As winter approaches, there are many steps that need to be taken to prepare your cattle. Because we never really know how long, how cold, and how wet and snowy any given winter will be, the best approach is to plan for a severe winter, be ready to address any disastrous stretches of extreme weather, and hope that the winter is actually much more mild than expected.
Whether you care for dairy or beef cattle, cows or calves, or multiple groups in these categories, there are several hard and fast rules to keep in mind. Obviously, the most severe of winter weather conditions can compromise any rules, but in general:
- Temperature: Cattle with a heavy winter coat can survive without additional energy down to around 20-degrees. For cattle with shorter coats (dairy, or non-acclimated beef cattle), this is closer to 30-degrees. Calves, with less body fat reserves, prefer temperatures 10-degrees warmer, so 30 or 40-degrees respectively. As a rule of thumb, for every degree that the temperature drops below this limit, the energy demands increase by 1% for beef cattle and 2% for dairy cows and for calves. A beef cow in 0-degree weather will require 20% more energy to maintain herself than at 20-degrees.
- Moisture: The above is true, given that cattle are kept dry. As soon as cattle are wet (due to snow, sleet, or steam inside a confinement), the lower end of their comfort zone increases by approximately 20-25 degrees or more, usually a few degrees on either side of 50-55 Fahrenheit. Additionally, being wet doubles the amount of compensatory energy needed. The beef cow above, standing outside on a day when the temperature is 0-degrees, now needs an additional 40% increase in her energy intake if she is wet!
- Wind: Unfortunately for us, the Upper Great Plains is known for brutal winters, where temperatures plummet and wind speeds soar, often at the same time. If cattle are housed outside, the wind-chill is the temperature that should be used. The air temperature is irrelevant if cattle are not protected from the wind. The air temp may be 32, but with a bit of wind, the wind-chill drops to zero, and that same beef cow still needs an additional 20% energy in her feed even though the thermometer says she’s well within her comfort zone.
- Water is one of the most important nutrients to remember in the winter. Sure, water intakes are expected to decline in the winter, but reduced activity and/or lack of availability due to frozen or partially frozen water sources is a significant cause of health problems in times of cold stress. We often overlook the importance of water in cold weather.
There are different ways to provide cattle extra nutritional energy in extreme weather. Providing extra grain/concentrate is the most common way to do this. An alternative, if possible, is to reserve some higher quality forages for winter, though grain availability and prices compared with the cost of high-quality forages make feeding extra grain more feasible.
So what have we learned in recent years? One of the most important advancements in facility design have to do with the understanding that too much warmth and shelter is often as damaging or worse than extreme cold. For cattle that are acclimated to cold temperatures, wind-breaks are preferred to enclosed shelters. For calves, or cows without heavy coats, fresh air and adequate air exchanges are needed to minimize the incidence of respiratory disease. Steamy, stagnant air is often high in ammonia, which damages lung defenses, and the high moisture in this air is very efficient at transmitting infectious disease-causing bacteria and viruses.
Specific to dairy calves, the energy requirements will increase by over 30% when the temperature drops below 30-degrees. Using a higher-fat milk replacer, adding fat to pasteurized waste milk, or feeding more milk solids to calves are all ways to increase energy intake. Calf blankets, so long as they are kept dry, will allow young calves to thrive at lower ambient temperatures.
