The effect of 15% lipid addition to perinatal sow's diet on piglet survival and performance was investigated with 85 litters over four farrowing seasons. Sows received either control or fat supplemented diets from d 109 of gestation through d 21 of lactation. Substitution of a casein-encapsulated white grease product for corn (i.e., an increase in diet fat by 15%) increased (P less than .05) piglet weight gain (230 vs 214 g/d) and piglet survival 84.9 vs 79.1% of live born pigs to 21 d of age. Piglet survival data, analyzed by logistic regression, indicated that a 15% increase in dietary fat increased the odds of piglet survival at all birth weights. However, the probability of piglet survival was most enhanced at birth weights between 700 and 1,100 g. Over this weight range, the survival rate of piglets from sows receiving the supplement was increased by 10 percentage units. Feeding a high fat supplement increased piglet survival during the first 3 d of life and again at d 9. The results of this experiment suggest a unique effect of including a high fat supplement late in gestation on piglet survival during the first several days of life. Logistic regression was shown to be an appropriate and useful technique for analysis of factors affecting piglet survival.
