Effects of diets with different concentrate-to-coarse ratios on growth performance, nutrients apparent digestibility, rumen fermentation, and serum immune indexes of autumn lambs.

The purpose of this experiment was to study the effects of diets with different concentrate-to-coarse ratios on the growth performance, rumen fermentation, nutrients apparent digestibility, and serum immune indexes of autumn lambs. Thirty 4-month-old F1 hybrid male lambs of 'Dubo x Small Tail Han sheep' were randomly divided into three groups, with 10 replicates in each group and one sheep in each replicate. Experimental Group I, Group II, and Group III were fed with diets with the ratio of concentrate to coarse of 40:60, 55:45, and 70:30, respectively. The results showed that the average daily gain of lambs in Group III was significantly higher than that in Group I (P<0.05), and the feed to gain ratio of Group II and Group III was significantly lower than that in Group I (P<0.05). The apparent digestibility of dry matter, organic matter, crude protein, and neutral detergent fiber in Group I was significantly lower than that in other groups (P<0.05), while the apparent digestibility of organic matter in Group II was significantly higher than that in Group III (P<0.05). The content of propionic acid in rumen of lambs in experimental group I was significantly lower than that in other groups (P<0.05), and the ratio of ethylene to propylene in experimental group I was significantly higher than that in other groups (P<0.05). The level of serum immunoglobulin G in Group II was significantly higher than that in Group III (P<0.05), and the level of serum interleukin-6 in Group II was significantly lower than that in other groups (P<0.05). The study indicates that when the concentrate-to-coarse ratio is 55:45, the growth of lambs in autumn can be healthier, the utilization rate of feed can be improved, the growth performance of lambs can be improved, and the economic benefits can be increased. [ABSTRACT FROM AUTHOR]