MAINTENANCE THE ENERGY REQUIREMENTS 299 



ration of the horse by subtracting from the total digested 

 nutrients the carbohydrate equivalent of the protein and fat 

 gained by the animal, disregarding the possible stimulating 

 effect of the feed. In this way, they find for the maintenance 

 ration 2955.4 grams total digested nutrients per head, equiva- 

 lent to 11.70 Therms or 12.1 Therms per 1000 pounds live weight, 

 a result notably lower than Wolff's. This difference is ascribed 

 by Zuntz and Hagemann to the larger content of crude fiber in 

 Wolff's rations, the work of digestion of this ingredient as es- 

 timated by them (777) very nearly accounting for the differ- 

 ence. 



c. Muntz's experiments. Muntz 1 in 1878-1879 attempted to 

 determine the maintenance ration of the horse by starting with 

 an insufficient ration and gradually increasing it until an equilib- 

 rium between feed and live weight was secured, seeking in this 

 manner to eliminate the stimulating effect of excess feed (392). 

 The trials were made on the horses of the Paris Omnibus Com- 

 pany, their work ration being known from previous experiments. 

 He found that a ration equal to -f% of the work ration and 

 which may be estimated to contain 12.1 Therms of metaboliz- 

 able energy per 1000 pounds live weight was slightly more than 

 sufficient for maintenance. 



d. Grandeau and LeClerc's results. Grandeau and LeClerc, 2 

 in addition to the experiments mentioned in connection with 

 Wolff's results, fed five cab horses a ration of 8 kgs. of hay 

 during a total of 14 periods of a month each (one to five periods 

 for each animal) during each of which the digestibility of the 

 ration was determined. On the average of all the periods, the 

 results per day and head were as follows : - 



Total digestible nutrients (fat X 2.4) 2783.7 grams 



Equivalent metabolizable energy at 3.96 Cals. per 



gram .' 11.03 Therms 



Daily gain in weight 0.19 kg. 



Average live weight 393.6 kgs. 



The foregoing ration, which was evidently somewhat more 

 than a maintenance ration, is equivalent to 13.1 Therms of 

 metabolizable energy per 1000 pounds live weight. This is 



1 Annales de PInstitut National Agronomique, Tome 3, 1876-1879. 



2 L'alimentation du Cheval de Trait, 1883, in. 



