Summer heat has arrived in the upper Midwest. As happens every year, slaughter weights decline because hot pigs don’t eat.

Every summer slaughter weights decline. USDA reports that for the past 10 years slaughter weights in July compared to early January are 8-9 pounds per pig lower for the Iowa/Southern Minnesota market.

One response often cited as a recommended management practice to help pigs cope with warm conditions is to give them more space. While this sounds good, the reality of production is just the opposite.

Because of seasonal infertility last summer/fall followed by a return to normal fertility patterns in the breeding herd, pig numbers in production facilities are the highest in summer months. This is why slaughter numbers are lower in summer months and peak in late fall.

This year, the early arrival of hot weather in the upper Midwest (remember the heat on Thursday at World Pork Expo?) along with the very hot temperatures in the southwest caused a rapid decline in US slaughter weights. In normal weeks, carcass weights of barrows and gilts gradually increases over the week with Friday’s weight generally being 2 lb heavier than Monday and Tuesday weights.

On the week of June 6, Wednesday slaughter weights were higher than Monday and Tuesday weights, but Thursday weights were the same as earlier in the week and Friday weights were 0.6 lb below Monday weights. Considering that barrow and gilt slaughter averaged about 385,000 head per day that week, this represents a lot of carcass weight.

For the week ending on June 10, the average carcass weight of all barrows and gilts slaughtered under federal inspection (LM_HG201) was 212.4 lb, down from the 213.2 lb average of the previous week. Weights declined to 210.5 lb for the week ending on June 17 and declined further to 209.3 lb for the week ending on June 24. This means in a 3 week period, weights declined just under 4 pounds. While this week isn’t ended, it appears that slaughter weights will be similar to last week.

The challenge for producers this summer and fall is managing sales. If space is available, producers naturally want to hold pigs a few extra days if necessary to attain desired slaughter weights since summer prices are always higher than fall market prices. At the same time, this year there is the industry concern of slaughter capacity going into October and November. This means the industry has to remain current on slaughter inventory so that more pigs don’t get pushed into the October and November window.

History suggests that once we return to cooler nights in late August, pig sale weights climb rapidly. At the same time the number of pigs sold rapidly increases due to the previous year’s seasonal infertility pattern. Once this cycle starts it’s just about impossible to get ahead on sales.

What’s your plan this year to avoid (or at least minimize) this problem in your flow? With predictions of weekly slaughter reaching as much as 2.5-2.6 million pigs for several weeks this fall, now is the time to ponder your plan, not in late August when the problem is too far along to remedy.