Fall is in full swing with it we usher in the cold weather and calf jackets. Chances are that when you woke up this morning, you checked the weather. You probably checked the weather before you went outside this morning to see if you needed to put on a coat. Does this make you think of your calves? Probably not, huh? Well, it should, because when you start getting cold and pull out a coat for yourself, you should do the same for your calves.
What is Cold Stress?
Cold stress, also called hypothermia, starts between 50°F (28°C) and 60°F (33°C) for newborn calves depending on their weight, and for calves older than three weeks it starts between 32°F (0°C) and 42°F (23°C). If managed improperly, cold stress can significantly cut into your profits and in some cases cost the life of a calf. Hypothermia, just like any other stressor event reduces calves’ immunity and carries with it the risk of more calves getting sicker. Managing through it is the best course of action. Moving, dehorning, and vaccination should be planned for to coincide with warmer spells during the winter months.
As we increase the productivity standards for our mature animals, we must also increase the standards for our young stock. Each step needs to be targeted for the wellness of the animals, starting with proper newborn care, colostrum feeding, and carrying into average daily gain. Calves born during the fall and winter come with the additional challenge of cold weather. Unlike summer calves, these animals need to expend energy not only for a living (maintenance) but also for keeping warm (thermal) and on top of it, as our protocols often demand, for benchmarked growth. Note that if you see a calf that’s shivering it is most likely fighting for survival, working its muscles to stay warm and burning a ton of energy – this calf needs help.
What Can We Do About Cold Stress?
Lucky for you, there is an arsenal of tools to help you out. Start by providing a higher plane of nutrition to give the calf sufficient energy to fight the elements. For newborn calves, it is especially critical that they are dried-off and fed four quarts of high-quality warm colostrum within the first half-hour after birth not only for the immunity aspect but also for the nutritional value.
Start With Nutrition:
Colostrum is higher in solids and in fat than regular milk giving the calf more energy to burn. If practical, feed more than one feeding of colostrum to fall and winter born calves. As indicated by research, colostrum increases the metabolic rate, helping calves to convert food into energy more efficiently thus keeping them warm through their transition into the real world. As calves get older, a more general increase of 50 percent in energy intake is recommended. This can be accomplished by adding an additional feeding to your typical protocol of twice a day feeding or by adding 50 percent to each of your feedings. It is very important to offer milk, water, or electrolytes at temperatures between 102F and 105F in order to aid in maintaining the calf’s body heat.
But nutrition can get expensive quickly and has its limits. Therefore, it is equally important to mitigate the outside factors and to prevent the calf’s exposure to the elements.
Provide Warm Bedding:
Start by making sure that calves have enough bedding — there is a reason why articles about the proper bedding show up in industry publications every winter, it is simply because it is so important. Much like you’d prefer to sit in a dry, warm office while you do your paperwork; a calf is better insulated in deep, dry bedding, where it can nest. Wet, shallow, or even sandy bedding will literally suck the heat away from the calf.
The wind chill factor is no joke and should be taken into account when caring for your calves. Make sure they are positioned out of the wind, either in a barn that offers appropriate shelter or in calf hutches that are turned away from the prevailing winds.
In all of our efforts the goal is to keep the calf’s natural hair coat dry, strengthening the first level of defense against cold stress. When the calf’s coat gets wet, the hair sticks to each other displacing the air that’s typically captured in the hair coat and effectively eliminating the insulation layer, which keeps the calf warm.
Calf Jackets an Added Layer of Warmth:
One very mighty tool is a calf jacket. If designed properly, the outer shell will prevent outside moisture from penetrating the calf’s hair coat, keeping the calf’s coat dry. The calf-jacket insulation layer should be made of moisture-wicking material, channeling the moisture away from the calf’s body and preventing sweat from building-up and getting the calf’s coat wet. Putting a calf jacket on a wet calf should be avoided. While the jacket might cover the calf, it won’t keep the calf warm.
Using calf jackets allows the calf to use less energy to keep warm and put it into growth instead. University research has proven that calf jackets increase mean average daily weight gain by one-third of a pound during the first three weeks of life allowing you to get to your weight targets sooner.
Animal comfort is very important, so make sure to check the fit of your calf jacket. The last thing you want is a jacket that falls off in the middle of a -20°F (-11°C) night. The front closure needs to stay securely closed and straps should be tightened to fit the size of the animal without interfering with freedom of movement. Putting a hand between the strap and the calf’s leg is a good way to test for proper fit. Never use a calf jacket where the strap comes across the belly and could rub against the navel. This kind of irritation quickly leads to an infection.
The animals that will benefit the most from wearing a calf jacket are smaller breed animals since the surface of their body is in higher proportion to the fat they carry and causing them to become cold more quickly. Those affected by dystocia (difficult calving) or suffering from sickness should be closely monitored as cold stress will affect them more severely.
I often get asked how long calf jackets should stay on and the right answer is that, like other things in farming, it depends on the weather. Calf jackets should come off between three and four weeks of age, when the calf is vigorous, but not in the middle of a -20°F (-11°C) cold snap.
Like most things, you get what you pay for. Lower cost calf jackets provide lower quality in fit and finish and will not yield the financial benefits that a higher quality jacket would. Better materials allow for better insulation and thermal properties and in design minimize the “cold sweat effect.”
Managing cold stress in calves will improve the morbidity rate and most importantly continue the calves’ growth. So next time you put on a coat to go feed your calves, make sure they are wearing one too.