Fontes lipídicas para vacas holandês no noroeste do Rio Grande do Sul durante o verão

Abstract

The objective was to evaluate the effects of the inclusion of different lipid sources in the diet of Holstein cows in a semi-confined system on heat stress, production, composition and profile of fatty acids in milk and animal behavior. Twelve Holstein cows were used, distributed in two 4x4 Latin squares with multiparous cows and a 4x4 Latin square with primiparous cows. The treatments used were Control, Protected Fat, Flaxseed and Mixture (Protected Fat + Flaxseed). On the 11th and 12th days of each experimental period, milk samples and milk samples were collected to evaluate the fatty acid profile, which were frozen at -20 °C for further analysis. On the 13th day of each period, the animal behavior was evaluated for 24 hours. Analyzes of variance were performed and, when necessary, the Tukey average comparison test was used. Grazing activity in both treatments had a higher peak after milking in the morning between 8 and 10 am. Milk production and milk production corrected for 3.5% fat showed no difference between treatments. Lactose production in percentage and in kg/cow/day did not differ between treatments. As for the production of solids in kilograms and in percentage, the treatments with protected fat and mixture were inferior to the treatment with flaxseed and all three did not differ from the control treatment. There was a higher production of stearic fatty acid (C18:0) for the flaxseed and mixture treatments, which did not differ from the Fat treatment, and the latter did not differ from the Control treatment. Lipid sources did not significantly alter milk production, but were significant in altering the fatty acid profile.