Summary of Article About Dexters

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"Bloodlines, Breed Structure, and the Influence of

Artificial Insemination in Dexter Cattle" 
by Andrew Sheppy

First Half of Summary (below)

Second Half of Summary

This Paper is from The World of Dexter Cattle: Proceedings of the First World Congress on Dexter Cattle, 1999, edited by A. Sheppy, published by the Dexter Cattle Society (UK), pages 146-167.

Andrew Sheppy is a lecturer, researcher and author on rare farm livestock breeds, especially poultry but also cattle and sheep. He is the founder of the Cobthorn Trust and of the British Rare Poultry Society. He has a longstanding involvement with the UK Rare Breeds Survival Trust, and has served as its Vice-President. He has a keen interest in Dexters, operating the Cobthorn stud. For the Cobthorn Trust website, see www.datazenith.com/cobthorn. This article has attracted interest partly because of the author's contentions about the pedigrees of some Dexters. See DCS UK Statement in response to inquiries from DCS NZ.

NOTE: Photos below were not included in the original paper, but have been added by John Paterson from various other sources.

~~ Start of Article Summary ~~

Contents:

Breed Structure

The Grinstead Influence

Modern Lines

Atlantic and Summerdale

Shadwell and Weatheroak

Doesmead and Woodmagic

Marsh and Parndon

Relationship of Lines

The Influence of Artificial Insemination

Breed Structure

Until only recently in the UK, there have been only about 200 annual registrations of Dexter cattle. Many herds are very small and on average there has been one bull registered for every four cows. Very low registrations were recorded in the UK in 1960s and 1970s when a number of major herds were dispersed without successors – only 3 bulls were registered in 1969 and 36 females in 1970. One other “bottleneck” of low registrations was in 1940-42. These “bottlenecks” have restricted the gene pool for subsequent pedigrees. Annual registered females doubled between 1983 and 1989 to just over 450. Other important influences on the development of the breed in the UK have been the acknowledged introduction of genes from other breeds through the Upgrading Appendix and the Experimental Register to the Herdbook. Sheppy also maintains there has been a “large amount of unrecorded introductions of other breeds, as witnessed by the appearance of polled and unusually coloured animals” (p.148).

Bloodlines

The Grinstead Influence

In 1911, Miss Muriel Rolls-Hoare (later Lady Loder) registered 3 Dexter bulls and 11 cows, the start of the Grinstead Herd, “the most influential herd of Dexters of all time” (p.149). This herd was very successful in the show-ring and was officially milk recorded. The herd finally dispersed in 1959. It supplied stock to most of the main herds in England and exported foundation stock to other countries. In 1930, Lady Loder purchased a bull called Ratcliffe Negro’s Manager who left a total of 52 registered offspring, including 12 bulls, at a time when Dexter numbers were quite low. “This bull is now in the pedigree of every single Dexter in Europe, and quite probably the rest of the world” (p.149).

Modern Lines

There has been rapid growth in Dexters in England since 1970 but the extremely small gene pool at that time means that it is possible to reduce the breed to as few as 8 families being the descendants of 8 high profile individual animals (this conclusion is based on an analysis of post-1970 pedigrees in the UK Herd Book).

Line 1: Atlantic – Atlantic Finbar (DCS Herd Book No. Exp10/B)

Mr & Mrs W.R.N. Tanner’s herd was the “best all-round Dexter herd of all time” (p.151). Established 1948 with Grinstead animals, it won top awards in the show-ring and in milking performance, and always produced black calves. When Mrs Tanner (photo to right, with Atlantic Alistair) retired she decided to have the entire herd slaughtered rather than dispersed. Atlantic Alison (photo to left) has often been referred to as the best example of the Dexter breed, produced 8,136 lbs (3,698 kgs) milk at 4.66% butterfat in 305 days in her 5^th lactation. Atlantic Finbar was 75% Dexter, his sire’s dam being a mix of Aberdeen Angus and Jersey [these bloodlines were introduced via the Experimental register as an attempt to overcome the bulldog calf problem]. Sheppy concludes: “So none of the subsequent animals can be guaranteed pure. This can only be regarded as extremely disadvantageous to the breed as a whole” (p.152).

Line 2: Summerdale – Canwell Buster (1982)

The Summerdale herd existed between 1955 to 1965 but produced a highly productive strain and some outstanding show animals. Canwell Buster [see photo to left, from DCS UK Herd Book] has been a popular sire and has had a major influence on the breed, siring many outstanding animals. However, he has tended to produce rather large animals and is suspected of carrying two genetic defects – hydrocephalous and antelope calf syndrome. His grandson, Bookhams Robert  [see photo to right, from DCS UK Herd Book], was the foundation AI bull for Australia and New Zealand. His influence in Canada is via the exported bull Cobthorn Constable.

Line 3: Shadwell – Shadwell Robert (1978)

This herd was owned by Tetleys, the northern England brewers. At its dispersal, two groups of females went overseas, one to the Isle of Man and the other to found the Cornahir herd of D.G. Couper in Ireland. Shadwell Robert also produces larger animals at times and his offspring have a high proportion of reds who “often, but not always, exhibit unusually dusky faces with black noses” (p.153). Shadwell Robert influences the Canadian herd via his offspring, Lucifer of Knotting and Cornahir Outlaw. Bookhams Robert, the first AI bull in Australia and New Zealand, was a son of Shadwell Robert.

Line 4: Weatheroak – Sylvan Ebony (1838)

Weatheroak was the herd of Thomas Merry, from 1942-1958. Sylvan Ebony, who was bred from two Weatheroak parents in 1959, became the most widespread AI bull in England, and his semen was exported to continental Europe. His daughters were exported directly to South Africa and USA, with more recent imports of the line to Canada, Australia and New Zealand. “This line has become known for very attractive small neat animals with some very impressive milk yields” (p.155).  Sylvan Ebony’s son, Sarum Bullrush, is an outstanding modern sire.

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