A Breeding policy for Minority Breeds
by G. L. H.
Alderson
This article was
first presented as a paper at the annual general meeting of the British
Caspian Society in November 1979. The examples quoted in the paper relate
to Caspian Miniature Horses, but the principles of animal breeding which
they illustrate apply with equal relevance to any minority
breed.
One of the most
contentious subjects in animal breeding is that of inbreeding. Some regard
it as a dangerous practice to be avoided at all costs, while others employ
a type of inbreeding (linebreeding) as a valuable aid in their breeding
programmes. Linebreeding can concentrate the qualities of an outstanding
animal in its progeny, but unplanned line breeding can reduce standards of
performance and fertility and in some cases will expose genetic defects.
Whatever its role as a factor for 'improvement', one thing is certain,
namely that inbreeding will lead to a narrowing of the genetic base of a
breed, and will and will reduce its flexibility and ability to adapt to
changing circumstances in the future. These dangers have been recognized
even by those who control the fortunes of the most popular breeds, and
they pose an appreciably greater threat to minority and rare
breeds.
In every breed
there are fashionable sirs and unfashionable sires. The former are
oversubscribed and the latter are neglected, and this concentration of
attention on a relatively small proportion of elite animals can lead to a
loss of bloodlines and associated genetic material. This in turn can
result in a rapidly escalating problem when breeders search desperately
for unrelated stallions to mate to their mares. Thus in a numerically
small breed there is a need for breeders to sacrifice some of the
independence of action and participate in a broader breeding policy
designed to safeguard the future interests of the breed as a whole.
Although it is not easy to persuade pedigree breeders to accept the
disciplines inherent in such a policy, from past experience it seems it
can be launched initially on a voluntary basis and it is usually accepted
without the necessity for any imposition provided the objectives and
reasons are explained sensibly.
Two Basic Principles
The
two basic principles of a group breeding policy are the maintenance of
distinct bloodlines, and the use of cyclic crossing between these
bloodlines to minimise the increase level of inbreeding. If those remnants
of the Caspian breed, which may or may not remain in Iran, are ignored
there are six extant sire lines in the breed on which to a base breeding
programme. All the stallions and mares are allocated to one of these lines
according to their type and the main influence in their pedigree. The best
mares in each line are mated to stallions in the same line (linebreeding)
in order to maintain each line as a distinct entity. The other mares are
mated to stallions in the next line in the cycle. Figure 1 (not reproduced) shows a typical pedigree of an
animal bred in this way, and its coefficient of inbreeding is less than 1%
in the first four generations.
Compensatory Mating
The
sequence of lines within the breed must be planned so that the weaknesses
of a particular line are corrected by the strengths of the next line. This
is known as compensatory mating and should be an integral part of any
breeding programme. Thus among Caspians the line based on Daria Nour is
noted for jumping ability, small size, good head and forequarters, but is
suspect on hocks and feet. In contrast the Palang line is very good for
confirmation, especially the hocks, but has a less refined head and is
taller than average. The Ruda line is of good type with a quality head.
Thus in a system of cyclic crossing the best sequence for these three
lines is Daria Nour, Palang, Ruba.
Sire Lines and Female Families
The stallions each line are detailed in Table 1.
The Ruba line is very dominant within the breed while both the Ostad and
Zeeland lines are very vulnerable. With a group breeding programme these
latter lines must be encouraged and expanded. Strictly the Ostad line does
not exist in Great Britain in direct tail male and must be reconstructed
from animals with a high concentration of Ostad in their pedigree. The
future of the Zeeland line depends on a single stallion.
In discussions on breeding programmes undue emphasis
tends to be placed on the males, but in practice, especially in
numerically small breeds, some females emerge as powerful influences.
Among Caspian mares, Taliyeh consistently breeds good foals and is the dam
of five stallions. Thus she is contributing significantly to the danger of
inbreeding. The limited number of female families in the breed accentuates
this danger and should be counteracted by the deliberate use of as many
foundation mares as possible to breed stallions.
Incrossing
One of the
problems of inbreeding is that it may lead to decreased vigour, reduced
performance and the emergence of hidden defects. Conversely the mating of
distantly related animals may produce foals of increased vigour. While the
mating of two inbred animals from different lines can lead to a high
degree of hybrid vigour. This latter technique, known as incrossing, is
used widely in plant breeding and was applied either by accident or design
in the breeding of the great Thoroughbreds of the postwar period. Sea Bird
II who won both the Derby and the Prix de l'Arc de Triumphe. Sea Bird II
was produced by mating an inbred mare from a French staying line to an
inbred stallion from an American sprinting line. The combination of
linebreeding and cyclic crossing which is recommended here, produces
incrossing.
Animals which are the product of
incrossing are likely to be above average performers, but their reputation
as stallions is unlikely to match their success on the race track. Thus
there is a continuing need to use linebred animals in the breeding
programme although their own performance may not be so
outstanding.
Selection and Culling
Traditional breeding programmes have been built
around outstanding animals such as Taliyeh. In some cases these animals
are identified by the 'eye' and skill of a breeder. In some cases the art
of breeding has been complemented by the science of genetics and the
progeny test is used more widely as a measure of excellence. But in both
cases the result is the same, namely the concentration of the breed on
fewer and fewer bloodlines. The most severe reduction in genetic material
in a breed occurs when there is extreme selection for the production of
outstanding individuals, such as Derby winners, rather than for the
average quality of the breed. However it is interesting to note that the
current record for the Derby has stood since 1935 and that for the Oaks
since 1927. Despite the better tracks improved riding and training
techniques, and better nutrition, the speed of the Thoroughbred is not
increasing. It may be that a performance peak has been reached or it maybe
that inbreeding is canceling out the effects of selection for improvement.
Examples can be drawn from the inbreeding of other species, especially
pigs, to show how intensive selection has led into a genetic
cul-de-sac.
The lesson for rare breeds such as the
Caspian is that attention must not be focused on a few fashionable
animals. Rather a broadly based breeding programme must be followed with
the emphasis placed on the culling of below standard animals to raise the
average quality of the breed. The severity of the culling must be governed
by population size, when a breed is low in numbers only defective or
markedly untypical females should be culled, and relatively high
proportion of stallions should be retained. It must be a basic rule that
no sire line or female family should be allowed to die out.
Function Efficiency
As a
minority breed increases in numbers the severity of culling may be
intensified to a limited degree, but still with the proviso that each line
and family is maintained. Furthermore the culling and selection should not
be unduly influenced by the vagaries of the showring fashion, but rather
by the characteristics of functional efficiency. These characteristics
include not only tooth and jaw structure, action, tail setting, etc., but
also the ability in jumping, eventing and driving competitions, for it is
the success and publicity achieved by the Caspian in these activities that
will serve to recommend it to the wider public. The process of
establishing a breed follows four phases. First its distinctive qualities
must be identified (e.g.. jumping ability, speed temperament). Second a
function must be identified (e.g. riding pony, racing pony, eventing).
Third its qualities and performance must be documented. Fourth its value
must be publicised.
Special Characteristic
The success of the whole breeding programme rests
on the initial assumption that the improvement of the distinctive
characteristics is the common aim of all the breeders. In the absence of
this objective the justification to conserve the breed is invalid. It is
pointless to use the breeding techniques described here to turn the
Caspian into yet another pony of the native British type. It is a
miniature, and during its evolution in the stony mountainous area of
northern Iran, it has developed those special qualities which are now of
great value and by which it is identified. The Caspian stands 10-12 hands
high but with the graceful conformation of a Thoroughbred or an Arab,
which makes it so suitable as a riding pony. This use, and its performance
in driving trials, is further enhanced by its kind and tractable
temperament. Its hooves are tough and hard, with a small frog, and never
need showing. Its hind quarters on occasion attract criticism from the
showring devotees, but it may be that the remarkable jumping ability of
the Caspian and its powers of acceleration stem from this aspect of its
confirmation, and emphasise the need to evaluate each animal more in the
rigours of strenuous competition rather than the showring. In this way the
Caspian can hope to retain its true and distinctive identity.
Copyright
Lawrence Alderson
Lawrence Alderson was involved with the Caspians at
the beginning of their history in the UK. He is now a trustee of Rare
Breeds International, a registered charity with aim of preventing the loss
of diversity in global farm animals. To find out more about RBI visit their website. This article
is reproduced with Lawrence's permission.
Editors note; This paper was first presented in
1979, and yet linebreeding is as, or even more relevant now than it was
then. With each successive generation the genes of Foundation stock become
more dilute. Brian Wood the society blood lines advisor reported that
analysis of bloodlines carried by Caspians registered in 1999 and 2000
showed that there were 11 bloodlines of 4% or less.
Brian Wood
writes in 'The Caspian' magazine on Caspian bloodlines and can advises
council on this subject.