162 



not easily secured, and therefore we would particularly recom- 

 mend the use of the formalin dip as the easiest method to employ 

 and one that should give excellent results in practice. 



Anyone directly or indirectly interested in potato growing 

 should make it a point to read this bulletin. It may be had free 

 of cost by the residents of Nebraska on application to the Ne- 

 braska Experiment Station. Lincoln, Nebraska. 



E. A. Burnett, 



Director. 



THE DAIRY COW. 



A cow requires food whether she is milking or not. The 

 amount of food necessary to maintain a dry cow in fair condi- 

 tion, so that she wall neither lose nor gain in w^eight, represents 

 what is called her "maintenance reciuirement." The mainte- 

 nance requirement of healthy cows of similar weight does not 

 vary much. If a cow is milking, however, she must consume and 

 digest food in excess of her maintenance requirement. Other- 

 wise she will lose in weight. The food consumed by a cow yield- 

 ing milk is thus utilized for two different purposes. One part is 

 required for maintenance, and this may be set down as working 

 expenses. The other part is utilized to fill the milk-pail — it is 

 the raw material from which milk is produced. What is a good 

 cow ? It is one which can digest and assimilate for milk produc- 

 tion an amount of food wdiich largely exceeds her maintenance 

 requirement. But cows vary widely in this respect. From the 

 University of Missouri there comes an interesting discussion of 

 this topic in Experimental Station Bulletin No. 2. During two 

 years the herd-testing at the station showed No. 27 cow- to be a 

 good milker, and her half-sister, No. 62, a bad one. They were 

 registered Jerseys. In the third year it was decided to compare 

 the food requirements of these cows, and for this purpose both 

 were calved, as it happened, the same week. During the lacta- 

 tion period the food to each was regulated so that the live- 

 weights remained constant, and the amounts of milk and butter 

 fat were then compared with the amounts of food consumed by 

 each cow. In the re.sults it was found that the good milker was 

 consuming about 2y2 times as much food, after deducting her 

 maintenance requirements, as did the bad cow. and she also ])ro- 

 duced about 2^/2 times as much milk. Altogether, with the good 

 cow, 35 per cent, of the ration went for maintenance and 65 for 

 milk ; with the bad one the figures were 56 and 44. Ten bad 

 cows may yield as much milk as five good ones, but they will 

 require twice as much food for maintenance purposes. As it is 

 onlv the food utilized in excess of maintenance that leaves a 



