Benchmarking sow herds

Viewing your sow herd as a living organism!

Dr. John Deen

The opportunity to compare sow herds is always a humbling activity. On the one hand, we are presented with a large amount of data, especially at the individual sow level. In comparison, postweaning growing pig records have much less data. With rarely any individual pig records growing, pig records are made up of discrete groups of pigs replaced every six months. Sow herds are different, from year to year they carry many of the same characteristics, even though individual sows are replaced over time.

In some ways a sow herd can be viewed as one living organism. It changes over time, but slowly, driven by infectious disease, the quality of management and the qualities of incoming young stock. In many ways, the US sow herd has been following an impressive pathway to greater productivity. The data shows herds with a mean pigs weaned per mated female of almost 27 piglets per year.

Yet, we must admit that there are also challenges in the management of sow herds. They can show up in a couple of different ways. First of all, we can have trends that are going in the wrong direction. An example of that is sow mortality, where we have seen the means trend upwards.

However, we can also look at the standard deviation (SD) to see if there is variation from farm to farm. The examination of variation is an approach that production analysis has performed across many industries. The idea is that if the standard deviation is large, we should be able to find solutions with internal comparisons within our industry. It’s called capability measurement and gives some guidance in improvement on our farms. If we take the SD over the mean, we have the coefficient of variation (CV).

Sow Mortality Rate

Some CVs, when comparing herds are relatively small. The total born per litter has a CV of 7%, suggesting that either the ability to change is outside the regular capabilities of the farms, or that the ability to change is widely available and regularly taken up. The sow mortality rate has a higher CV of 38%, as shown in figure 1. Not only is there a wide distribution, but you can also see that the distribution is somewhat skewed, with some herds particularly pulling the average up.

Some indicators have been particularly high CVs. Percent repeat services at a CV of 87% is one example where there may not only be differences in the capability of herds, but real differences in how the herds are managed. Differences such as this create a big question as to whether management strategies have been fully evaluated in their effect on the whole herd.

If I could give one generalization in this review, it would be that the largest capability variation is not in the output measures such as pigs per mated female per year, but in sow inputs. Mortality, replacement, and culling rates all have CVs and are driven by herd characteristics and are tied to high expectations of repeatable reproductive performance along with immutable breeding targets. Some of these measures appear to be like a loose rope tied to the back of a pickup truck. They are moving whipping around, with little to hold them down.

We do have new syndromes, such as pelvic organ prolapses and new PRRS variants, but there are also systematic pressures that need to be characterized in more detail. The CVs seen from farm to farm should lead to examinations of CVs within farms, looking at which production variables vary from week to week and month to month. These CVs may not only point out problematic areas, but areas where further examination may identify room for improvement.

Dr. John Deen
Dr. Deen is a distinguished Global Professor at the College of Veterinary Medicine, University of Minnesota. His work in research, teaching and extension has been in epidemiology and economics, focusing on measurement and optimization across competing needs in animal agriculture and human health. Dr. Deen earned hid DVM and PhD from the University of Guelph and gained board certification in the American College of Veterinary Practitioners and the American College of Animal Welfare.