Effect of Birth weight on Retention rate and Reproductive Performance of the Hyperprolific sow at First Parity

The reproductive efficiency of sows is crucial for the sustainability of any swine herd. A female's ability to contribute to the herd earlier, for a longer period, and more efficiently impacts her individual performance, characterizing her lifetime productivity. Birth weight is one of the factors that influence a sow's lifetime reproductive performance. To determine the influence of birth weight on sow performance during the first three farrowings, a prospective comparative study was conducted using 703 gilts preselected as future breeding stock at weaning. The sows were classified based on their birth weight (BW): ≤1.1 kg (n = 175), 1.2 to 1.4 kg (n = 223), 1.5 to 1.6 kg (n = 183), and ≥1.7 kg (n = 122). First-parity gilts with a birth weight (BW) between 1.2 and 1.6 kg had a higher selection rate, tended to have a higher service rate, reached puberty, and were bred at a younger age. Sows with a BW ≥ 1.7 kg had a higher growth rate and body weight at the time of service. The results of the study, at first farrowing, indicate that sows with a BW ≤ 1.1 kg are not candidates for selection as future breeding stock.