Fontes de lipídio e monensina sódica na fermentação, cinética e degradabilidade ruminal de bovinos

The objective of this work was to evaluate degradability in the rumen, fermentation and kinetics of diets with whole cottonseed or calcium salt of fatty acid, used as fat sources, with sodium monensin, as well as to verify the monensin effect on diet with cottonseed. Treatments consisted of three diets with monensin (control, calcium salt of fatty acid and cottonseed) and one diet with cottonseed without monensin. The incubation periods were 0, 3, 6, 12, 24, 48, 72 and 96  hours, and the ruminal liquid was sampled 0, 1.5, 2, 3, 4, 6, 8, 12 and 24  hours after feeding. Diets with cottonseed showed the highest degradability of the neutral detergent fiber and crude protein. Diets containing cottonseed with monensina showed the highest liquid passage and turnover. There were no differences, between the diets, related to ruminal pH, ammonia and volatile fatty acids. The fat sources, calcium salt of fatty acid and whole cottonseed, showed no deleterious effects of the fat on the rumen environment. The inclusion of monensin affects the degradability, rumen kinetics and fermentation, when high concentrate diets with fat as whole cottonseed is fed.