The occurrence of late weaners is one of the variables that should be reviewed, understood and fixed when the incidence rate increases or the interval becomes extended. In many situations the cause and subsequently, the solution, can be identified and targeted for improvement. The goal of this article is to provide definitions to better understand the implications of a longer weaning-to-service interval and also provide a set of practical interventions.

Introduction

A deep understanding of the cost structure, at every production phase, is required to thrive in volatile times. It is well known that after feed cost the second biggest input cost of the market pig is the cost of the weaned pig. Late weaners and procedures including skipping a heat increase the number of non-productive-days, negatively affecting the number of litters per sow per year, which in turn can decrease throughput and increase the cost of producing a weaned pig.

Definition

A late weaner is a sow that does not show estrus within the first 7 days after weaning. It becomes an issue when its prevalence is > 1% of the average sow inventory at any given time, when breed back is < 90% or when the farm average wean-to-service interval is consistently > 7 days. Seasonality may play a role by depressing feed intake. When this reduction of intake is found, younger parity females are especially vulnerable to delayed return to estrus and subsequently, may increase the occurrence in this group.

System Review

The table below summarizes the most relevant points that should be reviewed and a set of meaningful interventions to address the issue:

Justification & Interventions

A longer wean-to-service interval negatively impacts the litters farrowed per sow per year. The financial impact of this delay is strongly dependent on the geography, as it creates variations in feed, labor and facilities costs. Our experience suggests a decrease of 0.02 litters per sow per year with every additional day added to the wean-to-service interval for the farm. In terms of increased wean pig cost, and not considering the impact of the lost opportunity profit from unrealized pigs, the cost per inventoried sow is up by $7 to $10 per year, per every 10% of weaned sows that are late breeders.