Cow Camp Chatter:Hypothermia &Thermogenesis

Ron Torell, Long-Standing Educator and Advocate of Agriculture

Why do some calves survive being born on a cold, wet, blustery night while others under the same conditions die of hypothermia? Most will agree that these calves have a lot of heart with a strong will to live. When these nub-eared, bobtailed survivors are brought to the branding fire cowboys generally compliment the cow as a good mother. Much of the credit, however, can be attributed to the fascinating process of body heat generation known as thermogenesis. There are two types of thermogenesis: shivering and non-shivering.

Shivering thermogenesis helps the body create heat. The skeletal muscles create the shivering. The shivering heats up the body through this muscle activity and the hair’s insulation factor retains the heat.

Non-shivering thermogenesis is reliant upon energy. Energy, which is measured in calories, comes into the body as food. This energy, if not readily used, is stored in the body in the form of fat. Thermogenesis refers to the creation of heat from this fat. The ability of a newborn wet calf to dry off, warm up and bring its body core temperature to normal under adverse conditions is largely dependent on how much stored body fat is available.

There are both white and brown fat cells found in the body of both humans and animals. Much like money placed in a certificate of deposit in the bank, white fat cells are the primary long-term storage area of energy. The brown fat cells are the cells that compose adipose tissue specialized in storing readily available energy. They are like a furnace generating heat. These cells function just as split mahogany or crushed coal does in a wood stove. They burn faster and produce more heat providing immediate emergency access to the newborn calf.

Brown fat is extremely prevalent in healthy, newborn calves who exhibit tremendous amounts of non-shivering thermogenesis to regulate their body temperature. The brown fat is located around blood vessels and major organs insulating them. When triggered into activity it causes the blood to warm. The warm blood is then circulated throughout the body spreading the heat.

On a warm day without a challenge all may go well for a calf born from a thin cow that did not have adequate pre-partum nutrition and/or body condition. On a cold, wet day with the wind blowing the chances of that same calf surviving are slim since it may lack an adequate amount of stored brown fat to warm itself.

If hypothermia in newborn calves is a consistent problem on your ranch perhaps it can be traced back to thin cows. Nutritional management of the beef herd might be to blame. A calf may have the heart and will to live but if it has no fat storage hypothermia may take its toll primarily due to a lack of brown fat deposition during gestation.

It’s important to note that there are other factors that may contribute to hypothermia and impede thermogenesis. These may include an unusually long and difficult birth (dystocia), delayed delivery, oxygen deprivation at birth, calves born to first calf heifers, weak colostrums, or acidosis.

Should you find yourself in a situation of calving out very thin cows in inclement weather consider spending more time assisting those young calves at or immediately following delivery. Oftentimes a calf may not appear to be hypothermic. Upon taking its temperature you may find that the calf’s body temperature is below normal. The use of a thermometer is essential to determine the degree of hypothermia.

Returning a calf’s core body temperature to normal (100 F. for newborn calves) is of immediate concern to ward off hypothermia. Place the cold calf in a heat box or under a heat lamp, submerge it in a warm bath, put it next to the heater in the house or place it on the floor board heater of a pickup truck. These are all effective methods that may be used to bring the calf’s body temperature up to normal.

Feeding the hypothermic calf warm colostrum as soon as possible speeds recovery and increases the probability of full recuperation. Breathing the warm air coupled with consumption of colostrum heats the calf from the inside out and provides it with the needed energy to overcome the trauma it just went through.

It is paramount to stay focused on the year-round management of your cow herd. There is little that can be done during the last week or two of pregnancy to add brown fat to a fetus gestating in a very thin body condition cow. This process requires a constant effort. Many factors contribute to successful calving. These include selecting cows with good genetics that have functional udders and good mothering ability, providing adequate nutrition to the brood cow, upholding body condition throughout the year, maintaining a quality mineral program, calving in an area that offers protection, and calving in sync with Mother Nature.

That’s enough for this month. A special thanks to my wife Jackie for her part in writing Cow Camp Chatter. As always, if you would like to discuss this article or simply want to talk cows, do not hesitate to contact me at 775-385-7665 or rtbulls@frontier.com.

Reproduced by Permission