30 Experiment Station Bulletin 367 



Under these assumptions, time patterns were made up for the follow- 

 ing combinations of men and machines: 



1 man and 2 single units 



1 man and 1 double unit 



2 men and 3 single units 

 2 men and 2 double units 

 2 men and 4 single units 



The time patterns indicated that one man with two single units or 

 one double unit could milk 20 cows in approximately 42 minutes which 

 is 2.1 man minutes per cow. These time patterns were then checked on 

 selected farms where previous milking records were good. Several of 

 the operators approached the pattern in total time. For instance, one 

 man milked 18 cows in 37.5 man minutes and another milked 25 cows in 

 62 minutes. The first is at the rate of 2.1 man minutes per cow and the 

 second 2.5 man minutes. 



When the details of these actual milking records are placed on charts 

 and compared with the time pattern, the possibility of improvement in 

 timing the practices and in milking more efficiently is apparent. For in- 

 stance, the operator with one double unit followed a definite pattern in 

 milking but prepared the cows too far in advance. The other man with 

 two single units had several problem cows in the middle of the line and 

 the extra time required on them unbalanced the sequence and timing of 

 practices. He prepared some of the cows too far in advance and time 

 was lost because practices did not fit together. 



The charts showing detail milking records indicate the importance 

 of following a time sequence. The study indicates that individual dairy- 

 men who cull out problem cows, develop the essential skill in rapid milk- 

 ing, and adjust their practices to proper timing, can approach the goal 

 of tw r o man minutes per cow. 



H. C. Woodworth, K. S. Morrow, J. C. Holmes 



Studies on Bovine Mastitis 



Studies Mere continued on the treatment of bovine mastitis with pen- 

 icillin. One hundred and forty-one cows with streptococcal mastitis were 

 treated in 285 quarters with one, two, or three injections of penicillin. 

 The penicillin was administered via the teat canal in 50 ml. or 100 ml. of 

 sterile water or saline in doses of 20,000, 50,000, 75,000, 100,000, or 200,- 

 000 units per injection. Cows were considered cured when no mastitis 

 streptococci could be detected in the milk samples by bacteriological 

 tests at least one month after treatment. 



One injection of 100,000 units of penicillin per quarter cured 64 per 

 cent of the cows and 72 per cent of the quarters treated. One injection 

 of 200,000 units cured 86 per cent of the cows and 84 per cent of the 

 quarters treated. Two injections of 50,000 or 75,000 units at intervals of 

 24 hours were no more effective than one injection of 100,000 units. 

 Three injections of 20,000 or 75,000 units at 24-hour intervals produced 

 the highest percentage of cures, 92 per cent of the cows and 95 per cent 

 of the quarters being freed from infection by this procedure. 



