If there is one thing we know for sure about our Alberta climate, it’s that it is unpredictable and calving season is certainly no exception.
For newborn calves, especially higher risk calves, like those who have suffered dystocia, or born to sick or poorly conditioned cows, cold stress brought on by adverse weather conditions results in poor survival rates. For calves that do survive cold stress, it can set them behind, hinder their growth and place them at high risk for infectious disease.
“Calves that endure cold stress at birth are more susceptible to scours, pneumonia and other infections,” says beef cattle veterinarian and practice owner of Veterinary Agri-Health Services, Cody Creelman.
Newborn calves can encounter a dramatic temperature shift as they leave the warm, comfortable environment of the uterus and enter a cold winter-like environment. And while newborn calves can handle relatively cold temps, wind or precipitation can quickly sap body heat. Even a warmer windy day can be deceptive. When newborn calves are born, their temperature averages 40 degrees celcius, dropping to 38 to 39 degrees celcius within a few hours. If it drops below that, the calf is unable to thermoregulate. That is why it is important to ensure that calves born into adverse weather conditions are carefully monitored and assessed.
COLD STRESS – IS THAT CALF COLD OR NOT? ELIMINATING THE GUESSWORK.
“When it comes to assessing cold stress in calves, we need to be a little medical and scientific about it,” says Creelman. “We need to assess: is that calf truly cold or not? When it comes to combatting cold stress, we certainly want to identify whether or not that calf is getting attention from mom. Is that calf getting dried off, or is it at the mercy of the elements? If it is the latter, we need to get that calf inside and dried off and confirm if it is in a hypothermic state.”
“For that,” says Creelman, a [rectal] thermometer is a great tool. “We always think of a thermometer as a tool to identify fever; however, it is just as useful in identifying the severity of hypothermia that we are dealing with in that newborn calf.”
Creelman says that if that calf is cold and shivering and has a normal body temperature, then the standard procedure is to get that calf inside and out of the weather, dried off with towels or with a supplemental heat lamp or hairdryer, or some form of forced air. Although Creelman says that these procedures are great for drying off a “cold calf,” it is important to remember they are not effective for actually raising that calf’s core body temperature if you are dealing with a hypothermic calf.
“Once that calf is 35 degrees celcius or lower in that true hypothermic state, then it is difficult for us to raise that core body temperature using only forced air,” says Creelman. “These methods are great at maintaining temperature, but they are ineffective when it comes to raising their core body temperature.”
In those circumstances, Creelman says that warm water immersion is the best next step.
“Warm water immersion is really the only and most effective way to raise that calf’s body temperature. That has probably saved more calves than I can count,” he says.
For warm water immersion, Creelman recommends a warm bath temperature – one that is a good temperature for you is likely the ideal temperature for the calf. Once immersed, Creelman encourages patience, as it will take time for the calf to recover – taking up to 30 minutes for the animal to get to a normal body temperature. During this time, he says the water should be continually monitored for temperature, adding supplemental heat, or changing the water out a couple of times to keep it maintained at bath temperature.
“Once submersed, repeatedly check the calf’s temperature and stop warm water immersion when the calf has achieved and returned to normal temperature,” says Creelman. “Once the calf is at normal body temperature, we can then pull that calf out and thoroughly dry them off to maintain their body heat. From there, we need to provide supplemental energy on top of that. At this point, expedient assessment as to whether or not colostrum supplementation is not only necessary, but critical for that calf needs to be done. If the calf has not had colostrum, we need to have energy in its belly.”
Creelman recommends a supplemental glucose – like high energy colostrum. This will essentially increase their glucose or dextrose levels and ensure that there is some fuel in that baby calf so they can start maintaining their own body temperature once they have been brought back up to normal temperature.
A calf’s ability to absorb colostrum diminishes as well, he says, as its body temperature becomes colder – the absorption rate of forced-fed colostrum will be less than that of a warm calf.
“As newborn calves only have a finite supply of energy reserves when they hit the ground, it is not until they get that first suck of colostrum that they actually have the ability to create more energy and more heat through that colostrum. So that is why colostrum management is so important when it comes to cold stress and, of course, it is extremely important when it comes to defence against infectious disease as well. It is our first line of defence in terms of that calf’s entire immune system.”
According to Creelman, this ingestion of colostrum needs to occur within the first four hours of life.
“I tell producers to shoot for the four-hour mark with colostrum, within the first 24 hours of that calf’s life. Within four hours of birth is key because as that calf gets older and older, their gut closes to those antibodies that it is absorbing. And specifically, when we are dealing with cold or inclement weather, that newborn calf doesn’t have much more than a couple of hours of energy reserves to be able to keep its core body temperature high so we want adequate colostrum within those first four hours of life,” says Creelman.
SEVERE CASES OF COLD STRESS
In severe cases of cold stress, Creelman advises that a non-steroidal anti-inflammatory should be considered when there is tissue damage from cold trauma – like frostbite on ears or frozen feet and/or tails. In these cases, he says administering a non-steroidal anti-inflammatory will help with pain management as there will be inflammation in the tissue that is damaged but still viable. The medication can also help control the pain of frostbite in frozen tissue as it thaws out.
“Frostbitten extremities are susceptible to infection because they have been compromised. In these circumstances of cold stress, it is then up to the veterinarian’s discretion as to a recommendation for an antibiotic to help control infection. Unfortunately, there are instances where an anti-inflammatory is not going to help and we do have to make decisions to euthanize where prognosis is poor,” says Creelman. “But we do need to be careful as we don’t know the organ function of the calf at this point, and we don’t know kidney and liver function, so adding a med or drug without knowing its hydration levels or blood pressure status can have risks.”
There are things we can do to best prevent worst case scenarios like frostbite or death loss when it comes to cold stress in calves. They can start long before they are born by simply having adequate windbreaks, shelter and bedding in place while awaiting their arrival.
“When it comes to base management, most producers recognize that when the mercury drops below zero, an increasing level of care and attention needs to go into calving checks. That same frequency in checks needs to expand into frequency in bedding, as well as an increase in frequency in energy levels when it comes to feeding the cow herd. Be sure to have adequate windbreaks, shelter and bedding in place for calves. It will give your calves the best chance and prevent losses due to cold stress. We want to give those calves and those mamas as best a head start as possible – even before the calf enters the world,” says Creelman.
Dr. Cody Creelman is a beef cattle veterinarian and practice owner of Veterinary Agri-Health Services in Alberta.