Abstract

MOURTHE, M.H.F. et al. Performance milk composition and blood metabolites of Holstein x Gir cows grazing Brachiaria brizantha cv. Marandu grass supplemented with roasted soybeans. Arq. Bras. Med. Vet. Zootec. [online]. 2012, vol.64, n.5, pp. 1223-1231. ISSN 0102-0935.  http://dx.doi.org/10.1590/S0102-09352012000500021.

Feed intake, blood metabolites, and milk yield and composition of Holstein x Gir cows grazing Brachiaria brizantha cv. Marandu receiving 6kg/cow/day (natural matter based) of concentrate containing 0, 1.3, 2.6, 3.9kg/cow/day of roasted soybean seeds (RSS) were evaluated. The experimental design was four 4 x 4 latin square (LS) in wich each phase consisted of 10 days for diet adaptation period and 5 days for samples collection. Diet supplementation with RSS decreased linearly (P<0.05) the intake of pasture, total diet dry matter and neutral detergent fiber. The plasma glucose concentration was unaffected (P>0.05), but nonesterified fatty acids increased with RSS supplementation (P<0.05). There was no effect (P>0.05) of RSS supplement on milk production and composition, except the linear reduction on the content (P=0.10) and yield (P=0.08) milk fat, which can present positive financial implication to farmers, knowing that most of the Brazilian dairy use payment programs by milk composition.

Keywords : cattle; tropical grass; lipids; processing; concentrate supplement.