Winterizing your animals

By Dr. Ben Smith, WA Assistant State Veterinarian
Washington State Department of Agriculture

The cold weather has already started, but we still have a few months left to go before spring warms things up. Making sure your animals are winterized properly takes a little thought and preparation. The most important thing to remember is to provide a clean and fluid water source. If possible, water heaters will increase intake and decrease the incidence of colic. Animals can’t get enough fluid from eating snow, so don’t rely on this. Salt is another important source of minerals that is often overlooked. The loose form is better for getting correct mineral intake than blocks. The animal often cannot lick a block enough to really get proper levels of minerals in a deficient area.

Grass tetany, or low magnesium, is common in cows during spring calving and is linked to the level of mineral intake during the winter. Without appropriate supplementation an affected cow may require emergency measures to survive. Low magnesium in the blood of an animal can be caused by low magnesium levels in feed and/or reduced magnesium absorption.

Contributing causes of grass tetany include:

  • magnesium levels are lower in cool season grasses and cereals than in legumes or weeds
  • levels are low in grasses grown on leached acid sandy soils
  • levels are low when potash and nitrogen fertilizers are used and growth is vigorous
  • high moisture content in grass causing rapid gut transit and low uptake
  • reduced absorption of magnesium resulting from high rumen potassium and nitrogen and low rumen sodium
  • low energy intake, fasting or sudden changes in feed
  • bad weather, especially winter storms
  • stress such as transport or yarding
  • low roughage intake (young grasses have low roughage and often poor palatability)
  • low intake of phosphorus and salt

Making sure animals are up to date with all the vaccinations and deworming recommended for your local area is also a good idea. Cold snaps followed by warming trends can stress the animals and make it easier for pneumonia to set in. You don’t want to be feeding a large infestation of parasites either, so consider performing fecal eggs counts to determine whether appropriate treatment is required.

Blanketing animals is not really necessary unless they are old and having difficulty keeping on weight. As long as there is a windbreak, most large animals can stand very cold temperatures. Adequate protein and energy intake will provide the animals with thermoregulatory capability in most cases, provided they were in good shape coming into the winter. It is very difficult to get thin animals to gain weight in the wintertime without lots of extra nutritional help.

Even at this stage of the winter, you might consider analyzing your hay for protein, vitamin/mineral, and energy content. Just because it is green and looks nice, doesn’t mean it is any good. Sampling some bales and sending it to the lab is easy and not that expensive. Be sure to get a representative sample because the nutrient levels will vary within a field. The results from this analysis will give you a good idea of what supplementation, if any, is needed.

Performing a few of these common-sense maintenance activities will bring your animals through the winter in good shape. My grandpa always said you can’t starve a living out of a cow, and that’s a very true statement!