Production Team measures the region’s self-reliance for livestock feed


Posted: May 1, 2015

Production of livestock feed is no small thing in the Northeast, accounting for the use of roughly half of the region’s land in farms, according to earlier work by the Production Team. Now team members have taken their analysis one step further, estimating how many animals this acreage can support, and whether it’s enough to satisfy the region’s demand for animal-based foods like meat, dairy, and eggs.
Holstein dairy cows eating hay. Credit: Scott Bauer, USDA

Holstein dairy cows eating hay. Credit: Scott Bauer, USDA

"In the regional self-reliance work we did last year, we looked at the connection between the production of animal-based foods in the region compared to the regional consumption of those foods," said Zach Conrad, a Tufts University doctoral candidate and member of the Production Team. "What we’re doing now is connecting that to the rest of the food system, by estimating how much livestock feed is needed to raise the animals that ultimately produce our meat, dairy, and eggs in the region."

Conrad and his colleagues broke the problem down into two parts — looking at the feed requirements of the livestock in the region, and also at the amount of meat, dairy, and eggs consumed by people in the region — and then connected the two.

First the researchers worked with the data from the 2014 study to make the metrics compatible with the way livestock feed requirements are measured. For example, the earlier work estimated the amount — by weight — of animal-based foods consumed in the region. However, "livestock feed requirements are measured not only in pounds, but in terms of nutrients like crude protein and total digestible nutrients," noted Conrad. "So we converted the consumption of animal-based foods to protein and calories, which correspond to crude protein and total digestible nutrients, respectively,” he said. As the coordinator for this research, Conrad was charged with identifying incongruencies like these and converting earlier data into appropriate metrics so that various components of the study linked to one another accurately.

Nicole Tichenor, also a Tufts University doctoral candidate and Production Team member, was responsible for calculating the feed requirements for the number of animals consumed in the region, and had her own data challenges to wrestle with, resulting from the complexities that are inherent to animal production systems.

"In order to produce meat continuously, farmers maintain whole herds of animals," she said. Pointing to a beef calf as an example, Tichenor explained that in addition to raising that calf, a farmer maintains a mixed-age herd of male and female cattle to serve as breeding and replacement animals. Those animals need to be fed year-round, even after calves may be shipped off to be fattened elsewhere. Furthermore, some of those breeding animals will be removed from the herd each year and become beef as well. Therefore, for team members to estimate how much feed is needed to produce a certain amount of beef, they first had to account for how much feed an entire herd of cattle consumes.

That's where Christian Peters came in. Peters, a Tufts University assistant professor and co-leader of the Production Team, developed a livestock model "to estimate how much all of those animals need to eat on an annual basis, in addition to how much that calf needs to be eating from birth to slaughter," said Tichenor. Using this whole-herd approach, Peters' model calculates the feed needs for other animal production systems, too, including swine, chicken, turkey, dairy, and eggs. But, Tichenor pointed out, beef and dairy systems presented a unique challenge.

"The most complicated aspect I worked on was figuring out how to divide all beef that’s produced in the region between beef and dairy cattle," she explained. That's because beef and dairy production systems are complex and connected. On any given dairy farm, for example, some calves will be maintained for the breeding herd, some may be funneled into the veal supply chain, and some may be shipped to one or more feeding operations and raised to a mature slaughter age, similar to most beef cattle.

"Within the model I had to modify assumptions about cattle production to reflect regional trends, because in the end, those assumptions determine how much meat is produced," said Tichenor. "If you're feeding a veal calf, you don't have to feed it for very long, whereas feeding a calf that grows up to become a 1,200-pound steer requires a lot more feed." Tichenor developed a method for partitioning the beef that is produced in the region between beef and dairy cattle using the livestock model, which allowed her to realistically estimate how much feed was being required by these different systems.

In addition to the variability found in beef and dairy systems, "cattle are the only livestock category that are consuming large amounts of pasture or forages, and forages aren’t shipped the same distance that grains and oilseeds are," said Conrad. "So it's really important when analyzing a regional food system to carefully consider the feed requirements of cattle, in particular, because a lot of their feed—all of the pasture and most of the forage —would be sourced regionally, not imported from outside of the region."

Tichenor expects that the team's results will add a lot of context to discussions about regional food systems. "There's so much talk, especially in the Northeast, about scaling up local and regional meat production," she said. "I think an analysis like this sheds light on where we stand, and — if we are wanting to make that transition — on how much of a gap there is, and on the immensity of resources it can take to produce these various livestock products in terms of land use."

The researchers are finalizing their results now and will be submitting a manuscript for publication this summer. In addition to Conrad, Tichenor, and Peters, the research team also includes Timothy Griffin, an associate professor at Tufts University and co-leader of the Production Team, and Ashley McCarthy, a master's student at Tufts University.

More information about research conducted by the Production Team is available here.

-- by Kristen Devlin


Note: Conrad and Tichenor recently co-authored a paper that, although not related to the EFSNE project, may be of interest to our readers.