290 THE COMPLETE GRAZIER. BOOK ir. 



cow appears to possess a tolerably uniform composition, but the whole 

 of the fat is rarely obtained in the milking. 



Though much locomotion is detrimental to the yield of milk, it is a 

 mistake to suppose that uninterrupted confinement in the stall is the 

 most economical treatment for a milch cow. With moderate locomo- 

 tory exercise the slight reduction in quantity of milk appears to be fully 

 compensated for by the increased yields of solids. Munk, 1 to settle 

 this point, experimented with thirty cows, and found that when they 

 were allowed half an hour's daily exercise, the total quantity of the 

 milk as well as the fat and casein increased, though much exercise 

 exerted an adverse influence on the yield. When cows are on grass, 

 their increased appetite in the presence of abundance of food quite 

 makes up for any loss incurred in the movements necessary to obtain 

 that food. Hence it is desirable that stall-fed milch cows should have 

 daily exercise. 



It is, in a sense, due to a mere physiological accident that the fat 

 elaborated in the organs of a milch cow is excreted rather than stored 

 up in the system. And the metabolic activity of the secreting cells of 

 the mammary gland is closely connected with the exercise of the 

 maternal functions. We are utterly in the dark, says Dr. M. Foster, 

 as to why the uterus, after remaining apparently perfectly quiescent for 

 months, is suddenly thrown into action, and within, it may be a few 

 hours, gets rid of the burden it has borne with such tolerance for so 

 long a time. After birth, the maternal energy, previously occupied in 

 nourishing the foetus, is now directed to the secretion of milk, whereby 

 the nourishment of the offspring may still be maintained. 



Though it may be physiologically possible for a cow to give a copious 

 flow of milk, and simultaneously to undergo a marked increase in 

 weight, nevertheless, these two effects are generally in an inverse ratio 

 to each other. Thus, it is a characteristic of individual cows, and in 

 some cases of entire breeds, as the Herefords, the Galloways, and the 

 Aberdeen Polls, to lay on flesh rather than to make milk. Of the causes 

 which determine such idiosyncrasies little or nothing is known, just as 

 little or nothing is known as to why the same food, given freely to a 

 wether and to a steer, should be converted into mutton in the one case, 

 and into beef in the other. It is the duty of the breeder to discover 

 these and other idiosyncrasies, and to endeavour to perpetuate them, if 

 they appear to be desirable. In an insufficiently fed or starving animal, 

 the first demand the system makes is on the fat stored up within it, so 

 that a starving ox feeds as much on animal matter as does a lion. 

 Similarly, in a milch cow, the first effect of insufficiency of food is the 

 falling off in the amount of fat secreted by the mammary gland. Nor 

 can this secretion become at all marked in quantity till all the other 

 physiological requirements of the body have been first attended to. 

 This was very well exemplified in the case of a two-and-a-half year old 

 Southdown ewe experimented upon by Weiske. 2 The ewe lambed on 

 April 22, and was regularly milked three times daily, receiving at the 



1 "Bieder. Centr.," 1884. 

 -' "Bieder. Centr.," 1880. 



