Corn in western Canadian feedlot diets

Corn acreage is expanding across Canada. There are about 25 acres of corn for every acre of barley in Ontario and Quebec, where temperatures, day length and moisture allow predictable corn yields and feed quality. There are around eight acres of barley for every acre of corn in the Prairies, although ambitious breeding efforts are underway to develop short-season corn varieties and production strategies to suit Western Canada’s more challenging climate.

Corn can be ensiled as ground, high-moisture corn (a high-starch energy source) or as whole-plant silage (a moderate-energy source of fibre). It can also be ensiled as snaplage (the entire chopped ear of the corn, including the shank, cob, husk and grain), which lands somewhere in the middle.

A team of researchers led by the University of Saskatchewan’s Greg Penner ran a trial using these different forms of corn to partially replace barley in feedlot finishing diets.

What they did

After backgrounding on the same diet, a total of 320 crossbred steers (1,164 lbs.) were fed one of four finishing diets in a small pen trial (10 head per pen) in 2020 and 2021. The four diets were designed to find out what would happen when CDC Austenson barley silage and barley grain were replaced with Pioneer 7202AM dent corn silage, high-moisture corn grain, or corn snaplage.

The control diet contained 10 per cent barley silage and 88 per cent rolled barley (rolled to a processing index of 65 per cent). The second diet replaced the barley silage with 10 per cent corn silage, along with 88 per cent rolled barley. The third diet contained 10 per cent barley silage and equal amounts (44 per cent each) of rolled barley and ground high-moisture corn. The fourth diet contained 20 per cent corn snaplage to entirely replace the barley silage and lower the rolled barley grain content to 77 per cent. This ensured the dietary starch concentration was similar to the control. The rest of the diet was limestone, urea and a mineral/vitamin supplement. Steers were slaughtered after 99 (year 1) or 72 (year 2) days on feed. Live weights, average daily gain, feed intake, gain:feed, fecal starch content, liver abscesses and carcass data were measured.

What they learned

When it came to growth performance, the dry matter intakes, finished weights, average daily gains and gain:feed of steers fed the standard barley-based control diet were not statistically different from those of the steers fed any of the three corn diets. While fecal starch was very low in this study, fecal starch content was higher in the steers fed barley and high-moisture corn (2.2 versus 1.4 per cent) than the barley-based control diet.

As for carcass measurements, steers fed the barley and high-moisture corn diet had statistically heavier hot carcass weights (895 lbs. versus 884 lbs.) and higher dressing percentages (59.7 versus 59 per cent) than the barley-based control diet. This translated into carcass-adjusted final live weights (1,508 lb. versus 1,486 lb.) and average daily gains (4.2 versus 3.9 lb./day) that were greater than the steers fed the barley-based control diet. This suggests that the higher starch level of the barley and high-moisture corn diet (56 versus 52 per cent in the barley-based control diet) was enough to offset the starch lost in the feces while still promoting greater carcass weight. Neither the corn silage nor the snaplage diet differed from the barley-based control diet. There were no differences in yield or quality grades.

Overall, proportions of minor or severe liver abscesses were the same across all four diets (74 per cent). Severe liver abscesses were less common in steers fed the barley grain and snaplage diet than in steers fed the barley-based control diet (10 per cent versus 26 per cent). This was attributed to the higher “physically effective fibre” content in the snaplage diet (5.3 per cent versus 4.5 per cent in the barley-based diet) that may have helped maintain rumen health and moderate rumen pH.

Bottom line

Replacing barley silage with corn silage, or entirely replacing the barley silage and some of the rolled barley with corn snaplage, didn’t negatively affect finishing steer performance or carcass value. Replacing half of the rolled barley with high-moisture corn produced some benefits.

So what does this mean (or not mean) to you? Corn is standard practice in Eastern Canada. But if you’re new to growing and feeding corn in Western Canada, remember that varieties and growing conditions matter. High-moisture corn typically has a higher starch content than barley. Dent corn varieties (like the one used in this trial) typically have more digestible protein and starch than flint corn varieties. Dent corn is more commonly grown in the U.S. and Eastern Canada. Most of the short-season corn grown in Western Canada is flint corn. But starch contents and yields drop when corn is drought-stressed as it was in this study. In fact, drought was severe enough in 2021 that neither corn silage nor snaplage could be produced, and the second year of the study used corn silage and snaplage left over from the 2020 crop year. In contrast, barley grain and silage were grown in both years of the study.

Homegrown corn has significant potential in Western Canada’s feedlot sector, but more work is needed to breed the production risk out of it.

The Beef Cattle Research Council is a not-for-profit industry organization funded by the Canadian Beef Cattle Check-Off. The BCRC partners with Agriculture and Agri-Food Canada, provincial beef industry groups and governments to advance research and technology transfer supporting the Canadian beef industry’s vision to be recognized as a preferred supplier of healthy, high-quality beef, cattle and genetics. Learn more about the BCRC online.