Rations with high fat content, which was poultry fat in this study, are more difficult to make into pellets and to feed. 'With fewer overweight hogs and fewer light hogs, there was less dockage from the packer,' Spencer said. One reason for increased profit was less variation in weight of the barrows, which average 260 pounds per head when sold. 'The fat-and-lysine diet cost more per ton, but with improved performance it returned more profit after feed costs,' Spencer said. Pigs on the modified 'hot weather' diet returned $2 more per pig than barrows fed the corn-soymeal ration. There the payoff for the diet switch was found. 'Reduced feed intake combined with increased gains, leads to increased feed efficiency,' Spencer said.Īnother benefit of the farm study was that the researchers followed the barrows to the packing plant. Although, the pigs do not eat as much during hot weather, they continue to gain when fed the supplemented diet. These were gains similar to those at the MU lab.įeed efficiency also went up at the farm as it had in the lab.

Pigs grown on the farm had higher average daily gain, by 15 percent, during the two-week heat wave when fed the ration fortified with amino acids and 8 percent more fat. Fortunately, for the experiment, the researchers hit two weeks of very hot weather at the start of the study. In summer on the farm, temperatures were uncontrolled. 'It was like a lot of days in a hot Missouri summer,' Spencer said.Īnother bonus was improved carcass quality in the hams and loins from pigs fed the high-fat diet during heat stress.Īfter success with the experiment in the MU labs, Spencer, along with his PhD advisor Gary Allee, expanded their study to a commercial hog farm, where they tried their experimental rations in two confinement-finishing barns with 600 pigs in each. The hot chamber was at 95oF during the day and 85 degrees F at night. The cool chamber was kept at a constant 70oF.

They also produced gains similar to pigs reared in a cooler environment. The amino acids in the fat-added diets produced better gains at less cost, under heat stress, than the regular corn-soy diet. And, amino acids were also increased to maintain a constant lysine-to-energy ratio, which improved performance even above adding fat.įeed efficiency, as well as growth rate, improved. The modified diet contained 8 percent added fat over the regular diet. While pigs on the modified diet improved performance, pigs on a typical ration of corn and soybeans, which are heat producers, did not do as well. Joel Spencer, graduate student in animal science, found that when the 'heat increment' in swine rations was reduced and essential amino acids were added the pigs thrived.

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