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BackgroundNutrition is one of the most important factors that affect animal performance, and it therefore also impacts on financial results in beef systems. In this way, finding the best strategy for feeding supplements is of paramount importance. Aiming to evaluate the effect of supplement feeding strategies for beef cows in the last third of gestation, two experiments were conducted. In Experiment 1, 35 pregnant Nellore cows were assigned to a completely randomized design with four treatments: control, which received no supplement; supplementation for the last 30 d of gestation (30-d; 3.0 kg/d); supplementation for the last 60 d of gestation (60-d; 1.5 kg/d); or supplementation for the last 90 d of gestation (90-d; 1.0 kg/d). All supplemented treatments received the same total amount of supplement throughout the experiment: 90 kg (20% of crude protein). A second experiment (Experiment 2) was delineated to evaluate the effects of the amounts offered in Experiment 1 on intake and metabolism. Four multiparous pregnant Nellore cows were assigned to a 4 × 4 Latin square design, with periods of 15 d each.ResultsThere was a linear effect of the number of days of supplementation on calving body weight (BW; P < 0.05) and a quadratic effect on BW change from parturition to d 31 post-calving (P < 0.05), with cows on the 60-d strategy losing less BW post-calving. No difference was found in offspring birth BW (P > 0.10). A significant linear effect on interval from parturition to conception (P < 0.05) was observed, with the highest calving to conception interval being observed in the 90-d strategy. The level of supplementation did not affect forage intake or neutral detergent fiber digestibility (P > 0.10). Nitrogen excreted through urine tended to increase linearly with the level of supplementation (P < 0.10).ConclusionProviding 1.5 kg of supplement during the last 60 d of gestation improves cow performance after calving, reducing the magnitude of BW lost, and reduces the number of days from calving to re-conception in the following breeding season compared to the usually recommended period of supplementation of 90 d pre-partum.

The objective of the present study was to evaluate the endocrine and behavioral features of estrous-induced Alpine goats. A total of 36 nulliparous, 40 non-lactating and 42 lactating does were treated with intravaginal 60 mg medroxyprogesterone acetate sponges for 9 d plus 200 IU eCG and 22.5 microg d-cloprostenol 24 h before sponge removal. Plasma progesterone concentration was analyzed from blood sampled on days 0 (sponge insertion), 5, 8 (cloprostenol administration) and 9 (sponge removal) in 11 nulliparous, 13 non-lactating and 11 lactating does. Estrous response did not differ (P>0.05) among nulliparous (97.2%), non-lactating (90.00%) and lactating does (85.7%). Interval to estrus and duration of estrus did not differ (P>0.05) among nulliparous (22.8+/-9.9 and 25.6+/-6.8h), non-lactating (23.7+/-15.8 and 25.0+/-6.0 h) and lactating does (22.2+/-10.4 and 24.9+/-4.2h). The accumulative percentage of does in estrus during the first 36 h after sponge removal was 88.1%. The correlation between interval to estrus and duration of estrus was r=-0.32 (P<0.001). Endogenous progesterone production is decreased until day 8 or suppressed by MAP on day 9. Conception rate was greater (P<0.01) in lactating (77.8%) than non-lactating (44.4%) but similar (P>0.05) to nulliparous (60.0%) goats. Estrus can be efficiently induced by means of hormonal treatment in goats and acceptable fertility can be obtained regardless of animal category.

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RESUMO -Objetivou-se avaliar a influência da condição corporal ao parto sobre os parâmetros produtivos de cabras Alpinas no início da lactação. Sessenta e oito cabras foram distribuídas em três grupos, de acordo com o escore de condição corporal (baixo, entre 1,00 e 2,75; intermediário, entre 2,75 e 3,50; e alto, entre 3,50 e 5,00) e avaliadas do parto até a oitava semana de lactação. Realizaram-se o controle diário do consumo alimentar e da produção leiteira e avaliações semanais de peso corporal, escore da condição corporal e composição do leite. Os animais com escore corporal alto apresentaram menor consumo de matéria seca, fibra em detergente neutro e proteína bruta em comparação àqueles com escores corporais baixo e intermediário. O período médio de recuperação do consumo de matéria seca dos animais das três condições corporais foi de 16 dias (2,3 semanas) do pós-parto, com estabilização até o final do experimento. Na sexta semana de lactação, o peso corporal dos animais com escore corporal baixo se igualou ao daqueles com escore corporal intermediário. Não houve efeito da condição corporal ao parto nas variações de ECC e da produção leiteira ao longo do período. O teor de gordura do leite dos animais com escore corporal alto foi menor nas duas primeiras semanas pós-parto em comparação ao dos animais com escores corporais baixo e intermediário. Elevada condição corporal ao parto influencia negativamente o consumo voluntário de cabras leiteiras no início da lactação, mas quando se utiliza dieta de alta qualidade e com altos níveis de energia, a influência da condição corporal ao parto inexiste para variações de peso, de escore da condição corporal e produção leiteira dos animais.Palavras-chave: consumo, pós-parto, produção leiteira Body condition and productive performance of Alpine goat in early lactationABSTRACT -The objective of this study was to evaluate the influence of body condition at birth on Alpine goat productive parameters in early lactation. Sixty-eight females were assigned to three groups according to the body condition score (BCS) -low (1.00 -2.75); intermediate (2.75 -3.50) and high (3.50 -5.00) and evaluated from kidding to the eighth week of lactation. The feed intake and milk production were recorded on a daily basis and the body weight, body condition score and milk composition at weekly intervals. Animals with a high body condition score presented lower dry matter intake, neutral detergent fiber and crude protein compared to those with low and intermediate body condition scores. The average time for dry matter intake recovery of the animals with the three body condition scores was 16 days (2.3 weeks) postpartum, and stabilization by the end of the experiment. In the sixth week of lactation, animals with low body condition score had the same body weight of animals with intermediate body condition score. There was no effect of the body condition at birth on the body condition score changes and milk production during the experiment. The milk fat content of animals with high body condition ...

The present study was conducted to evaluate the effects of high and low supplementation levels pre- and post-weaning on performance, endocrine, metabolic, and reproductive responses of Nellore heifers. Fifty Nellore heifers with 132 ± 9.9 kg average body weight (BW) and 138 ± 19 days of age were supplemented from 4 to 14 months. The heifers were distributed into five supplementation plans: HH-6 g/kg of BW of supplement pre- and post-weaning, HL-6 g/kg of BW of supplement pre-weaning and 3 g/kg post-weaning, LH-3 g/kg of BW pre-weaning and 6 g/kg of BW post-weaning, LL-3 g/kg of BW pre- and post-weaning, and CC-control, no supplementation. Interactions were not significant (P > 0.10). The level of supplement fed pre-weaning did not affect any of the performance variables evaluated at the end of the experiment (P > 0.10). There was a significant effect of supplementation and level of supplementation fed post-weaning on average daily gain (ADG) and final BW (P < 0.05). Overall ADG was also affected only by supplementation and level of supplement fed post-weaning (P < 0.05) with animals receiving 6 g/kg of BW post-weaning gaining more weight. Follicular diameter was greater in animals that received 6 g/kg of BW post-weaning (P < 0.05). In summary, performance, endocrine, metabolic, and reproductive variables evaluated in the current study were improved by the level of supplement fed post-weaning. Heifers receiving supplementation of 6 g/kg of BW post-weaning had greater responses, independent of the level received during the pre-weaning phase.

Este artigo foi recebido em 4/7/2007 e aprovado em 6/11/2008 respectivamente, e os valores de BHBA ao parto, de 10,31 ± 3,0 mg/dL para os animais magros; 6,88 ± 0,9 mg/dL para os intermediários; e 4,21 ± 0,8 mg/dL para os animais gordos. Os valores de glicose ao parto foram de 112,54 ± 15,4 mg/dL para os animais magros; 90,93 ± 13,5 mg/dL para os animais intermediários; e 132,47 ± 26,7 mg/dL para os animais gordos.Os valores médios de colesterol total e de HDL nas oito primeiras semanas pós-parto foram de 109,01 ± 2,5 e 54,9 ± 1,39 mg/dL para os animais magros; 83,0 ± 21,7 e 56,0 ± 1,30 mg/dL para os intermediários; e 84,3 23,9 e 54,5 ± 1,93 mg/dL para os gordos. As alterações no metabolismo energético de cabras leiteiras de média produção diminuem, independentemente da condição corporal ao parto, quando fornecida dieta de alta qualidade e com altos níveis de energia.Palavras-chave: caprino, condição corporal, perfil metabólico, pós-parto Body condition and metabolic profile of Alpine goats at the onset of lactationABSTRACT -An experiment was carried out to study the influence of the body condition score at birth on blood metabolites of goats in early lactation. Sixty-eight goats were placed in three groups according to the body condition score (BCS) at parturition: from 1.00 to 2.75 (thin animals); 2.75 and 3.50 (intermediate body condition) and from 3.50 to 5.00(fat animals). The experimental was carried out in the first sixty days of lactation and blood sampling started after parturition at weekly intervals up to the eighth week of lactation. Analyses were made of the non-esterified fat acids (NEFA), betahydroxibutirate (BHBA), glucose, total cholesterol and high density lipoprotein (HDL). The plasma concentrations of the metabolites did not differ among the groups. The NEFA concentrations in the animals in the three groups at birth and in the first eight weeks of lactation were 658.46 and 232.90 mg/dL, respectively and the values of BHBA at birth were 10.31 ± 3.0 mg/dL for the thin animals, 6.88 ± 0.9 mg/dL for the intermediate animals and 4.21 ± 0.8 mg/dL for the fat animals.The glucose values at birth were 112.54 ± 15.4 mg/dL for the thin animals, 90.93 ± 13.5 mg/dL for the intermediate animals and 132.47 ± 26.7 mg/dL for the fat animals. The average of total cholesterol and HDL in the first eight weeks after birth were 109.01 ± 2.5; and 54.9 ± 1.39 mg/dL for the thin animals, 83.0 ± 21.7 and 56.0 ± 1.30 mg/dL for the intermediate animals and 84.3 ± 23.9 and 54.5 ± 1.93 mg/dL for the fat animals. The changes in the energy metabolism of dairy goats with medium production decreased, regardless of the body condition at birth, when supplied with high quality feed with high energy levels.

-To evaluate the effect of using urea in the diet on ovarian follicular dynamics and plasma urea and progesterone concentration, an experiment was carried out with 29 Alpine goats randomly distributed into four diets, each one containing 0%; 0.73%; 1.46% or 2.24% of urea on total dry matter. The follicular dynamics was monitored daily by ultrasonography. The estrous cycles were characterized by occurrence of two, three, four or five follicular waves. The emergence day of the first follicular wave in cycles with two waves, the length of the third wave and the maximum diameter of the largest follicle of the third wave in cycles with three waves presented a quadratic behavior according to the percentage of urea in the diets. In cycles with four waves, the urea intake did not influence the follicular dynamics. The interestrus and interovulatory periods and the luteal and follicular phases length did not differ among treatments. The plasma urea concentration did not differ among diets neither among collection weeks. Plasma progesterone concentration on the estrus day and on the 11 th day after estrus presented quadratic behavior, and on the 15 th day after estrus, it linearly reduced acording to the percentage of urea in the diets. The supply of urea in diets at levels up to 2.24% in dietary dry matter did not influence the dry matter intake and the urea plasma concentration. For goats, the emergence day and the length of the waves, the follicular diameter and the plasma progesterone concentration on the estrus day and in the latter stages of diestrus were altered when there was supply of urea in the diet.