Effect of the Degradation of Organic Matter and Crude Protein on Ruminal Fermentation in Dairy Cows

Abstract

The potential of the dacron bag technique to assess fluctuations in ruminal metabolites was studied using 40 Israeli-Friesian dairy cows assigned to an experiment with a 2 x 2 factorial design. Diets contained a low (62%) or high (65%) percentage of ruminally degradable CP and a low (55%) or high (59%) percentage of ruminally degradable OM. Metabolites were monitored before feeding and at 3 and 6 h postfeeding. Before feeding, total VFA and propionate were higher, and acetate and pH were lower, in diets containing a high percentage of ruminally degradable OM than in diets containing a low percentage of degradable OM. By 3 H postfeeding, acetate, butyrate and pH were lower, and propionate was higher, in the diets containing a high percentage or ruminally degradable OM than in the diets containing a low percentage of ruminally degradable OM. By 6 h postfeeding, propionate was higher, and acetate was lower, in diets containing a high percentage of ruminally degradable OM than in diets containing a low percentage of ruminally degradable OM. In the diets with a high percentage of ruminally degradable OM, before feeding and by 3 h postfeeding, ammonia concentrations were higher and lower, respectively, relative to the diets containing a low percentage of degradable OM. Milk yield and composition and DMI were similar among treatments. The correlation was good between the degradability data obtained by the dacron bag technique and the meal-induced variations in ruminal metabolites. The lack of a positive yield response to controlled fluctuations in ruminal metabolites may be related to surplus CP intake.

Efeito de fontes e teores de proteína sobre digestibilidade de nutrientes e desempenho de vacas em lactação

“…Sci. Maringá, v. 29, n. 3, p. 325-331, 2007 comparado com a soja tostada (McNiven et al, 1994), o farelo de glúten de milho (Higginbotham et al, 1989;Arieli et al, 1996) e a uréia (Broderick et al, 1993). A revisão de Santos et al (1998a) demonstrou que, de maneira geral, a fonte de proteína da dieta não afeta o consumo de matéria seca.…”

“…Tendência semelhante foi encontrada em outros trabalhos de literatura, ao comparar farelo de soja com soja tostada (Bernard et al, 1992), com farelo de glúten de milho (Klusmeyer et al, 1990;Arieli et al, 1996) e com uréia (Santos et al, 1998b). Entretanto, os valores de digestibilidade da MS, verificados neste estudo, encontram-se ligeiramente abaixo dos normalmente relatados na literatura.…”

Consumo, digestibilidade aparente total, produção e composição do leite em vacas no terço médio da lactação alimentadas com níveis crescentes de proteína bruta no concentrado

“…Tabela 6 -Valores médios de produção de leite não-corrigida (PL) e corrigida para 3,5% de gordura (PLG), eficiência de utilização de MS (kg leite/kg matéria seca consumida), eficiência de utilização de N (kg N-leite/kg N-ingerido), teores e quantidades de gordura (G) e proteína bruta (PB) do leite, em função dos níveis de proteína bruta no concentrado, coeficientes de variação (CV), probabilidades (P) para os efeitos linear (L) e quadrático (Q) e equações de regressão , 1996;Armentano et al, 1993;Robinson et al, 1991;Robinson & Kennelly, 1988). Para a produção de leite corrigida para 3,5% de gordura, os aumentos foram de 9,74%, ou 1,84 kg/dia, e as produções de gordura e proteína apresentaram incrementos de 0,08 kg/dia e 0,04 kg/dia, respectivamente, entre os níveis 20 e 23% de PB na MN do concentrado.…”

Effects of Different Ratios of Nonfibrous Carbohydrate to Ruminally Degradable Protein on In Vitro Fermentation and Lactation Performance of Dairy Cows

“…배양한 후에 각 배양물은 pH meter(WTW Co., 2) significance (i.e., ns: no significance, * : P < 0.05, ** : P < 0.01); 3) a,b means in the same row with different superscripts differ significantly. 2) significance (i.e., ns: no significance, * : P < 0.05, ** : P < 0.01); 3) milk urea nitrogen; 4) a,b means in the same row with different superscripts differ significantly.…”