Physicochemical composition and fatty acid profile of milk from F1 Holstein x Zebu cows fed with increasing concentrations of urea

Vanice Mendes de Souza, Vicente Ribeiro Rocha Júnior, Luciana Albuquerque Caldeira, Ana Paula da Silva Antunes, José Reinaldo Mendes Ruas, Criszoel Ferreira Souza, Ana Cássia Rodrigues de Aguiar, Dante Pazzanese Duarte Lanna

Abstract


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.


Keywords


Physicochemical composition; Soybean meal; Non-protein nitrogen.

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DOI: http://dx.doi.org/10.5433/1679-0359.2015v36n6Supl2p4435

Semina: Ciênc. Agrár.
Londrina - PR
E-ISSN 1679-0359
DOI: 10.5433/1679-0359
E-mail: semina.agrarias@uel.br
Este obra está licenciado com uma Licença Creative Commons Atribuição-NãoComercial 4.0 Internacional