A. O. Rhoad, formerly in charge of the Iberia experiment farm, checks the amount of sweat under the discs strapped around each of the two cows shown above, both of which have been exposed for the same length of time to the Gulf Coast sun. The animal at left is a zebu cow, the other is half zebu and half Aberdeen Angus. The zebu showed less evidence of perspiration. Experiments have also shown that cattle with Africander blood are better than Angus in the subtropics. The yearling below is a halfbreed Africander X Angus bull.
Until recently little conclusive work had been done to prove the merits of cross-breeding dairy cattle. Some experiments have now been completed at Beltsville that have included the crossing of Holstein with Jersey and Guernsey, Red Dane with Jersey and Guernsey, and Jersey with Holstein. Encouraging results have been obtained. The animal shown above may be considered a good example of a crossbred Dr hybrid. She was sired by a proved Red Dane bull on a Guernsey dam. Her record at 1 year and 11 months, milked 3 times a day for 365 days, is 14,055 pounds of milk with 4.79 percent or 674 pounds of butterfat. The following series of pictures includes groups of cows on which production experiments have been run. Unless otherwise indicated, all data are actual first-lactation records for 365 days, three milkings daily. An article on the crossbreeding of dairy cows begins on page 177.
Some tests have also been run on 3-breed crosses that were the result of mating 2-breed females to males of a third breed. The 10 animals shown above have been used in these experiments. Their rather complex parentage and milk production records are discussed on page 181.
by M. H. FOHRMAN
WE WONDERED whether the spectacular vigor of hybrid corn could be matched in dairy cattle—whether we could cross purebred, efficient Jerseys and Holsteins, for instance, and get an increase in milk that we could say was due to hybrid vigor. We started such an experiment in 1939, and our first results lead us to believe that a part of the gain we got might have come from the extra vitality.
We had some examples to follow. Breeders of poultry, swine, and beef cattle, and of corn and several other plants had had practical, even startling, results with crosses of different breeds. But little conclusive work had been done with dairy cattle. Nearly 30 years ago experiments in crossing Holstein-Friesian, Jersey, Guernsey, Ayrshire, and Aberdeen-Angus cattle were reported from Maine. Most of these experiments were made with mixed dairy and beef breeds and not dairy cattle alone. A study in the crossing of Guernseys and Holsteins was started in Massachusetts in 1911. At the University of Wisconsin some crosses were made with Jerseys, Holstein-Friesians, and Aberdeen-Angus. In most of the experiments, however, the level of the primary function of dairy cattle—milk production—and the transmission level of the bulls of the dairy breeds were not clearly established.
When the Bureau of Dairy Industry began to explore the field of cross-breeding of dairy cattle at Beltsville, we brought in foundation females from the proved-sire bred herds at our field stations—Holsteins from Huntley, Mont., and Mandan, N. Dak., Jerseys from Lewisburg, Tenn., and Guernseys from the Sandhill station in South Carolina. Females of the Red Danish milk breed were available at Beltsville, as well as proved Holstein, Jersey, and Red Danish sires. All foundation females were from production-bred herds—the bulls had proved they could beget heifers that surpassed their mothers. We felt that the blending of these proved stocks would bring forth any hybrid vigor that might be expected to result from interbreed matings.
The project differed from the usual pattern of crossing breeds in that it called for continuous introduction of new genes, the units of inheritance, through the use of proved sires of different breeds. We proposed to have only a limited number of interhybrid matings. Females resulting from mating Holsteins and Jerseys, for example, are mated to Red Danish sires for the three-breed crosses; such females, in turn, are mated to either Holstein or Jersey proved sires in a second round of the three breeds involved.