10 BULLETIN 045, U. S. DEPARTMENT OF AGRICULTURE. 



case of grade Guernseys. In a period of 30 days soon after calving, 

 these animals gave 1,009 pounds of milk on the average. Their rec- 

 ords may be compared with those of the other grade Guernseys of the 

 herd, selecting lactation periods later than the first and in which there 

 was no suspicion of abortion or other disturbing disease, and using 

 the best month's milk yield in each lactation period as the figure to 

 be compared with that given above. There are 4 animals with a total 

 of 8 lactation periods available for the comparison, and the average 

 best month's milk in the 8 lactation periods was 660 pounds. As the 

 grade Guernseys available for this comparison were rather few, the 

 same calculation was made for the grade Jerseys. There are 16 ani- 

 mals with 52 lactation periods available in this case. The average 

 best month's milk is 722 pounds. The grade Holsteins are not suffi- 

 ciently numerous to give figures of any value. 



No cow among the grade Jerseys and Guernseys of the general 

 herd has ever surpassed the 30-day record of cow 71. In only one 

 case has the average 30-day record given for cows 49, 54, 71, and 81 

 after the phosphate feeding, been surpassed, namely, with a best 

 month's milk yield of 1,041 pounds given by one of the grade Jerseys. 

 In only five cases has the lowest 30-day record among these four cows 

 been surpassed, namely, by best month's milk yields of 1,041, 988, 987, 

 1,004, and 943 pounds, respectively. 



The results show, therefore, that the cows of the general herd at 

 Beltsville suffered from an insufficiency of either calcium or phos- 

 phorus, or both, in their rations throughout their lives, both before 

 their first calves were born and afterwards. The following shows a 

 little more in detail than' has been done heretofore how they were fed. 



The young stock generally received milk until the animals were 

 six months old or more. The feeding of grain, hay, and silage, how- 

 ever, was started before the end of the first month and gradually 

 increasing quantities of these feeds were given until at the end of six 

 months the calves were taking 3 pounds of grain, 3 pounds of legume 

 hay, and 10 to 20 pounds of corn silage. After they were taken off 

 milk the calves were usually fed 3 pounds of grain, 3 pounds of 

 legume hay, and as much corn silage as they would clean up. The 

 grain mixture most used was grain mixture E. If they ate 25 pounds 

 of corn silage daily, which may be taken as a fair average, this ration 

 would supply 0.94 pound digestible protein daily and 8.16 pounds total 

 digestible nutriment. This is approximately the protein requirement 

 given in the Wolff-Lehmann feeding standards for growing dairy 

 cattle and somewhat more than the requirement for total nutri- 

 ment (10). 



