Influence Of Dietary Yeast Culture On The Lactation Performance Of Goats

Abstract

In a feeding trial lasted eight weeks, twelve primiparous Egyptian does (Baladi) aged 18 to 20 months old averaging 21.4 kg ± 0.69 were ranked a week after kidding in three groups and allocated randomly to one of three rations supplemented with dry yeast culture (YC) at 0, 1 and 2 g/kg concentrates mixture (CM). Unsupplemented or YC-supplemented CM were fed at 2% (on DM basis) of the average bodyweight with ad libitum berseem (Trifolium alexandrinum) hay for each group. The results indicate that YC supplementation increased (P<0.05) the daily intake of hay by lactating does, but the higher supplementation level (0.2% YC) was accompanied with a decrease (P<0.01) in digestion coefficients for CP, EE, CF and NFE for the tested ration. The lower supplementation level of YC increased the milk yield (4% FCM) by 15% than control, however, that increase did not achieve statistical level. Milk contents of fat, lactose and ash were not influenced by YC supplementation, while total solids and protein contents were lower (P<0.05) in YC-fed groups. Body weight was decreased in all groups with advancing lactation period. Ruminal fermentation showed higher (P<0.05) butyric acid and lower (P<0.01) isovaleric acid concentrations after four weeks of feeding the YC rations. The effect of YC on rumen fermentation, resulted in lower (P<0.05) NH3-N and acetate and higher (P<0.05) in butyrate concentrations. There was no consistent trend of ruminal branched chain fatty acids or valeric acid proportions on YC groups after eight weeks of feeding.At both sampling times (after 4 or 8 weeks of lactation) YC treatments did not have any significant effect on ruminal pH or VFA production. The higher cupplementation level of YC was associated with a higher (P<0.05) blood plasma urea-N, meanwhile, the total protein content in blood was stable and comparable between groups. It could be concluded that the daily inclusion of yeast culture at the level of g/kg concentrates was safe and possibly sound in feeding practices for lactation goats