ABSTRACT The objective of this study was to evaluate milk production and ingestive behavior of Holstein cows and the structural characteristics of Mulato II, a hybrid Brachiaria grass CIAT 36087 (B. ruziziensis × B. decumbens × B. brizantha), and Marandu (Brachiaria brizantha cv. Marandu) pastures under rotational stocking. The experiment was conducted from December 2011 to April 2012 after 10 months of adaptation to the grazing management objectives (25 cm pre-grazing height and 15-20 cm post-grazing height). An area of 4 ha was divided into 28 paddocks: 14 with Mulato II pasture and 14 with Marandu pasture. The treatments consisted of the two grasses and a completely randomized design of the grazing variables with six repetitions each (paddock of evaluation) was used. For the animal variables, a randomized matched pairs design of 20 Holstein cows forming 10 blocks of two animals with similar production each was used. The forage mass or accumulation rate did not differ between grasses. Mulato II pastures had a higher tiller population density (822 tillers m−2) and crude protein content (143.5 g kg−1) than Marandu pastures (636 tillers m−2 and 130.3 g kg−1 crude protein). Cows kept on Mulato II exhibited shorter nighttime grazing activity (234 and 246 min in summer and autumn, respectively) than animals kept on Marandu (273 and 394 min, respectively). The average milk yield during the experimental period was higher for Mulato II (15.3 kg cow−1 day−1) compared with Marandu (14.3 kg cow−1 day−1). Both grasses have potential to be used in milk production systems for the grazing management objectives evaluated.

The objective of the present study was to evaluate the genetic and non-genetic effects that influence vigor at birth and preweaning mortality in Nellore calves. A total of 11,727 records of births that occurred between 1978 and 2006, offspring of 363 sires, were analyzed. Poor calf vigor at birth (VB) and preweaning mortality divided into stillbirth (SB), early mortality (EM) and total mortality (TM) were analyzed as binary variables. Generalized linear models were used for the evaluation of non-genetic effects and generalized linear mixed models for genetic effects (sire and animal models). The incidences were 4.75% for VB, 2.66% for SB, 5.28% for EM, and 7.99% for TM. Birth weight was the effect that most influenced the traits studied. Calves weighing less than 22 kg (females) and less than 24 kg (males) were at a higher risk of low vigor and preweaning mortality. Preweaning mortality was higher among calves born from cows aged <3 and >11 years at calving compared with cows aged 7 to 10 years. Male calves presented less vigor and higher preweaning mortality than female calves. Selection for postweaning weight did not influence preweaning mortality. The heritability estimates ranged between 0.01 and 0.09 for VB, 0.00 and 0.27 for SB, 0.03 and 0.17 for EM and 0.02 and 0.10 for TM. Stillbirth should be included as a selection criterion in breeding programs of Nellore cattle, alone or as part of a selection index, aiming to reduce preweaning mortality.

Objetivou-se avaliar o efeito da inclusão de aditivos químicos na ensilagem de resíduos (entrecasca) da produção de palmito pupunha (Bactris gasipaes, Kunth). Utilizaram-se silos experimentais (baldes de 20 litros) providos de aparatos para determinação gravimétrica de perdas por gases e efluentes. Os tratamentos aplicados foram: controle (sem aditivos); ureia (1% da MV) e cal virgem (1% da MV). Decorridos 70 dias de armazenagem, os silos foram pesados, abertos e amostrados. As perdas por efluentes e gases aumentaram com a aplicação de cal virgem na ensilagem. As perdas totais de MS foram de 15,1; 14,4 e 26,6% nas silagens controle, ureia e cal, respectivamente. Em todas as silagens, houve redução no teor de FDN e elevação da fração FDA, o que indica desaparecimento da fração hemicelulose. A relação cálcio:fósforo aumentou substancialmente com a adição de cal virgem, de 4,1:1 na silagem controle para 15,6:1 na silagem com cal. O resíduo da extração do palmito pupunha pode ser classificado como alimento de média qualidade e alto teor de umidade. Os aditivos aplicados na ensilagem não são efetivos em reduzir as perdas fermentativas no processo de conservação.

Feeding animals with agro-residues may reduce costs and environmental concerns. The agroindustrial wastes used as ruminant feeding are an alternative for ambient problems caused by it accumulation. This study aimed to evaluate chemical additives on the ensilage of residues of pupunha palm (Bactris gasipaes, Kunth) production. Experimental silos (20 L buckets) were used equipped with meters to determine gas and effluent DM losses. The experimental treatments were: control (no additives); urea (1% - wet basis) and calcium oxide (1% WB). After 70 days storage, the silos were weighed, opened and sampled. Effluent and gas DM losses increased with the application of calcium oxide at ensiling. Total DM losses were 15.1, 14.4 and 26.6% for the Control, Urea and Calcium oxide treatments, respectively. In all the treatments there was reduction in the NDF and increase in ADF increasing rates, that showed hemicellulose disappearance. The Ca:P ratio increased dramatically after calcium oxide addition, from 4.1:1 to 15.6:1. The residue from pupunha heart of palm extraction can be classified as a medium quality foodstuff with high moisture content. The additive applied at ensiling are not effective in reducing fermentative losses during the conservation process.