Investigation of the effects on maternal parity on carcass traits of progeny in swine using on-farm test records

The purpose of this study was to evaluate the effects of sex, birth year, birth season, and parity of sows on their progeny using the following on-farm test records: Backfat Thickness (BF), Fresh Meat Percent (FMP), Loin depth (LD), Age at 90kg (90D), and Average Daily Gain (ADG). Statistical analysis was performed using data collected from 1,178 Yorkshire and 13,395 Landrace progenies, which were born from 119 Yorkshire and 1,191 Landrace sows, respectively between 2011 and 2015. All results of the analysis were statistically significant (P < 0.05) except the birth season effect on LD. For Landrace, the highest ratings were found to be at the $5^{th}$ parity (BF), at the $3^{rd}$ parity (FMP and LD), at the $2^{nd}$ parity (90D and ADG). For Yorkshire, the highest ratings were at the $2^{nd}$ parity (BF and FMP), at the $3^{rd}$ parity (LD), and at the $4^{th}$ parity (90D and ADG). Although the ratings of carcass traits of progeny appear to be higher between the maternal sow's $2^{nd}$ and $4^{th}$ progenitor, no significant relations to parity were found. Based on these results, we concluded that maternal parity is not significantly affect carcass traits of progeny and thus that the best slaughtering age of sows should not be determined solely based on maternal parity but also in consideration of other factors such as unit costs of production. The results of this study would provide fundamental information to future studies on the effect of economical parity on sows and swine breeding.