1012 



EXPERIMENT STATION RECORD. 



"It appears that there was upon an average 7.2 per cent more fat 

 recovered in the milk than was digested in the food fed." 



The total and digestible fat were calculated from average figures for 

 composition and digestibility of the feeding stuffs used. It is calculated 

 that had the percentage of digestible fat in the concentrated food been 

 0.38 per cent higher "it would have been sufficient to meet all the 

 demands upon the animals for the fat produced in the milk and the 

 increase in live weight of the animals during the trial." 



The results for 1893 of the test of breeds at the station are next cited. 

 It is shown that 23 cows in their first period of lactation, 18 in their 

 second, and 10 in their third consumed the following amounts of food 

 nutrients and produced the following amounts of fat in milk: 



Food nutrients eaten and fat produced in milk. 



Num- 

 ber 

 of 



cows. 



Period of lactation. 



Nutrients eaten. 



Albumi- 

 noids. 



Caiboby- 

 drates. 



Crude fat. 



' Pure ' 



fat. 



Fat pro- 

 duced 

 in milk. 



First 



Second 



Tliird 



Total 

 Ratio 



Pound*. 



22,911.20 



14,063.10 



6, 733. 60 



Pounds. 



113,388.10 



68, 023. 70 



30,961.70 



Pounds. 

 9,958.90 

 6, 454. 70 

 3, 160. 50 



Pounds. 

 8, 226. 10 

 5, 331. 60 

 2, 615. 50 



Pounds. 

 6, 810. 20 

 4, 363. 20 

 2, 272. 00 



43, 707. 90 

 3.25 



212, 556. 50 

 15.81 



19, 580. 10 

 1.46 



16, 173. 20 

 1.20 



13. 445. 40 

 1.00 



"There was during these three periods an average increase of 161 lbs., or a 



total of 3,134 lbs. in the live weight of the animals under experiment, and if we 



assume the estimate of 8.7 per cent as the amount of fat represented in this gain it 



. will amount to 272.7 lbs., which, added to the fat of the milk, will give 13,718.1 lbs. 



as the fat produced by these animals. 



"If now we allow the crude fat of the food to contain 17.4 per cent of impurities, 

 there would remain 82.6 per cent, or 16,173.2 lbs. of pure fat in the food eaten by 

 these animals, or 18 per cent more fat than was produced by them in their milk or 

 increase in weight. This will present a loss of 15.3 per cent of the pure fat through 

 lack of digestibility, a loss greater than appears to exist in many experiments 

 made. . . . 



"It would seem that until strong proof shall be submitted that the fat of milk is 

 derived from other constituents of the food its source at present must be held as the 

 fat present in the food of the animal. 



"It is proposed to make other experiments the coming season to clear up this 

 point, if possible." 



Effect of fat on the utilization of the albuminoids of the food, R. 

 Laas [Ztschr. physiol. Ghem., 20, ifo. 3, pp. 233-218). — In 2 experiments 

 dogs were fed on horse fiesh freed from fat as far as possible, a quantity 

 of fat being added to this in a second period. The results are believed 

 to warrant the conclusion that the utilization of the albuminoids of the 

 food is increased by the addition of fat — i. e., more nitrogen was stored 

 in the body on a constant ration of nitrogen when fat was added. 

 Accompanying this no diminution in the decomposition process in the 

 intestines could be detected. In this respect the action of fat is unlike 

 that of carbohydrates, which have been found to materially decrease 

 the splitting up of the albuminoids in the intestines. 



