Open AccessPhysicochemical composition and fatty acid profile of milk from F1 Holstein x Zebu cows fed with increasing concentrations of urea
Author(s) -
Vanice Mendes de Souza,
Vicente Ribeiro Rocha Júnior,
Luciana Albuquerque Caldeira,
Ana Paula Antunes,
José Reinaldo Mendes Ruas,
Criszoel Ferreira Souza,
Ana Cássia Rodrigues de Aguiar,
Dante Pazzanese Duarte Lanna
Publication year - 2015
Publication title -
semina. ciências agrárias
Language(s) - English
Resource type - Journals
eISSN - 1679-0359
pISSN - 1676-546X
DOI - 10.5433/1679-0359.2015v36n6supl2p4435
Subject(s) - lactose , zebu , urea , chemistry , latin square , fatty acid , lactation , composition (language) , somatic cell count , meal , zoology , food science , milking , soybean meal , biology , biochemistry , fermentation , ice calving , rumen , pregnancy , raw material , genetics , linguistics , philosophy , organic chemistry
We evaluated the physicochemical composition and fatty acid profile of milk from F1 Holstein × Zebu cows that were fed increasing levels of urea (0%, 33%, 66% and 100%, corresponding to 0%, 0.92%, 1.84% and 2.77% CP as NPN) as a substitute for soybean meal. Eight lactating F1 Holstein × Zebu cows producing an average of 10 kg of milk per day corrected to 3.5% fat, were placed in two 4 × 4 Latin squares (4 animals, 4 diets and 4 periods). Each experimental period lasted 18 days. Milk samples from each cow were collected from morning and afternoon milkings and analyzed for composition and fatty acid concentration. Milk urea nitrogen increased linearly (P < 0.05) with increasing dietary urea. Other variables including fat content, protein, fixed mineral residues, lactose, total nonfat solids, acidity, density, casein, cryoscopic index, somatic cell count, and milk fatty acid concentrations, were not affected by treatment. Thus, urea provides a viable alternative to soybean meal that does not affect the characteristics of milk from primiparous F1 Holstein × Zebu cows, producing up to 10 kg of milk corrected to 3.5% fat day-1.