The Impact Of Nipple Number And Parities On Reproduction Performance In Sows

This paper is divided into two parts:the relationship between the number of births and the inheritance of pig nipple number; and the impact of parity on sows’reproductive performance.(1) The relationship between the number of births and the inheritance of pig nipple numberInvestigation and analysis of the relationship between the number nipples and the number of births in 376 pigs(boars and sows) and 1,344 piglets by the SPSS 17.0 program. The results showed that:breed has no effect to nipple distribution and its litter size. Distribution of the number of irregular nipple is normal. A small number of samples or the Purposeful selection of samples.The number of pig nipple is genetically stable and tends to parents on behalf of the average number of nipples;The difference between the average number of births and the number of maternal nest nipple was not significant (P> 0.05);The difference between the number of male nipples and litter birth number was significant(P <0.05),which explains that it will raise the number of sows farrowing by choosing a few more nipple male boars.(2) Impact of parity on sows’ reproductive performanceA statistical analysis of 2009-2012 breed data of 3520 nest Duroc, Landrace and Large White sows from Anhui core stock field was made by SPSS 17.0. The results showed that:(1)The highest total number born of Landrace sows was 14.72 in the sixth child and the lowest value was 11.80 in the first child, sixth tire was more than the first 2.92 on average, there were significant differences (P<0.01),while the highest average weaning weight was 62.37 kg, appeared in the fifth tire and the smallest average weaning weight is 58.92 kg,and appeared in the eighth tire.The weaning weight of the fifth tire relative to the first, seventh and eighth tire were extremely significant differences (P< 0.01).(2) The total number of birth, litter weight at birth and weaning weight of Duroc gradually increased from the first to the sixth tire until the sixth births peaked and the value was 10.50,11.62 and 54.12kg.From the beginning of the seventh tires, the total number of births, the number of live child, litter weight at birth and weaning weight began to fall.The change in the number born alive is no law.(3) The total number of birth, litter weight at birth and weaning weight of Large White increased from the first to the fifth tire with increasing birth order until the fifth and sixth tires to maximum,then with increasing parity decreased. Total litter size and birth litter weight of Large White sows fifth and sixth tire relative to other parities were significantly different (P<0.05); the fifth tire born alive and weaning weight relative to the first parity, seventh and eighth parity existed significant differences (P <0.01).The above results showed that the parity had significant effect on the litter birth number, litter weight at birth,and weaning weight (P<0.05); With increasing birth order, litter size,born alive,litter weight at birth and weaning weight gradually increased and the sixth litter or fifth litter reached largest, while these indexes the seventh litter began to decline.