1004 



EXPEEIMENT STATION RECORD. 



0.12 11). of ether extract, dry, barren cows made an average daily gain of 0.23 lb. 

 Thededuction is made that a ration of 11.5 lbs. of dry matter containingO.6 lb. of digesti- 

 ble protein, 6 lbs of carbohydrates, and 0.1 11). of ether extract is sufficient for main- 

 tenance of dry, barren cows at rest in stall. It is tentatively suggested that for cows 

 at work in a dairy with ordinary good care and comfortable quarters the following 

 allowance of digestible nutrients per 1,000 lbs. live weight be made for maintenance: 

 Protein 0.7 11)., carbohydrates 7 lbs., and ether extract 0.1 lb., which is somewhat 

 lower than the Wolff standard. 



Nutrient requirements (pp. 98-112). — The experiments reported in Bulletin 71 of the 

 station (E. S. R., 13, p. 683) and di-scussed witli reference to jirotein requirements 

 are here discussed with reference to the other nutrients as well. It is believed that the 

 Lehmann factors for milk production prescribe more nutrients than are needed, 

 that the quality of milk is quite as important a factor as the quantity of milk in form- 

 ulating a feeding standard, and that heifers require more nutrients per pound of milk 

 yielded than do mature cows. Tables are given which show the calculated nutrients 

 in excess of that required for maintenance as given above used by mature cows and 

 by heifers in the production of 1 \h. of milk testing a given percentage of fat, and the 

 use of the tables is explained. .Some of the figures are given in the following table: 



Nutrients required hij mature rous (tnd lit/ heifers for the -producAion of one i>ound of milk. 



Fat content of milk: 

 2.5 per cent 



3 per cent 



3.5 per cent 



4 per cent 



4.5 per cent 



5 per cent 



5.5 per cent 



6 per cent 



Ether 

 extract. 



Pound. 

 0. 0127 

 . 0148 

 .0170 

 .0192 

 .0213 

 .02:35 

 .0256 

 .0278 



Protein requireuieutx (pp. 113-127). — In a feeding experiment from November 11, 

 1901, to February 17, 1902, the following grain i-ations were fed to different lots of 6 

 cows each: (1) Equal parts of corn, bran, and gluten meal; (2) four parts each of 

 corn and l)raii and one part of gluten meal; and (3) equal parts of corn, barley, and 

 oats. The nutritive ratios were, resi)ectively, 1 :6.3, 1 :7.7, and 1 :9.7. Data for 8 con- 

 secutive weeks are given, from which the following conclusions in substance are 

 drawn: "Rations having a nutritive ratio of 1:7.7 and 1:9.7, respectively, were as 

 effective in the i)roduction of milk, butter fat, and milk solids as was the one having 

 a nutritive ratio of 1:6.3. The protein required in milk production depends upon 

 the quantity and quality of milk yielded. In the production of butter fat actually 

 more but relatively less protein and other nutrients were required to a pound of butter 

 fat with cows giving milk containing a high pev cent of fat than with those giving 

 milk containing a low per cent of fat. In the production of milk solids less nutrients 

 were required to a pound with cows giving milk having a low per cent of butter fat 

 than with cows giving milk having a higher jier cent of fat." 



Influence of stage of lactation on nutrient requirements (pp. 128-148). — Data are given 

 showing the live weight, nutrients consumed, and milk, fat, and solids produced by 

 each of 8 cows at different stages of lactation. Averages are also given for 15 cows 

 during the first 9 weeks of lactation. The author makes the following deductions 

 from the data presented: 



" (1) During the early stages of the period of lactation cows lose rapidly in body 

 weight — of 15 cows the average decrease per cow the first week was 49 lbs. — and dur- 

 ing 56 days there was a daily average loss per cow of 2 lbs. 



