Effect of yeast culture supplementation to beef rations on feedlot performance, some rumen and blood parameters

Sixteen Holstein beef cattles, weighing 270 kg and 5-6 months age, were assigned to one of two treatments (8 animal per treatment) in a completely randomized design. All animals in both groups fed with basal diet containig; concentrated feed, barley, cottonseed meal and straw. Live yeast culture (Saccharomyces cerevisiae, 1,4 X 10(8) cfu/g) incorporated into yeast group rations 50 g/d. The study lasted 135 days. At the beginning of the trial, animals were adapted to the basal diet over a 15-day period. Feed consumption was measured daily, while body weight and body weight gain was measured monthly. At the end of the study, four animals from each groups were slaughtered and the hot carcass yield was determined. Rumen contents were collected on days 45th and 90th analyzed for pH, volatile fatty acids and ammonia-N (NH3-N). Dietary treatment had no effect (p>0,05) on DMI (Dry matter intake), FCR (Feed conversion ratio), final live body weight, and ADG (Avarage daily gain) (p>0,05). Carcass yield was significantly (p<0,05) increased by dietary inclusion of yeast so that carcasss yield was 50,65% and 52,75% in control and yeast group respectively, in the yeast group. There was also no significant (p>0,05) differences for rumen volatile fatty acids (VFA) and ammonia-N between each groups. However, rumen pH was lower (p<0,05) for the yeast group. No differences (p>0,05) between groups were observed regarding blood parameters.