872 EXPERIMENT STATION RECORD. 



stripplngs were obtained covered but .1 inontb or two during the entire lacta- 

 tion." In a few cases the amount of stripijinjis was considerable. In one case 

 there were 7!X).2 lbs. of strippings from one cow during Bio days. The machine 

 was unable to draw the nulk satisfactorily from another cow Ix'caiise of a 

 peculiar shaped udder. The cost of repairs and supplies of the nulking-machine 

 equiiiment and o nulkers for 2 years was $SS.97. 



The effect of alternate hand and machine milking was tried with 2 cows, 

 but the results were not satisfactory. " When machine milking and hand 

 milking are carried on irregularly and interchangeably the machine will not 

 draw all the milk and in consequence more strippings are obtained. It is 

 very evident that we can not make a comparison between two methods of milk- 

 ing by alternating these methods." In the case of hard milkers the sphincter 

 muscle at the end of each teat was treated with a dilator until the milk could 

 easily be drawn by hand, yet the machine was unal)le to remove the milk. The 

 teat cups and mouthpieces need to be changed as the lactation period advances. 



An average of 6 milkings required 67 minutes to milk 20 cows, producing 

 157.7 lbs. of milk, 29.5 of which was removed in the strippings, which required 

 24 minutes. In this case three machines were operated by one man. In 

 another test 12 cows were milked in 92 minutes with one milker. The quantity 

 of milk did not materially influence the time required in milking. 



The liacterial content of milk drawn by hand was compared with that drawn 

 by machine. "The aA"erage count in the case of the .'5 samples of machine- 

 drawn milk shows 37,090 bacteria per cubic centimeter of milk, while in the 

 hand-drawn milk there are but 3,310 in each cubic centimeter." When the 

 machine parts were thoroughly washed, scrubbed, and steamed for 20 minutes 

 each morning and at night rinsed in three waters and submerged in limewater 

 the bacterial content was slightly less in the machine-drawn milk than in the 

 hand-drawn milk. 



" The relief filters attached to the milkers when neglected are a continua'l 

 source of contamination. Air rushes in through these openings to relieve the 

 A'acuum caused by each pulsation of the machine and unless protected each 

 inflow of air will carry bacteria with it. This is especially true of the connector 

 relief filters which are suspended but a few inches above the floor while the 

 machine is in operation. During the time of the experiments cited here absorb- 

 ent cotton was placed in each relief just before milking. The use of these wads 

 of cotton checks contamination from this source entirely, as they stop and hold 

 all bacteria. 



" For soaking the tubing, lime has been used in every trial on account of its 

 antiseptic pi'operties and convenience. Other agents, such as formaldehyde, 

 would have undoubtedly given better results as their germicidal properties 

 would aid greatly in reducing the number of bacteria, but the use of a substance 

 of this nature is questionable if not dangerous and could not be recommended 

 for general use. The limewater used for this bath should be renewed every 

 4 or 5 days. If the antiseptic is to be of any benefit in preserving the rubber 

 and in retarding bacterial growth it must come in contact with every part of 

 the tubing. . . . 



" Heifers in their first lactation apparently give better results by machine 

 milking than do aged cows that have been accustomed to hand milking for one 

 or more years. 



" Some cows are not adapted to machine milking. 



" Manii)ulation of the udder is absolutely necessary in some instances before 

 all the milk can be drawn by the machine. 



" Two men operating 4 machines can practically do the work of 3 men milking 

 by hand. 



