Productive performance and composition of milk protein fraction in dairy cows supplemented with fat sources

Revista Brasileira de Zootecnia

Rennó, Francisco Palma²  Venturelli, Beatriz Conte¹  Maturana Filho, Milton²  Santos, Marcos Veiga dos²  Gandra, Jefferson Rodrigues²  Freitas Júnior, José Esler de² 

[1] Universidade de São Paulo

关键词: fat supplementation;    intake;    milk production and composition;    non-protein nitrogen;    true protein RESUMO Objetivou-se com este estudo avaliar a utilização de fontes de gordura em rações para vacas em lactação sobre o desempenho produtivo e a composição da fração proteica do leite;   

DOI  :  10.1590/S1516-35982010000400021

学科分类：兽医学

来源: Universidade Federal de Vicosa

【 摘 要 】

The objective of this study was to evaluate the use of fat sources in rations for lactating cows on the productive performance and composition of milk protein fraction. Twelve Holstein cows were used, grouped in three balanced 4 × 4 Latin squares, fed with the following rations: control; refined soybean oil; whole raw soybean; and calcium salts of unsaturated fatty acid (Megalac-E). Dry matter and nutrient intake, and daily milk production were evaluated. The samples used to analyze milk composition were collected in two alternate days and were obtained from two daily milking. Milk composition and total nitrogen, non-protein nitrogen and non-casein nitrogen ratios were analyzed. The casein, serum protein and true protein ratios were obtained by difference. Dry matter and nutrient intakes were lower when cows received the diet containing calcium salts of fatty acids, in relation to the control diet. Among the diets with fat sources, the one with whole raw soybean and calcium salts decreased milk production. There was no effect of fat sources added to the diet on crude protein, non-protein nitrogen, non-casein nitrogen, true protein, casein, casein/milk true protein ratio and serum protein. Similarly, the experimental diets did not influence the protein fractions when expressed in percentage of milk crude protein. The utilization of fat sources in diets changes milk production and composition of lactating cows, but does not influence the composition of milk protein fractions.

【 授权许可】

CC BY-NC