Taking the Chill Off Calf Performance as Cold Weather Approaches

As we enter the fall and winter months, it is important to make the season as easy as possible for our calves. Drastic weather changes and cold temperatures provide stress on young pre-weaned calves that can compromise calf health and performance. Exposure to cold and wet weather makes young calves more prone to weakened immune systems and the subsequent challenges that play havoc on growth potential. Taking steps now to winterize your feeding program and housing management practices can help reduce the impact of weather-related stressors on vulnerable calves.

Young Calf Vulnerability

The temperature at which calves experience stressors such as cold or heat depends upon the age and size of the calf, as both body fat cover and feed intake factor into the equation. According to Penn State University, calves up to one month old can begin experiencing cold stress at 50°F. On the other hand, calves from one month to weaning have a comfort zone between 46°F and 80°F, and begin to experience cold stress at around 28°F. The temperature at which a calf begins to experience cold stress is also dependent upon factors such as moisture and wind chill.

Pre-weaned calves have very little body fat (3.5-4%) to insulate their bodies against cold weather, making them more susceptible to cold stress, particularly in the first few weeks of life. Fat stores can be rapidly depleted if calves don’t receive sufficient nutrition during cold stress, which may further suppress their immune system and increase the risk of health challenges.

Additionally, lower winter temperature increases the maintenance energy requirements of the calf. Unlike mature animals, the young calf doesn’t have a functioning rumen that generates heat, and tremendous energy is required simply to maintain its body temperature. This extra energy usage often comes at the expense of meeting growth expectations.

Winterizing Your Calf Feeding Program

Calves need to consume more calories than full-grown cows to keep warm. Receiving the highest and most bioavailable plane of nutrition helps young calves stay healthy and reduces the effects of cold stress. Firstly, consuming high-quality colostrum after birth delivers the immunoglobulins required to support calf resilience to stressors. Colostrum is naturally high in fat and other nutrients that get the calf’s nutrition program off to a great start.

To bolster the energy of the pre-weaned calf diet, additional calories can be consumed through extra milk replacer or pasteurized whole or waste milk. Remember that a young calf’s intake of starter feed is not sufficient to provide additional calories, so they must be supplemented through milk or milk replacer. Fat supplements may further increase the level of energy calves receive.

Milk replacer should be high in quality (preferably all-milk protein or milk protein with plasma) and high fat (no less than 18%). When increasing milk replacer powder or adding a fat supplement, it is important to also increase the volume of water being fed so that the same dry matter content is maintained. When feeding pasteurized whole or waste milk, check the solids content to ensure the calf is getting the nutrients it needs, particularly when mastitic milk is provided, as it can vary

considerably in solids and nutrient content. The goal is to provide 12-13% total solids from waste milk. Use a brix refractometer to evaluate and adjust solids content.

Feeding milk at the proper temperature is another key practice to avoid exacerbating cold stress. Ensure the bottles or buckets used are at least room temperature before feeding so they do not contribute to cooling down the milk, and make sure milk replacer or waste milk is the correct temperature at the actual time of feeding.

Water is also essential to the calf diet, although availability can become problematic in the winter. Monitor water sources for icing and ensure calves continue to have access to water at least twice a day. Providing warm water 30 minutes after milk replacer or milk feeding can be beneficial in promoting starter feed intake, especially in older pre-weaned calves.

Reminders to Maintain Feed Equipment

When the weather gets bitter cold, it might be tempting to skip or skimp on cleaning and sanitation procedures. Yet maintaining clean equipment and utensils is exceptionally important to keep calves healthy during the winter months.

A few things to keep in mind:

· All feeding and treatment equipment that calves come in direct contact with should be cleaned regularly, including buckets, bottles and tubes.

· Use a chlorinated detergent in hot water to remove residue and pathogens.

· Use a clean brush to scrub surfaces inside and out.

· After cleaning, rinse all equipment with warm water and an acid sanitizer to prevent bacterial growth.

· Finally, dry all equipment thoroughly. Do not stack buckets until they are completely dry.

Calf Housing Seasonal Management

All year long but especially in winter, it’s critical to provide a clean, dry, moisture-free environment and minimize drafts. One important management practice is to immediately dry off the newborn calf.

Proper bedding goes a long way to maintain calf comfort. Coarse bedding materials like wood shavings do not provide a sufficient insulating effect or absorb enough moisture to keep the calf warm. Instead, clean, dry, deep-packed straw offers necessary insulation. The more a calf can nest in straw, the more insulated it will be. Conduct the kneeling test as a routine management practice by taking a knee onto the bedding to confirm that it is as moisture-free as possible. If your knee comes up wet, you must change the bedding.

Calf blankets also can be effective in providing additional insulation. Animals within the first three weeks of life benefit the most from calf blankets. Make certain that blankets fit appropriately and are cleaned between calves. Also check that the calf is not sweating beneath the blanket, which could cause moisture to build up on the haircoat and reduce the blanket’s effectiveness and may even promote further challenges.

In addition to clean, dry, absorbent bedding, proper ventilation in indoor facilities is also very important. Ventilation and air exchanges reduce dampness and bring in fresh air that helps prevent

illness. Furthermore, keep calf hutches sheltered from wind and in good repair to eliminate moisture entry.

In summary, now is the time to establish and execute protocols for feeding, sanitation and housing that will help your calves stay healthy and grow productively in the presence of cold stress. A bit of cold stress prevention will pay great dividends throughout the changes the winter season brings.

Bill Earley is the Dairy Business Manager for ADM Animal Nutrition, and since graduating from Michigan State University, he has served the dairy industry for nearly 40 years.