Effects of Photoperiod and Melatonin on Endocrine and Cashmere Growth in Cashmere Goats in Telogen

This study investigated the effects of photoperiod and implanted melatonin on the endocrine of some hormones relative to cashmere growth and cashmere growth.36 castrated Inner Mongolia white cashmere mature goats,23～25 kg of live body weight,were designed to three groups randomly which were treated with long daily photoperiod(LDPP,16L∶8D),short daily photoperiod(SDPP,8L∶16D) and natural daily photoperiod(NDPP),respectively.In each of the group,half of the goats were implanted melatonin monthly from Feb 20th to June 20th,the goats were fed in pens seperately.Cover coat sampes on bodyside were gathered monthly to analyze the cashmere growth rate and traits.Results showed there was a great difference in blood hormone conent in the treatments,melatonin was decreased with the increasing of photoperiod,implanted groups were higher than unimplanted groups.PRL,IGF-I were increased with the length of photoperiod,implanted groups were lower than unimplanted groups,such hormone pattern was advantage to ashmere growth.As a result,additive cashmere production was increased by 338.83 averagely.The textile value of new cashmere was still up to the grade A standard except for one group within grade B.