As winter settles in, farmers face significant challenges in maintaining the health and growth of their young stock. The plummeting temperatures can drastically increase the energy demands of calves, making it difficult for them to maintain body condition and achieve optimal growth rates. Dairy calves are particularly sensitive to temperature changes; unlike adult animals, they experience higher environmental stress due to the lack of heat production from rumen fermentation and underdeveloped subcutaneous fat reserves. Consequently, their energy requirements increase as they strive to maintain body heat in freezing conditions. Research indicates that calves under three weeks of age experience a 40% increase in maintenance energy requirements when exposed to temperatures of 37°F or lower, while calves over three weeks see a 13% increase (Ghasemi et al., 2017).
Despite consuming more starter grain compared to other seasons, calves average daily gain (ADG) was not significantly affected, as noted by Holt (2014), for calves up to 13 weeks. This highlights the disruptive impact of cold stress on animal productivity, which can interfere with the daily operations of dairy facilities. To meet the increased energy needs during the cold season effectively, supplemental fat can be incorporated into the diets of calves using starter grain. This provides an efficient energy source, helping calves stay warm, grow, and thrive during harsh winter conditions. It also is encouraged to introduce calves to starter as soon as 2 weeks of age to improve rumen development (Sander et al.,1959). Fat is an energy-dense nutrient, offering more than twice the energy per unit weight compared to carbohydrates and protein, making it an excellent supplement during the winter months. Adding fat to the diet of dairy calves helps meet the increased energy demands without significantly increasing the feed volume, which is critical for young animals with limited stomach capacity.
The primary benefit of feeding supplemental fat is the provision of additional calories without increasing feed volume. This is especially important during winter when cold stress may reduce the feeding frequency of calves and lower intake (Ghasemi et al., 2017). Additionally, integrating fat into the diet provides a consistent energy source that supports their energy requirements and enhances growth rates. Although some studies have shown that supplemental fats may limit dry matter intake and reduce ADG in thermoneutral conditions, Ghasemi et al. (2017) reported no significant decrease in dry matter intake when feeding 6% soybean oil supplemental fat during the winter months. Their findings indicated that combining supplemental fat with a high-protein or high-fiber starter grain was optimal for increased growth and performance. Beyond the energy boost, supplemental fats can support the development of the immune system in young calves. Essential fatty acids and certain hormones synthesized through fat supplementation can help maintain calf health during the cold season.
Calves might be reluctant to consume certain types of supplemental fats, but alternative forms can be added to their diet to boost intake. Vegetable oils like soybean oil, canola, and palm oil are commonly used due to their high fat content and palatability. These oils are easily digestible and can be added directly to starter feeds. Whole fat sources such as soybeans, sunflower seeds, or corn offer high oil content and additional nutrients like fiber and protein. Blended fats and tallow are also viable options that can be easily incorporated into calf diets.
Supplementing young animals with fat provides significant benefits, but it is essential to recognize and address potential challenges. As with any dietary change, fat should be introduced gradually to avoid digestive issues. Overfeeding fat can lead to complications such as diarrhea or reduced feed intake, so monitoring the inclusion level is crucial. Typically, 3-6% DM fat is recommended in the overall diet, though this can vary based on the calves' individual needs and environmental conditions. Another challenge is ensuring a balanced diet. While fat is energy-dense, it doesn’t supply all the necessary nutrients for growth. Therefore, ensuring that the diet includes adequate protein, vitamins, and minerals is vital to prevent nutrient imbalances. Combining supplemental fat with a high-quality milk replacer or starter grain helps provide a balanced diet that supports both growth and immune function.
Supplemental fat is particularly valuable for supporting the health and growth of dairy calves during the cold months. By offering a concentrated energy source, fat helps calves meet the increased energy demands associated with cold stress, enhances growth rates, and boosts immune function. With supplemental fat, dairy farmers can ensure their calves remain strong, healthy, and well-prepared for the challenges of winter.
— Sommer Thompson