A Study on the Production Efficiency of 30 Commercial Swine Herds II. The Relationship Among Production Indices

Abstract

The data collected during 1992 from 30 commercial swine herds using PigLIVE or PigCHAMP database was used to calculate series of production indices for each herd. The simple correlation coefficients between primary and secondary indices were examined a set of 15 members of secondary indices which were highly correlated with pigs weaned/sow/year. A linear regression model best explaining the variability in pigs weaned/sow/year was then constructed by means of All Subset Regression procedure of Statistix.tm Litters/sow/year (r = 0.93), born alive litter size (r = 0.75) and preweaning mortality (r = -0.25) were correlated with pigs weaned/sow/year. The linear regression model having wean to first service interval, farrowing rate, annual percentage increase in sow inventory, lactation length and % stillborn piglets as its independent variables, provided the best explanation for the variability in pigs weaned/sow/year (R-squared = 0.85, P<0.01). The sow lactation intake and the gilt management may be the two most important factors causing suboptimum performance among the herds studied.