by Jean Clavelle, Farm Animal Council of Saskatchewan
(The following is a CattleFACS brochure reprinted with the permission of the Farm Animal Council of Saskatchewan. FACS represents the livestock industry in advancing responsible animal care and handling practices in agriculture. )
The critical temperature below which an animal must increase heat production to keep warm (i.e. Eat more energy, reduce performance or use body reserves), is about -20°C for a mature beef cow on maintenance rations IF:
- She is in good condition (BCS 3.0).
- She has a dry winter hair coat.
- She is sheltered from the wind (and rain or wet snow if it is a regular occurrence).
- She has bedding to lie on.
Anything less than these “ideal” conditions means that the animal will be cold stressed at higher temperatures, -10°C or even 0°C.
However, regardless of condition, cattle need extra feed to get through a cold snap with a minimum amount of stress. This is absolutely critical for thin or moderate condition cows (BCS 2.5 or less) as they have little or no back fat to keep them warm.
Have your consulting nutritionist or Extension specialist, with information from a laboratory analysis of your feed or a program like Alberta’s CowBytes, balance rations for whatever is considered “normal” winter temperature, e.g. -20°C. Then be prepared to feed extra energy during cold weather by feeding additional grain or pellets (range or screenings) or even high quality hay.
Remember it takes time for cattle in the early part of winter to adjust to col. A cold snap in November or December when normal temperature is around -10°C will be felt more severely than a cold snap in January when normal temperature is around -20°C.
Increase energy at a rate of 1lb (0.5 kg) grain or pellets for every 5°C drop in temperature at mid-day below -10°C, (or -10°C, depending on your “normal” maintenance ration) to a maximum of 5lbs. (2.5 kg).
For example if the temperature drops overnight from -20°C to -35°C, increase grain by 3lbs (1.5 kg). If the temperature drops overnight from -10°C to -35°C the cattle need an extra 5lbs (2.5 kg) of grain to help maintain body temperature.
Be careful of any sudden increase in grain. Make sure that it is spread out so every cow has opportunity to eat. If temperature drops dramatically, divide the extra grain into morning and night feedings which will get the cows moving around and help avoid over consumption by few.
If a cold snap is anticipated, begin feeding a little extra grain (1 or 2 lbs; 0.5 or 1 kg) a couple days in advance. Continue feeding reduced amounts of extra grain two to three days after the temperature returns to “normal”. This will avoid sudden large changes in feed and present a more even flow of energy to the animal.
Watch for Rumen Impaction
Digestion of roughages in the rumen creates heat, which in the summer “goes to waste,” but in Canadian winters becomes an important part of animal maintenance, i.e. it is used to keep the animal warm.
Cattle will tend to sharply increase feed intake in cold weather in an attempt to maintain body temperature. They may consume more low quality roughage such as straw or chaff, especially if ground or chopped, than they can digest, which could result in rumen or omasal impaction.
DO NOT grind or chop low quality roughages too fine (3/4” or 1” screen max). It costs money and can create impaction problems. Feeding extra energy during a cold snap will reduce cold stress, maintain animal condition and reduce potential for impaction.
If you want to see this original CattleFACS brochure go to facs.sk.ca.