Thirteen other three-breed heifers were sired by Red Danish bulls, one by D-501, four by D-540, an inbred son of D-501, seven by D-508, and one by D-507. Five are from Holstein X Guernsey dams, six from Holstein X Jersey dams, and two from Jersey X Holstein dams.

Three other three-breed heifers were sired by Jersey No. 1114, two from Red Dane X Holstein dams, and the other from a dam representing three breeds.

Only eight of these three-breed animals have completed 365-day lactation records; their average is not conclusive, but it is impressive. The eight averaged 14,927 pounds of milk and 641 pounds of butterfat—average test 4.32 percent—at an average age of 2 years. The incomplete records available at this time do not indicate that this average will be greatly reduced, and it is significant that all but one of these three-breed heifers exceeded their two-breed dams in production of butterfat.

One of the striking characteristics shown by all of these crossbred animals is their persistency in milk production. Often the monthly butterfat production varies less than 10 pounds from the high month to the low month. This is perhaps one of the factors that adds to the production potential of the proved sires used in this study and in our other proved-sire breeding.

Some intermating of hybrids has already been worked into the project. That is being done in a limited way in order to check the transmitting ability of males bred like the females listed above. Crossbred bull X-120 was a son of Red Dane D-501 and his dam was a Holstein foundation cow. He was kept a while for use on heifers that might be difficult to settle and two of his daughters are in the herd. The first of these is X-49; her dam was a Holstein X Jersey female, and she is therefore a three-breed cow with Holstein in both sire and dam. She freshened at 2 years of age and produced 14,082 pounds of milk and 658 pounds of butterfat, testing an average of 4.68 percent. Her dam freshened at 2 years and 4 months and gave 12,584 pounds of milk and 606 pounds of butterfat with an average test of 4.82 percent. One case proves nothing but is an indication that the inheritance for milk and butterfat production should be the same in these males as has been demonstrated by the females of similar breeding.

Two other bulls have been sampled. X-179 is a son of D-501 and his dam is a Jersey X Holstein. He has three daughters in the herd—all from three-breed dams. X-191 is also sired by D-501, and his dam is a Holstein X Guernsey. There are six of his daughters in the herd, four from three-breed dams and two from two-breed dams.

A summary of the records completed by 38 two-breed and 9 three-breed cows shows an average of 13,273 pounds of milk and 599 pounds of butterfat—average test 4.55 percent; average age 2 years 2 months.

We are conducting this cross-breeding project in order to develop exact knowledge on the subject. Results obtained so far may warrant a few speculations as to the applications.

First, we must emphasize that production-bred foundation stock and production-proved sires were used almost entirely. It can be said, therefore, that similar results can be expected only where proved stock is used in making the crosses. This emphasizes the value of proved sires in breeding for milk and butterfat production. Factors that control those yields appear to be similar in the different dairy breeds. Numbers are large enough and we have enough combinations to indicate that we can repeat our good results if good sires are used.

The standard warning against cross-breeding is that "if Holsteins and Jerseys are intermated the resulting animals will produce Jersey quantity and Holstein quality of milk." This may be true with random-bred animals of the two breeds, but actually we can normally expect that the chances for Holstein quantity and Jersey quality of milk are as likely as the reverse, and that most of the offspring will produce at an interbreed level in both milk and percentage of butterfat.

This type of cross-breeding holds possibilities for expanding the usefulness of our registered cattle because proved sires of the different breeds must be used in all crosses—at the start and in later coatings—to maintain the high level of production and add hybrid vigor.

Commercial application awaits the demonstration of the hybrid's superior ability. Many commercial milk herds lack facilities for raising their own replacements, and are always in the market for dairy cows and heifers. Cross-breeding fits well into the latest advances that are being made in dairy cattle-breeding practices. Artificial insemination, for example, permits of the expansion of cross-breeding work without the necessity of keeping extra herd sires. Let us assume that a dairyman in a region with good pastures and an abundance of cheap home-grown roughage has followed a practice of selling about 10 or 12 extra heifers each year from a herd of 50 milking animals. This represents the surplus females above his requirements for herd replacements. If he is a member of an artificial-breeding association he can order semen from proved bulls of other breeds than the one he owns to impregnate 20 or 25 cows in his herd, and these crossbred calves will be sold as surplus. When the market appreciates the value of well-bred hybrid heifers, they should bring a premium price and will cost no more to raise than straight-bred heifers.

Hybridizing may also appeal to the man who has spent 10 or 15 years building up a good producing grade herd, only to find that the closed herd book is a bar to his ever having any of his good cows registered. To become a breeder of registered stock he must sacrifice his good grade cows and purchase registered females, even though his herd may have been bred entirely from registered bulls. His surplus cows are sold for dairy purposes and the basis of their value should be their production records. If cross-breeding can raise the level of production of cows in his herd, their value when sold should be increased correspondingly.

THE AUTHOR

M. H. Fohrman, head of the Division of Dairy Breeding, Feeding, and Management of the Bureau of Dairy Industry, has been in charge of the Department's dairy-cattle breeding work at Beltsville since 1921.