ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 99 



are high in temperature, there will be black particles in the 

 butter fat, so you do not get a clear reading. 



A Member: How often do you think a cow ought to be 

 tested in order to give a good idea of what she is worth.'^ 



Prof. Eraser: I think the best way is to make a week's 

 test, taking a sample of both morning's and night's milk every 

 time, putting it into a jar and then taking this composite sample 

 at the end of the week. It depends on how close he wants to 

 know what his cows are doing and also upon how much the 

 cows are varying. Take the first month after the cow calves, 

 you cannot tell so much by her test, she is liable to be up and 

 down more. Some cows' very first milk will test high. We 

 had a cow come in about five days ago, and she tested nearly 

 five per cent. She usually runs about three or four. That is 

 exceptionally high. For the first month they will usually be 

 low, so that if you are only going to make one or two tests, it 

 will be better to wait until a month or two along in the period 

 of lactation and then take a week's test. Then I do not think 

 it is necessary to test again until they are changed considerably 

 in 'the flow, when they run down again. Two or three times 

 during the period of lactation will give you a very good idea of 

 what the cow is doing, tests taken for a week. 



A Member: What chemical do you use in taking the com- 

 posite test.'^ 



Prof. Eraser. Potassium of bichromate. You can get it at 

 any drug store, but that is a rank poison and you want to be 

 careful. All preservatives are poison. The reason that it. is rec- 

 ommended is because it colors the milk, makes it a decided 

 yellow and there isn't so much danger of accidents. If you 

 want to get at what your cow is doing, take morning's and night's 

 milk together and test them for one day. 



A Member: Can cows be fed so that milk gets richer.? 



Prof. Eraser: No, not to a very great extent, if the cow is 

 already getting a fairly good amount of good nutritious feed. 

 Of course if she is sparingly fed it might be changed, but the 

 amount of fat in the milk, that is, the per cent, of fat, it is 

 pretty hard to change by feed. 



