Live-Stock Genetics 



25 



complicate the explanation of its find- 

 ings. 



Crossing Tunisian sheep with native 

 breeds, and with Shropshires, Oxfords, 

 Hampshires and Rambouillets, has been 

 under way for several years at the 

 Arizona station. There are now more 

 than 150 rams bred by the station, 

 from one-half to one-eighth Tunis, in 

 use in Arizona, which means that about 

 10,000 lambs containing Tunis blood 

 are produced each year. They are not 

 only particularly hardy and vigorous, 

 but have proved of great value in eradi- 

 cating Johnson grass (Andropogon hale- 

 pensis) along the irrigating ditches. 



MULE BREEDING. 



The breeding of mules is being studied 

 in Mississippi from almost every possible 

 aspect. Influence of the type, size and 

 quality of sire and dam respectively, on 

 offspring are being watched, the fertility 

 of the mule is being investigated in a 

 search for that apparently more or less 

 mythical "fertile mule" which is re- 

 ported in live-stock publications at 

 constant intervals, along with the equal- 

 ly mysterious "sheep-goat hybrid" for 

 which every breeder has probably 

 sought with interest at some time in his 

 experience. Finally, the relative quali- 

 ties of mules and hinnies are tested and 

 measured. 



The supposed existence of "racial 

 poisons" is being submitted to rigorous 

 scientific test in Wisconsin It has 

 long been admitted that certain poisons 

 — as well as unfavorable conditions — to 

 which a mother is exposed during preg- 

 nancy might injure the offspring, but 

 there has been more doubt as to the 

 effect of similar factors on the father, 

 although it has been widely believed 

 that alcohol and lead poisoning might 

 influence the reproductive capacity of 

 the male. After treating male rabbits 

 with lead and alcohol, Leon J. Cole has 

 compared their offspring with those of 

 normal males. "What appear to be 

 decisive results have already been ob- 

 tained. In the case of alcoholic poison- 

 ing of the male the most marked result 

 has been a lessening of his efficiency as a 

 sire, the alcohol apparently having had 

 some effect on the vitality of his sperma- 



tozoa. The 'leaded' males, on the 

 other hand, have produced as many or 

 more offspring than the normal fathers, 

 but their young have averaged smaller 

 in size and are of lowered vitality, so 

 that larger numbers of them die off 

 at an early age than is the case with 

 those from untreated fathers." Such 

 results, like the earlier ones of Stockard 

 with guinea pigs, must not be inter- 

 preted as meaning that exactly the 

 same thing occurs in man, but strong 

 presumption is at least raised as to the 

 actual existence of "racial poisons," 

 which the eugenist must investigate 

 directly in his human material. 



The inheritance of various characters 

 is being pursued exhaustively in pigeons, 

 particularly with a view to working out 

 the heredity of the small color differences 

 which are so important to fanciers; the 

 physiology of reproduction is also being 

 studied. Tri-coat color in guinea-pigs, 

 one of the favorite subjects for genetic 

 analysis, has been taken up, while the 

 effects of inbreeding are being noted in 

 fowls, and the inheritance of color in 

 Rhode Island Reds is made the partic- 

 ular subject of investigation. Inherit- 

 ance of certain peculiarities in the 

 reactions of rats to definite rations is 

 being investigated, and finally, the 

 inheritance of unit characters in cattle 

 has been attacked in a project that will 

 require many years for completion. 

 Two very distinct breeds, the Jersey and 

 the Angus, are being cross-bred, and in 

 addition to merely superficial points, 

 the behavior of such hereditary char- 

 acters as total milk production, per- 

 centage of fat, size and shape of oil 

 globules, viscosity and other properties 

 of fat, rate of growth and form of 

 animal's body are being watched. 



The Delaware station has for six 

 years been studying the effect of close 

 breeding in pigs, and has now begun the 

 same work with Guernsey cattle. As 

 results in investigation of this subject 

 are slow in appearing, the station can 

 not yet publish any conclusions. 



GRADING UP THE SCRUBS. 



The grading up of a flock of scrub 

 fowls is being carried on in a systematic 

 way at the North Dakota station, by the 



