The effect of weaner diet protein content and diet quality on the long-term performance of pigs to slaughter

Short and long-term effects of manipu- lating dietary CP content and diet quality in weaner di- ets on health and performance of pigs were investigated in a 2 × 2 factorial combination of CP inclusion (high- CP, 230 g of CP/kg vs. low-CP, 170 g of CP/kg) and diet quality (high-quality, cooked cereals, and animal protein vs. low-quality, raw cereals, and plant protein). Diets were fed ad libitum for 14 d postweaning to pigs weaned at 29.4 ± 3.1 d of age and 9.9 ± 1.0 kg of BW. From d 14 to slaughter at 104 ± 3 kg, all pigs were fed the same series of standard commercial diets. There were 15 replicates per treatment in the weaner phase ( 30 kg). High-quality diets promoted gut health as indicated by improved fecal lactobacilli to coliform ratio (P = 0.002) and decreased fecal entero- toxigenic Escherichia coli counts on d 11 postweaning (P = 0.028), reducing the risk of postweaning diarrhea and improving pig health from weaning to the end of the weaner phase. Reducing CP content had no effect on gut health. High-CP (P = 0.053) and high-quality (P = 0.025) diets independently increased ADG during the first 14 d postweaning compared with low-CP and low-quality diets, respectively. There were no interac- tions between dietary CP content and quality on any of the response criteria investigated. Despite differences in the immediate postweaning period, there was no effect of manipulating diet quality or CP content for 2 wk postweaning on lifetime performance with pigs reach- ing slaughter weight in 128 ± 7 d. These results indi- cate that high-quality diets may protect pig gut health during the immediate postweaning period. However, it may be possible to use less expensive, decreased qual- ity weaner diets without any adverse effects on long- term performance when weaning older, heavier pigs and where health status, environmental control, and stock management are all maintained to a high standard.