Throughout the hot summer months, those who care for dairy calves concern themselves with issues such as flies, excess heat, ventilation and fluid intake. Now that winter weather has arrived, calf care requires a somewhat different set of standards. While some calf care parameters are the same, cold weather care starts with ensuring that calves are warm and dry.
Every animal has a thermo neutral zone, or TNZ. Technically speaking, TNZ is the range of ambient temperature without regulatory changes in metabolic heat production or evaporative heat loss. More simply, it’s the environment in which the calf doesn’t lose energy trying to stay warm or cool.
The TNZ of a newborn calf is between 50 and 78 degrees. Any temperature that falls above or below that range means that the calf will burn energy to maintain its core temperature. A newborn calf’s entry into the world can be quite a shock when the weather is cold. Although the newborn calf’s first line of defense comes from the care and feeding of its close-up mother, once the calf hits the ground, it’s up to the farmer to ensure good care and feeding for the calf’s success.
Keep a pile of clean, dry terrycloth towels on hand for drying calves in cold weather. Move the calf to dry bedding as soon as possible after birth and rub the calf briskly. This rubbing increases heart rate and blood flow, which helps the calf prepare to stand. Dry, fluffy hair is an excellent insulator and will go a long way to help the calf stabilize its body temperature.
Weather conditions that create mud are potentially the hardest for calves to endure. Just-above freezing temperatures along with rain make it hard for calves to maintain core temperature. Calves that are stressed from scours, a difficult birth or pain due to injury have a harder time staying warm.
Winter calf housing doesn’t have to be complicated; just clean, dry and draft-free. Outdoor calf hutches require more bedding in cold months, and that bedding should always be as deep and dry as possible. Organic bedding (straw, shavings) is preferred over sand or other inorganic material. Damp bedding causes calves to lose body heat, and can contribute to microbial buildup.
Calf hutches should be placed in a well-drained area where water will not accumulate. Consider creating a sloped base for adequate drainage. Place hutches so that the prevailing wind does not blow directly into the front of the hutch. Locations that tend to be windy year-round are usually especially windy in winter. In these areas, a windbreak such as a building or a planned planting of evergreens can help reduce the impact of wind.
During extremely cold weather or cold temperatures combined with wind and precipitation, calves will do better with three feedings/day rather than two. Ideally, liquids (milk, milk replacer and water) should be fed as close to the normal body temperature of the calf (about 102 degrees) as possible. Milk that is colder requires energy to warm up.
Offer the same amount of milk at each feeding so that the calf has higher overall intake. If three feedings is impractical for your farm, offer more milk during each feeding. If you decide to use a more concentrated mix in severe weather, be sure to provide adequate water, preferably warm and not close to freezing.
The goal for small-breed calves is daily intake of 1.3 pounds of dry matter (DM) and 0.3 pounds of fat; while large-breed calves should consume 2.0 pounds of DM and 0.5 pounds of fat. Milk replacer is about 95 percent DM while whole milk is 13 percent DM. As with all calves, cold-weather calves benefit from a good calf starter ration, offered free choice as early as possible.
If the weather forecast includes heavy snow or a combination of snow and wind, be sure to prepare ahead of time so that calves are maintained on the same feeding and care schedule. In the case of hutches or other outdoor housing and a forecast of heavy snow, be ready to move calves before the snow becomes unmanageable. It’s important for calves to remain on the same schedule and receive the same level of care throughout the winter months.
Calf coats, or jackets, help reduce cold weather stress for newborns or weak calves. The Canadian Journal of Veterinary Research reported a 52 percent increase in overall animal insulation on calves that wore coats, despite sub-zero temperatures.
Calf care is ideally managed by designated personnel who are aware of protocol and biosecurity. Whether one person or several care for calves, it’s important to keep good notes on calf health, treatments and other observations. This means a better chance that the calf will be more closely monitored by the next person and a good history if a veterinarian becomes involved with treatment. It’s easy to skip note-taking when the weather is cold, but it’s important and should be a key part of each feeding.