This study investigated the effects of supplementing vitamins and minerals to sows during early gestation. A total of 36 primiparous sows were randomly assigned one day before mating to four dietary treatments that were applied from mating to day 30 of gestation. Treatment 1: low feed intake (1.5 kg/day) with standard vitamin and mineral provision (0.10% as fed); treatment 2: low feed intake (1.5 kg/day) with double the standard provision of vitamins and minerals (0.20% as fed); treatment 3: medium feed intake (2.0 kg/day) with standard vitamin and mineral provision (0.10% as fed); and treatment 4: high feed intake (3.0 kg/day) with standard vitamin and mineral provision (0.10% as fed). Results showed that sows in treatment 4 had the highest body weights at days 30 (179.17 kg) and 80 (211.97 kg) of gestation. Sows in treatments 2 and 4 also had numerically larger litters (12.50 and 12.74 piglets, respectively) than sows in treatments 1 and 3 (9.88 and 10.71 piglets, respectively), although this difference was not statistically significant. Additionally, treatment 2 and 4 sows tended to wean more piglets (11.00 and 11.20 piglets, respectively) than treatment 1 and 3 sows. Overall, both a high level of vitamin and mineral supplementation with a low feed intake (treatment 2), and a high feed intake with standard vitamin and mineral supplementation (treatment 4) during early gestation seemed to have the potential to increase litter size to a similar extent, although a high feed intake may be associated with non-significantly reduced piglet growth.

(Submitted 26 March 2025; Accepted 31 October 2025; Published 13 November 2025)