484 



IOWA ACADEMY OF SCIENCE Vol. XXV, 1918 



weight. These animals were of 75 per cent the same breeding, be- 

 ing sired 'by Rouge of Ames, 24405, a son of Rouge II 's Son, 

 while their dams were sired by Roiiue II 's Son, 18587. From 

 birth until the start of the digestion trial these heifers received 

 the same care and feed. Both were pregnant and in fair condi- 

 tion at the beginning of the experiment, and though No. 298 was 

 rather larger than No. 301, they were a very uniform pair in all 

 other ways. 



TABLE VII— ANIMALS USED IN TRIAL. 



Age 



Days Bred . 



Weight, lbs. 



Herd No. 298 



1 yr. 6 mo. 17 da. 

 63 

 650 



Herd No. 301 



1 yr. 5 mo. 27 da. 

 152 

 550 



Average 



1 yr. 



6 mo. 



108 



600 



The digestion trial was run for a period of five days preceded 

 by a preliminary period of seven days during which Sudan grass 

 was fed as the only source of nutriment to the heifers. In the 

 preliminary period it was found that 20 pounds per head per 

 day of the hay would be a convenient amount to feed, so this al- 

 lowance was used throughout the experiment and the material 

 left was weighed back daily. 



It has been found that the animals had no special need of be- 

 ing watered twice daily so the watering was done at the begin- 

 ning of each twenty-four hour period and the animals were 

 weighed before and after watering. The attendant collected the 

 feces with a scoop and deposited them in tarred galvanized iron 

 vessels which were provided with covers, 



A composite sample of the bay fed and one of tlie orts were 

 made at the end of the trial period. The feces from each heifei- 

 were mixed thoroughly and sampled at the end of each twentv- 

 four-hour period and these samples air-dried. At the end of the 

 trial an aliquot composite sample was made for the fece? pro- 

 duced by each of the heifers during the five-day trial period. 



The composite samples of feces, together with those of hay and 

 orts were chemieally examined according to the official methods. 



In Table VIII is given a summary of the hay and water con- 

 sumed and the feces produced daily by each jf the heifers. Only 

 the net consumption of hay is given and the feces production re- 

 corded opposite a daily consumption of hay is the weight of feces 



