SURGERY AND OBSTETRICS 359 



difficulty in farrowing. The characteristics, particularly of the lard 

 type of hog, are such that the space for a gravid uterus is encroached 

 upon and the channel through which the pig must be expelled during 

 farrowing is proportionally smaller than in the original hog. These 

 conditions are responsible for the difSculties of farrowing that are 

 so commonly encountered by the general practitioner. The practi- 

 tioners in hog-raising sections are finding that swine obstetrics re- 

 quires patience, care and skill if favorable results are obtained. 



AGE OF PUBERTY AND ESTRUM 



The appearance of puberty takes place at slightly different periods 

 in different breeds. Puberty is indicated by the appearance of es- 

 trum or heat. During this time the mucous membrane of the vulva 

 and vagina becomes congested and there is a gelatinous discharge 

 from the vulva. Sows in the period of estrum are restless and con- 

 stantly moving about, apparently seeking the opposite sex. The 

 estrual period usually persists for from twelve to forty-eight hours. 



The period of heat sometimes fails to occur in gilts and in sows 

 that have aborted. The cause of this condition in gilts may be due to 

 inbreeding, excessive fat, lack of sufficient exercise or diseases of the 

 genital organs. If the defect be due to overfeeding or lack of exer- 

 cise it can usually be overcome by diminishing the feed and making 

 the conditions such that abundant exercise will be taken. It is diffi- 

 cult to overcome this condition when it is caused by inbreeding or dis- 

 eases of the genital organs. It is advisable to administer such agents 

 as yohimbin and strychnin in some form in the feed to those cases 

 in which the individual is a good breeding type. Yohimbin may be 

 obtained in the form of an elixir or in tablet form. The dose of the 

 elixir is from one to two drams twice daily; each tablet as usually 

 prepared contains a single dose and one tablet should be given three 

 times daily. The strychnin may be given in the form of the elixir of 

 iron, quinin and strychnin, using one to two drams twice daily in 

 slop or as nux vomica, using one to two drams twice daily, in the 

 slop. 



The failure of the occurrence of estrum due to previous abortion 

 may be corrected by overcoming the diseased condition of the vagina 

 and uterus, which is described in detail under the topic of retained 

 placenta. 



