854 Popular Editions of Station Bulletins of the 



halves as the cows freshened in 1908-9 and to milk each cow bj 

 hand and machine in alternate periods of lactation. In this di- 

 vision the herd was balanced as carefully as possible with regard 

 to age and productive ability; and in subsequent changes due to 

 the dropping out of cows by reason of age, accident, illness, 

 sterility, etc., and the addition of others to maintain the herd, the 

 same idea of preserving the balance has been kept in mind. 



The w^ork has now been carried through the lactation periods 

 for 1910-11. In all, 29 cows have been compared during two or 

 more lactation periods, including five periods each for five cows, 

 four periods each for three cows, three periods each for nine cows 

 and two periods each for twelve cows, making 88 complete lac- 

 tation periods. During 43 of these periods the cow was milked by 

 hand and during 45 by machine. Taking the data just as they 

 stand and comparing the yields when any cow was milked by the 

 two methods during successive periods, it would appear that 32 

 such comparisons favor hand milking and 23 favor machine milk- 

 ing. But it is hardly fair to include all the data. In the several 

 years through which the tests ran, the yields of several of the 

 cows were abnormal for at least one lactation period, owing to 

 mishaps of one kind or another. Six young cows calved prema- 

 turely and three suffered so severely from indigestion that their 

 yields were seriously affected. Leaving out these abnormal lacta- 

 tion periods there remain 24 comparisons in favor of hand milking 

 and 19 favoring the machine. These figures apparently indicate 

 a s'light gain in production in favor of hand milking; but, as will 

 be shown later, the actual mathematical differences in yield are 

 so slight, considering the two groups as a whole, that the omission 

 of a very few cows whose yield showed great fluctuation would 

 shift the balance in either direction. 



As shown in Table I, which includes all the data unaffected by 

 noticeable disturbing factors, -the final balance in favor of hand 

 milking is only 6,000 lbs., merely the slightest fraction over 1 

 per ct. of the total production. 



In making the table several of the cows were included that were 

 milked more periods by one method than by the other, which 

 might be considered unfair; so in Table II the comparison is 

 restricted to an equal number of lactation periods for each cow 

 bv each method. 



