Corn and Barley in Veal Diets

A recent study conducted at Université Laval, Québec (by C. Noon, R. Seoane and S. Scott), and published in the Canadian Journal of Animal Science, explored the feeding value of barley and/or corn in red veal feeding programs. As research in veal nutrition is less common than in other livestock, this information is most welcome! The authors used one corn based and one barley based diet, plus three blends; 75:25, 50:50 and 25:75 by weight. The diets were whole grain plus supplement. The protein content of the overall ration was three staged. The 40 Holstein bull calves consumed the diets beginning at a body weight of 75 kg (165 lb.) until slaughter. The starter (23.5% CP) was fed for 21 days upon receiving calves, after which average weights were 120 kg (260 lb.). The growing phase diet (20.3% CP) was fed for 35 days, at which point animals averaged 180 kg (400 lb.). Finally, the 40 day finishing phase diet (18.7% CP) was fed until slaughter at an average 250 kg (550 lb.) weights. Overall ADG for this trial was about 4.0 lb. per day.

Results of Barley Inclusion

• in starter diets, a 50:50 ration produced higher intakes and ADG than any other combination of corn and barley, including straight corn or barley
• in grower and finisher diets, barley showed a lower digestibility and associated depression in performance than corn, at all levels of inclusion
  • 79% digestibility in all corn diets; only 59% for all barley rations
• greater incidence of diarrhea with increased barley level
• ADG drops proportionally per unit corn substituted by barley
• Poorer feed to gain conversion
• lower yield and carcass weight
• no benefit from even partial barley inclusion (e.g. 25%)
• meat colour unaffected

There are a number of explanations for this result. The most important is that whole barley seems to be a less suitable feed in grower and finisher phases:

1. The physical size of the barley grain and the animals’ ability to pass it through the rumen without being ruminated and chewed down like corn would be a major component. That is to say, whole barley may be passing through intact too easily; the authors did indicate that whole barley was found in the manure. The fact that barley is showing benefit in those animals under 260 lb., indicates that the animals may outgrow the barley in terms of physical size. However, a comparison of a processed barley (e.g. steam flaking, rolling), to corn may lead to a far more positive result. However, the economics of processing would become a factor.
2. The carbohydrate (starch) may not be as available, as barley is known to contain beta-glucans, a less digestible form of carbohydrate. This might be linked to the scouring, as undigested carbohydrate may be used by bacteria further down the gut causing gas and rapid passage, much like lactose intolerance in humans. In the future this might be overcome with available commercial enzymes (beta-glucanase), or low beta-glucan varieties.

Practical Implications

In young animals (under 260 lb.) the inclusion of barley seems beneficial and economical. However, as the animals get larger, more grain passes out of the rumen intact. Based on the digestibility value given in this research, whole barley would only be a cost-effective substitute for corn in growing and finishing veal if the price of barley was less than 75% of the price of corn per unit weight. The exact effect on digestibility of rolling barley or enzyme use is unknown for veal, but these could alter the feeding value of barley. But, until barley is less than 90% the cost of corn (such as from March to May on the Ontario market), this is probably not worth considering.

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