Colorado Agriscience Curriculum - Download Now PowerPoint by HC121106233745

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									Using EPDs in Selection
 Stolen and edited by: Brandon Freel and
                Daniel Powell
      Originally compiled by Colorado
           Agriscience Curriculum
               Objectives
► Define  Expected Progeny Difference.
► Identify terms associated with EPD’s.
► Interpret EPD categories.
► Analyze EPD variations within breeds.
You must first look at breeding values.

      Phenotype – The appearance of an animal.
      Genotype – What genes are present and
       how they are combined.




                                              3
How are Breeding Values Reported?
 (EPD) Expected Progeny Difference – A
    measurement of genetic potential based on
    the performance of relatives.

 (ACC) Accuracy is an important term used in
    understanding EPDs. It is a measure of
    expected change in the EPD as additional
    young are born to the sire. A high accuracy
    value is better as the chances of the EPD
    being correct rise.
                                                  4
How are Breeding Values Reported?
 Common EPDs: Performance-based, Carcass-based, and
   Ultrasound.
   ► Performance-based    EPDs – Are based on a measurement of
     how well the bull’s offspring perform. Examples of
     performance-based EPDs are birth weight, weaning weight, milk
     and yearling weight.
   ► Carcass-based – Are based on how well the bull’s offspring
     have performed on the rail. Examples of carcass-based EPDs
     are Rib-eye Area, Fat (Outer), Retail Product, and %
     Intramuscular Fat.
   ► Ultrasound EPDs – Done from an ultrasound of the actual
     bull. Examples of ultrasound EP’s are Rib-eye Area, Fat
     (Outer), and % Retail Product.


                                                               5
                How to Compare EPDs
         BW     WW    Milk   YW     Marb   REA    FAT    %IM    RE     FAT     %RP
                                                         F
Bull A   -0.5   +61   +15    +111   +.20   +.19   +.01   +.50   +.22   +.00    +.28
                                                  7                    4
Bull B   +0.1   +50   +21    +51    +.20   +.44   +.01   +.26   +.66   -.046   +.28
                                                  7
 EPDs can be useful for comparison. Look at the Select Sires Explanation
      for how EPDs are measured. For example Birth Weight is in pounds.

         How much more will Bull B weigh at birth than Bull A?
             Answer: .6 pounds.
         How much more will bull A weigh at weaning than Bull B?
             Answer: 11 pounds
         Which bull would be a better bull for heifers?
             Answer: Both would be fine. But smaller calves would come from A.
         Which bull has a bigger Rib-eye Area?
             Answer: Bull B
                                                                                 6
          Selection of Cows
   Culling – Cows should be culled from the
    herd based on the productivity of their calves.
   Evaluation – Cows should be culled based on
    evaluation of the udders, eyes, skeleton and
    teeth.




                                                 7
          Selection of Heifers
►   Try to select heifers that will conceive
    early in the breeding season, calve easily,
    produce a good supply of milk, wean a
    heavy calf, make a desirable genetic
    contribution to your cow herd, and have
    calves with desirable carcass traits.



                                              8
                    Accuracy



The reliability that can be placed on the EPD. Accuracy of
 close to 1.0 indicates higher reliability.
                               Herd

► Indicate the number of herds from which daughters are reported.
                Birth Weight
Predictor of a sire’s ability to transmit birth weight to
his progeny, compared to the progeny of an average
bull for a specific breed; expressed in pounds.
           Weaning Weight

Predictor of a sire's ability to transmit weaning
 growth to his progeny, compared to the progeny
 of an average bull for a specific breed; expressed
 in pounds.
            Yearling Weight

Predictor of a sire's ability to transmit yearling
 weight, compared to the progeny of an average
 sire for a specific breed; expressed in pounds.
              Maternal Milk
Predictor of a sire's genetic merit for that part of
 weaning weight attributed to milk and mothering
 ability. It is compared to daughters of an average
 bull for a specific breed.
       Scrotal Circumference

Predictor of the difference in transmitting ability
  for scrotal size, compared to the progeny of an
  average bull for a specific breed; expressed in
  centimeters.
               Objectives
► Define  Expected Progeny Difference.
► Identify terms associated with EPD’s.
► Interpret EPD categories.
► Analyze EPD variations within breeds.

								
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