Within- and between-litter variation of proximate composition in newborn and 10-day-old landrace swine

Proximate composition of individuals from four litters of newborn and six whole litters of 10-day-old purebred Landrace piglets from primiparous and multiparous dams was determined. A dramatic increase in ether extract percentage occurred during the first 10 postpartum days as moisture and ash percentages decreased and protein increased. Average values for newborn and 10-day-old piglets, respectively were: weight 1.39 +/- .26 and 3.07 +/- .57 kg, moisture 79.17 +/- .96 and 70.51 +/- 1.36%; ether extract, .55 +/- .17 and 9.92 +/- 1.46%; protein 12.07 +/- .73 and 14.90 +/- .38% and ash, 4.63 +/- .40 and 3.44 +/- .31%. Although variation in proximate composition was small at birth, within as well as between-litter differences were observed. Carcasses of the heavier newborn piglets had lower moisture and higher protein percentages. Variation in the proximate composition of 10-day-old piglets was greater and accounted for, in part, by within and between-litter differences, plus in the case of moisture and ether extract percentages, differences in 10-day gain. Average values for three 10-day-old, slow-growing piglets were birth weight, 1.39 kg; 10-day weight, 2.13 kg; 10-day gain, .74 kg; moisture 75.49%; ether extract, 3.43%; protein, 15.34%; and ash, 4.37%. Although these piglets had a slow growth rate, their ether extract percentages increased by sixfold over the average value found for newborn piglets.