Analysis Of Influencing Factors On Estrus Mating Rate Of Gilts And First Parity Sows And Establishment Of The Map Of Vulva State In Different Estrus Periods

The estrus mating rate of sows is a momentous indicator to measure the productivity of pig-raising enterprises and a key part to affect the economic benefits of pig breeding industry.Problems such as the lack of affection of gilts and the inability of some first parity sows to naturally estrus and breed have always existed in pig breeding enterprises.The purpose of this study is to collect the relevant indexes in the feeding process of gilts and first parity sows,and to study the effects of breeding sources,seasons,breeds,age,long pregnancy period,long lactation period and back fat on the estrus mating rate of reserve sows and first-born sows by using variance analysis and chi-square test.Using multiple linear regression analysis and multivariate binary logistic regression analysis,a model for predicting estrus mating rate was designed and established.To find out the factors that meaningfully affect the estrus mating rate and their suitable range,and provide basis for sow production management.In addition,pictures are combined with words to record and summarize the swelling degree,inner wall folds and mucus of vulva of gilts and first parity sows in estrus,pre-estrus,estrus and post-estrus,and establish a map.It provides real and effective materials for sow estrus identification,which is convenient for personnel to learn and thus reduces the error rate of sow estrus behavior identification.It is to jointly achieve the purpose of improving sow productivity,reducing the cost of sow feeding and achieving income generation.A total of 39232 gilts and 25736 first parity sows were collected in this study.The first part is the analysis of the influencing factors of estrus mating rate,mainly including the data of breed,pig type,season and day age;The second part is the establishment of vulva state map in different estrus periods,mainly including 10840 pictures of vulva and inner wall and data such as swelling,mucus,fold score,resting time length,mating result,litter size and so on.After analysis,the main results of this study are as follows:(1)In the single factor analysis of variance,the breeding season,the age of the first mating,the age of the first mating and the back fat of the first mating significantly affected the estrus mating rate of the gilts(P < 0.01);Chi-square test showed that breed,season(birth,mating,delivery,weaning),age(mating,delivery,weaning),long gestation period,long lactation period and back fat thickness(first mating,30 gestational years,108 gestational years and weaning)all had significant effects on the estrus mating rate of a sow(P < 0.01).(2)In the multivariate linear regression analysis,the breeding season and the first mating back fat significantly affected the estrus mating rate of gilts(P < 0.05),and the first mating day age had a very significant effect(P < 0.01).In the multivariate logistic regression analysis,the back fat of 30 pregnant years significantly affected the oestrus mating rate of a litter pig(P < 0.05),and the factors such as breed,mating season,weaning season,delivery age,long lactation period,weaning back fat and weaning head number significantly affected the oestrus mating rate of a litter sow(P < 0.01).(3)There was a positive correlation between the swelling degree index of gilts and first parity sows(r = 0.782)and the mucus content index(r = 0.957).The swelling degree of gilts was significantly higher than first parity sows(P < 0.01),but the amount of wrinkles was significantly lower(P < 0.01).(4)In that comparative analysis of the index of swelling degree,among which the redness and swelling degree in estrus is significantly higher than that in estrus(P < 0.01),pre-estrus was significantly higher than that in late estrus(P < 0.01),and estrus was significantly lower than that in the first three periods(P < 0.01).The amount of mucus in the middle estrus was significantly higher than that in the pre-estrus and post-estrus(P < 0.01),but there was no significant difference between the pre-estrus and post-estrus,and the amount of mucus in the estrus was significantly lower than that in the first three periods(P < 0.01).There is no significant difference in the amount of folds in the four stages of estrus cycle.(5)The static reaction mating rate,mating rate(including forced mating)and total mating rate of the first parity pig were significantly higher than those of the reserve pig(P < 0.01).The conception rate and delivery rate of first parity pigs were significantly higher than those of gilts(P < 0.05,P < 0.01).(6)The back fat thickness significantly affected the duration of reaction from preestrus to stillness,the number of live babies,the number of healthy babies and the weight of delivery litter(P < 0.05).To sum up,the estrus mating rate of gilts can be well predicted by three factors:the season of seedling entry,the back fat of first mating and the age of first mating.The estrus mating rate of first parity sows after weaning can be well predicted by eight factors: breed,mating season,weaning season,delivery age,lactation days,back fat at 30 gestational age,back fat at weaning and number of weaning heads.The swelling index of gilts is significantly higher than that of first parity sows,but the wrinkle index is significantly lower than that of first parity sows,and there are significant differences in swelling index and mucus index in each stage of estrus cycle.