Diseases of the Feet and Limbs 179 



the female, thus throwing increased weight upon his hind 

 limbs. Obviously any attempt at copulation aggravates the 

 local disease. The male should, therefore, be held out of 

 breeding until he has recovered. Sometimes it is wished 

 to breed a female suffering from some local, non-genital 

 disease which renders copulation difficult or dangerous for 

 her because of the weight of the male which she is called 

 upon to bear. Partial relief from the excessive weight may 

 be secured in cows and mares by using a breeding rack so 

 constructed that the female stands between two broad, 

 sloping shelves of such height that, when the male mounts 

 her, his fore feet rest upon the shelves and his weight is 

 more or less completely borne by these. The shelves must 

 fit closely against the sides of the female, in order to ob- 

 viate the danger of the male's getting his foot between the 

 shelf and the female, and should slope downward from the 

 head of the female. The breeding rack does more than 

 partly or wholly support the weight of the male. When it 

 fits closely and a beam is placed securely in front of her 

 sternum, her equilibrium is maintained and she can sup- 

 port without increased danger probably twice the weight of 

 which she would be capable otherwise. This is especially 

 true of the violent copulatory thrust of the bull. Not in- 

 frequently, when a cow is weakened and unsteady, or when 

 a small heifer is mounted by a large bull, the thrust causes 

 the cow or heifer to crumple up and fall headlong. 



It is unwise to breed a crippled or weak female unless it 

 can be reasonably determined that the patient will promptly 

 recover from the local disease. Otherwise, as soon as the 

 increased weight of pregnancy has to be borne by the weak 

 member, a new peril is encountered in the aggravation of 

 the disease. Pregnancy may occur and parturition may be 

 safely passed, but the progeny is rarely well nourished or 

 valuable. 



F. Paralysis and Plumbism 



Paralysis sufficient to interfere with copulation may oc- 

 cur in any animal, and from a great variety of causes. In 



