Be ready, winter could be harsh!
When winter nips at your feet, what strategies should be used in your daily routine to maintain the rhythm for growth in your herd? What measures should you adapt to optimise your animal’s comfort and minimise the risks of catching diseases?
It’s no secret that calves are the most vulnerable, especially those born during the winter months. Did you know that the thermoneutral zone (ideal temperature) for calves is between 10 to 20°C? In calf rearing, we must account for temperatures, winds and humidity as these factors influence the actual temperature calves will feel, affecting their ability to remain in their thermoneutral zone. A wet or shivering calf loses a lot of energy to maintain their body temperature, weakening their immune system and delaying their growth.
An important note: a just born calf retains only 3% of fat deposits compared to 16% of baby fat in human children. Of that 3%, only 1.5% can and will be quickly metabolised. Whether it’s for bovine or milk production, this reserve is important since it can be quickly and easily mobilised. In ideal situations, a calf will be born without complications, be dried by its mother and have access to colostrum fats in the first two hours of its life.
Their fat reserve will not be used and easily accessible should the calf need it in the first three weeks of life to combat light cold fronts or sickness. In less than ideal conditions where a calf has a difficult birth and isn’t dried off quickly but has access to an average temperature of 13°C, their fat reserve will deplete within 18 hours. If a stress factor, for example of temperature, is added to the mix, the fatty reserve will be depleted faster because of the surface contact to high weight ratio.
Since energy maintenance needs increase as the ambient temperature decreases, it’s imperative to adapt management of the calf. Minimally, we must ensure that not only the base needs are covered, but that the calf can double its weight within the first 60 days. General rule states that for each degree under 0°C, the calf requires 1.8% of additional energy - lacteal diets are the easiest way to supply this additional required energy.
What strategies should we favor to fulfill the basic needs, optimize pre weaning weight gain and ensure that the calf’s health does not take a turn for the worst by a lack of energy in their feedings? Here are a few to help calves face the Quebec winters.
INCREASE ENERGY INTAKE WITH MILK
Feedings should be adjusted to ensure that weight gains are similar during the winter season as it is in the summer. As a rule, it’s recommended to increase by 50% the energy intake during the winter season.
Increase the quantity of milk per meals
Inside barns when temperatures are around 5°C, add at least 1 additional liter of a milk replacement, or 0.5 liters per meal. If the calves are outdoors and temperatures range from -5°C to ‑15°C, feed them 1.6 to 2.25 additional liters per day. If the size of the feeding bottles limits the quantities that you can feed the calves, investing in a feeding bucket could be beneficial, making sure to cover it so it won’t lose its warmth too quickly.
Increase the fat and protein content in milk replacements
It’s important to increase the fat content to provide more energy.
LIMIT THE ENVIRONMENTAL IMPACT
Even if we provide sufficient energy to help the calves stay warm, limiting as much as possible the effects of the cold and providing adequate isolation is important.
Dry the calf
Dry hair provides more isolation than wet ones.
Offer warm colostrum as soon as possible after birth
Giving 3 to 4 liters of colostrum within the first 2 to 6 hours after its birth will prevent the calf from depleting its fatty reserves and maximizing the immune system’s efficiency which warms the calf.
Reduce heat loss with calf blankets
It's recommended to use calf blankets for at least one month after birth when temperatures vary between 5 and 10°C. With temperatures under 5°C, using the calf blanket for 2 months is a must. Make sure that the calf is dry, the blanket is well adjusted to its body and avoid removing it during extreme cold fronts.
Add infrared lamps (heating lamps)
Usually used in swine and poultry industries, these lamps work well in barns when avoiding accidents that could break the lightbulb. These will help the calf stay warm.
Offering warm milk and water
Giving a warm or hot liquid to the calves will help them stay warm and make sure that they don't use any energy in warming the liquid they're drinking. It's important to follow the supplier's guidelines on the optimal temperature as too hot risks denaturing the proteins. Warm water, between 15 and 20°C, twice a day is important, especially for outdoor niches. Using 2 buckets per calf, allows you to let one defrost while the other is being used.
Avoid creating wind chills
Making sure that the wind doesn't surpass 1 km/h at the calf's height and leaving minimally 2 to 3 feet between the wall and the park will provide a better air circulation and increase the ambient temperature of the niche by 8°C.
Offering a dry bedding that will cover the calf's legs when they are laying down
The bedding will insulate the ground when they lay down and reduce heat loss. Dry and abundant bedding will decrease bacterial contamination from the ambient air.
The best way to make sure that the strategies being used are working is to regularly measure the size of the calf, which allows you to determine if they’re doubling their weight gain in the first 60 days.
Source : « Maximiser la croissance des génisses malgré le froid » Le Producteur de lait québécois. January/February 2016 : pages 24-26.
Source : « Même si on annonce un hiver plus doux que la normale ». André Roy. Directeur, productions spécialisée et ventes OptiBoeuf s.e.n.c Sollio Agriculture