INBREEDING TESTS

Hawke's Bay Herald-Tribune, Issue 74, 14 April 1937, Page 15

INBREEDING TESTS

.. - -T || | ■ Tweiity Year* Success in America HEREDITARY FACTORS Inbreeding, fedred by most li,V6 stock m6n, biit U§ed With eXtreme sUccOss by dome, has been practised for 20 years in the Bufeau of Dairy Industry herd at BeltSVijUe, Md. (U.S.A.-), Without bad results. But the burean wams that its Success, as in all cases Of inbreeding, probabiy was due to the faet that the first sire was an excellent indivifiuai, able to pass on high production without redueing fertility or seriously weakeuing his otfspring. The ifibreeaiHg triale began in 1915, About 15 grade dairy cows were mated with a registered Hoistein bull. The bull was th8n mated with his daughters, An inbred soa^ with three straight crosses of the flrst bull, was chosen for the second sire. An inbred gt&ndson beoame herd sire Nd. 3.- .This grandson, mated to his own dam, sired the feurth herd huli# He in turn Was mated with this same dam to produce bull No. 5.' This hefd probabiy is the most inbred

in the country. DaughterS of the first bull and the fdundation cows avoraged an increU3e of : 1001b. fat a year. * These daughters mated to the inbred son of the first bull produced daughters which averaged 63 lb. more fat a year than their daifls. But when this inbred bttll Was mateii with his own daughters average fat de-^ clined about 171b., although it has remained at a high level with further inbreeding. Inbred calves' are somewhat llghter in weight, as are the mature inbred cows. The bureau concludes that the only why to find whether a dairy bull that increases production should be used .for inbreeding is to mate him with his daughters, If the bull has the right factors for inheritance production will be increased without a lowering of fertility or vxrility.