58 W. Hart WIG 



however, where exterior circumstances are not controlled 

 directly by man (for instance, diseases, epidemics, inferior 

 constitution and its consequences, all influence the lifespan of 

 animals). Here we get approximate real values of the life- 

 span, man and animals in their struggle with nature being 

 exposed to these influences everywhere. 



The major task in cattle breeding and veterinary science is 

 to analyse the struggle against the various factors which 

 shorten the age of productive animals and contribute to their 

 premature culling. In the following discussion of the age of 

 cattle and horses first of all the average age of living animals 

 and then the recorded average age of herd-book animals of 

 various species will be given. Finally the most important 

 reasons influencing the premature culling of animals will be 

 considered. The lifespan of cattle has been examined in detail 

 in recent years, but there are still only a few results regarding 

 horses. This fact is easily comprehensible because cattle 

 breeding is of great economic importance in many countries, 

 while the importance of the horse has diminished considerably 

 as a result of increased mechanization. 



Milch cows 



The research listed in Table I covers about 25 years, from 

 1932 to 1957. It will be noted that cattle of highland breeds 

 show a longer lifespan, 1-1 • 7 years on an average, than low- 

 land cattle. It is not possible to explain clearly how far this 

 difference is based on breed-conditioned, genetic factors and 

 how far it may be attributed to climatic circumstances, 

 quality of soil or economic reasons. The average lifespan of 

 the different breeds is between 4-7 and 9-35 years and the 

 general average age is 7-1 years. Three years may be sub- 

 tracted for breeding and the productive period therefore 

 amounts to 1-7 to 6-3 years. It is a fact proved by many 

 authors that the productivity of the animals rises according 

 to the number of lactations after the fifth to the seventh calf; 



