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GIRARD —
Cold weather is stressful both to cattle and stockmen alike. Cutting ice and being out in bone chilling temperatures makes it tough to provide feed and water to the livestock. Not to mention the extra stress placed on the cattle.
When cattle are exposed to cold temperatures their metabolic needs are increased because of several factors. These include: striated muscle shiver, faster heart beats, deeper breathes, increased urine flow, and increased functions in all tissues due to response from the pituitary gland. The net result is an increased energy requirement by the animal.
The term lower critical temperature is an important concept to understand before making feeding decisions. The lower critical temperature is the minimum temperature that the animal can be exposed to without energy requirements being raised. The critical temperature is determined by: whether the hair coat is wet or dry, the density of the hair coat, and the temperature adjusted for wind chill. Recommendations developed by beef research is to increase the amount of feed by 1 percent for each degree below the critical temperature if the hair coat is dry and by 2 percent for each degree below the critical temperature if the hair coat is dry.
The following chart lists the critical temperatures for beef cattle under different situations:
Hair Coat Temperature
Wet coat 59º F
Fall coat 45º F
Winter coat 32º F
Heavy Winter coat 19º F
Dry: Increase energy by 1% each degree below the LTC
Wet: Increase energy by 2% each degree below the LTC
To calculate an example situation for a cow with a dry winter coat:
Step 1: Determine the cow’s LCT (example: 32 degrees F).
Step 2: Estimate wind-chilled temperature (example: 20 degrees F temperature with 12 mph wind equals 7 degrees wind-chilled temperature).
Step 3: Subtract wind-chilled temperature from LCT to determine difference. (32 degrees minus 7 degrees equals 25 degrees below LCT).
Step 4: Adjust feed if needed. In this example the wind chill is 25 degrees less than the critical temperature for a cow with a dry hair coat so feed 25% above the normal daily energy amount.
To calculate the wind chill go to http://www.crh.noaa.gov/ddc/?n=windchill
Research conducted at Kansas State University compared two groups of cows. The first group of 30 cows were fed the same amount regardless of the weather conditions while the other group of 30 cows amount of feed was adjusted based on the cows lower critical temperatures. Cows on the diet adjusted for weather conditions gained 89 pounds more during the last half of gestation, showed a 17% increase in cycling 60 days post calving, and were 103 pounds heavier the next fall after the calves were weaned compared to cows on the diet that was not adjusted for weather conditions. The amount of additional feed to account for the cold weather events in this trial would be equivalent to 125 pounds of corn per cow. This study illustrates that effective cold weather feeding adjustments can result in better cow body condition and more efficient cow maintenance.
Cold weather is stressful both to cattle and stockmen alike. Cutting ice and being out in bone chilling temperatures makes it tough to provide feed and water to the livestock. Not to mention the extra stress placed on the cattle.
When cattle are exposed to cold temperatures their metabolic needs are increased because of several factors. These include: striated muscle shiver, faster heart beats, deeper breathes, increased urine flow, and increased functions in all tissues due to response from the pituitary gland. The net result is an increased energy requirement by the animal.
The term lower critical temperature is an important concept to understand before making feeding decisions. The lower critical temperature is the minimum temperature that the animal can be exposed to without energy requirements being raised. The critical temperature is determined by: whether the hair coat is wet or dry, the density of the hair coat, and the temperature adjusted for wind chill. Recommendations developed by beef research is to increase the amount of feed by 1 percent for each degree below the critical temperature if the hair coat is dry and by 2 percent for each degree below the critical temperature if the hair coat is dry.
The following chart lists the critical temperatures for beef cattle under different situations:
Hair Coat Temperature
Wet coat 59º F
Fall coat 45º F
Winter coat 32º F
Heavy Winter coat 19º F
Dry: Increase energy by 1% each degree below the LTC
Wet: Increase energy by 2% each degree below the LTC
To calculate an example situation for a cow with a dry winter coat:
Step 1: Determine the cow’s LCT (example: 32 degrees F).
Step 2: Estimate wind-chilled temperature (example: 20 degrees F temperature with 12 mph wind equals 7 degrees wind-chilled temperature).
Step 3: Subtract wind-chilled temperature from LCT to determine difference. (32 degrees minus 7 degrees equals 25 degrees below LCT).
Step 4: Adjust feed if needed. In this example the wind chill is 25 degrees less than the critical temperature for a cow with a dry hair coat so feed 25% above the normal daily energy amount.
To calculate the wind chill go to http://www.crh.noaa.gov/ddc/?n=windchill
Research conducted at Kansas State University compared two groups of cows. The first group of 30 cows were fed the same amount regardless of the weather conditions while the other group of 30 cows amount of feed was adjusted based on the cows lower critical temperatures. Cows on the diet adjusted for weather conditions gained 89 pounds more during the last half of gestation, showed a 17% increase in cycling 60 days post calving, and were 103 pounds heavier the next fall after the calves were weaned compared to cows on the diet that was not adjusted for weather conditions. The amount of additional feed to account for the cold weather events in this trial would be equivalent to 125 pounds of corn per cow. This study illustrates that effective cold weather feeding adjustments can result in better cow body condition and more efficient cow maintenance.
