Effect of breeds and day age on the growth performance and digestive organ weight in weaned lambs.

【Objective】 This study determined the effects of breed and age on performance and digestive organ growth in lambs.【Method】 120 sheep lambs from three breeds(Little-tail Han sheep,Tan sheep and Mongolia sheep,each N=40) weaned at 60 days old were selected and raised at the same conditions.The lambs were fed in three groups determined by breeds,and each group was divided into four levels by its slaughtered age,each level had 10 lambs.The measurements of relevant digestive organs were obtained and detailed after the lambs were slaughtered at 80,120,160 and 200 days old.【Result】 The results showed that the breeds and day age had significant effects on body weight(BW),average daily gain(ADG) and relative growth rate(RGR) in lambs(P0.05).Each group hadn't significant weight increase(P0.05) from 80 to 120 days old,and had significant weight increase from 120 to 160 days old(P0.05).From 160 to 200 days old,Han sheep and Tan sheep had significant increase in weight(P0.05).The Han sheep had the highest ADG and RGR,and Mongolia sheep had the lowest.Age had significant effect on the weight of stomach,liver and small intestine(P0.05).【Conclusion】 The period between 120 and 160 days old is fastest growth stage for lambs.The growth performance of Han sheep is better than Tan sheep and Mongolia sheep.The growth of pancreas for sheep lambs is earliest among stomach,liver and small intestine.