38 



MAINE AGRICULTURAL EXPERIMENT STATION. 



Climatic conditions as heat and cold have a marked effect on 

 some animals. A sudden drop in the temperature will some- 

 times cause a cow to shrink enough in milk flow to obliter- 

 ate any difference in yield that might be produced by the food 

 she is eating. Anything that causes nervous excitement may 

 cause a temporary shrinkage in milk flow. A change of milk- 

 ers, which one is sometimes obliged to make during an experi- 

 ment, may cause difference enough in the milk yield to spoil 

 the experiment. To eliminate some of these sources of error, 

 the experimenter employs as many animals as practicable and 

 takes careful note of all the conditions under which the experi- 

 ment is made. 



For the experiments wmich are given in the following pages, 

 six registered Maine State Jerseys, known by the numbers I, 2 > 

 3, 4, 5 and 6, were used. Their ages ranged from 5 to 8 years, 

 except Nos. 5 and 6, which were 3 and 4 years old respectively. 

 All were fresh in milk and in good condition. Their milk flow 

 was not quite up to their average for the reason that they were 

 recently purchased, and transportation caused a shrinkage from 

 which they did not recover. 



In the experiments conducted with these animals they were 

 divided into two groups or lots of three each, making it possible 

 to feed the two rations to be compared through each period, 

 thereby avoiding, to some extent, the errors caused by changes 

 in temperature, advance in the period of lactation, etc. 



In calculating the digestible nutrients in the foods used, the 

 American coefficients were employed, except for corn meal, for 

 which the German coefficients were used. 



DIGESTION COEFFICENTS USED. 

























it' 

















- 



* 



7-C 6 



Hay 



Silage 



Corn meal 



Gluten meal 



Cotton-seed ineal. 

 Bran 



53 



25 



63 



57 



73 



70 



92 



92 



91 



88 



64 



97 



6S 



72 



