Effects Of Season,Delivery Treatment And Backfat Thickness On Reproductive Performance Of Sows

Pig breeding has a long history in China.With the development of economy and the improvement of people’s living standards,people’s demand for pork will continue to increase.However,compared with developed countries in the aquaculture industry abroad,the reproductive performance of sows in China is relatively low.In order to explore the factors affecting the reproductive performance of sows,this experiment analyzed the relationship between conception rate,litter performance,piglet birth weight,and weaning weight of different breeds of sows in different seasons;The relationship between the use of Cloprostenol Sodium before delivery and the delivery time,delivery process,litter performance,and estrus rate within seven days of weaning in sows;The relationship between postpartum backfat and litter performance of different breeds of sows,as well as the relationship between weaned sows’ backfat and estrus rate within seven days of weaning.The main results were as follows:1.Effect of season on sow reproductive performance(1).Conception rate: the conception rate of Landrace × Large White sows in summer was significantly lower than that in autumn and winter(p<0.05);The conception rate of Large White × Landrace sows in winter was significantly higher than that in other three seasons(p<0.05);The conception rate of Yorkshire sows in summer was significantly lower than that in autumn and winter(p<0.05);The conception rate of Landrace sows in summer was significantly lower than that in other three seasons(p<0.05).(2).Litter performance: Landrace × Large White sows’ total litter size and healthy litter size in summer were significantly lower than those of the other three seasons(p<0.05);Large White × Landrace sows’ total litter size in summer were significantly lower than in autumn(p<0.05);Yorkshire,Duroc and Landrace sows’ total litter size and healthy litter size in spring were significantly higher than in summer(p<0.05);The total litter size and healthy litter size of Duroc sows were significantly lower than other sows.(3).Piglets’ birth weight and weaning weight: There was no significant difference in birth weight among different seasons among piglets.The birth weight of Landrace × Large White piglets and Large White × Landrace piglets in autumn was significantly higher than that in other three seasons(p<0.05).The birth weight of Yorkshire,Duroc and Landrace piglets in summer was significantly lower than in autumn(p<0.05).2.Effect of delivery treatment on the reproductive performance of sows(1).Day delivery rate: the day delivery rate of Landrace × Large White sows,Large White × Landrace sows,Yorkshire sows and Landrace sows injected with Cloprostenol Sodium was significantly higher than that of natural delivery(p<0.05).(2).Duration of labor: the duration of labor of Landrace × Large White sows and Yorkshire sows injected with Cloprostenol Sodium was significantly lower than that of sows not injected with Cloprostenol Sodium(p<0.05).The duration of labor was also shortened in other sows injected with Cloprostenol Sodium.(3).Litter performance and Estrus rate within seven days of weaning: the use of Cloprostenol Sodium will not have a significant impact on the litter performance and estrus rate within seven days of weaning of sows(p>0.05).3.Effect of backfat thickness on reproductive performance of sows(1).Litter performance: Duroc sows had the highest total litter size and healthy litter size(p<0.05)when with a postpartum backfat of 19-22 mm.The total litter size of Landrace sows was the highest when with a postpartum backfat of 19-22mm(p < 0.05).(2).Piglets’ birth weight: the difference of postpartum backfat will not have a significant impact on the birth weight of piglets of different breeds(p>0.05).However,sows with a postpartum backfat of 19-22 mm have the largest birth weight.(3).The estrus rate within 7 days after weaning: The estrus rate within seven days of weaning Landrace × Large White sows and Yorkshire sows was higher when the weaning backfat is 15-18mm(p>0.05).In summary,sows have the worst conception rate and litter performance in summer,while piglets have relatively higher weaning weight in spring.The use of Cloprostenol Sodium during the delivery process can improve the daytime delivery rate of sows,shorten the delivery process of sows,and will not affect the litter performance and seven day estrus rate after weaning;Sows with a postpartum backfat of 19-22 mm have a higher number of healthy piglets,and their birth weight is relatively high.Sows with a backfat of 15-18 mm at weaning have a higher estrus rate within seven days of weaning.