EFFECT OF SUPPLEMENTAL PIG MILK REPLACER ON LITTER PERFORMANCE - SEASONAL-VARIATION IN RESPONSE

The objective of this study was to determine the effect of supplementa l milk replacer on sow and litter performance. The study was conducted in 12 farrowing groups (171 litters) over a 3.5-yr period (October 19 90 to April 1994). Commercial milk replacer was prepared fresh daily ( 150 g/L) and offered with ad libitum access in the farrowing crates wi thin 24 h of parturition and was continued through weaning(d 21). Aver age pig weight (control, 5.5 kg/pig; supplemented, 6.4 kg/pig; P < .00 1) and total litter weight (control, 52.2 kg/litter; supplemented, 60. 9 kg/litter; P < .001) at weaning were greater for litters receiving s upplemental milk replacer. There was no effect (P > .2) of supplementa l milk replacer on feed intake, backfat thickness, or body weight loss in the sow. Consumption of milk replacer varied greatly among litters . A portion of this variation in intake was accounted for by differenc es in ambient temperature among farrowing groups. Average milk replace r intakes (liters per pig) from birth to d 21 were 2.5 L/pig (.375 kg dry matter) and 9.9 L/pig (1.49 kg dry matter) for pigs born during th e cool and warm seasons, respectively(P < .001). The weaning weight ad vantage conferred by milk replacer was most evident during the warmer months. Sow feed intakes averaged 5.8 and 3.9 kg/d over the same perio ds (P < .001). These results demonstrate the advantage of milk replace r on weaning weight and indicate that the greatest benefit from the su pplement is during the warmer months when sow feed intake and subseque nt milk production are lower.