MILK 219 



vious that if only cows with large yields were entered on the list, 

 at the end of the year the herd would show a higher average than 

 the truth would warrant. For this reason, and in hope of obtaining 

 commercial advantages from such high records, some dairymen have 

 preferred not to have the whole herd tested; but it is a rule of the 

 cow-testing association to obtain records of every animal in the herd 

 which has had one calf, and no records are published where such is 

 not the case. 



The cow tester takes part in the feeding of the cows, and while 

 doing so he weighs the amount of roughage and grain each cow re- 

 ceives and records these data in a book which he carries with him at 

 all times. The milk yielded by each cow is weighed and samples of 

 it are obtained for testing. Records of the feed and the yield for 

 each individual are again obtained and recorded the next morning, 

 and after breakfast the fat determination is made. During the fore- 

 noon the calculations are made and entered in the record book, which 

 at all times remains in the possession of the farmer. 



The milking is done at the usual milking time, in order that 

 the average yield may be obtained as accurately as possible. In case 

 of competition between the herds, there may be a tendency to milk 

 early in the morning on the day the tester is expected to arrive. In 

 this way the yield for the testing day might be somewhat increased. 

 To guard against this it is customary in some associations for the 

 cow tester not to follow a regular route, so that it will be impossible 

 for the dairyman to know the exact day on which to expect him. 



In weighing the milk a shotgun can a can 8 inches in diame- 

 ter and 20 inches high is used. It holds 35 pounds and has straight 

 sides, with a handle near the bottom so that it may be easily emptied. 

 The empty can should weigh even pounds so that mistakes in sub- 

 traction may be avoided. It has straight sides so that accurate samples 

 may be obtained by the use of an instrument known as a milk thief, 

 as with an ordinary milk pail with a flaring top an accurate sample 

 might not always be obtained, owing to the greater area of the milk 

 at the surface than at the bottom. If the herd is large it is desirable 

 to have two of these cans with straight sides so that the milker may 

 pour the milk into them and proceed to milk the next cow without 

 waiting for the tester to weigh and sample the milk. In this way 

 time is saved in the stable. 



For weighing the milk a special spring balance is used, weigh- 

 ing to 30 pounds and having two indicators, one of which is adjust- 

 able and should be set at zero when the weigh can is on the scales. 

 The balance is graduated in tenths of pounds and is frequently tested 

 so that any stretching of the spring may be immediately detected. 

 The milk is poured from pail to pail two or three times and the 

 sample for testing is taken immediately after such pouring is com- 

 pleted. 



The fat determinations are invariably made at the farm. The 

 reason for this is the difficulty in transporting the samples to the 

 creamer}'- without leakage, churning of the milk in hot weather, 

 etc., any of which renders correct determination difficult. Another 



