Effects of Feeding Level and Diet Type during Wean-to-Estrus Interval on Reproductive Performance of Sows

This experiment was conducted to evaluate the effects of feeding level and diet type during wean-to-estrus interval (WEI). A total of 542 females (PIC-Camborough®) were used from weaning to the subsequent farrowing. Treatments were distributed in a factorial design 2×2 with 2 feeding levels during the WEI (2.6 or 3.4 kg/d) and 2 diet types [gestation (3.2 Mcal ME/kg and 0.69% SID Lys) or lactation (3.4 Mcal ME/kg and 1.4% SID lys)]. Dietary treatments were: Gest-High (GH), Gest-Low (GL), Lact-High (LH), Lact-Low (LL). Females were blocked by body condition using caliper score, parity, and randomly assigned to treatments. Average caliper body condition was 13±2.0 and average parity was 4.5±0.19. Females were fed 2.3 kg/d from 0-30 d of gestation, then 1.8 kg/d until farrowing. Data were analyzed using generalized linear mixed models with pen as the experimental unit, week and body condition as random effect, and parity as covariate. The WEI was 0.2±0.12 d lower in the GH and LL compared to GL and LH (interaction, P=0.021). There were no evidences for differences between dietary treatments (P³0.16) in farrowing rate, total born, stillborn, total litter weight, and born alive weight index. here was a marginally significant (P<0.10) interaction for born alive litter weight, where GH and LL had heavier litter birth weight compared to GL and LH. There was a marginally statistically (P<0.080) higher born alive rate by feeding gestation diet compared to lactation diet and by low feeding levels compared to high (P<0.070), both driven by differences in mummified fetuses (P<0.004). Individual born alive weight was 1.24, 1.30, 1.30, 1.29±0.040 for GL, GH, LL, LH, respectively (P=0.110). In conclusion, born alive was maximized with gestation feed and 2.6 kg/d seemed to be adequate to maintain reproductive performance, although further research with larger sample size is needed to validate the numerical negative effects of 2.6 kg/d of gestation diet on piglet birth weight.

		Gestation			Lactation			Probability, P<
		3.4	2.6		3.4	2.6	SEM	Feed type	Feed amount	Feed type x Feed amount
WEI		4.1	4.3		4.3	4.1	0.12	0.469	0.965	0.021
Total born, n		15.4	15.0		15.1	15.1	0.36	0.719	0.610	0.587
Born alive, %		91.70	92.20		89.90	91.70	1.17	0.080	0.070	0.395
Litter born alive weight, kg		17.9	17.1		17.2	17.7	0.40	0.877	0.653	0.084
Individual born alive weight, kg		1.30	1.24		1.29	1.30	0.04	0.257	0.391	0.110