I have tracked the Iowa-Southern Minnesota live weight at slaughter (www.ams.usda.gov/mnreports/NW_LS720.txt) for many years. My original interest was in defining the impact of summer heat as measured by the significant annual decline in sales weight for barrows and gilts that always occurs between June 1 and September 1. On average, this decline from the January sales weight has been 8.5-9.0 pounds.

At the same time, this tracking has also allowed me to follow the increase in sales weight that we’ve come to expect every fall with the arrival of new crop corn and reduced heat. Last year in response to the significant increase in feed prices due to the drought shortened harvest the fall increase was curtailed significantly, with live weights under the 2011 weights all fall.

That is not the case this year. Live weights are soaring. Weights for the week ending November 9 were 6.3 pounds above last year and 8.2 pounds above the previous 5 year average. The weekly average last week was 280.8 pounds, the heaviest week average weight ever.

It turns out this increase in weight is not only an Iowa-Southern Minnesota phenomena. Slaughter weights for all federally inspected barrows and gilts is rapidly increasing this year. For the slaughter period from November 4 through November 11 the USDA reported 2.449 million barrows and gilts were slaughtered under their inspection with an average carcass weight of 212.05 pounds. Back in August, the average carcass weight was 203 pounds. This is a 9 pound increase in carcass weight for every barrow and gilt slaughtered.

It is really surprising that prices haven’t dropped further given the huge increase in tonnage. Much has been made about the ‘lack’ of supply this fall with slaughter numbers coming in below USDA Hogs and Pigs Report estimates. Because of this increase in carcass weight that is well beyond the typical ‘fall’ increase the supply of pork for consumers is running somewhat close to what was projected.

With the prospect of relatively low priced corn for the coming year and talk of possible pig shortages due to the PED virus I expect weights to continue to increase. If the incremental cost of gain is relatively low and space is available I expect production systems to target sales weight at the top of packer buying grids.