Trial Data

Calf Study of 100 bull calves started at Busse’s Barron Acres

The winter months at Busse’s Barron Acres (BBA) are a test of our calf raising skills. This past January we had a recorded low temperature of -23 degrees Fahrenheit and a recorded high of temp of 37 degrees Fahrenheit. We average 9 hours of daylight in January. This combination of long cold nights requires some extra measures to ensure that calves thrive during the winter months. One of the biggest tools used here at BBA during the winter is the Woolover Calf Jacket. We have been using this jacket since November 2000. We know jackets have been essential to keeping calves alive during our winter months, but this past winter we decided to try and measure how beneficial these jackets actually are. Our trial does not have results of calves not jacketed. We financially and professionally didn’t want to risk bull calves’ lives to experiment not using any jackets. Each bull calf included in this trial received the same nutritional diet. Calves are fed twice a day using a 22 percent protein/20 percent fat milk replacer. We feed 4 ounces of additional fat to calves to compensate for the cold temperatures.

  • Average weight: 96 lbs
  • 100 bull calves were started during the winter months of January, February and March.
  • Each calf was weighed on arrival.
  • All bull calves were sourced from one dairy and picked up within 24 hours of birth.
  • All bull calves were jacketed using a Woolover calf blanket upon arrival.
  • Each bull calf was delivered to an outside hut at Busse’s.
  • All bull calves were fed 1 pound of milk replacer with additional fat.
  • Calves were fed twice a day.
  • Weather information was collected and average mean temperature was calculated for each month.
  • Treatment data was recorded for each animal.
  • Average age at weaning 64 days.
  • Treatment rate very low.
  • One calf died of vaccine reaction and second bull calf culled for leg injury. Zero death loss due to illness.


Calves were weaned off milk, weighed and then moved to group pen. Bull calves averaged 1.39 pounds per day average gain. By using a milk replacer calculator designed to estimate average daily gain based on temperature and nutritional inputs, average gain should be approximately .61 lbs per day during the month of January. This equates to an additional gain of .78 pounds per day or 47 lbs total by weaning.


To account for this extra 47 pounds of growth, three areas can be considered. First, calves receive a calf starter upon arrival. By weaning time they are eating 6-8 pounds per day. This certainly provides the extra calories required to maintain growth. Next we still needed some way to combat extreme cold. We achieve this by keeping calves warmer. At the start of winter calf huts are turned south and bedded extra with a deep layer of straw. These measures help maintain the hut temperature. The final step is the Woolover Jacket. The calf now has a final layer of protection against the cold. Core areas of the calves’ bodies are covered and calories can be converted to growing instead of trying to stay warm. This results in bigger and healthier calves at weaning.

Post weaned calves were weighed at 100 days. Average daily gain at this point was 2.92 pounds per day. Average weight 306 pounds. Five month old bull calves were weighed a final time. The overall rate of gain for this period was 2.48 pounds per day. Average weight was 399.