302 DOMESTIC ANIMALS, DAIRYING, ETC. 



that a moderate proportion of the more nitrogenous concentrates 

 .seems to aid in securing the consumption of heavy rations. Kellner 

 recommends that at least 1 pound of digestible protein be supplied 

 in the ration for each 8 to 10 pounds of carbohydrates and fat to 

 each animal. 



Requirements for Milk Production. Of all forms of animal 

 production that of milk is perhaps the most variable and most in- 

 fluenced in its amount by the feed supply. The energy relations of 

 milk production have not been very fully investigated. Tentatively, 

 however, it seems safe to estimate that the production of 1 pound of 

 average milk, containing about 13 per cent of total solids and 4 per 

 cent of fat, will require approximately 0.3 therm of production value 

 in the feed. Naturally this amount would vary with the quality of 

 the milk, milk rich in fat and in total solids requiring more than 

 milk containing more water or a lower percentage of fat. This state- 

 ment is based upon the best authority. 



The matter of the protein requirements for milk production 

 has not been altogether cleared up. It seems to have been pretty 

 well demonstrated that, for a time at least, milk production may be 

 kept up on a supply of protein very slightly exceeding that found in 

 the milk produced (of course, in addition to the maintenance re- 

 quirement) . In the case of average milk, this would call for about 

 0.032 pound of digestible protein for each pound of milk. It has 

 not been demonstrated, however, that a cow can keep this up in- 

 definitely. Furthermore, for the production of liberal yields of 

 milk more protein seems to be required, or at least to be advantage- 

 ous. No definite statement can be made at present as to how large 

 an excess is necessary. For the ordinary commercial dairyman, how- 

 ever, it is believed that an allowance of 0.05 pound of digestible 

 protein per pound of milk will prove ample. 



Requirements for Work. Since the horse (or mule) is the 

 usual working animal in the United States, consideration will be 

 limited to this animal. There is on record a considerable amount 

 of data as to the relation between the work performed by the horse 

 and the amount of energy necessary to be supplied in the feed. 

 Where large numbers of horses are kept and the work is relatively 

 uniform in amount, it is possible to make fairly satisfactory compu- 

 tations from these data, although the method is somewhat compli- 

 cated. The amount of w r ork required of farm horses, however, is so 

 varied in amount and kind and so difficult of measurement or esti- 

 mate as regards amount, that it is scarcely practicable to base the 

 calculations of rations upon it. The large table herein probably 

 shows with at least a fair degree of accuracy the relative values of 

 different feeding stuffs as sources of energy for work production, 

 while the amount to be fed will ordinarily be based upon the obser- 

 vation of the feeder rather than upon arithmetical calculations. As 

 a sort of general average, however, Kellner recommends the follow- 

 ing rations for a 1,000-pound horse, the amounts stated including 

 the maintenance requirement: 



