Lippincott: Poultry, and Pure Breeding 



79 



juvenile expression of the barring fac- 

 tor, as found in Barred Plymouth Rock 

 chicks. 



The principal interest in this case is 

 the fact that a standard red and sup- 

 posedly pure bred family should carry 

 factors normal to other breeds, and 

 without being suspected. How these 

 factors found their way into the germ 

 plasm is a matter of conjecture. It 

 would appear unlikely that they should 

 have been introduced through any of 

 the known ancestors of the breed, but 

 the history of the formation of the 

 Wyandotte breed appears to be some- 

 what hazy, and this is a possibility. 



There is also the possibility, perhaps 



the probability, that cross breeding has 

 occurred at some time. The fact that 

 some individuals of this family, and all 

 of the few individuals of other families 

 that have been mated in a similar man- 

 ner, have not exhibited factors for these 

 foreign characters, seem to favor the 

 latter view. A cross with White Plym- 

 outh Rocks at some time in the past 

 might account for both the single combs 

 and the barring, since the latter variety 

 is single combed recessive white and 

 carries barring as a cryptomere. The 

 "hlue" factor appears to be more fre- 

 quent in occurrence in this family than 

 the barring factor. How or when it 

 was introduced one can only guess. 



Butter Fat vs. Body Fat 



In 1906 a test of soiling crops was 

 made involving the entire dairy herd of 

 The Pennsylvania State College. The 

 crops tested were rye, wheat, alfalfa, 

 timothy and clover, oats, oats and peas, 

 and corn. Among the points tmder ob- 

 servation were the effects of these vari- 

 ous crops on the live weight of the 

 cows, quantity of milk produced, and 

 its fat content. The test involved 

 thirty-one cows and extended from 

 May 17 to August 28. Not all the cows 

 were on test during the entire time, 

 so the total number of observations 

 was 173. 



When curves were plotted showing 

 the mean live weight and the mean fat 

 content for the various periods it was 

 found that "A gain in live weight is 

 in every instance accompanied by a de- 

 crease in the per cent of butter fat, 

 and a falling off in live weight in every 

 case but one accompanied by a gain 

 in the per cent of butter-fat. 



Including the records of 1902 and 

 1904 with those of 1906. the only years 

 when similar observations were made, 

 it was found that "When the cows 

 gained in live weight their milk fell off 



in richness and vice versa one hundred 

 and fifty-three times out of two hundred 

 and nineteen or almost exactly 70% of 

 the cases." 



At that time no attempt was made to 

 work out the correlation. This has since 

 been worked out and the correlation co- 

 efficient between increase or decrease 

 in live weight and increase or decrease 

 in fat content of milk for the 173 meas- 

 urements of 1906 found to be .47 with 

 a probable error of .039. The values in 

 live weight were taken by 10-pound 

 units and ranged from — 40 to 40. The 

 values in fat content were taken by 5% 

 units and ranged from — 2 to 2. 



While the popular belief has been 

 that cows placing fat on their bodies 

 put less in the pail actual data to con- 

 firm it have been comparatively 

 meager. The influence of feed upon 

 fat content of milk has been pretty 

 generally denied, but this test would 

 indicate that some feeds tend to pro- 

 duce body fat while others either di- 

 rectly or indirectly increase the secretion 

 of milk fat.— T. I. Mairs, State Col- 

 lege, Pa. 



