Field peas make an excellent feed for swine, a South Dakota State University researcher said. Hans Stein, a swine nutritionist and associate professor in SDSU's Department of Animal and Range Sciences, said 11 SDSU experiments over the past five years are the main nutrition studies that have been done so far using field peas in swine diets.
Though field peas historically have been used as human food, production has increased so much that they're increasingly being used in animal diets. Currently selling for about $3 a bushel, field peas can make an economical feed even for producers who don't grow them, Stein said.
“We've looked at the digestibility of the nutrients in field peas. We've found that all the amino acids are digested pretty much to the same degree as they are in soybean meal,” Stein said. “We've found that the energy concentration in field peas is similar to what you find in corn. And we've found that phosphorus is digested far better than in corn and soybean meal.”
SDSU also tested inclusion rates.
“Initially we went up to 36 percent in diets for growing and finishing pigs without seeing any problems. We had performance that was absolutely similar to what we found on a corn/soybean diet.”
A separate experiment increased the inclusion rate to 60 percent field peas, then lowered that to 48 percent and finally to 36 percent as pigs grew and their amino acid requirements dropped. Pigs performed as well as on the control diet.
That experiment also involved SDSU meat scientists, who looked at carcass quality and found no negative effects from the field pea diet. Palatability tests showed no difference compared to other pork when tested on consumers.
There are some points to consider when using field peas in swine diets, Stein said.
“As a rule of thumb, field peas will substitute two-thirds of corn and one-third of soybean meal. So if you include, say, 36 percent field peas, you can remove 24 percent corn and 12 percent soybean meal from the diet.”
Stein added that it's important to keep an eye on amino acids, since the amino acid profile is somewhat different from soybean meal. There is more lysine in the protein from field peas, but there's less methionine and threonine. Producers can take some of the lysine out of the diet and add methionine and threonine instead when they balance the amino acids in the ration.
Because of the increased phosphorus digestibility, producers can remove some of the monocalcium phosphate or dicalcium phosphate in the diet. There will be less excretion of phosphorus from pigs on the field pea diet compared to pigs on a corn/soybean meal diet.
Stein added that if producers add microbial phytase, they can completely remove the inorganic phosphorus from the diet, for a savings in formulation costs.
