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Midwinter inventory for swath grazing

Swath-grazing cattle without shelter often require 40-50 per cent more dietary energy

Midwinter inventory for swath grazing

Barley swath-grazing has become a viable alternative and practical means of feeding a low-cost forage to overwintering pregnant beef cows. Since nutrient supplementation may be required later on as they approach calving, producers should take a midwinter look at the feed value of swaths to ensure all nutrient requirements are always met.

It is well accepted the best cow candidates for barley swath grazing are early- to mid-gestation cows in reasonable body condition of 2.75 BCS (one = emaciated and five = obese). A barley crop late-seeded in mid-June and harvested in mid-September in its soft-dough stage lends itself to support most of these cows’ energy and protein requirements of 52-55 per cent TDN and eight to nine per cent crude protein fed daily for body maintenance, and to support an early-term fetus.

Nutrient supplementation of barley swaths is most likely needed as beef cows enter their last trimester of pregnancy. Cows require a higher plane of energy and protein nutrition — 55-60 per cent TDN and 11-12 per cent crude protein — as they are now supporting a late-term fetus and ideally maintaining an optimum body condition score of 2.75 by calving time. Don’t forget that first-calf replacement heifers entering the cow herd are also growing and thus have similar requirements.

The accompanying table of feed sample analysis taken some years ago by the Western Beef Development Centre (1998) illustrates how well typical barley swaths match the above dietary energy and protein needs of early- to late-gestating beef cows. Keep in mind that your feed samples may differ.

This information also shows barley swaths tend to degenerate in the field around mid-December, with higher fibre, less available TDN energy and also lower protein. This is the same understanding that many swath-grazing producers have experienced.

Some producers also realize that as the weather gets colder in January/February, their cattle tend to eat more of the swaths (up to 30 per cent more), yet may still lose some body condition, regardless of stage of gestation. I usually tell them that some western research on the effect of winter weather on beef cattle dictates that their dietary energy requirement “just to stay warm” increases by two per cent for every 1 C drop in temperature below 0 C. This means that their barley swath-grazing cattle often require 40-50 per cent more dietary energy while being left without any shelter on the open prairies.

Keeping requirements in mind, here is a simple protocol a rancher of 200 Angus x Simmental cattle that I visit, follows:

  • Swath carrying capacity — He currently estimates his carry capacity at 225 cow-days per acre. Over the years, this number changes greatly due to differences in estimated crop yield, herd size, replacement rates, weather and observed wastage.
  • Get ready to supplement — My friend saves a significant number of round mixed alfalfa/grass hay bales for his cows as they approach calving date of March 1. He also provides 20 per cent protein lick tubs at the rate of one block to 25 cows. These are provided near available automatic waterers where animals visit daily.
  • Provide a good mineral program — He feeds a 2:1 breeder mineral in loose form at the rate of 100 grams to all his beef cows. Its calcium and phosphorus complement the barley swaths as well as contain high levels of chelated (bioavailable) trace minerals and vitamins.
  • Be ready for challenges — Some years the snow is very deep on the swaths. His cattle seem to break through to a depth of about two feet. If the snow is heavily encrusted, my friend will take a loader and drive over the swaths. Note — he does not rely on snow as a water source since a few automatic waterers are set up near his home.

This action to overwinter his cow herd on barley swaths has worked for this producer over the years. He has been able to help his gestating cows meet their nutrient requirements and as a result achieve a trouble-free and successful calving rate. His overwintering costs are about half of a conventional hay/silage feeding program, which he feels anybody that is able to swath graze should achieve.

About the author


Peter Vitti is an independent livestock nutritionist and consultant based in Winnipeg. To reach him call 204-254-7497 or by email at [email protected]



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