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The Effects of an Altered Suckling Treatment on Piglet Performance during Late Lactation and the Nursery Period
Societal concerns regarding sow housing have renewed interest in lactational estrus stimulation. As manipulation of suckling pressure is a critical component of stimulating estrus in sows during lactation, the effects of an altered suckling treatment (ALT) on nursery pig growth were also studied in a 14-d experiment encompassing late lactation and the early nursery period. A total of 611 pigs (PIC 327 × 1050) nursing 54 sows were used over two farrowing groups. Sows were allotted to treatments on d 18 of lactation when all but the 5 lightest weight pigs from each ALT litter were split-weaned (SW) and moved to a nursery. Pairs of ALT litters were established within parity and the light pigs in these litters combined. Combined litters rotationally suckled each sow of the pair for 12 h/d from d 18 until weaning on d 25 (RS). Control litters were weaned on d 21. At weaning, pigs were randomly assigned to pens (7 pigs/pen). After weaning, pigs were fed a common feed budget of 1.8 kg/pig for Phase 1 followed by a Phase 2 diet until experiment completion. Pigs were weighed on d 18, 21, 25, 28 and 32 of age. Differences in weight gain, litter weight variation, and the association between pig weight category (<4.5, 4.5 to 5.4, 5.4 to 6.4, and >6.4 kg) on d 18 and treatment effects were evaluated. For the overall treatment comparison, growth to d 32 was similar (3.30 vs. 3.27 kg) between ALT and controls. An initial weight × treatment interaction (P<0.01) was detected for weight gain from d 18 to 32 because the RS pigs gained 15% more than lightweight controls while SW pigs were 15% lighter than heavyweight controls on d 32. The ALT litters had 50% less (P<0.01) variation from d 18 to 32 as measured by change in CV (-4.2 vs. -1.9) and SD (0.43 vs. 0.92) compared to control litters. When pig weight groups at treatment initiation were compared, the ALT treatment benefited (3.04 vs 2.59 kg; P<0.001) growth of light (<4.5 kg) pigs but reduced (3.43 vs. 3.70 kg; P<0.01) the weight gain of heavy (>6.4 kg) pigs versus controls. While the ALT treatment used to stimulate lactational estrus improved litter variation without negatively impacting piglet growth, additional investigation is needed to determine the effects of the ALT treatment on ultimate market weight and economic implications.
Keywords: intermittent suckling, nursery pig, split weaning