276 



THE BREEDING OF ANIMALS 



from these results, that early pregnancy and lactation 

 does retard the growth of the young mother. 



RETARDATION OP GROWTH DUE TO PREMATURE 

 BREEDING 



Measurements taken at maturity 66 months of age 



In the above table the measurements of the same 

 animals at full maturity are shown. At the time these 

 measurements were taken the parents were about five-and- 

 one-half years of age. The sow that was mated at the be- 

 ginning of puberty and bred regularly thereafter, produc- 

 ing sixty-nine pigs in nine litters, was smaller at maturity 

 than either of the other groups which were mated at an 

 older age. This result has been secured in a number of 

 similar cases. In other words, the breeding of sows at a 

 young age not only results in a temporary check to their 

 development, but tends permanently to decrease the size. 

 This permanent decrease is not very marked and practi- 

 cally may not be of great importance. It is clear from the 



1 Has produced 9 litters and a total of 69 pigs. 



2 Has produced 6 litters and a total of 49 pigs. 



3 Has produced 5 litters and a total of 32 pigs. 



