The effect of late gestation injectable vitamin A and D supplementation on sow and piglet performance

Vitamin A is an essential nutrient with an important role in animal health across livestock species. Insufficient dietary vitamin A intake is associated with decreased reproductive performance in females as well as impaired growth performance and health of the offspring. The aim of this study was to determine if an intramuscular injection of vitamin A and D (VitAD) given to sows on d 85 of gestation improved the survivability, growth performance, and health of the offspring from birth through the end of the nursery phase. Yorkshire or Yorkshire cross bred sows received either an injection of VitAD (312,000 IU vitamin A, 52,500 IU vitamin D. n = 9) or saline control (n = 10). At farrowing, birth weights, survival, and umbilical blood was collected on the piglets, and colostrum was collected from sows. Daily weights were taken from d 0 to 4, then weekly weights from d 8 to 63 on all pigs. Milk samples were taken weekly on sows from birth to weaning (d 28), and daily feed consumption for the sows was tracked during the lactation phase. Blood samples were obtained weekly from piglets through weaning (d 28). Subsequent blood samples were taken weekly through the nursery phase (d 28-d 63) from a subset of the original pigs to measure retinol from birth to d 63 and immune parameters from d 28 to d 63. All statistical analyses were run using a mixed linear regression model on SAS (9.4; SAS, Cary, NC). VitAD piglets tended to have a reduced average daily gain (ADG) from d 22 to d 28 (P = 0.08), and decreased circulating retinol concentrations on d 15, 22, and 28 (P ≤ 0.05) compared to control piglets. Fewer stillborn piglets (P = 0.01) were present in litters from sows treated with Vit AD compared to control sows. VitAD pigs had an elevated reticulocyte count on d 42 (P ≤ 0.01) compared to the control pigs. VitAD treated sows consumed less feed on d 15 (P ≤ 0.05) and had greater milk retinol (P ≤ 0.01) on d 8 of lactation compared to control sows. These results suggest that the administration of an injection of VitAD to sows on d 85 of gestation might improve offspring survival at birth, as well as decrease sow nutritional consumption requirements during lactation. Additionally, these results help to establish normal immune parameters and circulating retinol in pigs. Importantly, no negative effect of VitAD supplementation on growth rate or immune parameters was observed.