Factors influencing piglet average daily gain during the first week of lactation in hyperprolific sow under tropical conditions

Birth weight (BW) is a key determinant of average daily gain (ADG) in piglets; however, hyperprolific sow genetics, particularly under tropical conditions, have increased the proportion of low-birth-weight piglets. This study evaluated factors associated with ADG during the first 7 days of lactation within birth weight categories (1.3 kg). A total of 1,185 piglets from 97 litters that survived to day 7 were included. Factors analyzed were cumulative birth interval, birth order, colostrum intake per kilogram of body weight, rectal temperature at 24 h postpartum, sex, intrauterine growth restriction (IUGR), and cross-fostering. Birth weight, cumulative birth interval, birth order, colostrum intake, and rectal temperature were significantly associated with ADG. Piglets with high birth weight showed greater ADG (180 ± 4 g/day) than moderate (150 ± 4 g/day) and low birth weight groups (113 ± 5 g/day, P < 0.001). Regardless of birth weight, piglets that consumed 300–400 or >400 g colostrum/kg BW had significantly higher ADG than those that consumed 200–300 g colostrum/kg BW (P < 0.001). Within the high birth weight group, longer cumulative birth intervals (>240 min) and later birth order were associated with reduced ADG (P < 0.05). Rectal temperature at 24 h positively influenced ADG in moderate and high birth weight groups. Additionally, sex, IUGR, and cross-fostering affected ADG across birth weight categories. These findings emphasize the importance of neonatal vitality and management, particularly optimizing colostrum intake, maintaining thermal status, and appropriate cross-fostering, to improve early growth performance in piglets under tropical conditions.