As the weather turns colder there’s been a more frequent addition to our daily lunch menu from the Miner cafeteria: hot soup! On those colder days I’ve seen a lot more people enjoying a cup of soup to help warm them up after being out in the cold. Similarly, as it gets colder you might observe that your older calves are eating more of their starter to help meet their energy requirements. But what about your youngest calves?
Calves less than 3 or 4 weeks of age are probably not consuming enough starter to really contribute to their energy requirements. The youngest calves on your farm are completely dependent on the nutrients consumed in their milk or milk replacer. As the temperature drops it becomes more challenging to meet nutrient requirements for not only growth but also their basic maintenance requirements.
The thermoneutral zone of a calf under 3 weeks of age is between 59 and 77°. Below this and the heat that a calf produces is equal to the amount of heat lost and the calf experiences cold stress. Therefore, to maintain body temperature, the calf must either consume more energy or the calf will be forced to use what limited body reserves it has for this purpose. This prioritization of nutrients will always go first to maintenance (thermal regulation, immune and stress responses and then toward growth.)
The requirement for maintenance in a calf is quite substantial. Depending on your feeding program the calves on your farm could easily consume enough nutrients to meet their maintenance requirements. However, if you feed 4 to 6 quarts of milk or milk replacer per day then it becomes more challenging to meet maintenance requirements for the youngest calves during cold weather. As an example, the table above estimates the amount (in quarts) of whole milk or milk replacer (20% protein; 20% fat) required to meet the maintenance requirement of an 88-pound calf.
For calves being fed whole milk, if the environmental temperature reaches 23° or below the majority of a 4 qt. allotment is mostly going toward maintenance, leaving little to no nutrients for growth. For calves fed a more conventional milk replacer, the amount required to meet maintenance requirements per day is greater relative to whole milk. Below 41°, much of a 4 qt. allotment of a 20:20 milk replacer would be used for maintenance. As the temperatures drop below 14° almost 5 qts. or more are required for maintenance alone.
Meeting the maintenance requirement becomes more challenging when temperatures fall below 0°, which it often does in the North Country and in other parts of the Northern U.S. Although there are different ranges of feeding levels and milk replacer formulations, the big takeaway is making sure you’re meeting the needs of the calf so that she can meet her maintenance requirements and also continue to grow.
How can we achieve this in cold weather?
- Increase amount of milk or milk replacer fed per day. This can be achieved by increasing the quantity, either through an extra feeding or more milk during normal feedings.
- Supplement milk replacer with added fat or additional milk solids. With increased solids it is crucial to provide free-choice water.
- Switch to a more energy dense milk replacer that is formulated with higher fat concentrations.
- Increase starter intake. Make sure you are feeding a palatable starter. It is also very important to continue to provide water during the cold because starter intake is linked with water consumption.
Increasing starter intake is most likely the most challenging task in the youngest calves, so focus on the first three methods to maximize nutrients for maintenance and additional growth. Other calf management practices to keep in mind are to provide deep and dry bedding, calf jackets, minimize drafts, and make sure milk or milk replacer is fed to the calf at or above body temperature at time of delivery.
Now the big question: how are you planning to make changes to your “calf”eteria this winter?