On a recent visit to dairy land in central California, this question popped up again and again from dairymen. “It doesn’t get that cold here, why should I cover my calves with calf coats?”
This is a valid question. If we are comfortable outside in 50 degree weather with a light jacket, shouldn’t newborn calves tolerate that just fine?The answer is a little more complicated…
In the first 6 weeks of life, a calf’s THERMONEUTRAL ZONE is 50-78 degrees Fahrenheit. What is a thermoneutral zone, you say?
The thermoneutral zone is the safe range of temperatures that a calf may be exposed to WITHOUT needing to expend additional energy. Think a no shivering, no sweat zone (see diagram).
Exposure to such stress can increase risk of disease and death, prevent growth and immune system functioning, and affect the calf’s response to treatments as well as overall productivity.
So how can we prevent the calf from getting too cold or too hot? Let’s address the former as we’re headed into winter. There are a series of techniques which we’ll go into in another article, but let’s focus on 3 simple steps for now.
Dairy Herd Magazine “Time to Break Out the Calf Jackets” Excerpt: A recent study in the United Kingdom compared 40 Holstein calves reared from December through February (2018). Half received calf coats from 2 to 12 weeks of age, and half did not. The researchers found that the calves with calf coats gained an average of 11.68 pounds more than those without. In addition, the calves with calf coats:
Ate less feed, resulting in a savings of about $3.77 per head.
Had increased last rib girth measurement, indicating improved rumen development.
Had higher fecal scores and a lower incidence of scours.
As promised in our recent Calf Care & Disease PreventionThermoneutral Zone article, we’re following up with more techniques for calf care and disease prevention to ensure your calves are warm this winter. Cold nights can be especially brutal on young dairy cows, so make sure to address their needs before it’s too late. The most common calf care and disease prevention practices involve colostrum/milk supplements, calf coats, thick straw bedding, heated drinking water, and slower full volume airflow.
Aside from calf coats, bedding is the next most efficient way to keep your calves warm.Straw or long stemmed hay is the warmest and most absorbent bedding type. Studies from the University of Wisconsin determined health of calves with different levels of bedding and created a scoring system for bedding. A nesting score of 3 is ideal for newborn calves in the winter. Ideally when the calf nests you will not be able to see their legs. If your calves wear jackets, a nesting score of 2 is acceptable. To find out what your nesting score is, visit: UW Research.
About 12 inches of straw is recommended. Per 1000 pounds of animal, there should be approximately 25 pounds of bedding. Change bedding regularly to curtail ammonia exposure.
If you’re not using calf huts, ventilating your barn is the safest way to keep calves healthy and warm, prevent cold stress and hoof problems as well as prevent damage to membranes from ammonia exposure.
When it comes to ventilation systems, 3 details are important to consider:
Is the volume of fresh air input at it’s maximum?
Is the speed of the incoming air causing calves to shiver?
Is the flow direction accurately reaching the calves (4 ft off the ground)?
Determining the effectiveness of your air flow speed and direction will keep your calves warmer in winter. Maintaining full volume air flow entails they’re receiving the proper fresh air intake.
Bettermilk Holstein calf coats are made to prevent your calf from shivering on those cold days and nights. This affordable, ruggedly constructed coat comes with a Rip-Stop, water-repellant outer shell insulated with Hollofil. (Hollofil is the same material used in popular outdoor apparel and sleeping bags and is well known in the industry). The coat’s adjustable straps are triple-stitched, highly durable and stretchable to accommodate large animals–including goats, sheep, dogs, and other sizable creatures. The Large (Holstein) coat measures 35 inches long by 14.5 inches wide and is designed to fit a Holstein calf through its first 6 weeks of life.