242 Oattle Problems. 



profitable to breed as large calves as can be raised, by let- 

 ting them take and convert all the milk of the cows, so 

 forming large growth ; for, in nearly all cases, calves can 

 consume all the milk their dams yield, so making large 

 growth instead of small size. 



When inferior cows abort, the best course is to fatten 

 them, unless they are known to bring good calves, as some- 

 times may happen. 



Preventing Abortion. 



We have shown in preceding chapters that the relaxa- 

 tion of the udder-supply arteries results from an over- 

 rapid and excessive increase of blood ; that such rapidity 

 of increase in blood corresponds to increase in yield ; and 

 that very rapid increase in yield is therefore attended with 

 great danger of relaxing the arteries that convey blood to 

 the udder. It has long been a maxim — derived from the 

 experience of successful feeders and dairymen — that 

 changes in feed should never be rapid or great in extent, the 

 sufficient reason being that either increase or reduction of 

 feed causes a similar increase or reduction in the quantity 

 of blood in the circulation, thereby causing correspond- 

 ing changes in the extent of artery blood in steers and store 

 stock; and an increase or reduction in yield corresponding 

 Avith increase or reduction of feed and blood in milk- 

 yielding cows. The point to be especially considered is : 



That when feed is increased very rapidly, the increase 

 of blood is about as rapid ; and that when the arteries 

 are very rapidly engorged with blood, their walls or 

 tunics are liable to be thinned down and relaxed, thereby 

 losing the power to contract, from which loss of con- 

 tractile power abortion results, as explained in chapters 

 on that subject. Moderation, when increasing feed, 

 should therefore always be practiced, as even with store or 

 fattening cattle, rapid increase in feed cloys, and puts 



