Effect of L-carnitine on digestive processes, growth of bulls and milk productivity of cows
The object was to study the efficacy of protected preparation of L-carnitine in growing bulls and cows. First trial was performed on 6 Black-and-White, 8 mo aged bulls, fitted with rumen canules; half of bulls were given protected preparation Karnipass with 18% of L-carnitine, at the dose of 15 g/d in the course of 30 d. In the probes of rumen fluid taken at 1 hr before and 1-4 hrs after morning feeding, the indices of rumen metabolism and species composition of rumen microorganisms were determined. Second trial was performed on 16 Red-and White cows with milk yield 6400 kg; Karnipass was given at the dose of 15 g/d in the course of 140 d with registration of post treatment effect during 40 d. In bulls given L-carnitine, the level of NH<sub>3 </sub>in rumen fluid was decreased and content of VFA increased (P<0.05), total nutrients digestibility tended to increase, daily live weight gain was by 24% (P<0.05) higher in comparison to control. Feeding L-carnitine caused in cows the increase in 4% fat milk yield by 8%, in fat yield by 7.6%, in protein yield by 5.9%, with maintaining post treatment effect in the course of 40 d, and the decrease in the number of postpartal disfunctions and days open up to 99 d vs 105 d in control group.