Each year, I literarily see hundreds of preweaned dairy calves overwintered in outdoor calf hutches. Most perform well, but there are also more “poor doers” than I care to see. I find that each poor calf tells a similar story.
Some of the mediocre calves are shivering, others are skinny, a few calves are coughing (with nasal discharge), while others are scouring. These are familiar signs of cold stress, which lead to a high degree of morbidity (sickness) and mortality in calves. I recommend dairy producers take a brisk walk along a row or group of their hutches looking for ways to prevent or reduce any signs of cold stress in calves with a good winter action plan.
From a practical standpoint, cold stress in dairy calves arises when either dietary energy intake is inadequate or body heat loss is significant or both occurs. When this happens preweaned dairy calves tend to divert precious feed energy meant for good growth and strong immunity to just keeping warm.
Shivering only gets worse
Under moderate cold conditions, we might see dairy calves (as I first mentioned), simply shivering. When it gets just a few degrees colder, there is an almost invisible breakdown of limited fat reserves in a short period. As temperatures and wind chills become more extreme, calves seem to “give up” and become despondent as their natural thin layer of body fat disappears. These preweaned calves are often found dead as “starve-outs.”
Environmental research studying cold stress (and explains starve-outs) in dairy calves has demonstrated for every drop of the thermometer by 1 F below 50 F (10 C), a calf requires one per cent more energy (excluding other environmental factors such as wind chill and wet weather). Back on the dairy farm, it means that dairy calves overwintered in outside hutches on a brisk winter day of -15 F (-25 C) require at least 65 per cent more dietary energy compared to their counterparts raised in a heated calf barn.
To cover this extra dietary energy, there are many simple things producers can do to implement a good winter action plan, so winter nutritional status of preweaned dairy calves is achieved:
- Adjust hutch placement. A row of hutches should be positioned so it’s not in the direct path of cold northwest winds, such as near a row of trees, fence or other suitable windbreaks. Individual hutches should also be positioned so cold drafts and snow are prevented from circulating around or even inside each hutch, and a few hours in direct sunlight does not hurt, either.
- Elevate dietary energy intake. Feed whole milk or high-fat (20 to 25 per cent) all-milk milk replacer. Increase the amount of milk or milk replacer fed by two per cent for every 1 C degree, the temperature drops below 10 C (re: one per cent for every 1 F degree below 50 F). This advice means that if five litres of whole milk or milk replacer are routinely fed to each calf and the temperature drops from 10 C to 0 C (re: five litres x two per cent x 10 degrees drop = +1.0 litre), then a total of six litres of milk or milk replacer should be put in front of each calf. I would implement a third feeding, if this amount is too much for baby calves to consume.
- Maintain a good calf starter program. Calf starter should also be introduced to outside dairy calves just as those calves fed at any other time of the year. Two-week old calves won’t eat a significant amount of calf starter, but they will nibble on it. When they become five to six weeks old, one calf should consume to a kilo of calf starter per day and then can be weaned.
In the winter, a dairy friend cleans out the old calf starter every morning and replenishes hutches from calf starter stored in the breezeway of his barn. He feels that feeding frozen calf starter is like feeding ice pellets to his calves.
- Keep calves clean. It might be hard to clean dirty hutches in winter. However, replacing wet, soiled bedding with a good layer of fluffy straw effectively insulates calves from the cold. It also acts as a moisture barrier to keep them dry. One winter guideline for bedding suggests enough clean straw should be provided, so one cannot see the animals’ feet when they stand up. I would also wash the buckets in which milk replacer and calf starter are fed in the barn.
- Provide more TLC. From the start, people who use blankets on their calves in the hutches seem to have better winter-adjusted calves. I have also seen people that check on the condition of their calves in hutches more frequently, seem to catch the ones that are struggling (re: gaunt, have runny noses or loose manure) and treat them faster for a more effective recovery.
It has been my experience that these five practical recommendations lead to better-quality dairy calves raised in hutches over the winter. To me, it’s a tale of two dairy farms that I presently visit on occasion.
The first dairy farm lays a row of dairy hutches, just outside of the milking barn in the path of a direct arctic airflow with little bedding provided in the hutches. These calves are fed twice a day, a medium-fat milk replacer and calf starter buckets are filled every third day.
The second dairy farm has a good winter action plan: a row of calf hutches are placed away from any buildings near a long portable windbreak. Their calves are always nicely bedded with lots of clean straw. They are fed a high-fat milk replacer, three times a day and a high-quality calf starter, which is freshly provided every day.
Compared to the first dairy farm, the second dairy barn is well-known for producing healthy and frisky calves all year round.