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Adjust winter feeding program to help keep calves healthy

Emily De Benetti Published on 01 December 2014

The most efficient rate of growth a calf experiences is in the first month of life. Strong growth and good calf health is linked to improved performance of heifers with a trend toward earlier first breeding and increased milk yields.

However, calves are at a disadvantage in the winter months due to an increase in energy requirements for maintenance of body temperature and subsequent increased susceptibility to illness.

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If these energy needs are not met, the growth rate of the calf will be compromised, as will the immune system’s ability to ward off disease.

Paired with strong management, an adjusted feeding program for winter that provides adequate nutrients to sustain this increased energy demand, and which will support vigorous growth, will help keep calves healthy and growing through the winter.

When should you adjust your feeding program?

The thermoneutral zone is that temperature range in which no additional energy is expended in the maintenance of body temperature. Until calves reach 4 weeks old, this thermoneutral zone is between 10 and 25ºC, and beyond 4 weeks old to weaning, this zone expands to zero to 25ºC.

When the ambient temperature is below this temperature range, additional calories should be integrated into the calf’s diet to avoid diminished ability to maintain body temperature while sustaining growth and immune function.

Best approach to winter feeding

As the temperature drops further from the calf’s lower critical temperature (the lowest temperature in the thermoneutral zone), more energy is required to maintain body temperature. Adjustments in housing and feeding management will help compensate for these increased requirements.

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Amount and frequency of feedings

Providing extra calories through modification of the calf’s diet or increasing the amount of milk fed should both be done gradually. A high-protein, moderate-fat nutrient composition is exceptional for providing substrates for large frame and lean muscle growth.

However, the calf’s demands change as the temperature drops below its thermoneutral zone and the need for accessible and long-lasting nutrients becomes the limiting factor for continued maintenance of body temperature, growth and immune function.

Gradually switching to a 22/17, 26/18 or 22/20 milk replacer for winter feeding will better accommodate the calf’s change in metabolism experienced when devoting such a great amount of energy to maintenance of body temperature alone.

There needs to be sufficient energy available to properly metabolize dietary protein for tissue deposition. Digesting protein is more metabolically expensive than digesting fat, with sugars being the least metabolically expensive.

Fat is calorie-dense and is easily digested and utilized, allowing calves to utilize the protein components of their diet more effectively with adequate total calories to adjust for increased metabolic demands of homeostasis in cold weather.

The additional meal not only acts as an external transient heat source helping to keep calves’ body temperature up, but feeding more frequently has proven to improve feed utilization.

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Increasing volume fed by adding a feeding allows for the increased calorie intake to be best utilized with a more positive feed-to-gain ratio compared with feeding fewer, larger meals of the same dietary and total calorie composition.

Suggested winter feeding schedule

This minimum recommended feeding schedule (Table 1) allows for a total of 8.5 to 10 L intake with seven hours between daytime feedings and 10 hours between the night feeding and the morning feeding thereafter.

Spacing out the feedings gives calves a chance to regain their appetite between meals. Using an automatic calf feeding machine is also an effective tool.

With greater control of milk replacer concentration, mixing and temperature, automatic machines can also be set up with custom feeding schedules that easily accommodate higher volume intakes.

Consider incorporating an acidified milk replacer into your winter feeding program. Acidified milk replacer is effective in reducing bacterial counts as bacteria are unable to thrive in an acid environment.

An unfulfilled energy demand brought on by cold winter weather will draw energy away from the calf’s fragile immune systems, causing them to be more susceptible to pathogen stress which would normally not affect a calf that is not experiencing a negative energy balance to the same extent.

Increasing the energy allotment in the diet by increasing the volume fed will allow for the immune system to function to its full potential with the added bonus of a diminished pathogen.

Detecting cold stress

It is important to be able to notice cold stress in calves, as it is a sign their environment is too harsh or their feeding program is insufficient to provide the additional energy needed, or both.

Prior to the onset of cold stress, calves will experience reduced growth rates and immune function, as the sustained low temperatures they are exposed to are very costly on their metabolism.

Keen observation of calf health to help avoid illness is extremely important for calves that may be energetically compromised during these cold months.

Some signs of cold stress as presented by Saskatoon Colostrum Co. Ltd.:

  • The calf may be shivering or have noticeably rapid breathing.

  • The temperature and colour of excessively cold hooves or muzzle (pale pink, blue) may show that blood is being diverted from the extremities.

  • Decreased body temperature resulting in cold stress begins at 38ºC where normal body temperature is 39ºC.

Avoiding cold stress

The energy demands for maintenance of the calf can be decreased through winter management practices such as blanketing, keeping the calf and bedding clean and dry, providing adequate straw for nesting and providing ad libitum warm water.

These steps, along with an adjusted feeding program, will help your calves stay healthy and have strong growth through the winter months.  PD

References omitted due to space but are available upon request. Click here to email an editor.

Emily De Benetti
  • Emily De Benetti
  • Project Coordinator
  • Grober Nutrition

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