MILK-YIELDING CAPACITY OF COWS. 49 



development of the milking capacity of cows, and mainly to fix the average 

 yearly yield of milk of the different groups of cattle in their native districts. 

 Those kinds of cattle which are recognized as the richest milkers, the black 

 and the gray coloured Dutch breeds of the North German lowland cattle, as 

 well as those breeds, the milk of which is characterized by its extraordinary 

 richness in fat, such as the Channel Islands breeds, the Jersey, the Guernsey, 

 and Alderney, have their homes in districts with a maritime climate of 

 the above-described nature. 



Despite the commonly and emphatically expressed statement that 

 animals yielding a large supply of milk, always yield a milk with little fat 

 and solids, the question may be asked whether the animals and herds in 

 which this fact has been noticed are always fed with a sufficiently rich and 

 nourishing diet sufficient to enable them to attain to the limit of their 

 milking capacity. If this and the author believes that those who have 

 large experience of practical dairying have not a doubt on the subject is 

 not generally the case, we must freely admit that we know very little with 

 regard to the capacity of cows, yielding large quantities of milk, when they 

 are fed in such a way as to enable them to yield up to their full capacity. 

 There is no necessity, from a physiological point of view, for inferring that 

 a large milk capacity is necessarily always united with a low percentage of 

 fat and solids. 



20. Milk-yielding Capacity of Cows. A high milk-yielding capa- 

 city, i.e. the capacity to yield, within a certain time, a large quantity 

 of milk in proportion to live weight, and the secretion of a quantity 

 of milk greatly in excess of what is required for the sustenance of 

 the young, are independent of the form of the skeleton and the form 

 of the body of the mammal. Among the different kinds of ruminant 

 domestic animals, this capacity is most strongly developed in the 

 case of the goat, and least so in the case of the sheep. The power 

 of yielding large quantities of milk is not a natural characteristic of 

 the animals, but has been gradually developed in them, in the course 

 of time, through the influence of treatment by man. This property is 

 connected with hereditary qualities, but it is also, in a very variable 

 degree, an individual quality. Therefore, when special groups or 

 breeds of cattle are spoken of as being rich milkers, this denotes 

 nothing more than that it has been found by experience that rich 

 milking cows are more common in these breeds than in others. The 

 capacity, which has been artificially developed in a herd or breed, for 

 yielding a large quantity of milk, may be very quickly and very 

 largely lost again, if care be not continually taken to maintain the 



(M175) D 



