126 MILK 



according to the demands of the individual cow and thus insure 

 maximum production. 



A cow producing rich milk requires a larger supply of good food 

 with a larger proportion of protein than one producing a poor 

 grade of milk. At the end of the lactation period, when the sohds 

 of milk are relatively high, still more food is required than at 

 other times. Furthermore, young cows require more food than 

 older ones, because the requirement for growth exists. 



Woll and Humphrey have estabhshed the rule that each cow 

 should receive as many pounds of grain per day as she produces 

 pounds of butter-fat per week, or one-fourth to one-third as much 

 grain as she gives pounds of milk daily. In addition, she should 

 have as much roughage as she will eat up clean, preferably suc- 

 culent food, as grass, silage crops, and roots. 



The flavor of milk is influenced to a marked degree by the food. 

 Grazing on pastures in spring and summer produces a desirable 

 flavor and color of butter unless strongly flavored vegetation is 

 present. Objectionable flavors are produced by a number of 

 vegetables, such as cabbage, turnips, wild onions, spoiled silage, 

 rape, etc. 



The effect of water in the ration on the composition of milk 

 has recently been studied by Turner, Shaw, Norton, and Wright. 

 The authors sum up the results of their work in the statement "that 

 the watery character of the ration has no effect upon the fat 

 content of the milk," and they state further that there was no 

 variation observable in the milk constituents, and that rations of 

 varying water content have no effect upon the composition of the 

 milk. 



6. Influence of Weather and Temperature on Milk. — It has 

 been mentioned that there are seasonal variations in the com- 

 position and quantity of milk produced. Van Slyke and Pub- 

 low have stated that the greatest production of- milk and fat 

 commences about the middle of May and continues for several 

 months. Eckles and Shaw, on the other hand, seem to think that 

 milk produced in the fall and early winter has a higher percentage 

 of fat than milk produced in early spring and summer. Yslu Slyke 

 and Publow cite in support of their opinion not only their own anal- 

 yses in New York State, but claim that reports of the Vermont 

 and Wisconsin Experiment Stations are in harmony with their 

 own. Possibly climatic conditions have some bearing on this 

 point. 



White and Judkins believe that fat and plasma solids are lower 

 in summer than in winter and that the plasma solids decline at a 

 greater rate than the fat. "The general direction of both the fat 

 and sohds-not-fat tests for the winter calving cows is up, down, 



