This article written by Dr. Reynold Bergen, BCRC Science Director, originally appeared in the October 2017 issue of Canadian Cattlemen magazine and is reprinted on the BCRC Blog with permission of the publisher.
Averages are useful statistics, but sometimes averages can be misleading. As the University of Saskatchewan’s late Iain Christison said, “the average human has one breast and one testicle”. Canada’s rainfall may be close to average this year – but much of the country is experiencing severe drought, and most of the rest is soaked. Either way, low yields, unharvestable or spoiled forage mean that winter feed supplies will be below average in many places, and nutritional value likely won’t be average, either.
For instance, drought-stricken pastures and forage crops have lower levels of carotene, which cattle need to produce vitamin A. A recent paper from Cheryl Waldner and Fabienne Uehlinger of the Western College of Veterinary Medicine (Can. J. Anim. Sci. 97:65-82) looked at 150 beef cow-calf herds in Alberta and Saskatchewan. Calves born the spring following a drought had a much higher risk of vitamin A deficiency, and calves with severe vitamin A deficiency were nearly three times more likely to die than those with higher levels. Continue reading