22 March 1996


By Jessica Buss

CANADIAN milk producers are not only feeding to increase milk protein and reduce milk fat. They are also keen to increase cow yields.

The Cornwell family farm in Ontario, Canada, feeds a ration designed to produce high protein, low fat milk. This includes a high level of cereals. Their 210 cows typically receive 2-3t of grain a year, claims Don Cornwell. Cows average 10,300 litres, producing 350kg of fat and 320kg of protein.

The Canadian milk quota is based on butterfat and the farm has a quota of 65,000kg. Also 50% more is paid for protein compared with fat. "So, it makes economic sense to reduce fat and increase protein," he says.

High yielders are fed a ration that comprises 55% cereals. It is also high in crude protein at 19%, and includes rumen by-pass protein.

"The ration is balanced to keep fibre levels low and keeps the cow healthy." This typically includes compound pellets, roasted soya beans, high moisture shelled maize corn, fat, liquid brewers yeast, haylage, corn silage, salt, and minerals (see table). To buffer the acid in the silage based diet, it includes bicarb and limestone.

These diets are fed as a total mixed ration from a fixed mixer fed out using a motorised one-tonne feed cart. Mr Cornwell estimates that it costs 18.5p/litre to produce milk for which they are paid 24.8p/litre.

Grazing is considered uneconomic due to the short growing season. So cows are all fed stored feed and every effort is made to ensure its efficient use. The system also allows intakes to be controlled. In summer cows go out for exercise unless it is too hot.

Heat stress is more of a problem than cold stress although temperatures vary from 35C to -25C, claims Mr Cornwell. As a result the cow free-stall barn is fitted with a misting system and fans, as well as curtained sides which are used to adjust ventilation.

Mr Cornwell believes stress has been reduced by three-times-a-day milking which he began two years ago. This resulted in a 15 to 20% increase in cow yield.

Yields may be increased again as there is good chance BST will be used – when its use in Canada is approved – after assessing the economics.

"But the herd will not be cut down so that it can be used," says Mr Cornwell.

Cow ration for 45kg milk

Cow ration(kg DM)

21% pellets5.8

Roasted soya beans1.8


High moisture shellcorn4.8


Liquid yeast0.6

Corn silage4.7

Total dry matter intake25.6

The Cornwells cows are fed a total mixed ration for high protein and low fat milk that is 55% cereal.

Heat stress is a greater problem than cold stress at Corwic Farm despite temperatures falling to a numbing -25C in the long winter.