Desempenho produtivo e qualidade do leite de vacas F1 Holandês x Zebu em pasto suplementado com diferentes teores de proteína

Abstract

The objective of this study was the effect of different levels of protein in the concentrate on the production and composition of body milk and body score of F1 Holstein x Zebu (HZ) cows grazing Urochla brizantha cv. Xaraés irrigated in winter. The research was carried out in Felixlândia (MG) in the Experimental Field of EPAMIG, in Felixlândia (MG). Thirty-two F1 HZ vaccines, multiparous, 91 days postpartum, mean weight of 512.5 ± 48 kg and mean milk yield of 15.2 ± 0.6 kg day-1 were used. A completely randomized design was used in subdivided plot, with four treatments, eight replicates and six collection periods. Cows were grouped in only 9.5% crude protein; 16% of crude protein; consumed with a radius containing 23% crude protein; confined cows receiving corn silage ad libitum and containing 23% crude protein. The milk production was corrected in 23% of PB 18.2 kg of cow-1 day-1 milk, in relation to grazing cows. In grazing cows fed with 9.5%, 16% and 23% of protein did not obtain beautiful milk yields, 15.63, 15.91 and 16.07 kg of cow-1 day-1 milk, however they gained greater weight in confined cows. The content of 9.5% of unrestricted BP was not devalued in relation to milk production, the body capacity score (mean gain of cows in paste and promotion of body weight gain of 0.5 kg day-1 . A maize silage supplemented with 23% protein promoted better and milk quality can be used as an alternative in the dry season. The 9.5% PB content did not limit the productive performance of grazing cows and reported body weight gain.