Correlation Analysis between Litter Size and Primary Litter Weight,21-Day Litter Weight in Duroc Pigs

The indexes such as litter size,parity,litter weight at birth,21-day litter weight of 84 Duroc sows of new American variety were measured.The correlation and regression analysis of performances and analysis of variance were conducted according to litter size to explore the effect of parity on reproductive performance.The results showed that the difference of litter size,litter weight at birth as well as 21-day litter weight among groups was extremely significant(P0.01),and the difference of litter weight at birth when the number of live piglet was 7,8 and 9 was insignificant,while other groups' were significantly different or extremely different.The differences of 21d litter weight when the number of live piglet was 7,8,9,10,13 were all insignificant.The correlation analysis was carried out on litter size,parity,litter weight at birth and 21d litter weight.It was shown that there was no correlation between parity and 21d litter weight indexes,while other groups' indexes all reached the extreme level(P0.01).The comprehensive analysis revealed that the optimized economic benefits can be achieved when the number of live piglet ranged from 10 to 12.