INBREEDING LIVE STOCK' 



Dr. G. Pusch. 



The author reports experimental work 

 in inbreeding Toggenburg and Erzge- 

 birge native goats, and in inbreeding 

 Friesian milk sheep. In the experi- 

 mental work with goats Pusch used 18 

 females and 9 males, making 42 matings 

 and obtaining 77 offspring. With the 

 sheep he used five ewes and one ram, 

 making five matings and producing 

 nine lambs. 



The system of breeding followed by 

 Pusch with the goats was the mating of 

 a particular female with her sons for 

 several generations, thus greatly in- 

 tensifying the blood line and making 

 the animals very closely related. 



EFFECTS APPARENTLY DYSGENIC 



From two matings of a Toggenburg 

 mother and son two goats were pro- 

 duced that developed very badly and 

 showed chronic dizziness when mature. 

 A mating between daughter and sire 

 produced a kid of low vitality and with 

 chronic dropsy, confirmed by post- 

 mortem examination. 



The effect on the numbers of offspring 

 produced was noticeable with this very 

 close inbreeding. The kids became 

 lighter in weight and also more defec- 

 tive in body development. The addi- 

 tion of the blood of another though still 

 closely related line increased the number 

 of offspring produced, but this increase 

 soon disappeared when the close in- 

 breeding was again practiced. 



He reports one case in the Erzge- 

 birge gray goats in which a female 

 goat was mated with her son producing 

 Bruno 1. Bruno 1 mated with his 

 dam produced Bruno 2, and Bruno 2 

 mated with his dam produced Bruno 3. 

 From the first mating with her son she 

 gave birth to four kids. Of the four 

 progeny produced from this mating, 

 one was smothered while young, one 



was sterile as a male, and the other two 

 were most excellent individuals in 

 every way. The same Erzgebirge was 

 mated four times to a Toggenburg male. 

 Three of the matings produced two kids 

 each, and one mating produced three 

 kids. 



Five matings between brothers and 

 sisters in which five females and three 

 males were used showed most unfavor- 

 able results. From these matings six 

 kids resulted of which one was sound, 

 one epileptic, two bom dead from 

 different mothers, one rickety, and 

 one showed very unsatisfactory de- 

 velopment. 



In all the close inbreeding only one 

 goat did not become pregnant by her 

 son. She was proven to be fertile by 

 the fact that the next year she bore a 

 kid from another male. Her son was 

 likewise fertile with other females. In 

 several cases there was recognized a 

 distinct inclination to osteomalacia 

 (defective mineral metabolism in the 

 bones) in the offspring from close 

 mating, although care was taken to 

 give the animals proper feed and abun- 

 dant opportunity to exercise. 



INBREEDING GIVES POOR RESULTS 



In these experiments brother and 

 sister, sire and daughter, and dam and 

 son matings gave much more unsatis- 

 factory results than cross breeding, line 

 breeding, and moderate inbreeding. 



The work with the goats he sum- 

 marizes as follows: Twelve cross-bred 

 matings gave 26 kids, 25 strong, 1 in- 

 ferior (3.85%). Nine line bred matings , 

 or moderate inbreeding, produced 18 

 kids, 15 satisfactory, 3 inferior (16.67%). 

 Twenty-one very close matings pro- 

 duced 33 kids, 15 satisfactory, 18 in- 

 ferior (54.50%). 



Pusch summarizes his results with 



1 Translated from the German by F. A. Hays, Delaware College Experiment Station, 

 Newark, Delaware. 



