8.1 This chapter considers a case study of a traditional
genotype. The Blue Grey cow is an interesting animal
to study, since it is a crossbred between a bull
which is classed as a minority breed (Whitebred Shorthorn)
and a cow of a traditional Scottish breed (Galloway).
The resultant cow is subsequently crossed with a
variety of breeds, often continental breeds, to produce
a finished beef animal for slaughter.
8.2 The pure Galloway is a true hill breed, kept
in relatively harsh environments, particularly in
the hills and uplands of southern Scotland. There
are only a limited number of breeds which could be
used in these types of farming systems. The Blue
Grey cow is also able to survive in such conditions
while able to produce calves which will satisfy the
requirements of the market for quality meat.
8.3 There have been a number of experiments done
over the years looking at the performance of Blue
Grey cows and their calves. A comprehensive review
of the reproductive performance of Blue Grey cows
was undertaken by Osoro and Wright (1992). They reviewed
the performance of a total of 321 spring-calving
cows which had been used in a series of grazing experiments
between 1984 and 1987 at the Hartwood Research Station
of the Macaulay Land Use Research Institute. 237
of the cows were Hereford x Friesian while the remaining
84 cows were Blue Greys. The study looked at the
performance of spring-calving cows (mean calving
date 27th March). The mating period which was 10
weeks long each year started 1 week after turnout
in the middle of May.
8.4 Earlier work, (Wiltbank et al, 1964; Dunn et al,
1969; Hansen et al, 1982 and Rutter et al, 1984) had
established that a number of factors were responsible
for the length of time taken to get cows back in calf.
These included milk production, age of the cow, suckling
and genotype. Also heavily implicated was the condition
of the cow at calving which in turn is a function of
the level of nutrition in the period up to calving.
8.5 By the end of the mating period, there were significantly
more Blue Grey cows in calf than Hereford x Friesians,
with Blue Grey cows achieving a pregnancy rate of 90%
compared to only 83% in the Hereford x Friesian cows.
Of those cows which were pregnant, the period from
the start of mating to conception was shorter for the
Blue Grey at 17 days as opposed to 27 days for the
Hereford x Friesians. At calving the body condition
score of the Blue Greys was higher (2.54 compared to
2.37). The calves, which were all sired by Charolais
bulls, were however significantly heavier at birth
when their dams were Hereford x Friesian cows rather
than Blue Greys (41.2kg compared with 36.5kg). The
calves of Hereford x Friesian cows also grew faster
at 0.95kg/day rather than 0.84kg/day achieved by those
from Blue Grey cows, presumably as a consequence of
the higher milk yield in the Hereford x Friesian cows
(Wright and Russel, 1987). As a consequence calves
from Blue Grey cows tend to be 10-15kg lighter at weaning
than those from Hereford x Friesian cows (Hodgson et
al, 1980; Wright and Russel, 1987).
8.6 As part of the study, the age of the cow was also
taken into account. Up to the age of 7 years there
was no difference in the percentage of cows which were
successfully got back into calf. However above this
age, there was a significant decrease in the number
of Hereford x Friesian cows which became pregnant.
At 10 years of age virtually 100% of the Blue Greys
became pregnant while just over 60% of the Hereford
x Friesians were able to get back in calf. This suggests
that the replacement rate of the Blue-Grey cows would
be considerably less than the Hereford x Friesian.
8.7 Other studies on the Blue Grey cow suggest that
they calve slightly lighter than Hereford x Friesian
cows, that their intake at pasture is less, but their
milk yield is lower. Wright and Russel (1987) reported
milk yields of 8.93kg/day for Hereford x Friesian cows
and 6.88kg/day for Blue Greys. This lower milk yield
is primarily a function of their partitioning less
of their energy towards milk production and more towards
body reserves. As a consequence they tend to be fatter
than more productive genotypes and lose less weight
in lactation (Hodgson et al, 1980). It is not clear
if the superior reproductive performance of the Blue
Grey compared to the Hereford x Friesian observed by
Osoro and Wright (1992) is simply a consequence of
their having a higher level of body condition. Body
condition is known to have a strong effect on reproductive
performance (Wright et al, 1992).
8.8 In an experiment looking at the post-weaning nutrition
of calves Wright and Russel (1987) found that the Charolais-cross
progeny of Hereford x Friesian cows were heavier than
those from Charolais cross Blue Grey cows. The weight
difference remained constant throughout the experiment.
This suggests that the difference was not due to higher
potential for growth, but to the higher milk yields
which have been reported for Hereford x Friesian cows.
McDougal (1978) argued that the milk yield of the Blue
Grey could be improved by more rigorous selection of
Whitebred Shorthorn bulls. This would require records
to be kept of calf performance in order to identify
those bulls which conferred improved milking ability
on their daughters.
8.9 In conclusion, the Blue Grey cow tends to be fatter
at calving and has higher reproductive performance
and a more compact calving interval. Since it tends
to be fatter at calving, it requires less expensive
winter feeding. It also loses less weight during lactation
and therefore requires less autumn feeding to return
it to condition fit for calving. It is also able to
sustain its higher reproductive rate to an older age
thus leading to a much lower replacement cost than
a Hereford x Freisian cow. The weaning weights of the
calves are, however, lower than for genotypes with
higher milk yield potential.
8.10 For these reasons, the Blue Grey is well suited
to extensive production systems. Without the large
fluctuations in body condition, the Blue Grey is well
adapted to systems of lower inputs.
8.12 Since the Blue Grey cow is a crossbred, its
loss would have a serious detrimental effect on the
population of its parent breeds. The Galloway in
particular is important, being a true hill breed.
The production of females for subsequent crossing
with the Whitebred Shorthorn is a significant market
for many Galloway breeders. Significant reductions
in the numbers of Galloways would in turn have implications
for the biodiversity of hill and upland swards.
8.13 The Blue Grey cow itself is important in that
it can apparently survive in relatively harsh conditions
on terrain which may be difficult to graze with other
genotypes. The Blue Grey is well adapted to extensive
conditions and is longer lasting and cheaper to feed
than some other, larger types of suckler cows. The
Blue Grey is also easier to manage in terms of its
reproductive performance, being easier to get back
in calf after giving birth.
8.14 There is a need however for further studies of
the impact of the Blue Grey (and indeed other breeds)
on biodiversity and in particular its impact on the
composition of upland swards. As has been stated earlier,
little research has been conducted on the impacts of
different genotypes on biodiversity.
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