Summary of Article About Dexters

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"Dexter Cattle: Origin and Relationships" 
by Lawrence Alderson

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 139-145.

At the time this Paper was presented, Lawrence Alderson was Executive Director of the UK Rare Breeds Survival Trust. He is an international consultant on livestock breeding and production and on genetic conservation. Born on a Pennine farm, he went on to gain degrees in agriculture and education at Cambridge. He has assisted the creation of rare breeds conservation groups in many countries and is a Trustee and Founder President of  Rare Breeds International. He is author of  "The Observer's Book of Farm Animals"(1976) and "The Chance to Survive: Rare Breeds in a Changing World" (1978), the standard work on genetic conservation, as well as a number of other books and articles. He owns the Dynevor herd of White Park cattle which can be traced back to the ninth century.

Classification of Breeds of Cattle (Page 139)

Cattle breeds are often classified by key phenotypic characteristics, such as horns and coat colour, or in relation to their area of origin. Wilson (1909) suggested that white cattle in Britain were introduced by the Romans, polled cattle by the Vikings, and red cattle by the Saxons. This turns out to be over-simplistic. For example, it has been demonstrated that white cattle existed in Britain before the Romans and hornless skulls have been found in pre-Viking archaeological sites.

Alderson points out that recent classification approaches tend to recognise two main sources from which modern breeds have developed. The most ancient group is the "Western" one, dating from at least the second millennium B.C., and represented by long-horned breeds such as the White Park and Highland. These are often referred to as Celtic breeds, but this is not an entirely accurate description. A later influx of cattle from northern Europe comprised different types, including Scandinavian and short-horned red Germanic, and includes breeds such as Shorthorn, Lincoln Red, Norfolk Red and, later, the Friesian. Other minor influences have included those from neighbouring countries such as the Netherlands, the source of white-faced and belted cattle. Modern British breeds are descended from either one of the two major groups or from a mixture of them, such as the Ayrshire (Western x Shorthorn) and Galloway (Western x Scandinavian).

The history of most British cattle breeds is generally well-known for the last two or three centuries, sometimes even for much longer. "However, there are some breeds whose origin and development remains obscure, even within the last 200 years, and the Dexter falls into this group" (page 139).

Relationship of Dexter and Kerry Cattle (Pages 139-141)

Many agricultural historians and writers repeat uncritically a view that the Dexter was an off-shoot from the Kerry. The Dexter is seen to be a relatively young breed, having been reported in the literature first in 1776. It is supposed that the Dexter was developed by a Mr Dexter, after whom it was named in the early nineteenth century. Mr Dexter was agent for Lord Hawarden on Valentia Island in County Kerry, although some references state that he was based in County Tipperary. However, Alderson argues, there are distinct differences between the Dexter and the Kerry and a lack of precise information on the early development of the Dexter.

Alderson next lists five main similarities or links between Dexter and Kerry cattle:

1. They share the same area of origin, south-west Ireland. The Kerry was the dominant breed in south-west Ireland, though it probably suffered introgression from other breeds, including the Alderney in the eighteenth century and maybe even Indian zebu in the mid-nineteenth century. The Dexter was associated first with south-west Ireland in the late eighteenth century, becoming extinct in Eire before being reintroduced in the late twentieth century.

2. Both breeds are predominantly black. The Dexter has red and dun colour variations, and the Kerry had various colours and patterns in earlier times. Kerry patterns included the Drimmon type [white-backed], a colour pattern not recorded in Dexters. "Colour can be a misleading characteristic on which to base breed relationships. It is only in relatively recent times that most breeds have preferentially established a particular colour within breed standards" (page 140).

3. Both breeds are horned. Both are medium horned breeds, which might suggest a mixed ancestry. The Kerry is classified as a medium-long horn, while the Dexter is a medium-short horn.

4. Both breeds were originally registered in the same herd book, and some animals probably crossed the register divide. The Kerry and Dexter Cattle Society of England was established in 1892, with the Kerry and Dexter Cattle Society of Ireland established in 1917 but in 1919 being restricted to Kerry cattle. "More recently the same confusion has continued in South Africa" (page 140). Reciprocal introgression between the Dexter and Kerry has been recorded which should have increased the relationship between the breeds, regardless of close ancestry.

5. Dexter and Kerry cattle were often classed together at livestock shows. It was not until 1876 that the Royal Dublin Society imposed effective separation of the breeds in the show ring.

Development of the Dexter Breed (Page 141)

Alderson contends that these five similarities are not sufficient to support the view that the Dexter is an off-shoot from the Kerry. "It is appropriate to consider alternative hypotheses" (page 141) and he goes on to make four points.

1. Clearly a small type of cattle existed in Ireland more than two hundred years ago, probably the result of the effects of both environment and selection.

2. It is possible that the "achondroplastic factor" was introduced deliberately to emphasise the small size of the cattle. This has created a confusion between miniature and dwarf cattle.

3. At later stages it is known that there was introgression from various other breeds. Devon cattle have been recorded as one source. "The appearance in a breed, which has been selected for whole colour for many generations, of calves with significant white markings suggests that illicit introgression may have occurred" (page 141).

4. The experimental register permitted cross-breeding with the Aberdeen Angus and Jersey in particular. According to Alderson, this "provided a further opportunity for the ignorant or the unscrupulous to compromise the genetic integrity of the breed" (page 141). For example, in 1974 a farm park attempted to register a bull "which was 25% Jersey, 12.5% Aberdeen Angus, 6.25% Shorthorn and 18.75% unknown", the remainder of his ancestry being derived from Dexter animals in the experimental register. "The registration of the bull was not permitted, but the daughters of the experimental bull, Fircone, went into Appendix B in the Herd Book - only one step from full pedigree" (page 141).

As a result, the Dexter would have changed in type from the animals originally associated with Mr Dexter and its relationship to the Kerry would have become more and more remote.

Relationship of the Dexter to Other Breeds of Cattle (Pages 142-145)

Alderson examines three main sources of information that could clarify the Dexter's relationship to other breeds: biochemical analysis, linear assessment and production characteristics.

Blood-typing (Pages 142-143)

Alderson refers to three studies that have thrown light on the relationship of the Dexter to the Kerry and other breeds. Royle (1983) studied cattle polymorphisms in eight rare breeds and demonstrated that the Dexter was related most closely to the Belted Galloway, followed by the Shetland (see Table 1 below). The relationship of the Dexter to the White Park and Kerry was remote, which according to Alderson, "calls into question not only its common origin with the Kerry, but also the classification of the Dexter as a Celtic breed" (page 142).

Table 1: Relationship of the Dexter to seven rare breeds of cattle (from Royle, 1983)

Buys and Chiperzak (1992) compared blood types of Dexter and Kerry cattle and confirmed Royle's findings. A larger study by Blott et al. (1997) showed that the Dexter was most closely related to the Aberdeen Angus (see Table 2 below). Again the relationship to Celtic breeds such as the White Park and Highland was remote, with the Kerry being even more distant. Blott et al.'s research used multidimensional scaling, principal component analysis, and phylogenetic tree methods to calculate genetic distance. They wrote that the tree indicated that "the Piedmontese, Guernsey and Dexter are intermediate between the two major groups. However, the multidimensional scaling and principal component analysis suggest that ... the Dexter [is] part of the mainland British group" (Alderson, page 143).

Table 2: Relationship of Dexter cattle to ten other British breeds (from Blott, 1997)
 

Alderson concludes from these studies that "the Dexter, whatever its origin, has drifted or been selected to such a degree that it is not closely related to the Kerry and cannot be classified as a Celtic breed" (page 143).

Linear Assessment (Pages 143-144)

Symes (1981) correlated a number of linear measurements of 114 Dexter cows with the incidence of bulldog calves. For most measurements, the sample had a normal population curve, but for withers height, cannon bone length and metacarpal index the population divided into two separate overlapping groups. Dams of bulldog calves were concentrated around the average for those measurements that exhibited a standard population curve, but fell entirely within the lower curve for the other measurements. Alderson pointed out that these data indicate that there are differences of conformation within the breed apart from those associated with leg length. The long-legged type shows distinct similarities to dairy breeds, while the short-legged type has characteristics more in common with beef breeds (see Table 3 below).

Table 3: Comparison of conformation indices for Dexter cattle with seven other breeds (from Symes, 1981)

Production Characteristics (Pages 144-145)

"The value of production characteristics as indicators of different genetic types within the Dexter breed is limited by lack of data to demonstrate whether the differences are due to the effect of complex interactions within the genome, or simply are expressing an influence of the 'dwarf' gene" (Alderson, page 144). Nevertheless, Alderson believed the differences to be significant. Wilke (1996) compared a short-legged with a long-legged bull and found they showed marked variation in growth and feed conversion efficiency. Wilke suggested that the short-legged bull had no or very little muscle growth during most of the test, and was laying down fat. The animals showed some differences in conformation, especially for length of leg and withers height (see Table 4 below).
 

Table 4: Performance results for two Dexter bulls (from Wilke 1996)

The Rare Breeds Survival Trust operates a Traditional Breeds Meat Marketing scheme which includes an assessment of meat quality. These assessments show that, "while the meat quality from medium and long-legged Dexter cattle achieves a good standard, 'dwarf' type animals produce worse results. If they are slaughtered at a young age they show a poor meat/bone ratio; if they are slaughtered later they show a poor meat/fat ratio" (Alderson, page 145). While these differences are genetic in origin, it is not possible to determine whether lack of muscle in short-legged Dexters reflects a mixed breed ancestry, or whether it is directly associated with the "achondroplastic condition".

Conclusions (Page 145)

"While the early history of Dexter cattle is not documented clearly, records from later periods show the opportunity for significant introgression. Recent biochemical, morphological and production studies have confirmed that the Dexter does not belong to the Celtic or Western group of breeds, that it is not closely related to the Kerry, and that it owes a closer relationship to a mixed group of breeds. It has not been fixed into a consistent breed type as defined by linear assessment, although it is not clear how far the presence of the achondroplastic factor has introduced a confusing influence" (Alderson, page 145).

References Cited Above

Blott, S.C. et al. (1997), 'Genetic relationships between European cattle breeds', Animal Genetics.
 

Buys, C., and Chiperzak, J. (1992), 'A comparative study of blood groups in the Kerry and Dexter Cattle Breeds' in L. Alderson and I. Bodo (eds.), Genetic Conservation of Domestic Livestock (Vol. 2), CABI, Wallingford.
 

Royle, N.J. (1983), 'Polymorphisms of Rare Breeds of Cattle', University of Reading.
 

Symes, M.V. (1981), 'Achondroplasia in Cattle: A Survey of the Dexter Breed', University of Reading.
 

Wilke, P.I. (1996), 'The effect of size on growth performance in Dexters', The Dexter Bulletin, No. 132.
 

Wilson, J. (1909), The Evolution of British Cattle and the Fashioning of Breeds, Vinton, London.
 

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