Thursday, December 15, 2016

A bull mated to A cow aAa demo

A bull                                                             mated to                                  A cow

(Unique individual)                                                                                    (Unique individual)

                                                           Produces an offspring:

 A unique, individual phenotypic expression resulting from the genotype determined at conception and the impacts from the host environment(s) as the stages of growth, maturity and aging occur 

This “genetic makeup” is a result of gene pairings at conception for:

(I I I)     Quantitative genes                   additive traits                                 Pedigree information  
                                                                                                                          Phenotype evaluation 
                                                  ( linearly measurable )                                 PTA estimation
                                                  ( rankable intragenerationally )                 Genomic imputation


( I I )      Qualitative genes                    adaptive qualities                           “aAa” breeding guide*
                                                                                                                          “DMS” mating service
                                                  ( causal interrelationships )                         dominant/ recessive
                                                  ( co-balancing, non-accumulative )             B and K Caseins
                                                  ( identifiable intergenerationally )               B lactoglobulin


( I )       Interactive genes                     environmentally triggered              Full DNA mapping
                                                                                                                          epigenetic research

(1)     Quantitative genes are estimated from statistical regression of phenotypic data
(2)     Qualitative genes are determined from visual observation and analyzation
(3)     Mating selection can include both forms of information

Provided by Dr Royce Thornton, Instructor in Dairy Science
Agricultural Technical Institute, Ohio State University                             (2008)

“aAa”  was originally  “rounds”  and  “sharps”                (Greg Palen 2007)

Sharp:   physical characteristics related to production of milk over beef

              “Dairy”   [S front end]   will to milk, fast letdown, refined size

              “Tall”      [S body/udder]    fast growth, earlier maturity, high udder carriage

              “Open”   [S rear end]    room for udder, adds calving ease, persistency

Round:  physical characteristics related to sustaining production of milk

             “Strong”  [R front end]   circulatory system, muscularity, more size

             “Smooth” [R body/udder]   appetite, body conditioning, less (extremity) injuries

             “Style”     [R rear end]    blending of parts, cushioned joints, better mobility

You need cows ‘sharp” enough to milk but “round” enough to last

The overall balance of round to sharp elements in the physique has a significant impact on all physical functions—production, reproduction, health maintenance, adaptation to any changes in the environment, avoiding injury, sustaining physical vigor.

The analyzer’s challenge:

To be able to accurately analyze the differing levels or “sharp” to “round” so as to guide the owner/herdsperson in making a more accurate mating among sire choices.    More “sharp” cows can have a “round” element harder to detect, just as more “round” cows can have a sharp element harder to detect.     Few are all “sharp” and fewer all “round” today.

Heterosis vigor is maintained [in spite of increasing efi% of ranking sires] by accurately identifying both the actual round/sharp possession as well as the relative level of overall possession, and mating so as to avoid intensifying any qualities to the degree where the exclusion of other needed qualities begins.     This helps avoid inbreeding effects.

All six of the “aAa” qualities are necessary aspects of a functioning animal.    Matings that persistently prefer one level of qualities over another [which is what happens when we follow “single trait” selection methods] will over generations produce a progressive loss in function(s) related to the quality(ies) suppressed.

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