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Full-Text Articles in Life Sciences
Influence Of Age Of Dairy Cattle And Season Of The Year On The Sex Ratio Of Calves And Services Required For Conception, R. F. Morgan, H. P. Davis
Influence Of Age Of Dairy Cattle And Season Of The Year On The Sex Ratio Of Calves And Services Required For Conception, R. F. Morgan, H. P. Davis
Historical Research Bulletins of the Nebraska Agricultural Experiment Station
The present study was based on records of the dairy herd of the University of Nebraska for the period 1896 to 1934, and covers five breeds, Holsteins, Jerseys, Guernseys, Ayrshires, and milking Shorthorns. In all, 2,090 cows have been included. The purpose was to determine the influence of the age of the bull, the age of the cow, and the season of the year upon the number of services required for conception, and to determine also the influence of these factors upon the sex ratio of calves born, number of twins born, and the percentage of abortion.
Determining The Sex Of Day-Old Chicks, H. E. Alder
Determining The Sex Of Day-Old Chicks, H. E. Alder
Nebraska Agricultural Experiment Station: Historical Circulars
More than 2,000 years ago people were interested in determining the sex of the embryo in hatching eggs and the sex of day-old chicks. No method of determining the sex of day-old chicks (except of course in sex-linked chicks) was of the slightest value until the Japanese method was discovered and developed. About 1925 Japanese scientists discovered the presence of a rudimentary copulatory organ located on the ventral rim of the cloaca which was present in all day-old males and only a few day-old females.