Study On The Relationship Between Backfat Thickness And Reproductive Performance In Pregnant Sows

In order to study the correlation between backfat thickness and reproductive performance in pregnant sows,Data were collected on the initial and postpartum reproduction of 2552 female pigs from a pig farm in sichuan from September 2017 to July 2018,the date include total number born,number born alive,healthy number,weak number,number of stillbirths,litter weight and average birth weight.The data was sorted in EXCEL,the analysis of Bonferroni and pearson correlation of data compiled by using SPSS22.0,the linear and nonlinear regression fitting is made by scatter plot of each index.The main results are as follows:1.Subjective scoring results could not distinguish the actual backfat thickness of sows,nor could they distinguish the reproductive performance of sows.2.The backfat thickness of the first-born sows had a significant effect on the age of the first-mating.When the backfat thickness reached 5 grade,it was the best;There were no significant differences in total litter size,live litter size,healthy litter size,weak litter size,stillbirths,litter weight and mean birth weight among primipara sows with different backfat thickness at different gestational stages(P>0.05),There was no significant difference in total litter size and live litter size at different stages of pregnancy,but the total litter size increased first and then decreased with the increase of back fat thickness.In general,the backfat thickness of primiparous sows at different stages of pregnancy has no significant effect on their reproductive performance.3.There is a significant correlation between the backfat thickness and reproductive performance of the multiparous sows during pregnancy.There was a significant correlation between the backfat thickness on the day of breeding and the average birth weight of the piglets(P<0.01),The back fat thickness of pregnant 30 d is significantly correlated with total litter size(P<0.05)and mummy number(P<0.05),The back fat thickness of pregnancy 60 d is significantly correlated with total litter size(P<0.05),The back fat thickness of pregnancy 90 d is significantly correlated with the average birth weight of piglets(P<0.01).Linear regression and non-linear regression fitting showed that it was not easy to be too thin or too fat for multiparous sows at different stages of pregnancy,and it was most suitable to control back fat at 10-14 mm.4.The variation of Backfat in sows was significantly correlated with total litter size,healthy litter size,weak litter size and mummy size.Within the range of measurement,the total litter size and healthy litter size of sows will decrease as their backfat becomes thicker and thicker,while the weak litter size will increase.Therefore,it is very important for the sows to keep their backfat from 10 mm to 14 mm during pregnancy and keep the gestation period unchanged.