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United States Department of Agriculture
Abstract
The four regional animal research laboratories are: The Regional Animal Disease Laboratory at Auburn, Alabama; the Regional Poultry Research Laboratory at East Lansing, Michigan; the Regional Swine Breeding Laboratory with headquarters at Ames, Iowa; and the Western Sheep Breeding Laboratory at Dubois, Idaho. The major objectives of all these research units include the discovery of new scientific facts and the application of known principles of science to the control of animal diseases and parasites and the breeding improvement of farm livestock.
Since their organization seven years ago progress has been steady and significant. This progress is measured in three ways: The creation of physical plant facilities and animal material to permit the conduct of productive research projects; the improvement in cooperative relationships among research workers in the regions; and a long list of tangible research results in each field of endeavor. Only progress of the latter type will be reviewed here.
The Regional Animal Disease Laboratory program has been confined largely to studies on Johne's disease, coccidiosis, and internal parasites of cattle. In the work on Johne's disease an important advance has been made in discovering methods to produce allergins of greatly increased potency. Using these biologies as diagnostic agents it has been learned by survey that a large percentage of the herds tested in a given area contain reactors. Three distinct types of infection were observed—characterized by emaciation and diarrhea terminating fatally, some loss in weight and occasional diarrhea with occasional fatal termination and positive pathological evidence of the disease but no clinical manifestation. Sensitization by the causative organism caused allergic response to mammalian tuberculosis in about 30 per cent of the cases, a point of considerable importance in connection with tuberculosis eradication programs.
The studies on coccidiosis have identified the species existent in the region, determined the time required for sporulation and developed procedures for diagnosis and estimating degree of infection. Coccidia are present in practically every herd in the area. A method of controlling clinical coccidiosis has been developed and is being put into practice.
The work on internal parasites has shown: What species are prevalent and which are most harmful to cattle in the southern States; that cattle tend to throw off an infection with common stomach worm at the same time developing marked resistance to further infection; and established the efficacy of phenothiazine for gastrointestinal roundworms. A mixture of salt and phenothiazine kept before grazing cattle is not an effective preventative against infection with these parasites.
The program of the Regional Research Laboratory for the Improvement of Viability in Poultry has been confined to a study of lymphomatosis in its various forms. Quarantine measures have been developed which are effective in keeping out common diseases and parasites but are not effective against lymphomatosis. Evidence has been obtained that the egg is an important factor in the transmission of the disease. It has been possible to develop free but susceptible stock through selection of families free of any clinical manifestations of the disease and the use of rigid pen quarantine measures under conditions of complete isolation. Also susceptible and resistant lines have been developed by breeding from stock on the basis of incidence of lymphomatosis. Studies on the causative agent have been limited by the slowness with which lymphomatosis develops. A related strain of the causative agent has been located which has a shorter incubation period and gives a greater uniformity of reaction than material from lymphomatosis birds. The relationship of this tumor to lymphomatosis is now being studied.
The Regional Swine Breeding Laboratory has made very satisfactory progress on systems of breeding, measures for use in selection, the inheritance of characters and physiology of reproduction. In general some decline in fertility, survival and growth rates accompanies inbreeding but critical selection can prevent some of this. For growth rate, selection can offset the effect of inbreeding up to 15 percent per generation but fertility cannot be maintained without loss if the inbreeding is more than 4 percent per generation. It has been shown that purebred hogs can be inbred 3 to 4 percent per generation until about 30 percent is reached without much loss in productive characters if selection is critical. Individuals and lines this much inbred differ in many important physiological respects not discernible to the eye. Hybrid vigor can be expected from crossing lines within a breed if the lines are inbred 30 to 40 percent and are from unrelated foundations. The advantage shown is 
more pigs per litter at birth, 1 
more pigs per litter at 5 months of age and 30 pounds more live weight per pig at 5 months than the parent lines. Improvement of lines may be increased by using indexes based on number of pigs farrowed, weight and number of pigs at weaning, rate of growth to 5 or 6 months of age and a score for market desirability. The determination that variations in productivity of sows are 15 to 18 percent and variations in rate of growth to market weight are approximately hereditary is important in connection with selection of breeding stock. Maximum rate of progress with respect to traits 
to heritable will be made when at least of the boar pigs are grown out to 5 or 6 months of age before final selections are made. If to of the gilts are needed for breeding at least 
of all gilts should be retained until 5 to 6 months of age.
The program of the Western Sheep Breeding Laboratory is coordinated with that of the U. S. Sheep Experiment Station and the progress to date includes certain accumulations of result material from previous efforts. Thirty lines of Rambouillet sheep are being purified for useful qualities by the use of inbreeding and critical selection. In general, the procedures being followed are similar to those used in the Regional Swine Breeding Laboratory. The speed of inbreeding is much slower with sheep than swine for practical reasons and the lines have not reached a degree of inbreeding yet which merits crossing of lines. It has been demonstrated, however, that the crossing of inbred lines of sheep results in measurable improvement. Progress is being made in breeding away from wool blindness. Open faced ewes at the laboratory produced about 9 pounds more lamb than the wool-blind ewes. Also it has been demonstrated that neck and body folds and wrinkles in Rambouillet sheep are useless monstrosities. Very significant progress has been made in their elimination from the laboratory sheep. As in the swine laboratory it is important to determine the heritability of the characters having economic value. For sheep the laboratory has determined that clean fleece weight has a heritability of 38 percent and fleece length 36 percent. Studies on small sample shrinkage have shown that this technique has a workable accuracy and holds great possibilities for field use in connection with shrinkage appraisals. In the studies on shrinkage involving 38,000 pounds of the 1943 laboratory clip, it was demonstrated that former commercial shrinkage appraisals have been too high.
Progress in large animal experimentation is inevitably slow, hence only a beginning has been made at the various laboratories in the few years since they were established. Physical plants are established and animal material is available. Improvement in cooperative relationships between institutions and workers and the output of tangible research results should continue to expand in the future.
1 This is one of three papers on cooperative animal research and regional laboratories, presented before the opening session of the annual meeting of the American Society of Animal Production, December 1, 1944. Only an abstract of this paper is presented, owing to the fact that most of the results cited have been published in detail in technical papers by workers at the various laboratories.
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