Increasing weaning age: a tool to improve pig performance in a multisite production system

The objective of this study was to determine the effects of weaning age on pig performance in a multisite production system. A total of 1,176 pigs (PIC 337 × Camborough) were used in a 136-d growth trial with 21 pigs per pen, 14 replications per age on nursery and 10 on finishing phase, in a randomized complete block design with two blocks of nursery and finishing sites. All pigs within each block were weaned in a common day from a 5000- sow farm. Treatments included weaning litters at 19, 22, 25, or 28 d of age. Pen was the experimental unit for data analysis. Increasing weaning age from 19 to 28 d increased ADG (linear, P < 0.001), and ADFI (linear, P < 0.001), decreased removal rate (linear, P = 0.001), tended to increase G:F (linear, P = 0.081), and showed no evidence for difference in mortality rate (P > 0.05) in the initial 42 d after weaning. Finishing ADG also was improved (linear, P = 0.001) by increasing weaning age; however, there was no evidence for difference (P > 0.05) in removal or mortality rate in the finisher. When analyzed the ADG at a common day of life (164 d of age), no evidence for difference (P > 0.05) were found between the four weaning ages tested. In conclusion, the present study suggests increasing weaning age up to 28 d can be an effective management strategy to improve nursery and finishing growth performance in multisite pig production. However, the growth rate on a lifetime basis is not affected by the weaning age.