236 Factors associated with the farrowing rate in Brazilian batch farrowing sow farms

Abstract Introduction In the Brazilian swine industry, ~50% of the farms do not reach a target farrowing rate (FR) of 90%. It is known that environmental, management, nutrition, and health-related factors impair the ability of farms to achieve the target. This study aimed to evaluate predictors in Brazilian batch farrowing (BF) farms to identify drivers of FR. Methods An observational study was conducted in 25 BF farms (3- to 4-week batch intervals) and a survey with 41 questions gathered information on management practices, infrastructure, and health procedures. Retrospective monthly production data were collected (2022-2023) covering 555 herd-months observations. The outcome was analyzed using a binomial distribution and pairwise comparisons for FR marginal means were conducted using the Tukey-Kramer test. An initial univariate analysis was performed to assess the effect of each predictor using the GLMER procedure (R-software) with farm included as a random effect. Sixteen variables with P-value lower than 0.20 were selected to build a multivariable model using forward stepwise selection. Predictors with a P-value ≤ 0.05 were retained. Results The study farms had on average 1,031sows (330-3650), being 45.9% in 3-week and 54.1% 4- BF intervals. The overall average of FR was 89.9% (q1–87.0%; median–90.6%; q3–93.3%). Seven predictors were retained: percentage of mortality and re-served sows, day of estrus detection onset post-weaning, time spent on estrus detection, timing of group housing for gestating sows, daily stimulation for sows to stand, and season. The increase of 1% in the sow mortality and the percentage of re-served sows were associated with a decrease of 2% and 1% in the odds of the FR, respectively (P≤0.01). Table 1 describes each predictor with their respective average and confidence interval. Estrus detection starting on the day of weaning increased by 3.3% on FR compared to those starting one day post-weaning (P< 0.01). Lower FR was observed for housing sows 3-4-weeks compared to 1-week post-insemination (P< 0.01). Farms spending >25 min/50 females for heat check had higher FR than ≤25 min/50 females (P< 0.01). No difference was observed between farms that expend 15-25 min compared to those using less than 15 min/50 females. The FR was lower during fall compared to other seasons (P≤0.01). Farms that implemented a standardized procedure for standing sows once daily during gestation demonstrated 2.4% increase in the FR compared to farms that did not use this practice (P≤0.01). Conclusion The duration for estrus detection, estrus detection onset, practice of standing up the sows during gestation, reduction in sow mortality and reduction in the percentage of sows re-served into the breeding group must be revisited at the farm level for improving FR. Group housing gestating sows in different weeks post-insemination was not associated with FR, compared to sows kept in stalls.