Treatment of Bots in Horses. 633 



TREATMENT OF BOTS IN HORSES. 



By A. A. Broii-n, M.B., B.8. 



Bots, which are larval stages in the development of the bot fly 

 {Gasterophilus equi) , inhabit the stomach of the horse. The stomach 

 of the horse is divided into two parts. The left half is covered with 

 a lining which is a prolongation of the lining of the gullet, and is pale 

 in color, and does not secrete gastric juice. The right half is lined 

 with a reddish velvety membrane, and secretes the gastric juice. 

 The bots reside in the left half of the organ, and they remain there 

 during the greater part of autumn and the whole of winter. 



Bots present several phases in their development. 



(l.'i In the first stage the eggs are found adhering to the hairs of 

 the horse. The eggs are usually deposited by the tly on those parts of 

 the body of the animal readily accessible to his tongue, and on licking 

 his skin he removes the eggs and introduces them into his stomach. 



(2.) The egg undergoes the next stage of its development in the 

 stomach, and attains the grub or bot state. In this stage it maintains 

 its existence in the stomach. 



(3.) About the beginning of spring the bots spontaneously leave 

 the horse's stomach to undergo the third or pupa stage in the 

 ground. 



(4.) The fourth stage is the winged insect stage (botfly). The 

 adult flies prevail during summer and early autumn. 



As regards treatment, preventive measures are of paramount 

 importance, and should, as far as practicable, be carried out in those 

 districts in which bot flies extensively prevail. It is during the 

 summer and early autumn that the bot fly is seen hovering 

 about horses, always on the alert to dart down upon its victims and 

 deposit its eggs. The female has an arrangement (ovipositor) which 

 is a tubular prolongation of its body, by means of which it can 

 readily attach the eggs to the hairs of the horse by a glutinous sub- 

 stance which is secreted at the time of the deposition of eggs. Bot 

 flies make swift darts down upon horses and probably deliver a blow, 

 but they do not sting. At those seasons when bot flies prevail those 

 parts of the horse that he can reach with his tongue should, if 

 practicable, be examined, and if eggs are observed adhering to the 

 hairs they should be washed oft" with a 5 per cent, solution of caustic 

 potash. The alkaline solution dissolves the glutinous substance that 

 binds the eggs to the hairs. 



During the summer aiid early autumn, as a preventive for bots, 

 horses should be kept closely clipped and a 5 per cent, solution of 

 valei"ianate of soda in any crude paraffin oil should be rubbed over 

 those parts of the body accessible to the tongue. Besides valerianate 

 of soda, other substances, such as the fluid extract of asafoetida. 



