The effect of postulating diet intake on embryonic and fetal survival, and litter size in gilts

Abstract

The effect on reproductive performance of restriction of diet intake to body weight maintenance for 10 d after mating (R), versus a daily gain of 0.4 kg (C) was assessed in 264 Landrace (L) × Yorkshire (Y) gilts in a rotational crossbreeding program over 4 yr. Gilts were slaughtered during gestation at 30 d (49 gilts) and 60 d (52 gilts), or farrowed (163 gilts). Diet intake had no effect on survival at 30 d (C, 85.1% and R, 82.5%; P > 0.10) and 60 d (C, 81.8% and R, 82.4%, P > 0.10), or on litter size (C, 9.9 and R, 9.9 piglets born alive; P > 0.10). Breed difference in survival approached significance at 30 d (Y × LY, 88.3% vs. L × YL, 80.2%; P = 0.086), and decreased at 60 d (Y × LY, 83.3% and L × YL, 81.4%; P > 0.10). Breed differences in the number of piglets born alive were not significant (Y × LY, 10.2 and L × YL, 9.6 piglets; P > 0.10). Deaths during gestation and parturition averaged 25.6% (16.2% by 30 d; 1.7%, 30 to 60 d; 3.2%, 60 d to parturition; and 4.5%, during parturition (stillbirths)). The 17.9% death loss up to 60 d of gestation was due in part to a greater death loss associated with higher ovulation rates (R2 = 6.60) but was not influenced by individual sires, semen quality attributes, duration of estrus or body weight changes. Thus, in the crossbred gilt, the majority of death losses occur by 30 d of gestation, and do not appear to be affected by changes in diet intake early in gestation. Key words: Gilts, diet intake, embryonic survival, stillbirth, litter size