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Are Your Cows Too Big?                                                                  The Midwest Cattleman · February 25, 2021 · P9

        Match inventory to available feed resources.

         By Glenn Selk, Oklahoma State University Emeritus Extension Animal Scientist

         Mature weight and milk  The start of a new year would be
      production  of many commer- a  good  time  to  honestly  review
      cial beef cows are both greater  our cow herd weights and stock-
      than  they were  30-40  years  ago.  ing rates. The year 2021 would be
      Many ranchers have not recently  an excellent time to begin the pro-
      weighed the adult cows in their  cess of better matching the cows
      herd to know what average ma- to the forage base at our ranch.
      ture weight to expect. Therefore,
      most commercial ranchers would
      underestimate the mature size
      of their cows.  To expect large,
      heavy-milking cows to be in mod-
      erate body condition at calving
      and maintain condition through
      breeding, they must receive more
      feed than smaller, lighter-milking
         Fig. 1 uses the 1996 Nation-
      al Research Council’s guidelines
      to show the energy needs of two
      different body types and levels of
      milk production. These energy re-
      quirements would be representa-
      tive for cows calving in February
      and March and weaned in Octo-
      ber.  The  top  line  represents  the
      energy needs of 1,250-pound (lb.)
      heavy-milking beef cows vs. the
      lower line, which represents the
      needs of 1,100-lb. moderate-milk-
      ing beef cows. The values graphed
      are the megacalories (Mcal) per
      day required to maintain body
      weight throughout the year.
         The larger heavier-milking cow
      requires about 34% more energy
      on the average for an entire year.
      Consequently, an operation that
      was carrying 100 of the smaller
      cows must carry only 66 of the
      larger cows in order to use the
      same quantity of forage from that
      farm or ranch. She also will need
      34% more winter hay and supple-
      ment to maintain body condition.
      In some commercial herds, there
      are cows much larger than the
      1,250-pounders depicted in this
         As we take inventory at the be-
      ginning of 2021, this is a time to
      reconsider herd numbers and cow
      size to better fit the stocking rates
      required. Reduced stocking rates
      will be necessary if range and pas-
      ture condition has deteriorated in
      recent years. Diminished forage
      availability will lead to poorer
      cow body condition, more supple-
      ment and hay feeding, or both.
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