Sows mated in summer produce a greater proportion of born-light piglets (<1.1 kg) which contributes to increased carcass fatness in the progeny population. The reasons for the low birth weight of these piglets remain unclear, and there have been few successful mitigation strategies identified. We hypothesized that: (1) the low birth weight of progeny born to sows mated in summer may be associated with weight loss during the previous summer lactation; and (2) increasing early gestation feed allowance for the sows with high lactational weight loss in summer can help weight recovery and improve progeny birth weight. Sows were classified as having either low (av. 1%) or high (av. 7%) lactational weight loss in their summer lactation. All the sows with low lactational weight loss (LLStd) and half of the sows with high lactational weight loss received a standard gestation feeding regime (HLStd) (2.6 kg/d; d 0-30 gestation), whereas the rest of the sows with high lactational weight loss received a compensatory feed allowance (HLComp) (3.5 kg/d; d 0-30 gestation). A comparison of LLStd (n=75) vs HLStd sows (n=78) showed that this magnitude of weight loss over summer lactation did not affect the average piglet or litter birth weight, but such results may be influenced by the higher litter size (P = 0.032) observed in LLStd sows. A comparison of HLStd vs HLComp (n=81) sows showed that the compensatory feeding increased (P = 0.021) weight gain of gestating sows by 6 kg, increased (P = 0.009) average piglet birth weight by 0.11 kg, tended to reduce (P = 0.054) the percentage of born-light piglets from 23.5% to 17.1% but reduced the litter size by 1.4 (P = 0.014). A sub-group of progeny stratified as born-light (0.8-1.1 kg) or -normal (1.3-1.7 kg) from each sow treatment were monitored for growth performance from weaning until 100 kg weight. The growth performance and carcass backfat of progeny were not affected by sow treatments. Born-light progeny had lower feed intake, lower growth rate, higher G:F, and higher carcass backfat than born-normal progeny (all P < 0.05). In summary, compensatory feeding from d 0-30 gestation in the sows with high weight loss during summer lactation reduced the percentage of born-light progeny at the cost of a lower litter size, which should improve growth rate and carcass leanness in the progeny population born to sows with high lactational weight loss.

Objective: To determine if feeding a larger diameter pellet increases creep feed intake and growth rate of piglets during lactation, especially that of gilt progeny (GP) compared to sow progeny (SP), and stimulates feed intake after weaning. Materials and methods: Over two replicates, GP and SP (n = 2070) were allocated to two creep feed treatments, receiving either a 4 mm diameter × 4 mm length pellet or a 9 mm diameter × 12 mm length pellet, from 3 days of age until weaning. After weaning, pigs were split into male and female pens according to the type of pellet fed in lactation and fed a common diet. Feed disappearance was recorded before and after weaning (up until 10 weeks of age), along with piglet growth performance and all piglet mortalities and removals. Results: Total creep feed disappearance in lactation was higher (P < .001) in litters offered the larger pellet, but litter weaning weight for GP was not improved (interaction, P > .05). Gilt progeny were weaned lighter (P < .001) than SP. After weaning, pigs offered the larger pellet during lactation showed a tendency to receive less medication (P = .07) than pigs offered the smaller pellet. Growth rate and feed intake after weaning were both stimulated (P = .02 and P = .09, respectively) in pigs offered the larger pellet during lactation irrespective of sex. Implications: Offering a larger pellet creep feed to piglets in lactation can improve postweaning performance and reduce the postweaning medication rate.

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