The Effects of Mild Inbreeding on a Herd of Holstein-Friesian Cattle

Inbreeding, in some instances, has been an effective system of breeding for livestock improvement but never has come into very common use in purebred herds and flocks, presumably because the incidence of abnormalities and other undesired traits is higher among inbred individuals. In recent years and at the present time, inbreeding projects have been and are being initiated by many experiment stations to obtain a more conclusive answer on how to derive greater benefit from this system of mating. With few exceptions, these experiments with large animals, as well as those with laboratory animals, have resulted in reduced vigor as exhibited by slower growth, smaller size, greater mortality and lower production and fertility. The present paper reports the effects of mild inbreeding on several characteristics in a herd of Holstein-Friesian cattle.