Performance and nutritional parameters of lactating cows on pasture receiving castor bean meal

Abstract

This study aimed to evaluate the inclusion of castor bean meal in the diet for lactating cows on Bracharia brizhanta pasture and its implications for nutritional and productive parameters. Eight crossbred cows were distributed in two 4 x 4 Latin squares, with four (0%; 3.33%; 6.66% and 10%) inclusion levels of castor bean meal in the total diet. The experiment consisted of four experimental periods of 21 days each. The digestibility and dry matter intake were estimated from fecal output, checked with the aid of external (chromium oxide) and internal (iNDF) indicators. Urine and milk were collected to determine the nitrogen balance and microbial protein production. The inclusion of different levels of castor bean meal in the diet for lactating cows did not affect the intake of dry matter and nutrients, and the same lack of effect was found for the digestibility of dry matter and total digestible nutrients, variation in body weight, milk production, chemical composition of milk, microbial production and nitrogen balance. The inclusion of up to 10% castor bean meal in the total diet did not influence productive parameters evaluated, and the use was conditioned to the price of castor bean meal. Key words: Nitrogen balance. Consumption. Milk production. Microbial protein. ResumoObjetivou-se avaliar a inclusão de farelo de mamona na alimentação de vacas lactantes em pastejo de Bracharia brizhanta e suas implicações nos parâmetros nutricionais e produtivos. Foram utilizadas oito vacas mestiças distribuídas em dois quadrados latinos 4 x 4, com quatro níveis de inclusão de farelo de mamona na ração total; 0%; 3,33%; 6,66% e 10%. O experimento foi constituído de quatro períodos experimentais, com duração de 21 dias cada. A digestibilidade e o consumo de matéria seca foram estimados a partir da produção fecal, verificada com o auxílio de indicadores externo (oxido de cromo) e interno (FDNi). Foi feita a coleta de urina e leite para determinação do balanço de nitrogênio