Thanksgiving in the US is the time for many breeders when the weather starts to get a lot colder. Cold weather just like hot weather can have detrimental effects on the health and well-being of your calves. Here are 12 things you can do to prepare your calves for the cold winter months ahead.

Why are they stressed?

Cold stress in calves is caused by the environment surrounding them and includes low temperatures and wind chill factors. Even temperatures that we might consider moderate, like the ones we are experiencing this week, can cause cold stress in newborn and young calves. It is particularly stressful for calves younger than 3 weeks of age.  Newborn calves experience cold stress at just below 60 degrees F. Calves more than 21 days old can be cold stressed at 42 degrees F. They are susceptible to cold stress because they consume very little calf starter and have little or no stored fat to draw extra energy from. By the time the temperature reaches zero, a calf should receive 50 percent more energy (calories) just for maintenance.

Keep in mind that if an 88-pound newborn calf has to start using its own fat storage to stay warm, it has less than one day’s worth of energy and could easily die because energy for growth and developing immune function becomes short or nonexistent.

When to begin?

Start with what you know for sure.  If you feel more comfortable wearing longer sleeves or a warm sweatshirt while doing chores, it’s probably time to consider increasing calf rations.  Even though we’re ready to look after ourselves, research suggests that 67% of dairy producers do NOT make changes to their calf feeding practices in cool weather. It’s definitely too late if you wait until temperatures are consistently below freezing.

Key Management Factors to Limit the effects of Cold Stress

The following options can help reduce the effects of cold on calves.  Work with your nutritionist and veterinarian to determine the best options for your operation.

1. Monitor the weather
   Monitor temperature and increase feeding in response to cold weather.  At temperatures below 60 degrees F, calves must increase their energy consumption just to maintain their core body temperature.
2. Protect animals from the Wind
   Wind markedly increases cold stress.  Producers should provide housing that allows a space for calves to have fresh air yet protects them from drafts.
3. Bed well.
   Providing adequate dry bedding makes a significant difference in the ability of calves to withstand cold stress.  Bedding should be clean, dry and deep enough to completely hide a calf’s legs when they’re lying down.  Proper insulation will help calves stay warm without relying on energy reserves to regulate body temperature.  Calf blankets can also be used to help keep them warm. A deep bed of long-stemmed straw allows caves to burrow in and preserve body heat.  One way to determine proper bedding depth for cold weather is to look at the calf while it is lying down.  If you cannot see the calf’s feet, the bedding is deep enough
4. Keep bedding clean and Dry
   Wet bedding can cause problems. Also their coats must be dry.  Wet coats have greatly reduced insulating properties and make calves more susceptible to cold stress. Mud-caked coats also reduce the insulating properties of the hair. Calves have much greater heat loss through wet bedding compared with dry bedding.
5. Keep Calf clean and dry
   The calf’s coat must be clean and dry to provide maximum protection. Dirt or moisture on the coat reduces its insulation value dramatically.
6. Provide additional Feed
   Feed more hay and grain. If wet feeds are fed, make sure they are not frozen. By implementing a cold weather feeding program that meets increased energy requirements, producers can keep their calves healthy and growing.
   For example, a 100-pound calf at 50 F requires 1.1 pounds of dry matter just for maintenance.  That is equivalent to 8.8 pounds, or about 4.25 quarts, of milk.  In the case of milk replacer, that is about 0.5 pound of powder mixed to make 2 quarts.
   If producers only feed the minimum amount, calves will struggle to keep healthy and there will be a surge in mortality, especially among fall-and winter-born calves.
7. Feed at least two gallons of liquid nutrition each day.
   Calves fed less than two gallons of milk or milk replacer are more likely to fall behind on weight gain.  They are also more like to get sick.  Feed calves a full potential ration; calves fed a maintenance diet (less than 1.8 lb. Milk replacer daily) are more likely to fall behind on weight gain and become sick.
8. Add a third feeding of milk or milk replacer
   A third feeding of milk or milk replacer provides extra energy to the calf.  The additional helping, especially during cold weather, preferable late in the evening provides extra energy for young calves.  Calves fed three times a day show improved growth, better starts prior to weaning than calves fed twice daily.
9. Switch milk replacer for cold weather
   Milk replacers are available that are designed specifically for cooler temperatures.  These calf milk replacers have been developed to deliver optimal combinations of protein, energy and technologies to help during times of cold stress.
10. Provide Free Choice Water Available at all times
    Provide warm water with morning and afternoon feedings, and consider adding a third watering as well.  By feeding liquids at closer to the calf’s body temperature of 102 degrees F., you can reduce the additional drain on its energy reserve to warm it.  Other practices may include offering warm water two to three times daily to support calf starter intake.  As the rumen develops, the calf’s nutrient intake and ability to grow and develop immune functions improve.
11. Warming
    If a calf is cold-stressed, it will be more susceptible to disease, so warming the calf may be necessary.  The best method to use depends on your facilities.  Once the calf has been warmed, provide colostrums and maintain body temperature.  When the calf is warm and the situation has stabilised, move it back to its mother.
    1. Warm bath
    2. Warm blankets
    3. Hot box or warming box
12. Vaccination
    Cold stress leaves calves vulnerable to a host of health problems, including Pasteurella pneumonia, one of the leading causes of bovine respiratory disease. According to bovine veterinary practitioners, the most important diseases to vaccinate against include infectious bovine rhinotracheitis, bovine viral diarrhea, parainfluenza-3 and bovine respiratory syncytial virus.  Many herds will benefit from using a coccidiostat and a vaccine to help prevent Pasteurella pneumonia in calves.  Producers should watch their calves very carefully for the first sign of respiratory disease. Some advise calves be given a coccidiostat labeled for prevention and treatment of coccidiosis.  If not treated 12 to 21 days after infection, coccidiosis causes dramatic clinical signs, such as diarrhea, inability to absorb nutrients, depression, weight loss, secondary infections and sometimes even death. Once signs of coccidiosis appear, much of the damage already has been done and a preventive strategy is best.  Disease can progress quickly and treatment must be done early to be successful.  Waiting too long can lead to irreversible lung damage and chronic or dead calves.

THE BULLVINE BOTTOM LINE:

We can’t control the weather but we can do everything reasonable to reduce the effects of cold on calves. A well managed calf can survive and thrive in cold temperatures.

(See also: “CALF MANAGEMENT: Eight Ways to Ensure Calves Remain Alive and Thrive”)