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					        Bull Selection and
      Management Strategies



     Eldon Krebs, Whitestone Krebs Angus-Gordon, NE

Lori Schott, University of Minnesota Beef Center-St. Paul, MN
Most genetic progress is made
   through sire selection.
       Value Through Genetics
               Calving Ease
              Cow Size/Milk
            Growth/Efficiency
              Carcass Merit




“Very rarely is an effective breeding program
       based solely on a single trait.”
                                   American Angus Association 2005
•   Reproductive efficiency
•   Calving ease
•   Calf survival
•   Weaning Wt.
•   Post-weaning growth
•   Feed efficiency
•   Mature size
•   Red meat yield
•   Palatability
Visual   Appraisal

Performance    Evaluation
 Bull Confirmation
 Structural Soundness
 Temperament
 Sheath/Testicles/Eyes
 Masculinity
 Frame
 Fact#1 - all cattle are composed of the same three
 tissues - bone, muscle and fat.

 Fact # 2 - all cattle have the same number of
 bones and they are located in the same
 relation to each other. They are almost identical in
 shape and on a percentage basis, represent almost
 the same portion of all carcasses. On the other
 hand, the other two tissues - muscle and fat - vary
 greatly
 Fact# 3 - all cattle have the same number of
 muscles. They are attached to the skeleton in
 the same location in all cattle. What varies is the
 shape and size of these muscles.

 Fact# 4 - the correlation between the weight of
 a single muscle with the total muscle in
 the carcass is extremely high. This means that
 when you select for increased muscle in one
 area( for example, rib eye area), you will also
 increase the muscle in other
 areas by nearly the same amount.
 Fact# 5 - muscle moves when the animal
 walks. Fat is inanimate. Fat hangs and shakes
 while muscles move and bulge. Muscles are
 round -. Therefore a well muscled animal will
 have a round shape to its top, not a flat shape.

 Fact # 6 - it costs much more to put on a pound
 of fat than a pound of muscle. Most
 research indicates that it is 6 to 7 times more
 expensive. A certain amount of fat is required
 on the carcass and it is very desirable for it to
 be well marbled. Marbling is the small seams
 of fat in the muscle tissue and it is an important
 factor in the taste and tenderness of the meat.
 Mature  bulls should show masculinity with a
 burly, masculine head with coarse hair and a
 heavy jaw. They should show a crest or heavy
 muscling in the neck and shoulders indicating
 effects of the male hormone, testosterone. The
 testicles should be well-developed and
 properly balanced in relation to the age and
 size of the bull. The bull should indicate
 adequate libido or sex drive.
   Thick, heavy and long muscling is desired and indicated by
    length and size of muscling in the forearm areas and width
    and bulge of muscling in the stifle area as viewed from the
    rear and side.

   Width between the hind legs, both standing and walking, is
    also a muscling indicator. Thickness, length and bulge of
    muscling in the back, loin and round indicate muscling from
    the anatomical regions which contain the highest priced
    wholesale cuts.

   Length of muscling is largely determined by length of bone. If
    muscling is thick and bulging in one area of an animal’s body,
    the animal is usually heavily muscled throughout.
Frame size provides an estimate of rate of maturity,
mature size and carcass cutability at a given live
weight. Frame size is generally appraised visually
by bull buyers or measured in terms of hip height
adjusted to a standard age.
   Physical, Reproductive and Collection
    Evaluations (Sperm motility & Morphology)

   Evaluation will tell you if the bull is sexually
    mature and capable of settling cows.
Turning
 Cattle Data
Into...

               American Angus Association 2005
              American Angus Association 2006



...Decision
 Making
 Tools...
  Traits That We Measure

    Heritability Estimates
Reproduction    (low)      < .20
Growth       (moderate) .20 - .40
Carcass        (high)      > .40
Expected Progeny Difference

   EPD is the expected difference in future progeny
    performance of one individual relative to another
    individual(s).
   EPDs can be used to compare all cattle within a
    breed.



EPDs do not predict
actual performance.
             EPDs


Individual   Pedigree   Progeny
How are EPDs Calculated?
Birth weight EPD – (Example)

             BULL A         BULL B

BW EPD lb (s)       +0           +6

      The Expected Difference in the
    Progeny of Bull A and Bull B is 6 lb.

  But what will my calves weigh?
 EPDs Do Not Predict Actual Performance
   Expected Progeny Difference
              (Bull A vs. B)



           Breed

EPD, lb   Averagea    Bull A Bull B Diff
BW EPD     +2.3        +5        0    5
WW EPD     +40        +45      +30   15
YW EPD     +74        +75      +55   20
MILK       +20        +17      +27   -10
 Russia Carcass Weights           169 kg (avg)
 European Union Carcass Weights   317 kg
 United States Carcass Weights    349 kg (avg)
 Australia Carcass Weights        227 kg
 Brazil Carcass Weights           207 kg




Source: Meat International 2010
Carcass Size



950 lb     550 lb



                    Quality




     Muscling
American Angus Association 2005
Cattle Feedlot
  Nebraska
 Timmerman
   Feedlot
Colorado, USA

				
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posted:9/8/2012
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