One of the most significant trends in the livestock industry is the ongoing increase in the litter sizes birthed by sows each year. Indeed, the rate of increase has accelerated from 30 to 40 years ago. For example, the number of pigs saved per litter moved above seven in the 1960’s, but didn’t top eight piglets per litter until 1992. It then took the industry just over 12 years to push that figure above nine and just seven years to reach 10 pigs. Moreover, that figure soared above 10.5 last fall despite the 2013-14 PEDv outbreak.
The blue line in the following chart illustrates that strong upward trend. The red line represents the percent annual change in pigs saved per litter. Note the general 1% to 2% annual increase often posted in recent years, as well as the huge swings caused by the PEDv outbreak and the subsequent industry recovery.
We sometimes don’t give enough thought to the impact of such a strong trend. That is, if all else were kept equal, U.S. hog production would be rising to a similar degree each year. In fact, the March 1, 2016, U.S. market hog population, at 61.664 million head, topped the comparable level from 25 years ago by 15.841 million (34.6%). In contrast, the March 1991 breeding herd was stated at 6.997 million head, whereas it came in at 5.980 million head when USDA released its latest quarterly Hogs & Pigs report 10 days ago. That’s almost exactly 1.0 million fewer sows and boars on farms, producing about one-third more piglets than in the early 1990’s.
The second chart below depicts another facet of this story, that being the increased number of litters produced by sows than in the past. The green line represents quarterly breeding herd totals published by the USDA, while the red line is the number of sows farrowing during the following quarter. The blue line depicts those farrowings as a percent of the breeding herd total, Note particularly the big upward surge in those numbers from around 1997 through 2007, as well as the drastic reduction in the size of those quarterly shifts from those experienced previously. It seems pretty obvious that U.S. swine producers were working very hard to improve the productivity of their sows at that time, with the surge culminating in the 51.72% figure posted in the fall of 2007.
One has to suspect that 2007 peak marks the limit for managing sows through their cycles. Even amidst the historic hog/pork shortage of 2014, the industry failed to top that figure. In fact, the percentage figures seem to be trending lower in recent years.
We also can’t ignore another hog/pork production trend; that being the big increase in market hog weights. This increase makes perfect sense, because genetics, indoor housing and husbandry practices have clearly improved over time. As the following chart shows, barrows and gilts averaged about 250 lbs. per head on the hoof in 1990, but had seemed to plateau just above 270 lbs. in the mid-2000’s. That probably reflected surging corn prices at that time. I suspect shifting corn prices played significant roles in the weight fluctuations seen in the 2011-13 period. Producers clearly responded to the pig shortage of 2013-14 by pushing weights dramatically higher, especially with corn prices having declined substantially from their 2012 highs. Greatly reduced hog prices over the past 18 months have tended to push weights lower, but they obviously remain far above the levels of 10-20 years ago. That implies a commensurate increase in pork production per head and in total.
Ultimately, the U.S. hog industry is producing many more hogs and much more pork than in the past, and doing so in a much more efficient manner. I don’t really see the increases in litter sizes and in pig weights slowing substantially in the near future. I’m not sure the upward trend in farrowing percentage will resume. These underlying shifts imply a diminishing need for sows and boars to support the industry if the status quo is to be maintained. Indeed, the breeding herd may need to decline during the years ahead in order to keep the market from being swamped with pigs. Conversely, it’s pretty obvious the industry could grow rapidly if/when growing demand calls for accelerated production via higher prices.
