The effect of pre- and post-mating dietary restriction on embryonic survival in gilts

The aims of this study were to determine if pre- and post-mating feeding levels interact to affect embryonic survival, and to determine whether feeding to the maintenance requirement would impair embryo survival. Gilts were allocated to a pre-mating treatment of 1 or 0.8× energy maintenance from day 1 to 14 of their oestrous cycle prior to mating. From day 15 to mating all gilts were group housed and fed ad lib. Gilts were artificially inseminated at their third oestrus. The day after mating, gilts were group housed and allocated to post-mating treatments of 1.5 or 1× maintenance. Gilts were slaughtered day 25.5 ± 0.2 post-insemination and reproductive tracts collected. Gilts fed the restricted pre-mating diet lost significantly more weight than gilts fed the increased pre-mating diet (6.7 ± 0.8 versus 3.7 ± 0.7 kg). From mating to slaughter, gilts fed the restricted post-mating diet lost 0.5 ± 1.02 kg liveweight, while gilts fed the increased post-mating diet gained 5.7 ± 0.90 kg liveweight (P < 0.05). The pre-mating dietary treatment had no effect on any reproductive measure. Embryonic survival was greater (P < 0.05) in gilts fed the high post-mating diet compared with gilts fed the low post-mating diet (88.4 ± 2.5 versus 77.8 ± 4.0%), resulting in more (P < 0.05) conceptuses present (14.0 ± 0.6 versus 11.7 ± 0.7). There was no interaction between pre-mating and post-mating feed intake on any reproductive measure. These data demonstrated that reducing post-mating feed intakes to maintenance levels impaired embryo survival.