Repository: UIHistories Project: Board of Trustees Minutes - 1886 [PAGE 229]

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221 10th. Economy of production is quite as important as maximum product, especially in times of low prices.

CONTROLLING SEX IN BREEDING.

For several years past different suggested modes of controlling sex in breeding domestic animals have been kept in mind in the cattle breeding on the University farms. One result of these observations has been to suggest an explanation of some of the many positive statements that a given theory had been proven correct. In several cases we have had a noticeable series of calves of one sex—so noticable in number that, had the cows been bred in accordance with any one method or theory for controlling sex, there would have been a natural disposition to pronounce the theory proven true or false. At times there seems a striking tendency to the production of animals of one sex, either as the progeny of the sire or of one or more females. The Short-horn bull Oxford-Mazurka 40,199 gave us nearly three heifer to one bull calf for three successive years. On the other hand, a majority of the calves of his get during the last few months he was in use were bulls. Three Short-horn cows in the herd have given six, five and four calves of the same sex in succession; then dropped one of opposite sex. We have not found that reliance can be placed in the theories that sex can be controlled by service near commencement or near close of heat; before or after milking, or by having the animals coupled of different ages. On the other hand, we have not, in a series of years, been able to say positively that what is known as the Stuyvesant theory has been proven incorrect—unless cases of production of twins of opposite sex be counted violation of the theory. This theory is that conception at alternate periods of heat will produce offspring of different sex. The method of application i s : A cow having produced a calf, and it being desired to have the next of the same sex, the cow should be served at the second, fourth or sixth heat, until she stands to the service. If a calf of the opposite sex be desired, she should be served at the first, third or fifth heat. It is not held that our observations prove this theory correct; simply that we have not found, with certainty, exceptions to it in our herds. It not infrequently happens that the manifestations of heat in a cow are so slight or pass away so quickly that they may not be detected; hence this theory may be incorrectly held to have been sustained or its correctness disproved. A test has been made of the theory that the sex of the young can be controlled by half castration of the male—it frequently being stated that semen from the right testicle will produce only male, that from the left only female offspring. The left testicle was removed from a boar pig. Three sows afterward bred to him produced litters in each of which were pigs of both sexes in nearly equal number. The castration was done when the pig was quite young, and no other boar could have had access to the sows. In this case the result was directly at variance with the theory.