Effects of yeast spplementation on rumen fermentatation, microbial population and the performance of male fattening calves

The experiment was designed to investigate the effects of saccharomyces cerevisiae supplementation on the efficiency of rations containing different levels of concentrate in male Holstein calves. 36 male Holstein calves [average body weight of 175. 9 +/- 5.54 kg] were allocated into six treatments of 60, 70 and 80 percent of concentrate with or without yeast culture based on a 2 x 3 factorial design. The performance parameters [daily feed intake and gain] were recorded during 150 days of fattening period. At the end of the experimental period, the rumen content of animals were sampled by esophagus tube at 0, 3 and 6 hours after morning feeding and ruminal parameters [pH, VFAand NH3- N] and microbial population [total and cellulolytic bacteria, lactate utilizing bacteria and protozoa] were determined. All data were analyzed based on the complete randomized design in which the performance data were adjusted by covariance before analysis. Yeast supplement resulted the increase of the pH ,total volatile fatty acids and population of lactate utilizing bacteria and decrease of the level of NH3-N in the rumen fluid samples [p < 0.05]. The increase in the total number of rumen bacteria and protozoa was not significant. Feed intake and daily gain were higher in calves with yeast supplemented rations and 80 percent cocentrate [p < 0.05]. It can be concluded that the supplementation of yeast [Saccharomyces cerevisiae, S.C.47] could have a beneficial effect on the rumen fermentation and microbial populations in fattening calves. This in tum may results in an improvement of the animal performace especially when feeding high concentrate diets

[Experimental study on efficacy of supplemental organic and inorganic chromium in feeding of Shal fattening lambs]

Objective: Evaluating the differences in performance traits and carcass composition in Shal fattening lambs fed organic or inorganic chromium [Cr]

Design: Experimental study

Animals: Seventy fat-tailed ram lambs of Shal breed with an average body weight [BW] of 37.0 +/- 2.8 kg, randomly partitioned in seven groups

Procedure: Feeding a 60.5% barley-based diet [12.2% crude protein] supplemented with 0 [control], 200, 600, or 1000 ig/kg dry matter of Cr from chromium nicotinate [CrNic] and 200, 600, or 1000 ig/kg dry matter of Cr from chromium chloride [CrC13] to individually penned lambs, measuring dry matter intake [DMI] and average daily gain [ADG] through wk 12, and slaughtering lambs and determining carcass characteristics at the end of wk 15 of the experiment

Statistical analysis: Analysis of covariance for studying treatment differences and orthogonal coefficients for contrasting treatment groups

Results: Addition of 600 or 1000 ig/kg dietary dry matter of Cr from CrNic decreased ratio of DMI to% BW [P<0.04] but did not affect wk 6 and 12 body weights, ADG, daily DMI and ADG: DMI ratio. Backfat thickness increased by Cr [P<0.04]. Addition of 1000 ig/kg dry matter of Cr from CrNic increased loin-eye area [P<0.02] and muscle weight of right side carcass [P<0.04]. Percentages of water, protein, lipid, or ash in carcass muscle were not affected by Cr supplements, whereas weights of protein and ash in carcass muscle increased by Cr with more positive effect of 1000 ig/kg dry matter of Cr from CrNic [P<0.03]

Conclusion: The results of this study suggest that supplementation of chromium nicotinate may be beneficial for increasing lean tissue of Shal fattening lambs