Impact of Weaning Weight and Early Postweaning Growth of Pigs to Late Finishing Growth When Fed Either Corn- and Soybean Meal-Based Diets or Low Nutrient Excretion Nutrient-Dense Diets

The BW growth of 1,385 barrows and gilts was evaluated from d-21 weaning to 130 kg BW. The pigs were assigned to a 2×2 factorial arrangement of treatments. The pigs were fed a series of either standard corn- and soybean meal-based control diets or low nutrient excretion nutrient-dense (LNE-ND) diets from 1 wk postweaning to 130 kg BW and assigned to rooms with either deep pit or pull plug-recharge manure storage treatments. The pigs were weighed at weaning, at 7 and 14 d postweaning, and at approximately 2-wk intervals from 28 d postweaning to a mean BW of 130 kg. Mixed model nonlinear equations including pig-specific random effects were evaluated for the generalized Michaelis-Menten function. The serial postweaning BW data were fitted to a mixed model generalized Michaelis-Menten equation. Relationships of weaning BW to late finishing BW and days to 125 kg BW were different for each dietary treatment. Late finishing BW and days to 125 kg BW had nonlinear relationships with weaning BW for pigs fed the LNE-ND diets and had linear relationships for pigs fed the control diets. The predicted changes in subsequent BW of the LNE-ND diets per kilogram of change in weaning BW were greater for pigs with the lightest weaning BW than for pigs with average to above-average weaning BW. Across both dietary treatments, pigs with greater weaning BW and greater early postweaning ADG required fewer days to achieve target market BW.