Níveis de proteína no concentrado de vacas mantidas em pastagem de capim Tanzânia

• Ano de defesa: 2017
• Autor(a) principal: Pinheiro, Jéssica Karen
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Paraíba; Brasil; Zootecnia; Programa de Pós-Graduação em Zootecnia; UFPB
• Palavras-chave em Português: Vacas – Parâmetros ruminais; Leite de vaca – Suplementação proteica; Pastagens tropicais; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::PRODUCAO ANIMAL
• Link de acesso: https://repositorio.ufpb.br/jspui/handle/123456789/15895

The objective of this study was to evaluate the effect of protein levels on the concentrate supplementation on the ruminal parameters of cows kept in Tanzania grass pasture, which allowed to make inferences with the ruminal metabolism of lactating cows. In the first study, 4 crossbred Holstein x Gir crossbred cows with mean body weight of 653 ± 47 kg were used, distributed in a 4x4 Latin square experimental design. The treatments consisted of four levels of crude protein (CP) in the concentrate (12,57; 14,63; 16,87 and 18,60% CP in the dry matter). The average amount of 5 kg cow supplement day-1 was established according to the average daily supply determined for the group of lactating cows. This proportional supply of concentrate to the fistulated animals allowed to simulate the same rumen environment of lactating cows. There was no significant difference (P>0,05) for the pH and volatile fatty acids variables among the animals receiving the diets with CP levels in the concentrate. There was an increasing linear effect (P<0,05) of CP levels in the concentrate on the concentration of ruminal ammoniacal nitrogen. The diet with 12,57% CP in the concentrate compared to the others provided the maximum degradability of the dry matter and protein of Tanzania grass. The ruminal parameters of cows maintained in tropical pasture were not affected by diets with protein levels in the concentrate, except for the ruminal N-NH3 concentration, which showed an increasing effect due to the increase of nitrogen compounds in the diet. In the second study, twelve crossbred Holstein x Gir cows were used in the initial third of lactation, with a mean body weight of 533 ± 51 kg, distributed in a triple 4x4 triple Latin experimental design, which were submitted to the same PB levels in the first concentrate study. There was no significant difference (P>0,05) between supplements and milk production and composition. There was an increasing linear effect (P<0,05) of CP levels in the concentrate on milk urea nitrogen (MUN). The metabolizable protein requirements of cows in the initial third of lactation kept in tropical pastures producing around 25 kg of day-1 are attended by the pasture and concentrating with 12,57% CP.