Prof. Philip McEwen of Ridgetown Campus is in the final stages of a study that's assessing how restricting feed intake by 30 per cent affects gains and feed efficiency in market hogs, as well as carcass quality.

He says limit feeding is producing some interesting results.

"Whenever we have limit fed there is an increase in feed efficiency and decrease in feed cost," says McEwen. "During our first trial, meat tenderness was also improved for pigs limit-fed during the growing period."

In his trials, McEwen found that during the grower stage (30-60 kg), the limit-fed pigs were growing well, but not as quickly as the pigs that were fed on a free-choice basis. The big difference was observed in the final growth stage, from 60 kg to market weight, when all the pigs were given free-choice feed. Then, the pigs that had been restricted in feed earlier gained more quickly, and in some cases overtook the pigs fed free-choice throughout their growth period. All pigs, regardless of feeding strategy, reached market at the same time.

To date, one complete set of results has been analyzed, and the next two sets are under study. Prof. Ira Mandell, Department of Animal and Poultry Science and Prof. Peter Purslow, Department of Food Science, are also active partners in this research endeavour and have been investigating the carcass and meat quality differences.

Early results show the limit-fed hogs have improved meat tenderness. The researchers are studying what caused this effect, but suggest that the fast growth rate in the limit-fed hogs to catch up after feed restriction causes increased protein manufacture and breakdown, leading to improved muscle tenderness.

In a second phase of the study, the research team is working to identify endpoints and levels at which feed can be restricted to get optimum efficiency. The information from the completed trial will be shared with researchers and producers to improve feeding techniques in the hog industry.

Funding for this project has been received by Ontario Pork and the Ontario Ministry of Agriculture, Food and Rural Affairs.