| In order to know about the effect of sow’s energy and body condition on reproductive metabolism hormone level,litter size,litter weight and estrous interval,this experiment was carried out.There were 16 primiparous sows and 30 multiparous sows.According to the thickness of back fat on the 7th day before delivery,the primiparous sows were divided into two groups: high and low thickness of back fat.The multiparous sows were divided into three groups: high,middle and low thickness of back fat.The back fat thickness of sows was measured on the day of delivery,weaning and regrouped according to the thickness of back fat that day.The levels of FSH,LH,E2,IGF-1,Insulin,litter size,birth litter weight,birth uniformity,weaning litter weight,back fat loss during estrus interval and lactation were measured on the 7th day before delivery,the day of weaning and the 5th day after weaning.Analyzing the effects of sows body condition on reproductive hormone and sows performance at different stages.Comparing the differences between primiparous sows and multiparous sows.The main experimental results are as follows:(1)On the 7th day before delivery,IGF-1 increased with the increase of back fat thickness,the difference is significant,and weaning litter weight increased with the increase of back fat loss during lactation,the difference is extremely significant.(2)On the 7th day before delivery,on the day of delivery and on the day of weaning,the levels of FSH,E2 and Insulin increased with the increase of back fat thickness on the day of delivery and on the 5th day of multiparous sow after weaning.There was extremely significant difference between high back fat thickness sows and medium and low back fat thickness.(3)On the 7th day before delivery,there was significant difference in FSH level betweenmiddle and low back fat thickness.There was significant difference in Insulin level between middle and low back fat thickness sows on the day of delivery.(4)On the 7th day before delivery and on the day of weaning,the higher the thickness of back fat,the higher the level of LH on the same day and on the 5th day after weaning.The difference of hormone level among high,medium and low thickness of back fat was extremely significant;the level of LH increased with.There were significant differences between high back fat thickness sows and medium and low back fat thickness sows.(5)The level of IGF-1 in sows with low,high and middle back fat thickness decreased on the 7th day before delivery and on the day of weaning at 1.On the 7th day before delivery,there was extremely significant difference in hormone levels between low back fat thickness and medium and high back fat thickness.There was significant difference in hormone level between middle and low back fat thickness of sows on weaning day.On the day of weaning,the thickness of high and middle back fat had significant effect on the level of IGF-1 on the5 th day after weaning,and the thickness of middle and low back fat had extremely significant difference.(6)The higher the back fat,the more litter size and the higher the birth weight,the thickness of high back fat was extremely different from that of medium and low back fat.The weight of weaning litter increased with the increase of weaning back fat,the thickness of high back fat was extremely different from that of medium and low back fat.The estrus interval of sows prolonged with the increase of weaning back fat,there was significant difference between high and low back fat thickness multiparous sows(7)The greater the back fat loss of multiparous sows during lactation,the greater the weight of weaning litter,the significant difference,the shorter the estrus interval,the significant difference.This study analyzed the effects of sow back fat thickness at different stages on reproductive hormone level and reproductive performance.It provides guidance for enterprises to adjust production from the direction of controlling back fat thickness,which could also help pig enterprises to increase production. |
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