FACTORS IXFLUENCIXG MILK PRODUCTION 303 



or the Guernsey and lack the deep yellow color of the latter. 

 Whether one breed is more profitable than another largely 

 depends upon the individual animals, the amount of milk 

 produced, and its cost of production. 



The influence of age on milk production has been care- 

 fully studied by various investigators. On this subject 

 Eckles states* that "a dairy cow, on the average, as a two- 

 year-old may be expected to produce about 70 per cent; as 

 a three-year-old around 80 per cent; and as a four-year-old 

 about 90 per cent of the milk and butter-fat she will pro- 

 duce under the same treatment when mature." As a rule, 

 we expect a cow to be at her best from six to eight years of 

 age, but there are remarkable records that have been made 

 by cows well along in years. The Jersey cow Pogis Irene 

 2nd, at 18 years of age produced 9,930 pounds of milk, which 

 would be an excellent record for a .Jersey in her prime. 



The influence of the period of lactation on milk produc- 

 tion is of interest. Under normal conditions a cow should 

 be milked about ten months, go dry two, and produce a 

 vigorous, healthy calf. The natural tendency is for the cow 

 of dairy type to keep up her milk flow fairly well for the 

 first seven months, after which it gradually declines. Prof. 

 F. W. Woll made a study of the production of some 300 

 cows in the Wisconsin Dairy Cow Competition, 1909-1911, 

 and he reportsf that "the normal decrease in the flow of 

 milk in well managed dairy herds is about 5 per cent a month 

 during the second to seventh month of the lactation period, 

 about 10 to 12 per cent during the eighth and ninth months, 

 and 20 per cent for the tenth and subsequent months." 



The relationship of condition of the cow to the quality 

 of her milk is very marked. If the cow is in good flesh, she 

 will yield more and richer milk than if in thin flesh. It is 

 a well recognized fact to-day, that dairy cows fattened and 

 in high condition when they come fresh, produce a milk 



*Dairy Cattle and Milk Production, 1911. 

 ■ fProductive Feeding of Farm Animals, 1915. 



