Winter means managing cold stress in calves

Winter means managing cold stress in calves

FOR many states, this winter has brought some of the coldest temperatures in decades. Extreme weather means that livestock producers have to take additional steps to prepare their animals, especially cattle producers with newborn and young calves.

Dr. Noah Litherland, assistant professor and dairy cattle extension specialist at University of Minnesota, recently offered producers tips for managing cold stress in calves.

According to Litherland, if calves are not growing or are losing bodyweight, then the start of the first lactation is being delayed and potentially being compromised. Cold stress diverts energy away from growth and immune function.

He said nutrition and management are the keys enabling calves to: (1) grow during cold stress, (2) resist digestive and respiratory disease and (3) minimize stressors.

The first goal is to meet the increased energy requirement for maintenance during cold stress, and the second is to provide enough energy above maintenance requirements to keep calves growing at a rate of at least 1.0-1.5 lb. per day.

Cold stress begins when temperatures drop below 60 degrees F for calves fewer than 21 days of age and when temperatures drop below 42 degrees F for calves more than 42 days of age.

Calves are born with limited body fat reserves. Even calves that are six weeks old still have less than 4% fat in muscle tissue. The ratio of external surface to internal mass is extremely important. The smaller the calf, the more important this relationship becomes. For example, Litherland reported that Jersey calves have a 15% greater maintenance energy requirement than large-breed calves.

Clean and dry hair coats provide greater insulation from heat loss. Calves can also shiver, which generates heat when muscle fibers rub together. Muscle glycogen is in short supply in calves, and the glycogen fuel tank is very shallow in a newborn calf; therefore, Litherland said shivering is not a sustainable source of warmth in calves.

When feeding calves during cold stress, Litherland said one goal should be providing adequate amounts of energy from fat and lactose. Calves can "burn" protein for energy, but priority use of protein should be for muscle and bone growth, not as a source of energy. Litherland suggests three main ways to increase caloric intake from milk:

1. Add a third feeding. Feeding during the coldest time of the day will likely provide the biggest benefit. Feeding three instead of two daily meals will increase the amount of solids by one-third; so, for example, increase the amount from 1.5 lb. per day to 2.25 lb. per day.

2. Increase the feeding volume by one-third in two feedings. This will deliver the same amount of nutrients as adding a third meal. The challenge here, according to Litherland, is that some young calves may not be able to consume that much milk, and a large meal size may predispose calves to digestive upset and reduce starter grain intake.

3. Add supplemental fat. In a University of Minnesota trial, adding a quarter-pound of a 60% supplemental fat increased calf growth rate during the first three weeks of life. Supplemental fat does tend to suppress starter grain intake, so Litherland said to use fat only for the first 14 days of life and then slowly wean calves off of supplemental fat.

According to Litherland, rumen development associated with starter intake is really helpful to cold-stressed calves because microbial fermentation produces a large amount of heat. He said to be sure starter grain is palatable, fresh and within easy reach of the calves.

Additionally, Litherland emphasized the importance of providing at least 1 gal. of fresh, warm drinking water per calf per day for the first month and 2 gal. during the second month of life. If calves are not eating starter grain by day 10 or 14 of age, then something is wrong and it is time to start troubleshooting starter quality, calf health and feeding practices.

Because calf health during cold stress can be a major challenge, Litherland stressed the need for feeding adequate amounts of colostrum, dipping the navel at least twice, drying calves thoroughly with towels and keeping the environmental temperature above 50 degrees F for newborns during the first 48 hours.

Additionally, he said calf jackets are a must if the ground has frozen and the calf is younger than three weeks of age.


Limit hospital pen moves

When a dairy cow develops a disease, dairy farms immediately work to get her back to normal health. This typically begins by moving the cow to a hospital pen. According to Zoetis, however, this common task may actually be doing more harm than good.

"We think about a hospital as a place to get well, but that isn't necessarily the case," said Dr. Mike Lormore, director of dairy technical services at Zoetis. "Hospital pens can be a risky place, especially for fresh cows, and this can affect the entire dairy. Producers need to understand the risks of managing hospital pens and work to avoid unnecessary pen moves."

According to U.S. Department of Health & Human Services estimates, one in every 20 inpatients has an infection related to hospital care.

Dairy hospital pens are similar in that they can be risky environments, especially for fresh cows that may have depressed immune systems, increasing their likelihood of contracting a new infection.

"With proper treatment and care, a dairy cow has a good chance of recovering from an initial disease incident," Lormore explained. "However, if a cow gets a second disease, especially salmonellosis or mycoplasma mastitis, it's much more likely that the cow will not recover to previous production and health. Additionally, she is at great risk of early removal from the herd."

The prevalence of salmonella has been on the rise across U.S. dairies, and in a hospital pen, the risk is even greater. Research has found that a cow is 11 times more likely to contract the bacteria in a hospital pen than anywhere else on the dairy. Salmonella infections can lead to reduced milk yield, weight loss, poor reproductive performance and death in dairy cows.

Mycoplasma bovis is another bacterium that cows can easily contract in the hospital pen. In one study referenced by Zoetis, 70% of cows entering the hospital pen contracted M. bovis clinical mastitis within 12 days of entering the pen.

During their stay in the hospital pen, fresh cows can become carriers of disease. If they don't show signs of a clinical infection and are returned to their regular pen, the bacteria they are subsequently carrying can follow them back to the milking herd. This, Zoetis said, puts the entire herd at risk.

Zoetis said avoiding hospital pen moves, especially for fresh cows, should be a priority to help protect dairy cow wellness. Veterinarians should be the first resource for finding ways to avoid moving cows to hospital pens.

"The biggest mistake dairy producers make is not working with their veterinarian enough on treatment protocol development and execution," Lormore said. "Producers need to establish a valid veterinarian/client/patient relationship so they can work together with their veterinarian to find solutions that better manage fresh cows and avoid risky hospital pen moves."


Fuel Up to Play 60

With research showing that increased physical activity and better nutrition can lead to improved academic performance, Fuel Up to Play 60 — the nation's largest in-school nutrition and physical activity program, which was founded under the leadership of America's dairy farmers — recently celebrated five successful years.

Since the program launched, it has reached 38 million kids in 73,000 schools with the tools, grants and resources needed to make school environments healthier and more active.

To mark the occasion and look to the future, the National Dairy Council, National Football League, GENYOUth Foundation, U.S. Department of Agriculture, U.S. Department of Health & Human Services and U.S. Department of Education recently recommitted their efforts and assets for five more years to help Fuel Up to Play 60 continue to build on its success in creating healthier school environments.

"America's dairy farmers have always had a long-standing commitment to the health and wellness of America's children," said Jerry Messer, a dairy farmer and chairman of the National Dairy Council. "Students spend 2,000 hours per year in school, and we are proud to help empower them to improve that experience. Fuel Up to Play 60 is a powerful legacy to leave to future generations."

The $250 million public/private partnership is implemented through the support of health professionals, education, physical activity, nutrition, government and corporate organizations that come together to positively affect school health.

Volume:86 Issue:02

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