CONSIDERATIONS STATISTIQUES SUR LA PREDISPOSITION STERILE D'ETE CHEZ LES TAUREAUX DE RACE HOLLANDAISE PRODUITS AU HOKKAIDO

概要

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Predisposition and some other suspected factors of summer sterility were studied with Holstein bulls born in Hokkaido and used in centers for artificial insemination of cattle in Honshu, Shikoku, and Kyushu. The centers reported the number of bulls which suffered from summer sterility and its clinical signs and symptoms from April 1,1963 to March 31,1965. Susceptibility to the disease was compared statistically from the data with respect to the distribution of ages, pedigrees, coefficients of inbreeding, ages of sire and dam at the time when the dams were inseminated, full-brother bulls, ages at the beginning of confinement in the centers, the group A1 bulls which did not suffer from the disease during the abovementioned period, and the group A2 bulls in which the disease was observed. The results obtained were as follows. 1) Greater susceptibility to the disease was found in bulls born from sire over 9 years in age and dam under 4 years of age ; those born from both sire and dam over 9 years of age ; those born in August and October ; or those above the age of one year kept at the centers. 2) It is not probable that the bulls which descended from any certain ancestor or which belonged to a certain family were more susceptible. 3) No relation was found between the order of birth of full-brother bulls and their susceptibility to the disease.
北海道大学の論文