Effects of Molasses-Urea Supplementation on Weight Gain,Ruminal Fermentation and Major Microbe Populations of Winter-Grazing Sheep in Inner Mongolia

The present experiment was conducted to determine the effects of Molasses-Urea Supplementation (MUS) on weight gain, ruminal fermentation and major microbial populations in sheep on a winter grazing regime in Inner Mongolia. Total 40 sheep, allowed free consumption of MUS after grazing, served as a treatment group, while 30 sheep, fed only by pasture grazing, served as a control group. Ruminal fermentation parameters, consisted of pH, Bacterial Crude Protein (BCP) and ammonia nitrogen (NH3-N) were measured. In addition, numbers of five symbiotic bacteria were investigated. The results showed as follows: the average daily weight gain, concentration of NH3-N and numbers of protozoa were significantly higher (p<0.05) in the treatment group than those in the control group. Contrastingly, no significant difference was found in BCP concentration and pH between the two groups. At the end of the experiment, the populations of Selenomonas ruminantium,Anaerovibrio lipolytica,Fibrobacter succinogenes,Ruminococcus flaveciens and Ruminococcus albus in the treatment group were significantly higher than those of the control group (p<0.05). These results demonstrated that greater weight gain could be induced during winter in Inner Mongolia by improved nutritional status through promotion of microbial populations using urea and sugar.