Menu

Description: Oscar Hafs with Windrow Golden Jim on Hafs' farm, shortly before the bull was purchased by a commercial bull stud. Most US dairy cattle were bred by a farm bull until the 1960's. Typically, a single bull might be used for a herd with 30 or 40 milking cows, including the heifers. Larger herds required more than one bull. Although most herd bulls were selected from cows farmers thought to be the best, little was known about their ability to transmit superior milk production. Furthermore, farm bulls sometimes had low fertility, they often spread venereal diseases and too frequently they injured or killed farmers. After 1960, artificial insemination (AI) organizations perfected methods to select bulls for genetic merit, procedures that could not be replicated on a single farm. In AI, a single proven sire might produce enough sperm for as many as 100,000 inseminations annually. Accordingly, by 2000, for more rapid genetic improvement the majority of US dairy cows were artificially inseminated.

Resolution: 2807x2000

File Size: 2.29 MB