A competent teenager can take a growing hog, and monitor its growth, care for its health and well-being, feed it well, and probably choose the day to be able to market a nice hog right in the target of a grading grid. A competent manager of an entire finishing herd has the same objective but rather than working with an individual hog, needs to manage a population. Add to this the constraints of time, the need to ship in lots, and the variation in the herd, and it is easy to see why not all hogs marketed hit the grid as well as they might. The figure below shows a realistic distribution of weights in a shipment of market hogs. While the majority of carcasses may well get a high index, depending on the yield class obtained a good proportion – perhaps as much as 15 to 20 per cent – could be significantly below their potential, just because they are a few kilograms heavy. This represents lost revenue.

Analyst Dr Dennis Dipietre has stated: "The root cause of high–cost systems is almost always traceable to high variance production." ¹ Reducing variation is, therefore, a main path to increased profit.

So, what can be done to reduce variation?

According to Dr Mike Tokach², variation in weaning age in an operation is one of the biggest drivers of variation in final market weight. Reducing the variation in weaning age requires weaning multiple times per week. Some of the production systems Dr Tokach worked with increased farrowing capacity in order to increase average weaning age. For example, adding the equivalent of one half of one week's worth of farrowing capacity would allow an increase in the weaning age of all pigs on the farm by three days. The payback from this investment comes from all pigs weaned rather than just the pigs weaned from the added spaces. Increasing weaning age appears to decrease variation as well as improve growth performance.

Another approach is the use of opportunity barns to separate out the smallest pigs – say, five to 25 per cent, depending on the system – and raise them separately. Separate management of the smallest pigs in these opportunity barns (or rooms) allow the provision of special diets in an attempt to increase growth rate. The result is that while variation in the original weaning group is not reduced, the variation within the production unit is reduced. Of course, the system must be designed with opportunity space in mind to be able to take advantage of this method of reducing variation.

Other worthwhile methods to reduce variation might be: selecting sires with similar indexes; feeding multiple diets within groups; nutrient management of the sow to reduce lightweight pigs at birth; and ensuring adequate access to water.

Some options that might seem attractive at first do not seem worth either the time or the cost, according to Dr Tokach. Firstly, there are several procedures that can be used to increase the weight gain of the smaller pigs in the group in an attempt to reduce variation. These include: split suckling, use of complex nursery diets or supplemental milk, or shifting the smallest pigs to higher producing sows. These technologies all have been proven to slightly increase the weight gain of the small pigs and reduce variation at market weight. The impacts are all relatively small and the economic payback appears to be small to non-existent.

Of course, the final cause of variation in the hogs reaching the plant comes back to shipping decisions. Providing feedback about success and failures in hitting shipping targets to those responsible for selecting hogs for shipping, and determining the shipping schedule, can help in reducing this variation. This is especially effective if there is some incentive provided for improvement.

References

1. DiPietre, D. 2010. A Holistic View of the Future. Proceedings of the 10th London Swine Conference. p17-20.
2. Tokach, M. et al. 2007. New Tools to Manage Variability Throughout the Pork Production Chain. Proceedings of the 7th London Swine Conference. p19-33.