Douglas Sampaio Henrique

Padrão Nictemeral do pH Ruminal e Comportamento Alimentar de Cabras Leiteiras Alimentadas com Dietas Contendo Diferentes Relações Volumoso: Concentrado

The objectives of the present study were to characterize nictemeral pattern of ruminal pH and feed behavior of dairy goats fed diets presenting different ratios of roughage:concentrate. Five non pregnant non lactating goats, ruminally cannulated, and averaging 58 kg were used during the five experimental periods. A 5x5 Latin square was used to evaluate five treatments consisted of roughage to concentrate ratio of 100:0, 80:20, 60:40, 40:60 e 20:80. Diets were fed every 6h in order to reduce ruminal pH variation during the 24h period. After adaptation to experimental diets, a 48h period was given to measure ruminal pH hourly for 24h, to be used as a covariate, following a study of feeding behavior where measurement was taken at every 10 minutes for the remaining 24h period. It was observed that increasing level of concentrate resulted in reduction of pH, especially when concentrate accounted for more than 60%. Treatment effect was also observed on time spent eating, ruminating and idling. Time spent eating was greater as percentage of roughage in the diet increased, especially over 60%. Roughage content of 100% presented the highest value of rumination time and the lowest value for idle, following diets containing 80 e 60% respectively. There were no difference between diets containing 40 e 20% roughage, which presented the lowest value for rumination and the highest for idle time.

Estimation of the total efficiency of metabolizable energy utilization for maintenance and growth by cattle in tropical conditions

Data of 320 animals were obtained from eight comparative slaughter studies performed under tropical conditions and used to estimate the total efficiency of utilization of the metabolizable energy intake (MEI), which varied from 77 to 419 kcal kg-0.75d-1. The provided data also contained direct measures of the recovered energy (RE), which allowed calculating the heat production (HE) by difference. The RE was regressed on MEI and deviations from linearity were evaluated by using the F-test. The respective estimates of the fasting heat production and the intercept and the slope that composes the relationship between RE and MEI were 73 kcal kg-0.75d-1, 42 kcal kg-0.75d-1 and 0.37. Hence, the total efficiency was estimated by dividing the net energy for maintenance and growth by the metabolizable energy intake. The estimated total efficiency of the ME utilization and analogous estimates based on the beef cattle NRC model were employed in an additional study to evaluate their predictive powers in terms of the mean square deviations for both temperate and tropical conditions. The two approaches presented similar predictive powers but the proposed one had a 22% lower mean squared deviation even with its more simplified structure.

Dairy goat husbandry amongst the household agriculture: herd and economic indexes from a case study in Rio de Janeiro, Brazil

Dois sistemas de producao de caprinos leiteiros praticados de acordo com o modelo familiar foram avaliados quanto a geracao de renda. Um teste para verificacao de viabilidade economica do empreendimento foi executado utilizando-se dados coletados de agosto de 2004 a julho de 2005. As fazendas, denominadas A e B, eram pequenas propriedades produtoras de cabras Saanem em sistema intensivo. Indices de rebanho, rendas, impostos, combustivel, energia, concentrado, custos de oportunidade e capital de interesse foram computados para estimacao da renda liquida e da taxa de retorno do capital para avaliacao do quanto o negocio pode ser atraente em geracao de renda. Os indices de rebanho foram afetados significativamente pelas decisoes tomadas pelos administradores e interferiram sobre as quantidades e tendencias relacionadas a producao de leite. Na unidade B, a variacao sazonal reduziu com a inducao de cio, uma pratica nao realizada na unidade A. O ganho de peso diario das cabritas apos a desmama (89 e 76 g/dia para A e B) foi baixo em comparacao as recomendacoes atuais. As medias dos registros de lactacao (441 e 606 L/cabra) e fertilidade (86,95 e 85,71%) estiveram nos limites preconizados na literatura. Tarefas diarias na unidade B consumiam 5 horas e 55 minutos para producao media de leite de 40,9 L/dia, enquanto na unidade A correspondiam a 8 horas e 16 minutos diarios para producao media de 32,2 L/dia. A unidade B apresentou custo total de producao (R

Composição corporal e exigências de energia de mantença em bovinos Nelore, puros mestiços, em confinamento

0,79548/L) menor que o da unidade A (R

Characteristics of the dairy goat primary sector at the Rio de Janeiro State, Brazil

1,50239/L), mas operava de forma lucrativa. A unidade A apresentou margem bruta positiva (R

Net efficiency of metabolizable energy utilization of purebred and crossbred Nellore young bulls fed diets with different concentrate levels

0,284/L), mas nao operava de forma lucrativa. A renda gerada em B era equivalente a um salario mensal de R

Degrabilidade Ruminal da Matéria Seca e da Fibra em Detergente Neutro de Alguns Volumosos Utilizados na Alimentação de Cabras Leiteiras, Submetidas a Dietas com Diferentes Relações Volumoso: Concentrado

732,96 (US

Chemical composition, fermentation, in vitro digestibility and in situ degradability of sugar cane silages with Lactobacillus, urea and agricultural byproduct

278,52), renda competitiva se comparada ao salario minimo brasileiro, de R

Cinética de Degradação de Alguns Volumosos Usados na Alimentação de Cabras Leiteiras por Intermédio da Técnica de Produção de Gases sob Diferentes Níveis de pH

300,00 (US

Nutritive value of Tanzania grass for dairy cows under rotational grazing

114,00) por mes. Estes resultados corroboram a hipotese de que a producao de caprinos leiteiros serve adequadamente ao modelo de producao familiar e gera renda competitiva.