You have probably seen the articles over the last three years…, reporting on Dr Chad Deckow’s work in genetics at Penn State University. Influenced by the thinking of older geneticists such as Leslie Hanson of University of Minnesota (see his article in the April “Progressive Dairyman”) his team of researchers have sought out rare semen on bulls from 50+ years ago whose line of sire (Y chromosome) descent differs from what has come forward after the implementation of linear trait type evaluation with “modified contemporary comparison” production indexes.
“Ranking” of sires under various composite indexes (combinations of production and type, now also with health traits) has steadily reduced the number and diversity of sires considered to be “sires of sons” for competitive AI service. Since the introduction of Genomic selection and its focus on “accelerating” generations, the number and diversity of “bull mothers” has also been reduced, and pedigree inbreeding coefficients (as monitored by Dr Hanson) have risen fast.
Why do we fear inbreeding?
There is an observed general loss of “vigor” traits as the genotypes being mated become more “homozygous” (similar in gene possession). Under Genomic selection, the highest ranking females to mate to the latest ranking sires would be their full sisters… those with genotypes that possess the same “marker genes” as their full brothers. This constitutes “inbreeding” on the molecular level as well as (and perhaps more relevantly to the issue) on the ancestral level.
In spite of this, AI studs pursue ever-closer matings as they produce the higher imputed indexes under the current Genomic selection procedure. To Dr Hanson and many others this is a basis to pursue crossbreeding (assuming other breeds still have different genotypes in ranked sires).
JUST WHO ARE “ANCESTORS IN COMMON” TO HOLSTEINS TODAY
According to Dr Deckow (confirmed in Holstein USA “Redbook” sire summaries) the two sires who dominate AI sire lines are Round Oak Rag Apple Elevation (born 1965) and Pawnee Farm Arlinda Chief (born 1962). For a period of time until 1990, a third sire, Penstate Ivanhoe Star (born 1960) was in the running, until two lethal recessives (*CVM and *BLAD) carried by “Star” and his prominent son, Carlin M Ivanhoe Bell, put them into the background of pedigrees with no new “Y” chromosome descendants surviving in sire line AI. In the case of “Elevation” and his contemporary “Chief” they represent half of the total genotype (roughly ¼ each) carried by a typical modern Holstein. ( In fact, the only two sires active in AI in the USA today that do not carry the “Y” chromosome from “Elevation” and “Chief” are Dun Did Black Onyx and Gloryland Jaguar, available from Triple Hil Sires [which we carry] . )
made the 1960s a seminal era in Holstein breeding?
By 1960, frozen semen was a fully adapted AI technology, allowing any breeder with a semen tank full choice of sires as desired in mating to his better cows. Both “Chief” and “Elevation” rose to the top of Holstein USA’s TPI ranking list, and “Star” was high on the list of sires proved to mate well with these two stellar sires. All three of these were found to be improvers for Protein % once this trait was first summarized in the 1970s (and drove USA genetic exports to Europe in the 1980s, reinforcing demand for their descendants as embryo donors).
Hidden underneath the obvious that fascinates data-driven geneticists, are some similarities in how these super sires were originally bred: aAa Breeding Guide (Weeks Analysis) was used to plan the matings producing them: linebreeding (to Johanna Rag Apple Pabst) had influenced the ancestors behind them. These sires were all bred prior to the “contract mating” era that controlled new AI sire selections from 1980 forward, by Breeders whose primary focus was the generation of useful heifer replacements, and they considered more than “indexes” to do so.
What was unique about “Johanna Rag Apple Pabst”?
Hartford WI in 1921 [100 years ago], this bull came from a dam who had
produced 1034 pounds Butter (890 lbs butterfat) from 19786 pounds of milk in
365 days as a three year old, a remarkable accomplishment, roughly twice
what better Holstein cows usually produced under similar farm management—and at
a level of butterfat 1.0% higher than Holstein average. This cow had a symmetrical udder with four
evenly-placed teats of moderate size that would adapt to the new milking
machines being developed. Young “JRAP” was shown extensively and in
spite of his “round” appearance was so functionally correct he was “All
American” three years in a row. His
owners, after four years of service, consigned him to the 1926 “Clark’s
Holstein Classic” as a newly-proven sire. This was an annual extravaganza with 250
breed history used to be made
A newer Holstein breeder in Quebec, Thomas Macaulay (whose business was Insurance and as an amateur geneticist had a sideline in breeding hybrid seed corn) had been seeking a herd sire for his Mount Victoria herd (prefix: Montvic). He had specific goals: 4% butterfat (Canada’s Holsteins were notoriously low in that era), machine milkable udders, and sound type with no hidden recessives that would support a sustained linebreeding program.
He ended up paying $ 15,000 to get JRAP at the Clark Classic. After the sale he negotiated the return of JRAP to his breeder’s farm to be bred to as many of his own daughters as possible in a time period determined by the eventual railroad shipping of the bull across the border. Those inbred calves (six later going to Mt Victoria a year after) included a prizewinning two year old at the Royal Winter Fair and a new two year old butterfat record – pretty much confirming JRAP possessed no lethal recessives and had the genetic quality to withstand linebreeding.
How many purebred breeders in the AI era stick with a plan, beyond using the highest indexing or show type sires to compete in those high profile but limited size markets? A century ago, as the dairy industry was growing and developing, most leading breeders had an outline to follow irregardless of prestige or popularity – they expected the cattle produced from their breeding to be useful in improving the herds (and therefore the well being) of neighboring dairymen.
Lines of descent from JRAP to “Ivanhoe” -- “Arlinda Chief” -- “Elevation”
The Montvic herd only had 20 years to develop (1922 to 1942) with JRAP at its head from 1926 to his death in 1933. Only 70 head were catalogued for the dispersal (36 cows, 34 heifers and bulls) forced by Mr Macaulay’s death and the strictures of World War II on available labor. Yet the release of these animals into the broader Holstein fraternity (up until then only service bulls had been sold to others) quickly influenced early AI cooperatives in Canada and Eastern USA to acquire Montvic-descended bulls for their farmers.
Ivanhoe Star (1960)
JRAP sired Montvic Chieftain: who sired Raymondale Successor: who sired Raymondale Ideal Successor: who sired Montvic Rag Apple Gladiator: who sired Osborndale Ty Vic : who sired Osborndale Ivanhoe: who sired Penstate Ivanhoe Star.
Farm Arlinda Chief (1962)
Sir Inka May *RC sired Carnation Emperor: who sired Emperor of Mount Victoria: who was bred to JRAP- sired Montvic Rag Apple Colantha Abbekerk: who birthed Montvic Rag Apple Sovereign *RC: who sired ABC Reflection Sovereign *RC: who sired Rosafe Pearl Hannibal: who sired Pawnee Farm Reflection Admiral: who sired Pawnee Farm Arlinda Chief.
Actually, “Arlinda Chief” carries eight pedigree crosses to JRAP as a result of a deliberate line-breeding from a series of “Rag Apple” herdsires used by Lester Fishler in Nebraska.
Rag Apple Elevation
Wisconsin Admiral Burke Lad, bred to his own daughter, sired Weber Burke Cyclone: who sired Wis Ideal: bred to his paternal sister, sired Wis Burke Ideal: who, bred to his own daughter, sired Tidy Burke Elevation. (The dam of old “Lad” shares some ancestral relationship to JRAP). This is the inbred “Burke” sire line that produced Round Oak Rag Apple Elevation.
JRAP sired Montvic Chieftain, who sired Montvic Chieftain 6th, the first “Rag Apple” sire behind the dam of “Elevation”; next came Montvic Pathfinder Prizetaker (sired by Montvic Pathfinder, son of Montvic Chieftain from a JRAP daughter); then Glenafton Gaiety (seven crosses to JRAP); then Osborndale Ivanhoe. This the ancestry of Round Oak Ivanhoe Eve, linebred “Rag Apple” the dam of Round Oak Rag Apple Elevation.
Where did that take us?
“Elevation” sired Hanoverhill Starbuck. His two most AI- dispersed sons were Madawaska Aerostar and Ronnybrook Prelude. The great Picston Shottle is sired by a “Prelude” son and from an exceptional “Aerostar” daughter.
Contemporaneous to “Shottle” and with some similar pedigree influences is Braedale Goldwyn. His biggest impact comes through sons “Atwood”, “Aftershock” and “Gold Chip”. He holds a record as siring the most daughters scored “Excellent” under Canadian type classification.
“Arlinda Chief” sired SWD Valiant. He in turn sired Hanoverhill Inspiration the first Canadian AI sire to produce over one million straws of semen, and who sired the grandam of “Shottle”.
“Arlinda Chief” sired Milu Betty Ivanhoe Chief (from an Osborndale Ivanhoe dam). He in turn sired Cal Clark Board Chairman (from an “Elevation” dam). His most widely-dispersed son is To-Mar Blackstar (whose dam combines “Ivanhoe”, “Elevation” and “Arlinda Chief”).
What sire combining “Elevation” and “Arlinda Chief” with multiple pedigree crosses to both is a dominant sire line progenitor in the Genomic era? “Mountfield SSI Dorcy Mogul” (recently deceased after producing 1.7 million straws of semen, with more sons, grandsons and further descendants among Genomic selected AI sires worldwide than any other sire.)
“Ivanhoe Star” sired Carlin M Ivanhoe Bell *BL. Before BLAD recessive was identified, this sire was on track to dominate the “Net Merit” index world. An influential son who escaped the curse of BLAD was Southwind Bell of Bar-Lee.
IS LINEBREEDING A GOOD THING, OR A RISKY THING?
Based on the history of cattle breeding in the AI era, it can be both. Earlier sires in formative AI were generally linebred, and they are the foundation for modern sires in use today.
At the same time, we keep being told that inbreeding is a potential danger to the functionality and profitability of our cattle. Little consensus exists on how this danger occurs—most advisors focus on pedigree interrelationships, but others suspect it is “like to like” mating systems (following index ranking without regard for physical mating characteristics over multiple generations).
The latest question is how much of this is a result of being so focused on only one “Y” chromosome in the sire lines being selected for AI? Again, there are mostly questions and a paucity of answers.
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