The objective of this study was to evaluate the effects inclusion of 0%, 33.3%, 66.7% and 100% natural matter (NM) of mesquite pod meal (MPM), in substitution of corn, on the intake, digestibility and feeding behavior of lactating Saanen goats. The forage:concentrate ratio in the diet was 40:60, using elephant grass silage as a forage source. Eight adult lactating goats with about 60 days in milk and weighting 50 kg were divided into two 4 × 4 latin squares and four 17-day experimental periods. Dry matter (DM), crude protein (CP) and total digestible nutrient (TDN) intakes were not influenced by MPM levels. Ether extract (0.51; 0.34; 0.36; 0.20 kg/day) and non-fiber carbohydrate (NFC) (0.54; 0.53; 0.49; 0.36 kg/day) intakes showed a linear effect with increased MPM. Organic matter (OM) and NDF intakes presented a quadratic behavior. The maximum OM intake was estimated with the replacement of 40.5%. The maximum estimated intakes for NDF were 0.665 kg/day and 14.8 g/kg body weight, with a replacement close to 60%. Nutrient digestibility coefficients and TDN levels (655.0 g/kg) were not affected, except for NFC. The time spent eating, ruminating and idle was not influenced by the addition of MPM. The feeding rate of DM had a linear decrease which reflected the intake restriction. Corn replacement with MPM should not exceed 40.5%, although its total replacement does not interfere with the intake of DM, CP and TDN on the apparent digestibility of nutrients and most ingestive behavior parameters.

Objetivou-se neste trabalho avaliar os efeitos da inclusão de ureia em dietas contendo farelo da vagem de algaroba sobre o balanço de nitrogênio, N-ureico no plasma e parâmetros ruminais em ovinos. Foram utilizados oito animais, machos castrados, com peso médio de 33,5 kg, distribuídos em dois quadrados latinos 4 x 4. Os tratamentos constituíram da inclusão de níveis de ureia na dieta, sendo: 0; 0,5; 1,0 e 1,5% da MS total. A dieta foi fornecida como dieta total na relação volumoso:concentrado de 40:60 com base na MS total da dieta. Foi realizada a coleta total de urina e fezes e determinada a excreção de nitrogênio. Foi coletado sangue, seguido com a extração do plasma e determinação do N-ureico. Para avaliação do pH e N-amoniacal no líquido ruminal foram utilizados quatro animais fistulados no rúmen. A ingestão de N (31,68 g dia-1) e perdas vias fecal (7,94 g dia-1) e urinária (9,95 g dia-1) não sofreram alterações. As concentrações de N-amoniacal e N-ureico no plasma aumentaram de forma linear. O pH ruminal foi semelhante entre os tratamentos. A inclusão de ureia não influencia o balanço de nitrogênio, porém eleva as concentrações de N-amoniacal no rúmen e N-ureico no plasma podendo influenciar o gasto de energia no organismo.

The goal of this study was to evaluate the effects of including urea in diets containing mesquite pod meal on nitrogen balance, plasma urea-N and ruminal parameters. Eight gelded males, with mean weight of 33.5 kg, were divided into two 4 x 4 Latin squares. Treatments consisted of following urea levels in diet: 0, 0.5, 1.0 and 1.5% of total dry matter. The diet was provided as total diet a 40:60 forage: concentrate ratio based on total diet DM. Total urine and feces were collected and nitrogen excretion was determined. Blood was collected, followed by plasma extraction and quantification of urea nitrogen. To evaluate pH and ammonia-N in rumen fluid, four rumen fistulated animals were used . Intake of N (31.68 g day-1) and losses through feces (7.94 g day-1) and urine (9.95 g day-1) did not change. The concentrations of ammonia-N and plasma urea-N increased linearly. Rumen pH was similar among treatments. The inclusion of urea does not influence the nitrogen balance, but increases the concentrations of rumen ammonia-N and urea nitrogen in plasma, which may influence energy expenditure in the body.

Objetivou-se avaliar o efeito de teores crescentes de PB na MS total da dieta (11,5; 13,0; 14,5 e 16,0%) sobre os consumos e a digestibilidade total dos nutrientes e a produção e composição do leite de vacas leiteiras no terço inicial da lactação. O experimento foi constituído de quatro períodos experimentais de 15 dias, sete para adaptação dos animais à dieta e oito para coleta de dados. Foram utilizadas oito vacas, manejadas em cochos individuais, distribuídas em dois quadrados latinos balanceados 4 × 4. Utilizou-se concentrado à base de farelo de algodão e fubá de milho (40%) e, como volumoso, cana-de-açúcar corrigida com 1% de uréia + sulfato de amônio (9:1), na proporção de 60% (% MS). Os consumos médios diários de nutrientes, exceto EE e CNF, diferiram à medida que os teores de PB da dieta aumentaram. Os teores de PB na dieta não afetaram os coeficientes de digestibilidade aparente total dos nutrientes. A produção de leite corrigida ou não para 3,5% de gordura e seus componentes (gordura, PB e lactose), expressa em g/dia, e o nitrogênio uréico no leite (NUL) tiveram efeito linear crescente, enquanto a eficiência de utilização de N sofreu efeito linear negativo dos teores de PB da dieta. A dieta com 16% PB resultou em valores numericamente maiores de consumo e produção do leite e de seus componentes se comparada às dietas com menores teores de PB.

The objective of this research was to evaluate the effect of increasing levels of CP in the total DM of diet (11.5, 13.0, 14.5 and 16.0%) on the intakes and the total digestibility of nutrients and the milk production and composition of dairy cows in initial third of lactation. The research was constituted by four experimental periods of 15 days each, seven for adaptation of the animals to the diet and eight for data collection. Eight cows, individually fed, were distributed to two balanced 4 × 4 Latin squares. A cottonseed meal, ground corn-based concentrate (40%) was used and, as forage, sugar cane corrected with 1% of urea + ammonium sulfate (9:1), in the proportion of 60% (%DM). The daily average intakes of nutrients, except for EE and NFC, differed as the levels of CP increased in the diet. The protein levels in the diet did not affected the coefficients of total apparent digestibility of the nutrients. Production of fat corrected milk, 3.5% or not and its components (fat, CP and lactose), expressed in g/day, and milk urea nitrogen showed increased linear effect, while the N efficiency showed negative linear effect of the CP levels in the diet. The diet with 16% CP provided values numerically greater for intake and milk production and its components as compared to diets with lower levels of CP.