The Study Of Effect Of Over-early Weaning Small Tail Han Ewes On Reproductive Performance (Oestrus Time) In Different Nutrition Levels

The study of effect of over- early weaning Small Tail Han ewes on reproductive performance (oestrus time ) in different nutrition levelsZhang hai taoFaculty of animal science and technology,GAU,Lanzhou,One experiment was conducted using eighteen over-early weaning (10–15days) Small Tail Han ewes to evaluate the effect of nutrition level (high: DE=11.33MJ/kg, CP=17.75%, middle:DE=10.45MJl/kg,CP=14.16%,low: DE=9.72 MJ/kg,CP=12.43%) of diets on the oestrus of ewes. A single facterial arrangement was adopted in the experiment, ewes were divided into three groups and allotted to three diets. The results showed that:(1) the daily feed intake of ewes was high(P＞0.05)and weight increase averagely was rapid (high was rapider than middle)( P＜0.05) before ewes oestrus(0～14 days), which were reverse in oestrus and were same after oestrus. (2) The oestrus time of the ewes in high nutrition level group(37.2d)( P＜0.05) and middle group(36.7d) ( P＜0.01) were earlier than that of low group, and that of ewes in the sheep market was 57d, which was later than that of high, middle and low nutrition level The oestrus rate of the ewes of high,middle and low nutrition level groups were 83.33%,100% and 33.33% respectively; (3)The content of plasma albumin(P＜0.05) and plasma urea nitrogen( P＜0.01) of ewes in high nutrition level group were higher than that of low group, and the content of plasma total protein of ewes in high and middle nutrition level groups were higher than that of low group( P＜0.01), (4) The content of plasma FSH and LH of ewes were inhibited negatively feedback by 17β-E2 before oestrus and FSH was positively inhibited feedback after the oestrus, but the function of P4 was reverse to LH ;the content of hormone of ewes in high,middle nutrition level groups can promote oestrus. The results of this study demonstrate that the diet of the high and middle nutritional level were benefit to promote oestrus of ewes and the middle nutrition level was the best.