In our harsh Canadian climate, cold weather can take its toll on everyone, including calves. Whether your calves are inside or outside, cold weather is very stressful for them. Here are some calf management tips for cold weather.
Are you feeding enough energy in the winter months?
When the temperature drops, calves require more energy for maintenance and growth. Calves will use their own fat reserves for energy if the extra energy is not supplied. The fat reserves in a young calf are not very large.
Once the fat deposits are used up, the calf starts to break down muscle for energy and heat production. Calves will lose weight and have a weakened immune system. This will make them more susceptible to pneumonia and diarrhea.
The low critical temperature is the temperature below which calves begin to require extra energy to maintain body temperature. For calves zero to 3 weeks old, the low critical temperature is 20ºC, and for calves older than 3 weeks, it is 10ºC.
Therefore, for young calves, as the temperature drops below 20ºC, we should consider feeding more energy. The main reasons for the differences in low critical temperature are calf size and rumen function.
Small calves have a larger surface area relative to their weight. This means they lose heat faster. A functional rumen produces heat, which helps to keep the calf warm. If calves are shivering after feeding, they are cold and not being fed adequately.
At a temperature of 10ºC, a 45-kilogram calf will require 6 litres of milk replacer to have a growth rate of 0.45 kilograms per day – and will need 8 litres at -12ºC for the same growth rate.
As temperature drops and calf size increases, the amount of milk replacer fed also increases. If calves only receive 4 litres of milk replacer per day at -12ºC, there will not be enough energy to meet their maintenance needs, and calves will therefore lose weight.
Another method of increasing energy in cold weather is feeding whole milk. Whole milk has approximately 25 percent more energy than a 20-20 milk replacer.
Jersey milk has almost 50 percent more energy than 20-20 milk replacer. Adding a midday feeding can help to increase the energy intake. The recommendation is to feed a minimum of 8 litres a day (6 litres in smaller breeds).
Milk temperature is essential for calf health. Whole milk should be fed at 38ºC and milk replacer between 40 and 42ºC.
Do calves have access to starter and fresh water?
Calves should also have access to starter and water daily. This may be more problematic in the winter, but it is essential. If calves are outside in extreme weather, water should be offered at least three times a day for a minimum of 30 minutes.
Calves cannot drink ice. Research has shown that calves with free-choice water, versus no water, have a 45 percent increase in starter intake and 60 percent in weight gain in the first four weeks of life.
Starter intake is important because it increases rumen development. A functional rumen is a fermentation vat that produces heat and helps to keep the calf warm.
In addition, starter intake helps meet the energy requirements in cold weather. Even calves 1 week old should be offered a small amount of calf starter.
Do calves have a clean, dry and draft-free environment to lie?
Bedding management is an extremely important part of calf health. Calves lie down a lot. Newborn calves will spend approximately 80 percent of their time lying down, and 6-week-old calves will spend 75 percent.
That translates into upwards of 19 hours lying down per day.
Ensure that calves have enough bedding to keep them warm and dry. Calves lose heat by conduction. That means heat is transferred down through the bedding. Cold concrete, gravel and sand increase conduction losses.
These make a good base, but bedding needs to be added on top. The best bedding for calves outside in hutches is wood shavings covered with straw. Calves should be able to “nest” in the bedding, which helps reduce heat loss.
The legs of the calf should be covered by the bedding when lying down (nesting score 3). A nesting score of 1 is when calves lie on the bedding and their legs are visible.
It is important that the calves’ hair coat is clean and dry. This allows the calf natural insulation from the cold and limits heat loss through evaporation.
Calf coats can also be used when the temperature drops. Coats can increase the nesting score by 1. Bedding needs to be dry. If you are not sure if the calves have enough dry bedding, do the “kneel test” where you kneel on the bedding for 20 seconds.
If your knees are damp or wet, it is time to change or add bedding. When the bedding is wet, the calf’s energy needs for maintenance increase. The calf’s environment should also be draft-free.
Are the feeding utensils clean?
The cleanliness of feeding utensils (pails, bottles, nipples) is also crucial for healthy calves. For diarrhea that occurs early in life (less than 2 weeks old), sanitation is often the most frequent cause.
When feeding equipment is not properly cleaned, there is more opportunity for disease-causing bacteria and pathogens to grow.
By feeding calves with “dirty” equipment, we are inadvertently feeding and exposing our calves (and their fragile immune system) to large amounts of pathogens.
The following four steps will go a long way to help improve calf health:
- Rinse all equipment after every use in warm water. (This removes milk proteins and dirt before washing.)
- Wash all equipment with soap and bleach in water greater than 50ºC.
- Rinse all equipment in an acid solution (reduces the pH in order to reduce bacteria regrowth).
- Dry all equipment on a drying rack after every washing.
With winter upon us, just remember that the colder it gets, the more energy a calf needs to maintain heat and to keep growing. Following these simple calf management tips will help improve calf health on your farm.
PHOTO: In winter, it is important that calves have access to feed and water at all times. If they are outside, they need a minimum access of three times a day for 30 minutes. Photo provided by Jodi Wallace.
- Ormstown Veterinary Hospital
- Howick, Quebec
- Email Jodi Wallace
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