer mais informações sobre as estratégias nutricionais para o melhor desenvolvimento das novilhas Nelore e melhorar o desempenho das vacas, foram realizados três estudos e os resultados são apresentados em quatro artigos. No primeiro trabalho, foram utilizadas 80 vacas Nelore grávidas (6 meses de gestação) com idade inicial de seis anos e peso inicial médio e escore de condição corporal inicial de 515,5 ± 1,34 kg e 4,68 ± 0,15, respectivamente. O delineamento experimental foi inteiramente casualizado, com quatro tratamentos e vinte repetições. As estratégias avaliadas foram suplementação com 1 kg/vaca/dia de suplementação somente no pré-parto, somente no pós-parto, no pré e pós-parto, e somente mistura mineral ad libitum durante o pré e pós-parto. Observou-se o efeito da suplementação sobre o peso corporal (PC) das vacas no parto e sobre o peso dos bezerros ao nascimento (P <0,05). Houve também efeito da suplementação no pré e pós-parto (P <0,05) no PC final, ganho médio diário e escore de condição corporal final dos animais. Houve uma tendência, com a suplementação no pós-parto, de maior produção de leite das vacas (P = 0,065) e, para os seus componentes, houve efeito de suplementação no pós-parto apenas para proteína do leite (PL) (P = 0,003). Houve um efeito da suplementação no pós-parto sobre nitrogênio ureico sérico, glicose, ácidos graxos não esterificados, β-hidroxibutirato e progesterona (P <0,05). Todos os metabólitos foram influenciados (P <0,05) no dia pós-parto. As vacas suplementadas no pós-parto apresentaram maior taxa de concepção do que a observada em animais não suplementados (P = 0,005). A suplementação com 1 kg/dia de suplementação com 28,6% de PC no pré-parto melhorou algumas das características produtivas, no entanto, a suplementação no pós-parto permite efeitos mais expressivos sobre a eficiência produtiva, metabólica e reprodutiva das vacas. Portanto, a suplementação no pós-parto é recomendada quando os animais têm escore de condição corporal vi (ECC) adequada ao parto. As bezerras das vacas do primeiro experimento foram utilizadas no segundo trabalho para avaliar estratégias de suplementação no sistema creep-feeding. Utilizaram-se quarenta e quatro bezerras Nelore, com idade e peso médio inicial, de quatro meses e 147,6 ± 1,34 kg, respectivamente. Um único suplemento com aproximadamente 20% de proteína foi fornecido em quantidades diferentes dependendo do peso corporal (PC). Os tratamentos consistiram no suprimento de 0,0%, 0,2%, 0,4% ou 0,6% do PC deste suplemento. Observou-se aumento do efeito linear (P <0,05) do peso corporal final e ganho médio diário de novilhas com aumento da suplementação. A suplementação múltipla aumentou o consumo, em kg/dia, de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), matéria seca digerida (MSD) e nutrientes digestíveis totais (NDT). Não houve efeito da suplementação (P> 0,05) nas concentrações de AGNE. Houve um efeito linear crescente (P <0,05) de suplementação sobre as concentrações de insulina. Conclui-se que a suplementação melhora o desempenho, as características nutricionais e metabólicas dos animais, sendo o suprimento de 0,6% do PC de suplemento com 20% de PB o tratamento mais efetivo. As mesmas novilhas foram utilizadas no terceiro experimento após o desmame para avaliar os efeitos da suplementação estratégica de novilhas Nelore após o desmame à concepção. As estratégias avaliadas foram: BAAL - suplementação com 0,2% de PC/animal/dia de suplementação nos primeiros 90 dias e suplementação com 0,6% de PC/animal/dia nos 90 dias subseqüentes; MEME - suplementação com 0,4% de PC/animal/dia durante 180 dias; ALBA - suplementação com 0,6% de PC/animal/dia de suplementação nos primeiros 90 dias e suplementação com 0,2% de PC/animal/dia nos 90 dias seguintes; e MM - apenas mistura mineral ad libitum durante os 180 dias. Observou-se que a suplementação melhorou o desempenho dos animais durante os primeiros 90 dias de experimento, o que pode ser verificado pelo ganho médio diário (GMD) das fêmeas (P = 0,001). O mesmo fato foi observado na fase de transição seca/água, onde a suplementação melhorou o peso corporal final (PCf) (P = 0,002) e GMD (P = 0,001). Verificou-se também que a suplementação múltipla aumentou o consumo de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), matéria seca digestível (MSD) e nutrientes digestíveis totais (NDT) durante todo o experimento e fibra em detergente neutro digestível(FDNd) e fibra em detergente neutro corrigida para cinzas e proteínas (FDNcp) apenas na transição seca/água. A suplementação aumentou o coeficiente de digestibilidade aparente de MS, MO, PB, vii FDNcp e NDT (P <0,05), ou seja, de todos os parâmetros analisados. Os níveis de nitrogênio ureico sérico (NUS), glicose (GLIC), insulina (INS) e progesterona (PROG) foram maiores em novilhas suplementadas do que em novilhas não suplementadas (P < 0,05). Por outro lado, a suplementação reduziu as concentrações de ácidos graxos não-esterificados (AGNE) (P = 0,001). Finalmente, foi obsevado que a taxa de concepção foi maior em novilhas suplementadas (P = 0,002). Concluiu- se que os melhores níveis de NUS, INS, GLIC, AGNE e PROG das novilhas suplementadas associadas ao maior PCf, digestibilidade e consumo dos componentes da dieta proporcionaram melhor desempenho reprodutivo para as novilhas suplementadas, independentemente da suplementação.
Reproduction is the main limiting factor in meat production efficiency and the low offtake rate observed in the Brazilian herd reflects the low fertility rate of cows and the late age at puberty of replacement heifers. In order to provide more information about nutritional strategies to better develop Nellore heifers and to improve dams’ performance, three studies were conducted and the results are here presented in four papers. In the first paper, were used 80 pregnant Nellore cows (6 months gestation) with initial age of six years and mean initial weight and initial body condition score of 515.5 ± 1.34 kg and 4.68 ± 0.15, respectively.The experimental design was completely randomized, with four treatments and twenty repetitions. The strategies evaluated were supplementation with 1 kg/cow/day of supplementation only in the pre-partum, only in the postpartum, in the pre and postpartum, and only ad libitum mineral mixture during the pre and postpartum.The effect of supplementation on the body weight (BW) of cows at calving and calf weight at birth (P <0.05) was observed. There was also effect of pre and postpartum supplementation (P <0.05) on the final BW, mean daily gain and final body condition score of the animals. There was a trend of postpartum supplementation on milk production from the matrices (P = 0.065) and, for its components, there was post-partum supplementation effect only on milk protein (MP) (P = 0.003). There was an effect of postpartum supplementation on serum urea nitrogen, glucose, non-esterified fatty acids, β- hydroxybutyrate and progesterone (P < 0.05). All metabolites were influenced (P < 0.05) by the postpartum day. Cows supplemented postpartum had a higher conception rate than that observed in non-supplemented animals (P = 0,005). Supplementation with 1 kg/day supplementation with 28.6% of CP in pre-partum improved some of the productive characteristics, however, postpartum supplementation allows more expressive effects on the productive, metabolic and reproductive efficiency of cows. Therefore, postpartum supplementation is recommended when the animals have adequate body condition score (BCS) at calving. The heifer calves of cows used in the first experiment were used in the iii second paper to evaluate supplementary strategies in the creep feeding system. Were used fourty-four Nellore heifer calves, with age and initial mean weight, of four months and 147.6 ± 1.34 kg, respectively.A single supplement with approximately 20% of protein was provided in different amounts depending on body weight (BW). Treatments consisted in the supply of 0.0%, 0.2%, 0.4% or 0.6% of BW from this supplement.Increasing linear effect (P < 0.05) of final body weight and average daily gain of heifer calves were observed with increased supplementation. Multiple supplementation increased consumption, in kg/day, of dry matter (DM), organic matter (OM), crude protein (CP), digested dry matter (dDM) and total digestible nutrients (TDN).There was no effect of supplementation (P > 0.05) on NEFA concentrations. There was an increasing linear effect (P < 0.05) of supplementation on insulin concentrations. It is concluded that supplementation improves the performance, nutritional and metabolic characteristics of the animals, being the supply of 0.6% of BW of supplement with 20% of CP the most effective treatment.The same heifers were used in the third experiment after weaning to evaluate the effects of strategic supplementation for Nellore heifers after weaning to conception. The evaluated strategies were: BAAL- supplementation with 0.2% of BW/animal/day of supplement in the first 90 days and supplementation with 0.6% of BW/animal/day in the subsequent 90 days; MEME - supplementation with 0.4% of BW/animal/day for 180 days; ALBA - supplementation with 0.6% of BW/animal/day of supplement in the first 90 days and supplementation with 0.2% of BW/animal/day in the subsequent 90 days; and MM - only mineral mix ad libitum during the 180 days.It was observed that supplementation improved the performance of the animals during the first 90 days of experiment, and this fact can be verified by the heifers' average daily gain (ADG) (P = 0.001).The same fact was observed in the dry/water transition phase, where supplementation improved final body weight (fBW) (P = 0.002) and ADG (P = 0.001).It was also verified that multiple supplementation increased dry matter (DM), organic matter (OM), crude protein (CP), digestible dry matter (dDM) and total digestible nutrients (TDN) during the whole experiment, and digested neutral detergent fiber (dNDF), and neutral detergent fiber corrected for ash and protein (apNDF) only in the dry/water transition.Supplementation increased the total apparent digestibility coefficient of DM, OM, CP, apNDF and TDN (P <0.05), that is, of all analyzed parameters. Serum urea nitrogen (SUN), glucose (GLUC), insulin (INS) and progesterone (PROG) iv levels were higher in supplemented heifers than in non-supplemented heifers (P <0.05). On the other hand, supplementation reduced the concentrations of non- esterified fatty acids (NEFA) (P = 0.001). Finally, it was found that the conception rate was higher for supplemented heifers (P = 0.020). It was concluded that the best levels of SUN, INS, GLUC, NEFA and PROG of the supplemented heifers associated to the higher fBW, digestibility and consumption of the diet components provided better reproductive performance independently of the supplementation.

This study investigated the abundance of harbour seals (Phoca vitulina) on inter-tidal sandbanks, mother-pup interactions as well as the impact of anthropogenic disturbance during breeding season. The abundance was a composite picture of harbour seals of different age and sex, and increased gradually towards peaks in June. Although the sandbank water inlet was the longest time emerged, mother-pup pairs and other seals hauled out more abundant on the other sandbanks, probably due to space availability, differences in sandbank structure and distance to human activity. Mothers and their offspring were found to be mostly inactive during haul out. Mothers initiated significantly more frequently interactions i.e. hauling out, entering water and suckling. Seals hauled out at sandbanks close to the dyke were most frequently disturbed by pedestrians. Important regarding the impact on the seals seemed to be the group size of pedestrians and the distance to the seals (on dyke or seaside of it), i.e. pedestrians seaside disturbed more seals. This applies also to the disturbance by marine activity, e.g. distance of seals to the engine boat. Jet fighters were shown to affect the highest mean number of seals per event. After anthropogenic disturbances separations of mother and offspring were not recorded, e.g. due to seals being in the water; however, the steep edges as result of the culvert at water inlet lead to a few separations. The most frequent behavioural response towards anthropogenic disturbance was commotion with a probably lower level of energy costs during the energy consuming lactation period.

O Hormônio Concentrador de Melanina (MCH) está associado ao controle da ingestão de alimentos, peso corporal e homeostase da energia. Além disso, a lactação é um modelo fisiológico importante para estudar a integração do hipotálamo com os sinais sensoriais periféricos, como a sucção e também aqueles relacionados ao balanço energético. Concentrações mais elevadas de mRNA de MCH têm sido encontrados durante a lactação na área preóptica medial (MPOA) e na parte anterior do núcleo paraventricular do hipotálamo, especialmente em torno do 19º dia de lactação, quando este hormônio revela o seu pico mais alto de expressão do mRNA. O significado fisiológico desse fenômeno não é muito bem compreendido. Neste sentido, o objetivo do presente estudo foi contribuir para a investigação dos fatores que influenciam os sistemas endócrinos e sensoriais na expressão da MCH e a sua relação com alterações neuroendócrinas e comportamentais que envolvem o final da lactação, o desmame e a perpetuação do ciclo reprodutivo. Ratas Wistar (n = 56), foram divididas em subgrupos de quatro animais, as quais foram sacrificadas do 15º ao 21º dia de lactação, com (CS) ou sem (SS) sucção. O MCH e a proteína Fos foram avaliados na área hipotalâmica lateral (LHA), MPOA e área incertohipotalâmica (IHy). A MPOA mostrou uma relação inversa existente entre Fos e MCH. Além disso, observou-se um aumento da proteína Fos no grupo CS, o qual foi menos intensa durante o 18º dia de lactação quando comparado com o 15º dia. Além disso, duplas marcações para MCH e Fos não foram encontradas. Nossos resultados sugerem que a sucção é capaz de influenciar o MCH ao redor do 19º dia de lactação na LHA. Portanto, as áreas que foram encontradas com marcações para Fos podem ser capazes de se comunicarem com as regiões que possuem neurônios produtores de MCH, ou os mecanismos de ativação da expressão de MCH não são repassados via Fos. Sendo assim, parece existir uma relação indireta entre as áreas de ativação neuronal e MCH durante a sucção.
Melanin-Concentrating Hormone (MCH) has been largely implicated in the control of food intake, body weight and energy homeostasis. Moreover, lactation is an important physiological model to study hypothalamic integration to peripheral sensory signals, such as suckling stimulus and also those related to energy balance. Higher concentrations of MCH mRNA have been found during lactation in the medial preoptic area (MPOA) and in the anterior part of the paraventricular nucleus of hypothalamus, especially around the 19th day of lactation when this hormone reveals its highest peak of mRNA expression, and decrease after weaning. The physiological significance of this phenomenon is unclear. In this sense, the aim of the present study was to contribute to the investigation of sensory and endocrine factors influencing in the expression of MCH and its relationship to neuroendocrine and behavioural changes involving the end of lactation, weaning and perpetuating reproductive cycle. Wistar female rats (n= 56), divided in subgroups of four animals, were sacrificed every day from 15th to 21st day of lactation, with (CS) or without (SS) suckling stimulus. MCH and Fos immunoreactivity (MCH/Fos) was evaluated in the lateral hypothalamic area (LHA), MPOA and incerto-hypothalamic area (IHy). The MPOA showed an inverse relationship between Fos and MCH. Also, we observed an increase in the Fos of the group CS, which was less intense on 18th day when compared to 15th day, while MCH was increased. Besides, no colocalization between MCH and Fos was found. Our results suggest that suckling stimulus is able to influence the MCH around the 19th day of lactation in LHA. Therefore, the areas were we found Fos might have stimulated MCH-producing neurons. Hence, an indirect relationship between the areas of neuronal activation and MCH during suckling stimulus seems likely.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This study was carried out in order to evaluate the milk yield and composition from ewes of two genetic groups, as well as the influence of milk yield on performance, carcass characteristics and live weight components of nursling lambs maintained exclusively on ryegrass pasture (Lolium multiflorum LAM.). It was evaluated twelve Texel x Ile de France crossbred ewes (beef crossbred ewes) and twelve Texel (1/4) x Ile de France (1/4) x Lacaune (1/2) ewes (dairy crossbred ewes). It was included in this study only single delivered lamb and their mothers, totalizing 24 lambs from the same Sulffolk ram. The animals (ewes and lambs) were maintained throughout the experimental period in annual ryegrass in continuous grazing system with variable stocking rate. The estimation of milk yield was performed weekly. Milk samples were collected for laboratory analysis of protein, fat, density, acidity and lactose. There was a difference (P<0.05) among genotypes for milk yield (g/day), with a quadratic effect over time. Milk composition variables were not affected by treatments. The lambs were slaughtered when reaching 28 kg body weight. There was no effect (P>0.05) of the genotype of the lambs neither to the average daily weight gain nor to slaughter age. Also, there was no effect of genotype (P<0.05) on farm weight, body condition and leg length. Concerning carcass traits, only the empty body weight was affected by treatments. The gastrointestinal tract was higher (P<0.05) for lamb sons of beef crossbred ewes. Therefore, it can be inferred that the higher milk production by dairy crossbred ewes did not influence the carcass of their lambs, but induces a slower development of gastrointestinal tract of these animals comparing to lambs from the beef crossbred ewes.
O objetivo deste estudo foi avaliar a produção e a composição centesimal do leite de ovelhas de diferentes grupamentos genéticos, assim com a influência da produção de leite no desempenho, características de carcaça e componentes do peso vivo de cordeiros lactentes mantidos exclusivamente em pastagem de azevém anual (Lolium multiflorum LAM.). Avaliaram-se 12 ovelhas do cruzamento alternado entre as raças Texel x Ile de France e 12 ovelhas F1 provenientes do cruzamento entre as raças Texel x Ile de France (!) x Lacaune (!). Em ambos os tratamentos as fêmeas eram paridas de cordeiros simples, totalizando 24 cordeiros de cruzamento industrial, machos não castrados e fêmeas, filhos de reprodutor da raça Suffolk. Os animais (ovelha + cordeiro) permaneceram durante todo o período experimental em pastagem cultivada de azevém anual, em sistema de pastejo contínuo com lotação variável. A estimativa da produção de leite foi realizada semanalmente. Amostras do leite foram coletadas para análises laboratoriais dos teores de proteína, gordura, densidade, lactose e acidez. Foi observada diferença (P<0,05) entre os genótipos para a produção de leite (g/dia), demonstrando um comportamento quadrático. Para as variáveis da composição do leite não foi encontrada diferença entre os tratamentos. Os cordeiros foram abatidos ao atingir 28 kg de peso corporal em jejum. Não houve efeito (P>0,05) do genótipo dos cordeiros para o ganho de peso médio diário e nem para idade ao abate. Nas características corporais in vivo houve diferença entre os tratamentos (P<0,05) para o peso vivo de fazenda, condição corporal e comprimento de posterior. Quanto as características de carcaça, somente o peso de corpo vazio diferiu entre os tratamentos. O trato gastro-intestinal foi maior (P<0,05) para os cordeiros filhos das ovelhas cruza carne. Pode-se inferir que a maior produção de leite pelas ovelhas cruza leite não influenciou nos rendimentos de carcaça de seus cordeiros, mas sim no desenvolvimento mais lento do trato gastro-intestinal destes animais em relação ao cordeiros provenientes das ovelhas cruza carne.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico
The aims of the first and second chapters were to estimate equations that predict the milk yield and dry matter intake of lactating Nellore cows and the dry matter intake of suckling Nellore calves; and to evaluate the effects of days of lactation on intake and nutrient digestibility, performance, milk composition, and microbial efficiency of Nellore cows and their calves. In the experiment I, fifteen multiparous Nellore cows were used, and the diet consisted of corn silage and concentrate. The experiment started on the day of calving, and the lactation period was considered to be from the day of calving until 210 days later. Milking was performed on the 7th and 15th days after calving, and again every 15 days. Additionally, calves were fed corn silage ad libitum and concentrate. The intake of the animals was recorded daily. Digestibility assays were performed every 28-d; fecal samples were collected individually over three consecutive days (6h00, 12h00, and 18h00), while urine samples were collected on the second day of collection. Nutrient intake decreased (P < 0.01) for cows while nutrient digestibility increased (P < 0.001) during the lactation period. An associative effect was observed between feed and milk intake and nutrient digestibility when calves started to receive concentrate and roughage, and it appears that the apparent digestibility of mixed feeds does not equal the sum of the digestibility of each separately measured component. Cows had little reduction in BW during the first 28-d period; afterwards, there was a quadratic effect on BW gain. The average daily gain of the calves increased (P < 0.001) during the lactation period. Microbial efficiency (g CP/kg TDN) did not change (P > 0.05) in either Nellore cows or their calves during the lactation period. Milk composition of Nellore cows did not change (P > 0.05) during the lactation period except for protein, which varies from 3.57 (Month 1) to 3.97% (Month 7). DMI of Nellore cows may be estimated by the following equation: DMI = 24.78 + 0.035 × week – 0.009 × week2, while milk yield (MY) can be estimated by MY = 8.761 – 0.0664 × week. DMI of the calves may be estimated by the following: DMI = 0.00289 × exp (exp(-0.5672) × (exp(-0.0773 × week)-1) / (-0.0773)) . Therefore, nutrient intake decreases for cows and increases for calves while nutrient digestibility decreases for calves and increases for cows during lactation period. Also, an associated effect between milk and solid feeds increased DM digestibility. Nellore cows produce milk with an average of 4.58% lactose, 5.61% fat, and the milk protein varies from 3.57 to 3.97% according to the lactation period. Also, we recommend the use of the equations proposed here to estimate the DMI of lactating Nellore cows and their calves. Also, the equation to predict MY is recommended since it presented with the best results for Nellore cows. The aim of the third chapter was to evaluate the effects of the reduction of Ca and P levels in diet on nutrient apparent digestibility and intake, performance, microbial efficiency, and the energy and protein requirements for growing Nellore heifers and steers. In the experiment II, fifty animals were used, of which 32 were Nellore heifers and 18 were Nellore steers. Four animals of each sex were used as baseline reference animals and were slaughtered at the beginning of the experiment. Four animals from each sex were fed at MAIN by receiving 11 g/kg BW, whereas 10 steers and 24 heifers were assigned to the ADLIB group. The ADLIB heifers were divided further into 4 groups according to dietary treatment: 1) Ca and P fed at their proposed requirements (CaPR) with a 50:50 roughage:concentrate (R:C) diet, 2) CaPR with a 70:30 R:C diet, 3) 43% of their proposed requirements for Ca and 80% of their requirements for P (CaPL) with a 50:50 R:C diet, and 4) CaPL with a 70:30 R:C diet. The ADLIB and MAIN steers were fed CaPR with a 50:50 R:C diet. Half of the ADLIB steers and heifers were slaughtered at d 50; the other ADLIB animals were slaughtered after 100 days of the feeding period, whereas all MAIN animals were slaughtered at d 100. Total feces and urine were collected from all animals for 72 h prior to slaughter. After slaughter, EBW was measured. The NEm and MEm requirements were estimated by exponentially relating heat production and metabolizable energy intake; NEg was estimated based on the EBW and EBG. The NPg was estimated based on the EBG and RE. Dry matter digestibility and the apparent absorption and retention of Ca and P were similar across Ca and P treatments. Final body weight, and consequently ADG, was higher (P < 0.05) for heifers that were receiving the high compared to the low concentrate diet, but dietary Ca and P concentration did not affect (P > 0.05) performance. The NEm and MEm requirements were 70.1 and 118 kcal/kg EBW0.75, respectively. Net protein for maintenance was 1.28 g/kg BW0.75 and NEg and NPg were estimated from the following equations: NEg = 0.053 × EBW0.75 × EBG0.6301 and NPg = 137.85 × EBG – 0.05 × RE, respectively. Under the conditions of this experiment, reducing the dietary concentrations of Ca and P had no significant impact on the intake, digestibility, or performance of growing Nellore heifers and steers. For chapters 4 and 5, data from another experiment (experiment III) was collected and added to the data of the experiment described in the third chapter (experiment II) in order to estimate the net requirements for maintenance and growth as well as the retention coefficients of 13 minerals (macro elements: Ca, P, Mg, K, Na, and S; and trace elements: Co, Cr, Cu, Fe, Mn, Se, and Zn) for Nellore cattle. The description of experiment II can be seen in the third chapter, while 37 Nellore bulls were used in experiment III. Bulls were divided into 3 groups: 1) baseline reference animals (n = 5), 2) animals fed at maintenance (MAIN, n = 4), and 3) animals with ad libitum access to feed (ADLIB, n = 28). The 28 ADLIB plus 4 MAIN animals were slaughtered at 4 different points (42, 84, 126, and 168 d, n = 8 – 7 ADLIB plus one MAIN/time point). The net requirements for maintenance and the retention coefficient were estimated by using the apparent absorption and retention data, as well as by using body composition. Equations were developed for each mineral as a function of empty BW by using an exponential model. The net requirements for growth for each mineral was determined based on the derivative of these equations. The net requirement for maintenance and the retention coefficients were 17.0 g/kg BW/d and 61% for Ca, 16.4 mg/kg BW/d and 82% for P, 33.0 mg/kg BW/d and 70% for K, 17.2 mg/kg BW/d and 98% for Mg, 8.5 mg/kg BW/d and 58% for Na, 2.5 mg/kg BW/d and 21% for S, 3.00 μg/kg BW/d and 16% for Cr, 1.30 μg/kg BW/d and 50% for Co, 0.03 μg/kg BW/d and 2% for Cu, 1,626 μg/kg BW/d and 43% for Fe, 14.2 μg/kg BW/d and 0.4% for Mn, 0.3 μg/kg BW/d and 15% for Se, and 280 μg/kg BW/d and 6% for Zn. Under the conditions of these experiments, the equations that were generated indicate that for a 300 kg Nellore cattle with 1.00 kg of ADG, the dietary requirements are 23.3 g/d for Ca, 15.4 g/d for P, 16.7 g/d for K, 5.59 g/d for Mg, 6.52 g/d for Na, 25.5 g/d for S, 48.9 mg/d for Cr, 26 mg/d for Co, 385 mg/d for Cu, 1,545 mg/d for Fe, 250 mg/d for Mn, 5.26 mg/d for Se, and 378 mg/d for Zn.
Os objetivos do primeiro e segundo capítulos foram estimar equações para predizer produção de leite e consumo de matéria seca de vacas Nelore lactantes e consumo de matéria seca de bezerros Nelore lactentes; e avaliar os efeitos dos dias de lactação no consumo e digestibilidade de nutrientes, desempenho, composição de leite, e eficiência microbiana de vacas Nelore e seus bezerros. No experimento I, quinze vacas Nelore multíparas foram utilizadas e a dieta consistia de silagem de milho e concentrado. O experimento iniciou no dia do parto e o período de lactação foi considerado do dia do parto até 210 dias de lactação. A ordenha foi realizada no sétimo e décimo quinto dia após o parto e novamente a cada 15 dias. Adicionalmente, os bezerros foram alimentados com silagem de milho e concentrado. O consumo dos animais foram medidos diariamente. Ensaios de digestibilidade foram realizados a cada 28 dias; amostras de fezes foram coletadas individualmente durante três dias consecutivos (6h00, 12h00 e 18h00), enquanto que amostras de urina foram coletadas no segundo dia de coleta. O consumo de nutrientes diminuiu (P < 0,01) para vacas enquanto que a digestibilidade dos nutrientes aumentou (P < 0,001) durante o período de lactação. Efeito associativo foi observado entre alimento, consumo de leite e digestibilidade dos nutrientes quando os bezerros começaram a receber concentrado e forragem e isto acontece quando a digestibilidade aparente da dieta não é igual à soma das digestibilidades de cada componente medido separadamente. Vacas apresentaram redução no PC durante os primeiros 28 dias; depois, houve efeito quadrático para ganho de PC. O ganho médio diário dos bezerros aumentou (P < 0,001) durante o período de lactação. Eficiência microbiana (g PB/kg NDT) não alteraram (P > 0,05) nem para vacas Nelore nem para bezerros Nelore durante o período de lactação. A composição do leite de vacas Nelore não altera (P > 0,05) durante a lactação exceto para proteína que varia de 3,57 (Mês 1) para 3,97% (Mês 7). O consumo de vacas Nelore pode ser estimado pela seguinte equação: CMS = 24.78 + 0.035 × SL – 0.009 × SL2, enquanto que a produção de leite (PL) pode ser estimada por PL = 8.761 – 0.0664 × SL. CMS de bezerros pode ser estimado pela seguinte equação: CMS = 0.00289 × exp (exp(-0.5672) × (exp(-0.0773 × SL)-1) / (-0.0773)). Portanto, o consumo de nutrientes diminui para vacas e aumenta para bezerros enquanto que a digestibilidade dos nutrientes para bezerros e aumenta para vacas durante a lactação. Também, um efeito associativo entre leite e alimentos sólidos aumentou a digestibilidade da MS. Vacas Nelore produzem leite com média de 4,58% lactose, 5.61% gordura e a proteína varia de 3.57 para 3.97% de acordo com o período de lactação. Também, nós recomendamos o uso das equações aqui propostas para estimar CMS de vacas Nelore e seus bezerros. Também, a equação para predizer PL é recomendada uma vez que apresentou os melhores resultados para vacas Nelore. O objetivo do terceiro capítulo foi avaliar os efeitos da redução dos níveis de Ca e P na dieta na digestibilidade aparente dos nutrientes, consumo, desempenho, eficiência microbiana e exigências de energia e proteína para machos castrados e fêmeas Nelore em crescimento. No experimento II, cinquenta animais foram utilizados sendo 32 fêmeas Nelore e 18 machos castrados Nelore. Quatro animais de cada sexo foram usados como referência e foram abatidos no início do experimento. Quatro animais fde cada sexo foram alimentados ao nível da mantença recebendo 11 g/kg PC, enquanto que 10 machos castrados e 24 fêmeas foram designados ao grupo ad libiltum. As fêmeas alimentadas ad libitum foram posteriormente divididas em 4 grupos de acordo com os seguintes tratamentos: 1) Ca e P alimentados às exigências propostas (CaPR) e relação volumoso:concentrado (V:C) de 50:50, 2) CaPR e V:C de 70:30, 3) 43% das exigências para Ca e 80% para P (CaPL) e V:C de 50:50, e 4) CaPL e V:C de 70:30. Os machos castrados alimentados ad libitum e ao nível de mantença foram alimentados com CaPR e V:C de 50:50. Metade dos animais alimentados ad libitum foram abatidos aos 50 dias enquanto que os restantes foram abatidos após 100 dias do período de alimentação. Todos os animais alimentados ao nível de mantença foram abatidos aos 100 dias. Coletas totais de fezes e urina foram coletadas de todos os animais por 72 horas antes do abate. Após o abate, o PCVZ foi medido. As exigências de ELm e EMm foram estimadas exponencialmente relacionando produção de calor e consumo de energia metabolizável; ELg foi estimada baseada no PCVZ e GPCVZ. A PLg foi estimada com base no GPCVZ e ER. A digestibilidade da matéria seca e a absorção e retenção aparente de Ca e P foram similares entre os tratamentos. Peso corporal final e consequentemente GMD foram maiores (P < 0.05) para novilhas recebendo dietas com alto concentrado quando comparado à dieta com mais baixo concentrado, porém a concentração dietética de Ca e P não afetaram (P > 0.05) desempenho. A ELm e EMm foram 70.1 e 118 kcal/kg PCVZ0.75, respectivamente. Proteína líquida para mantença foi 1.28 g/kg PC0.75 e ELg e PLg foram estimadas pelas seguintes equações: ELg = 0.053 × PCVZ0.75 × GPCVZ0.6301 e PLg = 137.85 × GPCVZ – 0.05 × ER, respectivamente. Sob as condições deste experimento, a redução as concentrações de Ca e P não apresentam impacto no consumo, digestibilidade ou desempenho de novilhas e machos castrados Nelore. Para o capítulo 4 e 5, dados de outro experimento (experimento III) foram coletados e adicionados aos dados provenientes do experimento II para estimar as exigências líquidas para mantença e ganho bem como o coeficiente de retenção de 13 minerais (macro: Ca, P, Mg, K, Na, e S; e micro: Co, Cr, Cu, Fe, Mn, Se, e Zn) para bovinos de corte. A descrição do experimento II pode ser visualizada no terceiro capítulo enquanto que 37 machos Nelore não castrados foram utilizados no experimento III. Os animais foram divididos em 3 grupos: 1) referência (n = 5), 2) animais alimentados aos nível de mantença (MAIN, n = 4), and 3) animais com livre acesso à alimentação (ADLIB, n = 28). Os 28 ADLIB mais 4 MAIN foram abatidos em 4 tempos diferentes (42, 84, 126, e 168 dias, n = 8 – 7 ADLIB mais um MAIN por tempo). As exigências líquidas para mantença e o coeficientes de retenção foram estimados utilizando absorção aparente e dados de retenção. Equações foram desenvolvidas para cada mineral em função PCVZ utilizado o modelo exponencial. As exigências líquidas para ganho de cada mineral foram determinadas baseada na derivada destas equações. As exigências líquidas para mantença e os coeficientes de retenção foram 17.0 mg/kg PC/d e 61% para Ca, 16.4 mg/kg PC/d and 82% para P, 33.0 mg/kg PC/d e 70% para K, 17.2 mg/kg PC/d e 98% para Mg, 8.5 mg/kg PC/d e 58% para Na, 2.5 mg/kg PC/d e 21% para S, 3.00 μg/kg PC/d e 16% para Cr, 1.30 μg/kg PC/d e 50% para Co, 0.03 μg/kg PC/d e 2% para Cu, 1,626 μg/kg PC/d e 43% para Fe, 14.2 μg/kg PC/d e 0.4% para Mn, 0.3 μg/kg PC/d e 15% para Se, and 280 μg/kg PC/d e 6% para Zn. Sob as condições destes experimentos, as equações geradas indicam que para um bovino com 300 kg de PC e 1,0 kg de GMD, as exigências dietéticas são 23.3 g/d para Ca, 15.4 g/d para P, 16.7 g/d para K, 5.59 g/d para Mg, 6.52 g/d para Na, 25.5 g/d para S, 48.9 mg/d para Cr, 26 mg/d para Co, 385 mg/d para Cu, 1,545 mg/d para Fe, 250 mg/d para Mn, 5.26 mg/d para Se, e 378 mg/d para Zn.

Resumo: Conhecer o comportamento dos bubalinos é importante para estabelecer práticas de manejo que favoreçam o bem-estar e bom desempenho produtivo. Com os objetivos de descrever o comportamento de búfalos nas primeiras horas após o parto e investigar as causas de falhas na primeira mamada, foram observadas 42 búfalas e seus bezerros, em três propriedades produtoras de leite. Os registros foram realizados nas primeiras horas após o parto, utilizando-se amostragem focal e coleta contínua em partos ocorridos de agosto de 2007 a novembro de 2008. As variáveis consideradas para búfalas foram: Tempo deitada (TD); Tempo de contato com a cria (TCC); Tempo de contato com a cria nos primeiros 30 min. (TCC30), Tempo em outras atividades (TOA) e Tempo sem atividade aparente (TSAA). Para os bezerros: Latências para ficar em pé (LP), para tentar mamar (LTM) e para mamar (LM). Bezerros filhos de búfalas com problemas no aparelho mamário tiveram dificuldade em obter o colostro. Nos partos com falha na mamada as mães passaram mais tempo deitadas, sem atividade aparente e cuidaram menos do bezerro (TCC30). A latência do bezerro para ficar em pé afetou TD da mãe. As búfalas primíparas dedicaram-se menos ao bezerro nos primeiros 30 min. que as de duas ou mais crias. A interferência de outras búfalas (INTERF30) diminuiu o tempo que a mãe cuidou da cria (TCC30) nos primeiros 30 min. As variáveis LTM e LM tiveram efeito de TCC30. Sugere-se o cuidado no manejo de búfalas primíparas e de úberes pendulosos e/ou tetos grossos e compridos. O ambiente necessita ser mais estudado a fim de que sejam diminuídas a interferências de outras búfalas no relacionamento búfala-bezerro.
Abstract: Knowing the bubalines behavior is important to stablish management practics in impruve the welfare as well the productive performance. Aiming describe bufaloes behavior at the first hours after birth and investigate causes of first suckling missing, 42 female bufaloes in conjunction with its calves were observed in three dairy farms. Registers were done at the first hours after birth, using a focal and continuous sampling colecting in births happened from August 2007 to November 2008. The variables considered to the bufaloes were: Laytime (LT); Calves' Time Contact (CTC); Calves' Time Contact at the 30-first minutes (CTC30); Time in Other Activities (TOA) and Time in Apparent Leisure (TAL). To the calves: Stand up Latency (SL), to Try suckling (TSL) and to suckling (SL). Calves which mother had mamal aparel problems had difficulty in obtain the colostrum. In missedsuckling births mothers spent higher time laid, with apparent leisure and took care less of their calves (CTC30). The calf latency to stand up affected mother's LT. The primipare buffaloes took less care to their calves in the firsts 30 minutes than the multiparous. The other buffaloes interference (INTERF30) minimize the CTC30. The TSL and SL had the CTC30's effect. It is suggested the primipare buffaloes and pendant udders and/or thick and long teats require carefull manegement. The environment needs more studies in order to minimize the other buffaloes interference in the buffalo-calf relationship.
Orientador: Humberto Tonhati
Coorientadora: Luciandra Macedo de Toledo
Banca: Evaldo Antonio Lencione Titto
Banca: Mateus José Rodrigues Paranhos da Costa
Mestre

Undernutrition and suckling effects on reproductive performance in cattle were investigated. It was therefore, the aim of this study to (1) evaluate reproductive parameters that were to be used in assessing reproductive function in heifers and postpartum cows; (2) to assess the effect of undernutrition and realimentation on ovulation and ovarian cyclicity in beef heifers; (3) to assess the effect of suckling intensity alone or in combination with undernutrition and the time postpartum in delaying reinitiation of ovulation in lactating beef cows. The results of this experiment showed that following the reduction in feed intake to half maintenance requirements there were four different types of changes in ovarian cyclicity recorded in the ten heifers. Group 1. Three heifers (No.1, 2 & 3) became acyclic without going through an oestrous cycle. Group 2. Four heifers (No. 4, 5, 6 & 7) went through one normal oestrous cycle each before becoming acyclic. Group 3. One heifer (No. 8) underwent two normal oestrous cycles before becoming acyclic. Group 4. Two heifers (No 9 & 10) continued to cycle without becoming acyclic. One of these two heifers (No. 9) had four short oestrous cycles of 8, 9, 11 and 11 days while No. 10 had three short oestrous cycles of 10, 12 and 12 days. During nutritional acyclicity there were no increases in LH concentration over the basal concentration following naloxone challenge irrespective of the dose used. During undernutrition, one heifer (No. 8) failed to exhibit an oestradiol-induced LH surge while the two heifers (NO. 9 & 10) exhibited a oestradiol-induced LH surge. There were no LH surges following PRID withdrawal in nutritionally acyclic heifers.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Conhecer o comportamento dos bubalinos é importante para estabelecer práticas de manejo que favoreçam o bem-estar e bom desempenho produtivo. Com os objetivos de descrever o comportamento de búfalos nas primeiras horas após o parto e investigar as causas de falhas na primeira mamada, foram observadas 42 búfalas e seus bezerros, em três propriedades produtoras de leite. Os registros foram realizados nas primeiras horas após o parto, utilizando-se amostragem focal e coleta contínua em partos ocorridos de agosto de 2007 a novembro de 2008. As variáveis consideradas para búfalas foram: Tempo deitada (TD); Tempo de contato com a cria (TCC); Tempo de contato com a cria nos primeiros 30 min. (TCC30), Tempo em outras atividades (TOA) e Tempo sem atividade aparente (TSAA). Para os bezerros: Latências para ficar em pé (LP), para tentar mamar (LTM) e para mamar (LM). Bezerros filhos de búfalas com problemas no aparelho mamário tiveram dificuldade em obter o colostro. Nos partos com falha na mamada as mães passaram mais tempo deitadas, sem atividade aparente e cuidaram menos do bezerro (TCC30). A latência do bezerro para ficar em pé afetou TD da mãe. As búfalas primíparas dedicaram-se menos ao bezerro nos primeiros 30 min. que as de duas ou mais crias. A interferência de outras búfalas (INTERF30) diminuiu o tempo que a mãe cuidou da cria (TCC30) nos primeiros 30 min. As variáveis LTM e LM tiveram efeito de TCC30. Sugere-se o cuidado no manejo de búfalas primíparas e de úberes pendulosos e/ou tetos grossos e compridos. O ambiente necessita ser mais estudado a fim de que sejam diminuídas a interferências de outras búfalas no relacionamento búfala-bezerro.
Knowing the bubalines behavior is important to stablish management practics in impruve the welfare as well the productive performance. Aiming describe bufaloes behavior at the first hours after birth and investigate causes of first suckling missing, 42 female bufaloes in conjunction with its calves were observed in three dairy farms. Registers were done at the first hours after birth, using a focal and continuous sampling colecting in births happened from August 2007 to November 2008. The variables considered to the bufaloes were: Laytime (LT); Calves’ Time Contact (CTC); Calves’ Time Contact at the 30-first minutes (CTC30); Time in Other Activities (TOA) and Time in Apparent Leisure (TAL). To the calves: Stand up Latency (SL), to Try suckling (TSL) and to suckling (SL). Calves which mother had mamal aparel problems had difficulty in obtain the colostrum. In missedsuckling births mothers spent higher time laid, with apparent leisure and took care less of their calves (CTC30). The calf latency to stand up affected mother’s LT. The primipare buffaloes took less care to their calves in the firsts 30 minutes than the multiparous. The other buffaloes interference (INTERF30) minimize the CTC30. The TSL and SL had the CTC30’s effect. It is suggested the primipare buffaloes and pendant udders and/or thick and long teats require carefull manegement. The environment needs more studies in order to minimize the other buffaloes interference in the buffalo-calf relationship.

Das Ziel der vorliegenden Studie war die Untersuchung der Effekte einer automatischen ad libitum Beifütterung von Milchaustauscher zusätzlich zur Sauenmilch in der Abferkelbucht auf den Gewichtszuwachs, die Verlustrate und die Notwendigkeit medikamentöser Behandlungen der Saugferkel. Zudem wurde der Einfluss der Ersatzmilch auf die Körperkondition der Sauen analysiert. Desweiteren wurde untersucht, ob ein Einfluss auf medikamentöse Behandlungen der Sauen, die Gesäugegesundheit und das Bakterienspektrum der Sauenmilch gegeben ist. Außerdem sollten Aussagen zum hygienischen Status des Milchtassensystems und der angeschlossenen Rohrleitungen und Behälter getroffen werden.

Demands are placed on cattle producers to provide a steady supply of beef at a competitive price. Producers must maximize beef output while minimizing input expenses without compromising product quality. The use of growth implants has become a common practice among cattle producers. The objective of this study was to evaluate the effects of two implant strategies on the average daily gain of suckling calves rotationally grazed on Kentucky – 31 endophyte-infected tall fescue and Kentucky – 31 non-endophyte-infected tall fescue. Eighteen cows with spring calves (N = 18) were used in this study. Calves were grouped by birth date into four blocks. Within each block, calves were stratified by sex and 45d of age body weight into three implant treatment groups for a total of six calves per treatment (n = 6, control 90.3 ± 9.7 kg, zeranol 102.9 ± 10.9 kg, and progesterone (100 mg) and estradiol benzoate (10 mg) 92.4 ± 10.3 kg). Calves were weighed and re-implanted at 129 d of age (84 d after initial implant). Zeranol treated calves were re-implanted using the same implant as the initial implant. Progesterone and estradiol benzoate treated calves were re-implanted after reaching a minimum body weight of 181 kg with either 200 mg progesterone and 20 mg estradiol benzoate or 200 mg testosterone propionate and 20 mg estradiol benzoate depending on sex. Data were analyzed using the REPEATED function in the MIXED procedure of SAS. No interactions were found among sex and treatments for 84d weight gains and 140d weights. There were also no main effects found for 84d weight gains and 140d weight gains. Forage analysis suggested that low crude protein and energy content may have contributed to the low ADG. Low endophyte concentrations may also have played a role.

Orientador: Francisco Stefano Wechsler
Banca: André Mendes Jorge
Banca: Ciniro Costa
Banca: Deiler S. Costa
Banca: Valter J. Onsellen
Resumo: O objetivo desta pesquisa foi avaliar a influência do grupo genético do bezerro no comportamento de mães e suas crias. Usaram-se 24 vacas Nelore paridas e seus bezerros, dos quais oito eram Nelores, oito ½Simental ½Nelore, e oito ½Red Angus ½Nelore. Avaliaram-se as medidas de freqüência e duração das mamadas, tempo de pastejo e ruminação dos bezerros e vacas. Os bezerros puros mamaram mais freqüentemente que os mestiços (3,51 vs. 3,17 vezes/dia), porém com menor duração de mamada (7,37 vs 7,80 minutos). A freqüência de mamadas, duração de cada mamada e tempo total de mamadas diminuíram com o aumento na idade do bezerro. Nos bezerros, pastejo e ruminação aumentaram com a idade; porém, nas vacas, aumentou o tempo de pastejo e diminuiu o de ruminação com o passar dos dias. Os bezerros mestiços pastaram, em média, 18 minutos a mais que os puros, e os machos, 16 minutos a mais que as fêmeas. Os bezerros machos ruminaram, aos 40 dias de idade, 25 minutos a mais que as fêmeas, mas esta diferença diminuiu com a idade e desapareceu por volta dos 220 dias. As mães de mestiços ruminaram, em média, 10 minutos a mais que as mães dos puros. O comportamento da mãe e de sua cria é influenciado pelo grupo genético desta última.
Abstract: The objective was to evaluate the effect of a calf's genetic group on the behavior of dam and calf. We used 24 Nellore dams and their calves, of which eight were Nellore, eight were ½Simmental ½Nelore and eight ½Red Angus ½Nellore. Grazing and rumination times, as well as suckling frequency and time, were measured. The straightbred calves suckled more often than the crossbreds (3.51 vs. 3.17 times/day), but their suckling lasted less time (7.37 vs 7.80 minutes). Suckling frequency, suckling length and total time spent suckling decreased as calf age increased. Calf grazing and rumination time increased with age; however, the cows' grazing time increased and rumination time decreased as the days postpartum went by. The crossbred calves grazed, on the average, 18 minutes longer than the crossbreds, and the males grazed 16 minutes longer than the females. The male calves grazed, at 40 days of age, 25 minutes longer than the females, but this difference decreased as they grew up and disappeared around 220 days. The dams of crossbreds ruminated, on the average, 10 minutes longer than the dams of straightbreds. In conclusion, dam and calf behavior are influenced by the calf's genetic group.
Doutor

The study discusses the role of a wet nurse regarding the protection of a child in ancient Egypt. There is evidence of the phenomenon of the wet nurse dating from the Old Kingdom’s Pyramid texts, depictions in tombs from the New kingdom, to contracts between the wet nurse and her employer from the Late Period. They were most frequent in royal and elite families and made it possible for the mother to participate in social activities without worrying about feeding her baby, as well as being a symbol for economic wealth.  Wet nurses have been found depicted in funerary contexts, holding ritual protective objects, and been mentioned in protective spells targeted towards children. This shows that the wet nurse had a part in the protection of a child and the intention behind this study is to discuss her participation in it and what it involves. The sources used in this study are to contain two subjects to be of relevance: wet nurse and the protection of a child, which lead to a restricted amount of material to analyse. The material studied contains of amulets, serpent staffs, three apotropaic wands, depictions from two graves and one protective spell. The analysis resulted in a conclusion claiming that the practice of protection is a part of the wet nurse’s occupation and were practiced with at least an apotropaic wand. Moreover, the depiction of her holding apotropaic wands in funerary contexts representing rebirth shows that the wet nurse is present and offering protection in the events of a child’s birth.

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The objective of this work was to test the effect of the presence or absence of the calf in the activities of estrous, follicular dynamics and hormone secretion of Bos indicus cows. Forty and six cows were divided in 3 groups. In group with contact (CC), the calves were prevented from suckling by being confined into a pen, that allowed auditory, olfactory and visual contact of the cows with their own calves (n=17). In group without contact (SC), the calves were weaned and prevented from any contact. In control group (T), the calves weren t weaned, remaining with their mothers (n=12). The CC group showed greater ratio of cows in estrous (76.5%) when compared to T (16.7%), but no difference from SC (64.7%). The CC group showed greater ratio of ovulation (76.5%) when compared to T (33.3%) and an apparent difference (p=0.06) when compared to SC (64.7%). The duration of estrous was lesser (p = 0.04) in group CC (8.4 h + 4.4 h) than the SC (12.9 + 13.4 h), however the group T (11 + 1.4 h) was not different from the others. The average interval between weaning and onset of estrus (35 + 6.3 h), weaning and end of estrus (44.4 + 5.4 h), intensity of estrus behavior (26.6 + 24 mounts), weaning and time of ovulation (70 + 12.7 h), onset of estrus and time of ovulation (33.3 + 9.3 h) and the end of estrus and time of ovulation (23.3 + 10.3 h) were not observed differences.The T group achieved 48 + 8.4 h of interval between weaning and the LH peak while in the weaned groups (CC and SC) the average interval was of 45.3 + 10.4 h, showing no differences between the CC group (42.5 + 8.2 h) and the SC (47.5 + 11.8 h). The interval between the peak of LH and the time of the ovulation presented a general average of 24.8 + 7.7 h, showing no differences between the groups T (25.5 + 5.7 h), CC (24.9 + 8 h) and SC (24.5 + 8.6 h). It was found that the contact between cow and calf during weaning was not different from that of the cows without any contact and there was no advantage in restricting contact between cow and calf. It was confirmed that weaning has a beneficial effect on the percentage of estrous and ovulation when compared to cows not weaned.
O objetivo deste trabalho foi estudar o efeito da presença ou ausência do terneiro nas atividades de estro, dinâmica folicular e níveis hormonais em vacas de origem Bos indicus. Quarenta e seis vacas foram divididas em 3 grupos. No grupo com contato (CC), os terneiros foram desmamados e impedidos de mamar, mas mantidos em um curral, o qual permitia contato auditivo, olfativo e visual das vacas com sua cria (n=17). No grupo sem contato (SC), os terneiros foram desmamados e impedidos de qualquer contato (n= 17). No grupo T (n=12), as crias não foram desmamadas, permanecendo juntas às suas mães, constituindo o grupo testemunha. O grupo CC (76,5%) apresentou maior proporção de vacas em estro quando comparado ao T (16,7%), mas não diferente do SC (64,7%). O grupo CC possui maior porcentagem de vacas ovuladas (76,5%) quando comparado ao T (33,3%) e uma diferença aparente (p=0,06) quando comparado ao SC (64,7%). A duração do estro foi menor (p = 0,04) no grupo CC (8,4 h + 4,4 h) quando comparado ao SC (12,9 + 13,4 h). O intervalo entre o desmame e o início do estro (35 + 6,3 h), o desmame e o final do estro (44,4 + 5,4 h), a intensidade do estro (26,6 + 24 montas), o desmame e a ovulação (70 + 12,7 h), o início do estro e a ovulação (33,3 + 9,3 h) e o final do estro e a ovulação (23,3 + 10,3 h) não foram diferentes entre os tratamentos. As vacas do grupo T obtiveram 48 + 8,4 h de intervalo entre o desmame e o pico de LH enquanto que nos grupos desmamados (CC e SC) o intervalo médio foi de 45,3 + 10,4 h, não havendo diferença entre as vacas do grupo CC (42,5 + 8,2 h) e SC (47,5 + 11,8 h). O intervalo entre o pico de LH e o momento da ovulação apresentou uma média geral de 24,8 + 7,7 h, não havendo diferença entre os grupos T (25,5 + 5,7 h), CC (24,9 + 8 h) e SC (24,5 + 8,6 h). Verificou-se que o contato da vaca com a cria durante o desmame não foi diferente das vacas sem contato algum e não houve vantagem em restringir o contato da mãe com sua cria. Ficou confirmado que o desmame exerce um efeito benéfico na porcentagem de estro e ovulação quando comparado a vacas não desmamadas.