The Lactation Period 37 



normal wild or semi -wild cow would be likely to pro- 

 duce in a year. Numerous cows have lived that have 

 produced more than ten times this amount, or 24,000 

 pounds of milk in a year, the largest amount on record 

 being 30, 318 J pounds of milk given by the Holstein 

 cow, Pietertje 2d, in 1888. 



Factors in the production of milk. The chief fac- 

 tors on which the production of milk depends are: 

 (1) Maternity, or the period of lactation; (2) the 

 inherent capacity of the cow, which in general is 

 largely determined by her breed and hereditary char- 

 acteristics, but always to a greater or less extent inde- 

 pendent of them; (3) the amount and character of 

 the food supply. 



The lactation period. As has already been stated, 

 the domesticated cow has been developed so that the 

 production of milk is practically continuous. Never- 

 theless, pregnancy and parturition play a very impor- 

 tant part in the production of milk. While cows 

 may, and often do, secrete milk continuously for two, 

 three or four years without producing a calf, on the 

 other hand, the birth of a calf serves to stimulate 

 the secretion of milk to such an extent that prac- 

 tically all dairymen are agreed that milk is produced 

 under the most favorable conditions when the cow 

 produces a calf at regular intervals each year, and 

 this regardless of the value of the calf when born. 

 It is also found that a period of rest before par- 

 turition is essential to the largest production of milk 

 after the calf is born; that is to say, the cow will 

 secrete more milk in a year if she goes dry for two 



