Proved-sire breeding stands now as a demonstrated method of uninterrupted improvement in the producing ability of dairy cattle, and the measure of this development in the females in the Beltsville herd is a clue to the value of the males produced under this system of breeding when they are used as herd sires. Their inheritance is the same as that of the females, and this is borne out by the results which have come in from herds that have used such young bulls in cooperation with the station where they were bred.

The part of the breeding program carried on with cooperating dairymen and herds at several institutions has yielded a large amount of data in the course of proving the young bulls from our various station herds. This now furnishes abundant proof that these young sires carry the same quality of germ plasm as their half sisters that are developed and tested in our own herds.

Of the 332 proved bulls, 264 sired daughters that averaged better than their dams. This is nearly 80 percent of the bulls, compared to about 48 percent proved in Dairy Herd Improvement Association herds. The 4,619 daughters of these bulls produced an average of 690 pounds more milk and 30 pounds more butterfat than their dams. Proved-sire breeding has thus demonstrated its value as a means of breeding young bulls capable of raising production levels in most dairymen's herds.

The supply of good dairy sires has always been limited. The policy of raising and selling only a part of the young bulls dropped in most herds has further restricted the number. The result is a price level out of reach of many dairymen who need better bulls. These factors no doubt have had a part in holding down the national level of milk production. Good germ Plasm is wasted also by keeping meritorious bulls in service in single herds.

To alleviate this situation and provide service by good sires on a wider basis, there has been a tremendous development during the past 6 years in the organization and development of artificial-breeding associations. The idea first took hold in New Jersey and has now spread to most of the dairy States. The type of organization varies from the small local unit Owning its own bulls, to the central bull stud plan, where the bulls are located in one place and semen is drawn and processed for distribution to the inseminators in a large number of local units. It has been particularly helpful to the owner of a small herd, as his breeding fees for artificial insemination total less than the cost of keeping a herd sire. It also relieved him of the problem of purchasing a new and satisfactory bull every 2 or 3 years, and in most cases it has made available to him service from bulls of better quality than he could afford to buy.

Starting with a few thousand cows a year impregnated by this method, the total quickly climbed to about half a million, and at the rate of expansion anticipated by some associations, a million cows a year will soon be bred artificially. Single bulls have sired thousands of calves, and most astonishing of all is the number of females inseminated from the diluted semen had in one ejaculate. During the busy breeding season, 150 cows bred from a single service is not uncommon.

Production figures compiled by the New York Artificial Breeders' Cooperative, Inc., at Ithaca, N. Y., tell a story well worth considering. Twenty-seven of the sires used in that cooperative now have one or more daughters in milk from dams which also had production records. The report lists a total of 178 daughters sired by these bulls with average production of 11,984 pounds of milk and 442 pounds of butterfat. The dams of these daughters produced 11,656 pounds of milk and 418 pounds of butterfat, a net increase of 328 pounds of milk and 24 pounds of butterfat. The sample is small compared to the vast number of cows bred, but it is a fair criterion of what has happened in all herds whose owners were fortunate enough to have had the use of these bulls. It is also a splendid testimonial to the judgment of the committee responsible for selecting sires. An estimated 80,000 cows were bred in the cooperative in 1946 40,000 heifer calves born in a single year with an inheritance to produce 24 pounds more butterfat annually than their dams is bound to lift average production. Then, too, sons of those proved bulls will join lesser herds, there to spread their good qualities.

Similar encouraging results are reported from New Jersey and Maine; altogether, there is much to anticipate from artificial insemination. A note of caution : The men who pick out the bulls should not be pushed too hard by desires to expand operations to the extent that they feel obliged to lower their standards of selection.

More testing is required to furnish a broader foundation for constructive breeding. Membership in Dairy Herd Improvement Associations is still only a small percentage of those who own dairy cows. Herd improvement testing has grown in scope, but still only a small part of the herds of registered cattle have an over-all testing program. Sixteen thousand bulls have been proved in association herds since bull proving was started, but fewer than half of them had daughters with average production better than their dams; of the bulls that proved to be desirable, only a small number were still alive when the proof came in.

Keeping bulls until the proof is in is an important part of cow testing. Artificial breeding associations are always on the lookout for good proved sires, and the quality of the sires holds the key to expansion and development of the associations. It would be well to consider offering more pay in order to get testers who measure up to the demands for adequate cow-testing work. This includes the job of sending in the records for proving bulls and setting up the records in the owners' herds so that they tell the story of his own breeding progress.

Better methods of selling young bulls likewise are worth consideration. In Michigan a plan was inaugurated of pricing young bulls in herds of Dairy Herd Improvement Association members so that value was established at an early age and the bulls could be sold before the cost of feeding made them too expensive for small dairymen. Owners of registered stock might well give thought to the plan, in order that more good bulls can be raised and sold for breeding.