winter calf management

The winter months can be a challenging time for pre-weaned calves because during cold weather calves need to use a significant proportion of their dietary energy to maintain their body temperature.  We do not want them to use all their daily calories for this purpose because we still want them to grow and thrive.  The calf’s thermoneutral zone is between 10 and 20 °C, and in this zone, calves do not need to use any energy to keep their bodies warm or cool.  The additional energy cost to the calf in temperatures of -10°C or colder can be enormous, particularly if they are also in a drafty area or their bedding is wet or damp.  There are strategies that can be taken to mitigate the effects of the cold weather on our calves’ performance. 

1.     Provide more calories in their diet

2.     Help prevent the calves from becoming cold stressed

3.     Ensure calves are well protected from disease

The strategies that provide more calories in the calf’s diet include:

1.     Increasing the amount of milk fed to the calves either by more milk/milk replacer (MR) per feeding (ie: from two to three litres per feeding); or feeding the calves more frequently (ie. from twice daily to three times per day, or utilizing free choice feeding systems (acidified milk programs)).

2.     Changing to a MR that contains a higher percentage of fat.  Use a winter milk replacer which is formulated to contain 20% fat (instead of the 16-18% fat in regular Milk Replacer), so the calf consumes more calories with the same daily MR intake.

The strategies that prevent calves from getting cold include:

1.     Providing calf blankets/jackets from the day they’re born to 3-4 weeks of age.  The blanket adds another layer of insulation over the calf’s body.

2.     Providing a deep bed of straw for the calves to lie in so their legs are completely buried.  The straw acts like an insulating blanket, holding in their body heat.  Shavings do not allow calves to bury.  Ensure that the bedding is ALWAYS dry.

3.     Keep calves out of drafts.

The strategies that ensure calves are well protected from disease include:

1.     Ensure your colostrum management program is adequate.  This can be determined with a simple blood test which measures if the calf received adequate amounts of antibodies in the colostrum that it was fed (termed passive transfer). To ensure adequate transfer of antibodies, the calf must get the colostrum soon enough after birth (first feeding ASAP, a second feeding within 12 hours of birth); they must be fed enough colostrum (minimum 3 litres per feeding for the first 2 feedings); the colostrum must be of high quality (can be measured by a brix refractometer or colostrometer); and must be clean and fresh.  When calves have failure of passive transfer (FPT), they will not acquire the necessary protection against common pathogens (diarrhea and pneumonia-causing viruses and bacteria).  Also, when calves get cold stressed, their immune system can get compromised and make them much more susceptible to disease. 

2.     Vaccinate your cows with a modified-live virus respiratory vaccine (ie. Express-10) and a vaccine targeting calf diarrhea (Scourguard-4KC).  Vaccination enhances the development in the udder of the proper quantity and quality of antibodies in the cow’s colostrum which get passed on to the calf and helps protect them until their own immune system becomes sufficiently developed to fight diseases.

These strategies can make a significant difference in the health and performance of your calves during the winter months.  Let us know if we can assist you to optimize your calves’ health this winter.

(Dr. Brian Keith, 2015)