Page 13 - MWC 2-3-2022s
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The Midwest Cattleman · February 3, 2022 · P13
       Cold Stress and Beef Cows

       By Steve Boyles, OSU Extension Beef Specialist

         Factors that create stress  as scours.    Animals in poor  the current calf crop (milk
      during the winter months  condition before calving, pro- production) and next year’s
      are cold, wind, snow, rain,  vide inferior colostrum and  calving                date     (rebreeding
      and mud. The primary effect  lower milk production.  This  date).
      on animals is due to tem- can lead to lighter weaning                   In most years hay and
      perature.  All these factors  weights  or fewer  pounds of  stockpiled forage can ade-
      alter the maintenance ener- calf to sell. Females that are  quately provide the needed
      gy requirement of livestock.  in less than desirable body  nutrients, but it  can vary
      Maintenance        requirement condition at calving are slow- widely and should be tested
      can be defined as the nutri- er to return to estrus. Body
      ents required for keeping an  condition at calving affects                         continued on page 31
      animal in a state of balance
      so that body substance is nei-
      ther gained nor lost.  An in-
      teresting thing to note is that
      while energy requirements
      increase, protein require-
      ments remain the same.
         Some published sources
      contain nutrient require-
      ments for beef cattle that
      include guidelines for ad-
      justing rations during winter
      weather. Even without pub-
      lished sources, competent
      livestock producers realize
      the need for more feed during
      cold weather. Make sure that
      water is available. If water is
      not supplied, cattle will re-
      duce feed intake.

      Daily dry matter intake of
      beef cows with respect to
      lower temperatures

      Temp, F        Intake, % Change
         < 5                  1.16
         5-22                 1.07
        22-41                 1.05
        59-77                 1.03

         The metabolic response to
      the stimulus of cold involves
      practically all the systems of
      the  body.  The striated mus-
      cles shiver, the heart beats
      faster, breathing becomes
      deeper, urine flow is in-
      creased, and the sympathetic
      and pituitary controlled sys-
      tems are activated to elevate
      biological oxidations (energy
      expenditure or heat produc-
      tion) in all tissues. The result
      is an increase in the cow’s re-
      quirements for energy.
         Spring calving cows, and
      particularly  heifers,  in  poor
      body condition are at risk for
      calving problems. The result
      may be lighter, weaker calves
      at birth, which can lead to a
      higher death loss, and more
      susceptibility  to  things  such
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