The effect of dose timing schedule on live performance, carcass cutting yields, and fat quality of market gilts managed using GnRF immunization

Lay Summary This study examined how the timing of a two-dose GnRF immunization program affected live performance, carcass traits, and fat quality in gilts. The study was arranged as a 2 × 2 factorial, with main effects of the interval between dose 1 and dose 2 of the GnRF immunization (4 or 6 weeks) and the interval between dose 2 and marketing weighted averages of 49 days (long) or 35 days (short); marketing interval. Results showed that changing the interval between doses had limited impact on live performance, carcass characteristics, and carcass quality. However, the marketing interval had meaningful effects. Gilts marketed sooner after the second dose consumed less feed and had more favorable feed conversion compared with gilts marketed later. In contrast, gilts marketed later had greater fat deposition and heavier, firmer bellies. Producers using GnRF immunization should carefully manage the timing of the second dose relative to marketing to balance growth performance with carcass and processing quality goals.