Growth of suckling piglets in litters standardized by weight.

This study examined the relationship between birth weight and growth performance when suckling piglets were reared in litters standardized by birth weight. Forty-four gilts (Landrace × Large White) due to farrow during the same week were selected. Piglets born to those gilts were individually weighed at birth and cross-fostered to obtain litters with 11 piglets and standardized birth weight (CV, lower than 5%). Based on average birth weight, 4 litter weight classes were established: class 1 (> 1.10 kg to ≤ 1.33 kg), class 2 (> 1.34 kg to ≤ 1.46 kg), class 3 (> 1.47 kg to ≤ 1.57 kg), and class 4 (> 1.58 kg to ≤ 1.88 kg). At 21 d of age, piglets were weighed to determine BW and calculate ADG and weight gain relative to birth weight. A completely randomized experimental design was used with birth weight classes as treatments. At 21 d of age, the average BW of piglets from the heaviest birth weight class (5.67 kg) was greater (P < 0.05) than the lightest class (5.06 kg); however, all classes had the same ADG (P < 0.05). There was a positive correlation (r = 0.184; P < 0.01) between birth weight and weight at 21 d of age, but birth weight was not correlated (r = -0.040; P = 0.37) with ADG during the suckling phase. Therefore, piglet birth weight did not influence weight gain when piglets were reared by sows in litters with standardized birth weight.