912 EXPERIMENT STATION RECORD. 



herds in the State, and then to substitute gradually for these rations others consid- 

 ered by the station as better adapted to milk and butter production. 



Twenty-one herds, comprising 277 cows, were fed rations recommended by the 

 station 4 weeks after feeding the original rations, the comparative results showing an 

 average daily increase of 0.25 lb. in yield of milk which, added to 0.85 lb., the esti- 

 mated shrinkage on a uniform ration due to advance in lactation, makes a total gain 

 of 1.10 lbs. The recommended rations contained 0.66 lb. grain and 0.51 lb. protein 

 more than the original rations, but 1,070 calories, 1.47 lbs. of dry roughage, and 3.1 

 lbs. of silage and roots less than the original rations. Taking into consideration the 

 increased yield of milk, a saving in the cost of food, and an increase in the value of 

 the manure, a total daily gain per cow of 2.02 cts. resulted from the change of rations. 



It is not believed by the author that this saving was due solely to the increase, in 

 protein fed, but that part of it was due to an increase in the amount of grain fed. 

 The addition of protein was most effective when the original ration contained less 

 than 1.5 lbs. of protein. The cost of food in the recommended rations was less than 

 that in the original rations owing to the smaller quantities of nutrients fed. Decreas- 

 ing the fuel value of a ration when it was above the standard either did not affect or 

 increased the value of the ration. The food cost of milk was not materially affected 

 by the substitution of rations. 



The results on the whole justify recommendations previously made by the station 

 that more protein than is ordinarily contained in dairy rations may be fed with econ- 

 omy, but that in so doing greater emphasis should be placed upon the increased 

 value of the manure. 



On the protein question, with special reference to the protein minimum of 

 milch cows, M. Hindhede (Ber. K. Yet. Landbohojskoles Lab. Landokon. Forsog. 

 [Copenhagen], 55 {1904), pp. 74-104)- — The author discusses the results of the feed- 

 ing experiments with milch cows at Copenhagen Experiment Station, which have a 

 bearing on the question of the physiological and economic minima of protein in the 

 rations of dairy cows. 



Reference is made to the dietary studies by Atwater and Rubner in regard to the 

 protein requirements of man, and it is shown that the need of protein in the nutri- 

 tion of man is much smaller than has heretofore been assumed, and the same 

 apparently holds true in the case of rations for dairy cows as well. The author con- 

 cludes that protein has no special value for increasing the milk secretion, unless the 

 amount supplied is exceedingly low. While Wolff recommends feeding digestible 

 protein estimated as equivalent to 0.90 lb. per 10 lbs. of milk, the author finds that 

 only one lot out of the 28 in the experiments received as much. 



The lots fed large amounts of protein in their rations received, on the average, 0.44 

 lb., and those fed small amounts received 0.26 lb. of net digestible protein per 10 lbs. 

 of milk. The experiments indicate that the fat of the milk is not formed from the 

 protein of the food, since the protein supplied in the rations may be reduced until 

 there can be no excess available for fat formation, without causing any decrease in 

 the total fat of the milk. Above the physiological minimum protein is valuable, 

 therefore, only for its potential fuel value, and it is, therefore, not advantageous to 

 go far beyond the minimum, although the loss thus incurred is, to a large extent, 

 offset by the increased value of the manure. 



Under certain conditions there may be an economical minimum, below the 

 physiological minimum, and, according to the evidence at hand, no deleterious effect 

 on the future production of the cows will be apparent if less than the physiological 

 minimum is supplied for a considerable period of time. — f. w. woll. 



Records of dairy herds, A. J. Glover (Illinois Sta. Circ. 84, pp. 38, figs. 21). — 

 Records of 10 dairy herds for 2 years are summarized and illustrations are given of 

 many of the cows. The work is a continuation of that published in Bulletin 85 and 

 Circular 77 of the station (E. S. R., 15, p. 292; 16, p. 402). 



