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One problem is that the economic value of theproduct of a beef cow is around 25 percent (oreven less) of that of a dairy cow. Nevertheless,in populations in which AI is used, embryotransfer was found to be useful for obtainingmore bulls from top cows. The females pro-duced by embryo transfer would be worth mar-ginally more than females produced conven-tionally, but the costs and influence of malescould spread over the population through theuse of AI. The extent of this use of embryotransfer would be very small; only a few hun-dred bulls would be produced per year for verylarge populations, and over 99 percent of thepopulation would reproduce conventionally.However, such programs could have consider-able economic benefit. Care must be taken tominimize increased inbreeding of the popula-tion with such a breeding scheme.Summary.—●●●AI could substantially improve economical-ly important traits in beef herds. However,because of the diversity of traits consid-ered important by different breed groupsand the lack of a national beef testing andrecording system comparable to NCDHIP,economic estimates of its value have notbeen developed.A sexing technology to produce mostlymales (they grow faster than heifers) couldbe of enormous potential benefit to thebeef industry. However, no successfultechnique yet exists.Estrus cycle regulation could lead to a sub-stantial increase in the number of beef cat-tle in AI programs. The net benefit of thistechnology, coupled with AI, may be ashigh as $50 million per year. Similarly, theavailability of reliable progeny recordswould add to the beneficial impact of AI inbeef and would probably contribute sig-nificantly to its use in beef cattle.OTHER SPECIESSwine.—Much progress has been made inimproving the overall biological efficiency ofpork production in the United States. Improved
188 ●Impacts of Applied Genetics —Micro-Organisms, Plants, and Animalsgrowth rates, feed efficiencies, carcass merit,and litter sizes have helped keep pork pricesdown and improve its quality in the Nation’smarkets. Pork today is leaner and contains morehigh-quality protein calories than it was just afew decades ago.AI in swine production could expand, al-though it will be limited by the relatively poorability of swine sperm to withstand freezingand by the problem of detecting estrus. It willbe encouraged by the strong trend toward con-finement housing and integration of all phasesof hog production. The industry—especially theindividual, family-farm type units—would bene-fit by the establishment of a progeny testingscheme to identify superior boars. Publiclyavailable information on genetic merit woulddecrease dependence on a few corporate breed-ing organizations.