C C*ROWTHKR AND H. E. WoODMAN 



55 



Table VII. 

 Condensed summary for Cow C between the days 608 and 722. 



Daily ration: 21-5 lb. seeds hay + 1 lb. linseed cake. 



Analytical Total N Total N Nett change 



days consumed retained of weight 



lb. 

 + 13f 

 + 107 



94 



546 



Total N 

 consumed 



gm. 

 14,039 

 81,015 



gm. 

 + 472 

 + 1005 



Days from 

 calving 



1 



2 

 3 



4 

 5 

 6 



7 • 



8 



9 



10 



11 

 12-14* 

 15-17 

 22-24 

 25-28 

 29-31 

 32-35 

 36-38 

 43-45 

 46-49 

 50-52 



Daily 

 yield 



lb. 

 3-62 

 8-75 

 20-09 

 28-87 

 25-56 

 27-91 

 28-56 

 28-93 

 29-71 

 29-19 

 29-87 

 29-56 

 28-25 

 26-79 

 26-85 

 27-36 

 27-21 

 27-35 

 26-72 

 26-75 

 26-14 



Table VIII. Mtll- records of Cow D. 



N 



/o 

 3-110 

 2-210 

 1-097 

 0-807 

 0-657 

 0-628 

 0-631 

 0-596 

 0-582 

 0-578 

 0-552 

 0-525 

 0-531 

 0-507 

 0-494 

 0-472 

 0-477 

 0-490 

 0-479 

 0-498 

 0-498 



N in 

 milk 



gm. 

 .51-07 

 87-73 

 KMXKI 

 105-711 

 76-17 

 79-52 

 81-74 

 78-22 

 78-44 

 76-.52 

 74-80 

 70-40 

 68-07 

 61-63 

 60-20 

 58-57 

 58-88 

 60-80 

 5813 

 00-45 

 59-07 



Days from 

 calving 



53- 56 



57- 59 



64- 66 



67- 70 



71- 73 



79- 81 



82- 84 



85- 87 



88- 91 



92- 94 



99-101 



102-105 



106-108 



1U9-112 



113-115 



120-122 



123-126 



127-129 



130-133 



1.34-136 



Daily 

 yield 



lb. 

 26-34 

 25-75 

 24-80 

 24-95 

 25-77 

 23-25 

 22-70 

 22-49 

 22-27 

 22-32 

 21-62 

 22-50 

 20-92 

 22-44 

 21-66 

 19-37 

 19-50 

 18-,59 

 19-28 

 18-. 54 



N 



% 

 0-499 

 0-497 

 0-485 

 0-511 

 0-510 

 0-509 

 0-511 

 0-534 

 0-523 

 0-529 

 0-555 

 0-547 

 0-5.56 

 0-545 

 0-552 

 0-570 

 0-558 

 0-569 

 0-549 

 0-575 



N in 

 milk 



gin. 

 59-58 

 56-75 

 54-57 

 57-83 

 59-63 

 53-70 

 52-40 

 54-50 

 53-87 

 53-57 

 54-40 

 .55-85 

 .52-73 

 55-50 

 ,54-17 

 .50-07 

 49-35 

 48-00 

 48-03 

 48-37 



From analysis of composite milk samples. 



SUMMARY. 



This communication deals with the results of two experiments in 

 which the "nitrogen-balance," or difference betweezi nitrogen-consump- 

 tion and nitrogen-excretion by the cow, has been studied over prolonged 

 periods, starting with the "dry" cow, not in calf, proceeding through the 

 whole period of pregnancy and well into the period of active lactation. 



Experiment 1 was performed throughout with the two cows, " dry "' 

 and not in calf, receiving a basal ration of hay to which was added in- 

 creasing amounts of maize meal with a view to securing a progressively 

 increasing consumption of nitrogen. This experiment lasted 196 days, 

 during which period determinations of the nitrogen- balance were made 

 on 90 days. 



Experiment 2 was carried out similarly with two cows, and covered 

 a period of 722 days, including 546 days on which determinations of the 

 nitrogen-balance were made. Throughout the whole of this period one 



