PSVII-9 - The Impact of Increasing Dietary Manganese on the Reproductive Performance of Sows

Abstract: The objective of this study was to determine the effect of dietary manganese (ProPath^® Mn, Zinpro Corporation) on the reproductive performance of sows. Sows (N = 39; 231 ± 8 kg) were randomly assigned to one of three dietary levels of Mn (CON: 0 ppm Mn; PRO20: 20 ppm Mn; PRO40: 40 ppm Mn). Experimental treatments were initiated at breeding and continued through two parities. Sows were blocked by parity within each farrowing group and dietary treatments were represented within each block. Data were analyzed as a randomized complete block design using the MIXED procedure of SAS with diet as a fixed effect and block as a random effect. Dietary treatment did not affect sow body weights (P > 0.10). Lactation feed intake was increased in PRO20 sows compared to CON and PRO40 sows (P < 0.05). PRO20 and PRO40 sows farrowed heavier piglets (CON 1.23 kg; PRO20 1.57 kg; PRO40 1.40 kg; P = 0.001) with improved average daily gain to weaning (CON 213 g/day; PRO20 237 g/day; 220 g/day; P < 0.05), compared to CON sows. Milk fat content (average from d 7 and 14 of lactation) was lowered in PRO20 (5.5%) and PRO40 sows (6.1%; P < 0.05) compared to CON sows (7.8%), possibly due to increased milk demand from the piglets. There were no significant differences in milk mineral concentrations during lactation or piglet tissue Mn-superoxide dismutase (MnSOD) activity at weaning (P > 0.10). On day 3 of lactation, prolactin concentrations were similar across treatments (P > 0.10), whereas progesterone concentrations tended to differ in response to Mn level (CON 23.70 ng/mL; PRO20 26.15 ng/mL; PRO40 22.10 ng/ml; P = 0.09). Supplementary dietary Mn throughout two gestation and lactation cycles led to increased birth weights and pre-weaning growth of piglets.