Published online by Cambridge University Press: 27 March 2009
Migration of pedigree Ayrshire cattle in the British Isles is estimated for 1927 and 1946 from samples of herd-book registrations. Most migration is from Scotland, particularly Ayrshire, to England, but considerable numbers were also transferred between regions within Scotland or England. A larger proportion of bulls than of cows was moved in this way. Only a small proportion of animals had two parents bred in the same herd as themselves. If the males and females registered from England in 1946 were the sole parents of the next generation, the latter would still have more than half Scottish blood.
The amount of movement of Ayrshire cattle shown by these data virtually precludes genetic differences between regions, but not perhaps between herds. Other implications of movement are discussed.