The Influence Of Sows’ Backfat Thickness At Farrowing&Weaning, And Farrowing Month On Reproductive Performance

The reproduction traits of sows is an important indicator for productivity of pig farm, is also acritical factor influencing the economic benefit. Backfat thickness is related to body fat closely,and is a good predictor of reproductive performance, but the commonly used visual scoringmethod is not accurate. In this paper, ultrasonic wave was used to measure backfat, and therelationship between backfat thickness and reproductive performance was analyzed. Farrowingseason also affect the reproductive performance of sows, in this paper the influence of farrowingmonth on reproduction traits was also analyzed.1. This experiment was aimed to reveal the effects of sows’ backfat thickness at farrowing and atweaning on Reproductive Performance. The backfat thickness at farrowing and at weaning wasdetermined by type-A ultrasonic device. According to the backfat thickness at farrowing, sowswere divided into group1(<10mm), group2(10mm-13mm), group3(13mm-16mm), group4(>14mm); According to the backfat thickness at weaning, sows were divided into group A (<7mm), group B (7mm-10mm), group C (10mm-13mm), group D (13mm-16mm), group E (>16mm); According to the loss of backfat thickness during the lactation period, sows were dividedinto group I (<3mm), group II (3mm-6mm) and group III (>6mm). The results showed that therate of sows producing stillbirth is10%in group2, which is the least in the4groups; and theaverage weaning-estrus interval of group C is significantly shorter than other groups. During thelactation period, the loss of back-fat thickness in group Ⅲ is higher than groupⅠandgroupⅡevidently, and the average weaning-estrus interval of group C was also markedly higherthan groupⅠand groupⅡ. The study indicated that sows with medium backfat thickness atfarrowing and weaning shown best reproduction performance. And an regression equation wasestablished to forecast estrus date based on backfat thickness at weaning: Y=31.787-6.169X+0.440X2-0.009X3.2. In this study the reproduction records of a Pig Farm were collected to analysis the breedingseason on reproductive performance of sows and provide effective suggestions and theoreticalbasis for pig production. The results show that: Seasonal variations don’t have a notable effect onthe average litter size or the average alive litter size. The average litter size of February is thelowest and the average alive litter size of August is the lowest. The average dead litter sizes of Julyand August are relatively high compared with that of the other months. The data suggested that themethod of heating in winter and cooling in summer under the condition of local climate works.But in hottest months more measures should be taken for better cooling effect, and in winterventilation of piggery should be enhanced to improve air condition.This study provided new data for swine reproduction and will be helpful formanagement of sows.