The Performance of Pregnant Beef Cows Relying on Snow as a Water Source

Body mass change, water influx, metabolic heat production and rectal temperature were measured in four pregnant beef cows offered only snow as a water source (snow cows) and in four pregnant beef cows that also had access to heated water (water cows). The study was carried out during winter (December to March) in Alberta, Canada. There was no difference between treatment groups in any of these measurements indicating that the snow cows were obtaining adequate water to satisfy their requirements and that no added nutrient energy was required to melt the snow and bring the water to body temperature. Milk yield in the two groups, measured in early spring when water was available to all cows, was similar as was the growth rate of the calves. Milk yield averaged 8.2 kg d −1 during weeks 2–4 of lactation and 4.6 kg d −1 during weeks 14–16. Average daily gain from birth to weaning (6 mo) of calves suckling the snow cows was 0.74 kg and of calves suckling the water cows was 0.70 kg. It was concluded that there was no detrimental effect of withholding liquid water from pregnant beef cows when snow is available and that cows can use snow as their only water source for lengthy periods of time during winter. Key words: Pregnant cows, snow, water, water influx, metabolic heat production