Author(s): RODRIGUES, P. R.; MENEZES, L. de M.; SILVEIRA, I. D. B.; SUÑÉ, R. W.; CARDOSO, F. F.

Summary: Among the environmental factors that contribute to calf growth during the pre-weaning period, the most important is the milk provide by its dam. In this sense, not only the amount but also its constituents are important because they must meet the calves nutritional requirements at this developmental stage. The aim of this study was to evaluate the milk chemical composition from different genotype beef cows machine milked in three lactation periods (early, middle and end). The study included 66 cows of the following genotypes: Angus cows (ANAN), Angus x Caracu (ANCR), Angus x Hereford (ANHH) and Angus x Nellore (ANNE). Milk fat percentage was higher for ANCR and ANNE (3.78% and 3.79%, respectively), not differing between them. For protein, ANCR (3.16%) was superior to other genotypes, except ANNE (3.12%). The ANNE genotype had a lactose percentage of 4.77%, being higher than the other evaluated genotypes. Values for total solids of ANCR and ANNE (12.44% and 12.69%, respectively) were also higher than the other genotypes, again not differing between them. There was variation in the milk composition among the measured periods. Lactose percentage assessed during late lactation was lower than in the two earlier periods. For the milk fat percentage, there was an increase in late lactation compared to assessments in the earlier periods. The total solids and protein percentage increased concentrations from early to middle and from middle to late lactation periods. We conclude that the milk chemistry composition of beef cows is influenced by genotype the lactation period.

Publication year: 2011

Types of publication: Abstract in annals or event proceedings

Unit: Embrapa Southern Livestock

Keywords: Composição Química, Gado de Corte, LINA, Leite, Leite Instável Não Ácido, Sistema de Criação extensivo