A path analysis of the factors associated with seasonal variation of breeding failure in sows

Abstract

1), wean to service interval (WSI ≤ 5 d and > 5 d) and parity (parity 1, parities 2 to 5 and parity > 5) on the seasonality of breeding failure. Population attributable fraction (PAF) was calculated to determine the contribution of each risk factor. Overall breeding failure proportions were 23.5 and 20.9% in summer and other months, respectively. The likelihood of breeding failure was higher when sows were artificially inseminated (AI) only once, and 6 and 5% of breeding failures in the summer and other months, respectively, were attributable to single insemination. The likelihood of breeding failure was 1.5 and 1.4 times higher when WSI was > 5 d in the summer and other months, respectively, and 14% of breeding failure in summer was attributable to increase in WSI in summer, and in other months it accounted for 10%. Parity 1 sows reduced the proportion of breeding failure in the population in months other than summer [odds ratio (OR) 0.78]. Sows of parity 2-5 reduced the proportion of breeding failure in both seasons (OR 0.81 and 0.78 in summer and other months, respectively).