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Impact of feeding level post-weaning on wean to estrus interval, conception and farrowing rates, and subsequent farrowing performance
Previous research has demonstrated that increasing post-weaning feed intake of sows with poor body condition can improve reproductive performance. The objective of this study was to determine the effect of feeding level from weaning to breeding of sows with good body condition on subsequent reproductive performance. Six hundred thirty eight sows (PIC 1050, C29 and C22) were randomly allotted within parity block (P1, P2, P3+) to one of three treatments after being weaned and moved into the wean sow room to evaluate the effect post-weaning feed intake on sow reproductive performance. Treatments were as follows: 2.7 kg of feed daily, 3.6 kg of feed daily, and 5.5 kg of feed daily. Sows in the study had a body condition score of 2.75 or greater based on a 5 point scale with 3 being ideal condition and had a standard lactation length between 18-23 days. At weaning, sows were blocked based on parity and day of weaning and then randomly assigned within block to one of the three treatments. Diets for the study were corn-soybean meal based with dried distillers grains with solubles and were formulated to contain 0.55% SID Lys and 3.2 Mcal Mod ME/kg. All other nutrients met or exceeded NRC requirements for gestating sows. All sows were fed twice daily, with their daily allotment equally divided between the two feedings. Sows were provided free access to water. Treatments were maintained until the day the sow was first bred. At breeding, sows were provided 1.8 kg/day ration throughout the gestation period. Data were analyzed using Proc Mixed with LSMEANS reported. Main effects of parity and treatment and the interactions were evaluated. Sow feed intake differed between treatments (2.68, 3.54, 5.18 kg/day; P<0.01). Average wean to estrus (5.13, 4.98, and 4.97 days; P>0.10), conception rates (95.63, 95.58, 94.67%; P>0.10), and subsequent total born (14.33, 13.93, 13.92 pigs/sow; P>0.10) were not significantly different between treatments (2.7, 3.6, or 5.5 kg, respectively). There were no parity by treatment interactions. In conclusion, when sows are in good body condition at weaning, there was no benefit on conception rates or subsequent born alive when feeding above 2.75 kg/d.
Keywords: sow, wean to estrus, feed intake