Vet's Perspective

Nov 29, 2013
by WLJ

‘Winterizing’ your herd



Although we have seen a fairly mild progression of winter in many areas thus far this year, prior experience tells us that the weather is known to change without much rhyme or rhythm!

Between the harsh winds and sub-optimal temperatures, cattle can be faced with tough living conditions that adversely affect healthy body condition and immune system function. It is important to remember that what producers do and don’t do during the fall months can affect next year’s calving success, conception rates and weaning rates.

According to Dr. Dennis Hermesch of Novartis Animal Health, cows can typically maintain body condition while the ambient temperature is above 30 to 40 degrees Fahrenheit. Temperatures that dip below 30 degrees Fahrenheit are more of a concern regarding the maintenance of body weight; thus causing a need for more dietary intake or energy in order to keep the body warm and functioning optimally. An increase in protein levels for the daily ration may be indicated in order to aid energy production via rumen microflora.

This is especially important for pregnant cows; the digestible energy will ultimately go towards keeping the dam warm instead of developing the calf and creating colostrum—a potential economic loss to future estrus cycles and neonatal calf disease. Hermesch recommends adding 1 to 2 pounds of crude protein per head every two days to compensate for marginal winter grazing. Producers who have not analyzed their rations with a nutritionist or veterinarian are strongly recommended to do so.

Besides slightly increasing the crude protein within the ration, as well as providing wind shelter to the herd, many producers will utilize rumensin (an ionophore that can aid in shifting the rumen microbe population and pH, thus enhancing feed efficiency) in hopes to decrease some of the grain feed costs. Soil samples can be analyzed by your local university extension agent in order to determine mineral deficiencies or supplementation needed. A sample of forage can also be analyzed for proper energy and protein intake with regard to gestation and age factors in particular groups of animals. Now is the best time to evaluate your feeding program with an animal nutritionist or veterinarian to determine proper energy and supplement needs. Having an accurate portrayal of the quality of your forage may prevent from under-feeding or over-feeding and demonstrate financial savings in the long run.

Possibly one of the most overlooked aspects of winter care is the access to fresh water. Animals need adequate hydration above all in order to digest other nutrients. When access to water is limited, animals can quickly become dehydrated and rapidly decrease in energy production for all body systems. Water tanks that may freeze easily should have heating devices to ensure a constant fresh supply.

While running cattle through chutes during the fall pregnancy examinations and vaccinations, it is also important to note the body condition score of each animal. Without a calf by her side, directly after weaning is a time period when cows may rapidly gain condition if not assessed early on. This “scoring” system evaluates each animal’s fat deposits relative to its skeletal structure, using numerical values of “1” (emaciated) to “9” (obese). A quick palpation over the back, tailhead, and hindquarters can reveal whether each animal is going into winter with too little or too much fat. One must keep in mind the age and breed of animals when conducting scoring; older animals tend to carry less fat along the top-line than younger cattle. Thin cows will tend to look “sharper” or more angular compared to fatter and more “square” animals. Not only can the body condition score affect the animals’ performance over the cooler months; excessive fat deposition around the vulva and rectum may restrict proficient breeding and calving in the future. Producers should aim for a body condition score of 5 or 6 in pregnant cows as we go into the winter months, as the developing calf and cold weather will utilize daily nutrients from the dam. Utilize this opportunity to have a closer examination of bulls, as well, by evaluating body condition and breeding soundness.

A final step in preparing for winter weather involves making necessary culling decisions. Many producers base this decision on the diagnosis of open cows during routine rectal palpation.

Running animals through the chute will also allow for a quick examination of udder condition, hoof health, and oral or eye lesions (such as ‘cancer eye’ or pink-eye ulcerations). A ‘smooth’ or broken mouth demonstrating worn teeth may indicate a need for feed supplementation. While considering rising feed costs, one must ascertain whether holding on for another year for an animal will still be profitable in the long run. Management considerations may also center on the need for replacement heifers. Questions one may ask are: What are the current and future market prices? Do I have the labor and finances to buy animals? Do my facilities need work?

Your local veterinarian, livestock nutritionist and university extension agent can provide further information regarding vaccination, nutritional and other management aspects in order to increase efficiency and performance within your herd. Any down time available can be most optimally used to conduct a complete review of your herd’s management plan and make updates for the next year. — Dr. Genevieve JM Grammer is a veterinarian working out of the Pikes Peak region; please direct correspondence to