The energy calves need is most readily available to them via the fat in their diets. The best milk replacers start with high-quality, (human) edible-grade fat sources, which are the gold standard for animal milk replacers. Research supports the use of these high-quality fats to maintain the best possible performance of your replacements. Providing these fats in a protein-encapsulated form ensures they will be well emulsified upon mixing, leading to the highest digestibility for the calf.

But how much fat do calves really need to maintain healthy growth through the winter months? Calves may need one-third more energy when temperatures drop from 55 to 25°F. Realize, though, that the extra energy required is not used or available for growth or support of a developing immune system; the extra energy is diverted from weight gain and the growth to maintenance of core body temperature. Some researchers estimate that 20% more energy is required for immune system development.

What are the ways to maximize or increase energy intake during times of cold weather?
Based on the NRC predictions, feeding an extra 2 ounces per feeding of 24:18 milk replacer (i.e. a 14-ounce feeding versus 12 ounces) will result in positive weight gain during extreme cold more reliably than formulating a 24:20 and keeping the feeding rate the same. Other options include:

  • Increase the liquid feeding rate by 25 to 50%.
  • Give an extra pint morning and night.
  • Feed an extra half to full bottle at noon to calves less than 3 weeks of age. If limited by bottle size to a specific liquid amount, increase the milk replacer powder dilution rate to a 25- to 50-percent higher mixing rate, and then feed a normal amount of liquid. Do not exceed 15% solids and keep water available.
  • Keep free-choice water available if at all possible. Calves consume considerably more starter when water is available.
  • Don’t forget the “warm soup effect.” Warm fluid feeding can warm moderately chilled calves.

What about supplementing extra fat?

Fat supplements add energy, but feeding more than 4 ounces per calf per day often results in reduced starter intake. Here are some guidelines for using a fat supplement:

  • Adding 2 ounces per feeding of a fat supplement that contains 60 percent fat to 10 ounces of a 20% fat milk replacer (mixed into 2 quarts total solution, fed twice daily) is equivalent to feeding a milk replacer with 27 percent fat. 
  • Be aware of the maximum total solids percentage for a solution of 15%.    

Source: Vita Plus Starting Strong newsletter