Removing the two heaviest pigs from a finishing pen before sending pigs to market, also known as “topping,” improves the growth performance of the remaining pigs, according to Kansas State University research. Based on the income-over-feed cost, topping two pigs 15 days before closeout is the most optimal time.
In their experiments, researchers randomly assigned pigs to one of three groups:
Removing no pigs
Topping two pigs
Pulling four pigs per pen 15 days before marketing the remaining pigs in the group.
In the end, the final revenues were similar between groups, but feed usage and cost was reduced as pigs were topped from the group. They did note, however, that removing more than two pigs did not provide significant additional benefits.
The overall average daily gain and average daily feed intake did increase by increasing the number of pigs removed, and feed efficiency improved in pens that were topped relative to pens where the group remained intact. Weight discounts were highest in pig groups that remained intact versus those that were topped.
Feed efficiency did improve in all pens that were topped compared to pens that were not topped. However, pulling out more than two pigs per pen did not result in any additional improvement in feed efficiency. The researchers point out this suggests that the increase in average daily gain when an increasing number of pigs were removed from a pen was mainly due to the increase in average daily feed intake.