149 Analysis of culling pattern during breeding cycle and lifetime production from the aspect of culling reasons for gilts and sows in southwest China

Abstract

Abstract Unplanned removal of gilts and sows shortens the longevity and decreases the production efficiency. Analyzing and monitoring culling pattern conduces to administrative decisions on productivity and economic results of breeding herds. To investigate culling pattern during breeding cycle and lifetime production from the aspect of culling reasons, 19,471 culling records of 24 pig herds from January 2016 to December 2017 were collected in southwest China. Lifetime pigs born alive (LPBA) and parity for culling reasons were analyzed using mixed linear model (PROC MIXED) with culling reason as fixed effect and farm and year as random effects, respectively. For reason distribution at different parities and breeding cycle analysis, chi-square test (PROC FREQ) was performed for the comparison between any two culling reasons with an adjusted significant level when overall difference was significant. Results showed sows culled for stress and death (SD), lameness (LA), common disease (CD), and return to estrus (NP) had less than 20 of LPBA (P < 0.05). Gilts mainly culled for anestrus beyond 9 months (AB9), CD, and LA, while weaning sows for reproductive system disease (RS), CD, and anestrus beyond 7 days (P < 0.0033). Gestating sows mainly culled for NP, CD, and SD, while lactating sows for low or no milk production (NM), poor litter size, and CD (P < 0.0033). Moreover, sows mainly culled at parity 0, 1, and 2 (P < 0.0024). Besides CD and RS, LA and NP were the primary reason for parity 1 and 2 culls, respectively. In conclusion, SD, LA, CD, and NP sharply decrease sow lifetime production. AB9, RS, NP, and NM mainly occurred in gilts, weaning, gestating, and lactating sows, respectively. Low parity sows had more risks of CD, RS, LA, and NP.