Wednesday, June 7, 2017

When does “linebreeding” turn into “inbreeding” ?

From the September October 2015 Dairy Route Letter

Linebreeding  has provided us some of the most consistent milk genetics in every dairy breed. 

Historical examples would include Pawnee Farm Arlinda Chief (Holstein), Observer Chocolate Soldier (Jersey) and Selwood Bettys Commander (Ayrshire), all of whom advanced their breed production with help from the technology of frozen semen and distributive power of AI, creating new sire lines.    The greatest example before AI could be Sybils Gamboge (Jersey), whose four years of natural service, in only six herds after he was imported in 1919 set a new production benchmark and produced a bloodline that lasted 60 years.   This bull had 14 of 16 ancestors in his fourth generation either sons or daughters of one cow, Oxford Lass.     (This differs from the linebreeding that produced the “Rag Apple” bloodline, also successful for 60 years in Holsteins, but the original source bull Johanna Rag Apple Pabst was not himself linebred.    He was an outcross to the cows originally served by him.   Likewise, most of the best Brown Swiss are linebred to Jane of Vernon, also an outcross to the sires with whom she was mated.)

The mark of a successfully linebred bull (or cow) is a predictable pattern in his progeny for the physical traits.   Improved production is a by-product of improved physiques; consistency in this improvement is the goal in animals selected for linebreeding propogation.    When consistency is overlooked (as it could be when genetic evaluations only consider the comparative averages of progeny results) the linebreeding effect can quickly turn into inbreeding depression instead of the desired homozygous gene possession.

Linebred sires are desirable for outcrossing because we assume them to have fewer genes in common with our cows.    In the earlier days of AI, most sires were linebred; a dairyman using AI could combine these bloodlines and get a heterosis response (hybrid vigor).     The same concept drives crossbreeding, except we have to remember that the hybrid vigor runs out in three generations.    

Back to inbreeding:  all inbred animals do not express inbreeding depression.    An example might be Tidy Burke Elevation, result of breeding a cow to her own sire, who was already closely linebred.    He survived a crippling injury for eight years, including a truck ride as a mature bull from Kansas to Ohio when he entered AI service at NOBA, producing semen that bred Round Oak Ivanhoe Eve in Virginia, producing Round Oak Rag Apple Elevation who today has the highest frequency in Holstein pedigrees.
“Elevation” reflected the heterosis of inbred “Burke” sire mated to linebred “Rag Apple” dam.

“Elevation” also represented the “aAa effect” on the physique of using a “round” weight sire on a “sharp” weight cow.    “Elevation” weighed 2600 pounds at maturity, scored 96 points, and lived 15 years.    In his generation this translated to +3.00 Type and +1500 Milk maintaining both bf% and pr%
while in descendent generations we know him to transmit good DPR and Productive Life genes.

Linebreeding can accentuate the bad as well as the good..

Braedale Goldwyn (Semex) was a high profile sire of his generation, used extensively for AI sons and in the cow lines for many high Genomic value youngsters today, with a parallel reputation for siring “show type” heifers that develop into “Excellent” cows (he has the most EX daughters of any Canadian bull).
 He was described by “aAa” as 2-4-3-1-6-5 (Tall + Strong + Open).     His daughters are highly angular (called “dairy” in linear trait terminology) and his better daughters came from cows with some width of body, spring of rib and substance of bone.   You see these “Goldwyn” tendencies in his son “Atwood”.
“Goldwyn” lived eight years (2000-2008) and was unable to mount the last year of that life, semen was always limited supply.   He had a high-strung temperament and was difficult to handle.   He also has the  reputation for siring nervous cows that die easily and suddenly (not alone among bulls from the “Gypsy Grand” cow line).    Physically tall in front end, narrow chest, slabby rib, shallow flank, curved rear legs, bad thurl position:  (in that sense, an exaggeration of his sire’s tall but stiff physique)

                                                                                                                        Pawnee Farm Arlinda Chief
                                                                              Walkway Chief Mark        
                                                                                                                        Walkway Matt Mamie
                           Mark CJ Gillbrook Grand                                                    (No Na Me Fond Matt)                                             
                                                                                           S W D Valiant
                                                           Welcome Valiant Gingersnap
Sire:                                                                                                                 Welcome Jupiter Gala
Shoremar James                                                                                              (Bis May Astro Jupiter) 

                                                                                                                        Hanoverhill Starbuck
                                                                               Madawaska Aerostar
                                                                                                                        Madawaska Shady
                                                                                                                        (Clinton Camp Majesty)
                            Stelbro Jennie Aerostar                                                         
                                                                                                                        Hanoverhill Inspiration
8 crosses to “Ivanhoe”                                           Stelbro Joanne Inspiration
7 crosses to “Arlinda Chief”                                                                           Stelbro Ester Jeanne
   *(3 thru “Chief Mark”)                                                                               (Puget Sound Sheik ??)
   *(4 thru “Valiant”, sire of “Inspiration”)
7 crosses to “Elevation”
4 crosses to “Fond Matt”                                                                               Hanoverhill Starbuck
4 crosses to “Astronaut”                                       Madawaska Aerostar
                                                                                                                        Madawaska Shady
                                                                                                                        (Clinton Camp Majesty) 
                             Maughlin Storm *BRF
                                                                                                                        Hanoverhill Inspiration
                                                                               Wykholme Dewdrop Tacy
                                                                                                                        Wykholme Dewdrop Gail
Dam:                                                                                                                (Fairlea Royal Mark)
Braedale Baler Twine       
 VG 86 – 2yrs                                                                                                  Walkway Chief Mark
                                                                              Mark CJ Gillbrook Grand
                                                                                                                Welcome Valiant Gingersnap
                                                                                                                         (SWD Valiant)
                             Braedale Gypsy Grand                             
                              VG 88 – 5 yrs                                                                    Madawaska Aerostar
                                                                              Braedale Moonriver ET                                                   
                                                                               GP 83 – 2 yrs                    Sunnylodge Chief Vick
                                                                                                                         (Walkway Chief Mark)
5th dam by “Elevation”, 6th dam by “Sheik”, 7th dam by “Fond Matt”

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