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 avaliar os efeitos da adição de farelo da vagem de algaroba (0; 33,3; 66,7 e 100%) em substituição ao fubá de milho sobre a excreção de derivados de purina, estimada com coleta total de urina, e sobre os parâmetros ruminais (pH, amônia e ácidos graxos voláteis) de cabras em lactação. Utilizaram-se oito cabras adultas lactantes distribuídas em dois quadrados latinos 4 × 4 e alimentadas com dietas isoproteicas, compostas de 40% de silagem de capim-elefante e 60% de concentrado. Não houve efeito significativo da adição de farelo da vagem de algaroba sobre os parâmetros ruminais. O pH manteve-se em faixa adequada, entre 6,85 e 7,03, e a concentração média de nitrogênio amoniacal ruminal foi de 6,97 mg de N/100 mL de fluido ruminal. As concentrações de acetato e propionato variaram de 9,47 a 10,54 e de 4,79 a 6,58 mM, respectivamente. As excreções (mmol/dia) de alantoína, ácido úrico, xantinahipoxantina, a quantidade (mmol/dia) de purinas absorvidas, o fluxo intestinal (g/dia) de nitrogênio microbiano e a eficiência de síntese microbiana (PM/kg NDT) apresentaram resposta linear negativa à substituição do fubá de milho pelo farelo da vagem de algaroba. A estimativa da síntese de proteína microbiana em cabras deve ser calculada pela excreção de derivados de purinas a partir de equações obtidas com caprinos.

The objective of this study was to evaluate the effect of adding mesquite pod meal (0, 33.3, 66.7 and 100%) to substitute corn meal on purin derivative the excretion, estimated by total urine collection, and on the ruminal parameters (pH, ammonia and volatile fatty acids). Eight lactating goats were used and distributed in a 4 × 4 Latin square and fed iso-protein diets consisting of 40% elephant grass silage and 60% concentrate. There was no significant effect from adding mesquite pod meal on the ruminal parameters. The pH ranged from 6.85 to 7.03 and the ruminal ammonia concentration averaged 6.97 mg/100 mL. The acetate and propionate concentrations ranged from 9.47 to 10.54 and 4.79 to 6.58 mM, respectively. The excretion (mmol/day) of allantoin, uric acid and xanthine-hypoxanthine, the quantity of absorbed purines, the nitrogen microbial intestinal flow (g/day), microbial nitrogen synthesis (g/day) and efficiency of microbial protein synthesis efficiency, expressed in g of microbial crude protein/kg of the total digestible nutrients, presented linear negative response to corn replacement with mesquite pod meal. Microbial synthesis in goats must be estimated by the purine derivatives excretion using equations obtained from goats.