WEATHER STRESS IN CATTLE
This information seems to be pertinent to recent weather changes and the time of year. A meeting (back in Jan 1987) in Denver brought forth some interesting facts that need to be shared regarding weather stress, what it does, and how to manage it. Heat stress affects ADG in an exponential manner. Cold stress affects conversions in a linear manner. Whether or not the animal is wet or dry is most important. The coldest month is usually also the wettest because of cold, wind, moisture. Black cattle absorb more heat than light colored cattle on sunny days, up to 20 degrees on the surface of the skin. Light weight and thin larger cattle are most often affected with increased death loss while we see the most weight loss in heavier cattle. Fluctuating temperatures have more to do with health than performance. Cold raises appetite if behavioral conditions don’t outweigh the increase. However, when cattle have to wade through 2 foot thick mud or frozen pens to eat frozen feed and drink cold water in cold weather, then their appetites will decrease, causing not only lower gains, higher conversions, but also increased sickness and death apart from death loss due to exposure alone. Maintenance requirements go up 22% in Colorado (which is not too far from the Northern Texas Panhandle) in January, not counting loss due to wet lots and possible decrease in consumption. Therefore, cold weather does not always cause an increase in consumption compensating for an increase in maintenance requirements. FACTORS AFFECTING COLD:
LOW CRITICAL TEMPERATURES (temperature at which there is weight loss on a maintenance diet).
Effective ambient temperatures are factors of temperature, humidity, sunshine, rain/mud or snow. Impact on maintenance requirement is linear below critical
temperature. Cold weather also alters digestibility, with lower gut volume, and higher
rate of passage of feed. View Past Article about
Calves and Vaccinations |