Drenching – giving a medicine or liquid preparation by mouth into the stomach of an animal.Most worm remedies (anthelmintics) are administered by drenching (dosing), as are preparations such as bloat treatments, treatment for diarhhoea and constipation and other medicines. Incorrect drenching can cause inhalation pneumonia, which is difficult to treat and can prove fatal. It is essential that the owner always follows manufacturers’ directions when administering any treatment by mouth. Always use the correct dose for the age and size of the horse. If a horse is weak or undernourished smaller doses should be used. Some horses will tolerate being drenched with a syringe and if so this method should be used. (See opposite.) This is a suitable method of giving oral medication and worm remedies. The syringe is pushed up against the side of the horse’s mouth, avoiding the teeth and the plunger slowly depressed to allow the liquid into the mouth. Many horses will not allow drenching with a syringe or bottle and in these cases a stomach tube will have to be used. This is a skilled procedure requiring expertise and should never be undertaken by inexperienced personnel. Usually the procedure will be done by a veterinarian. The stomach tube is a 3m long stiff, smooth tube with a 10-20cm outside diameter. The front end is rounded and a funnel is inserted for poring liquids at the back end. The tube is softer and more flexible than that used for cattle. Unlike with cattle, in horses the tube in inserted through the nasal cavity. Method The nostril (usually the left) is cleaned and a twitch applied to the upper lip. The point of the tube is inserted into the nostril. With the right forefinger and thumb the tube is held down on the floor of the nasal passage, while gently pushing the tube in with the right hand. The tube will travel through the nasal cavity for about 25cm before reaching the larynx and oesophagus. When the tube reaches the larynx the horse will swallow. By gently pushing the tube at exactly the same moment as swallowing it will pass through the pharynx into the oesphagus, another 7-100mm. If the horse does not make the reflex swallowing motion when the tube touches the larynx, it should be gently moved up and down against the larynx until the horse swallows. When the tube is pushed in it can be seen on the left side of the neck moving down the gullet in the groove just above the windpipe. If the horse coughs or chokes, or if the tube moves easily with no obstruction, it may have entered the windpipe by mistake. The tube should be gently withdrawn into the mouth and the procedure started again. Once the tube has reached the stomach, the end should be raised to a level above the horse’s throat and the liquid poured into the funnel. When all the liquid has drained into the stomach, the funnel end should be lowered to below the horse’s throat and the tube slowly withdrawn. There may be some bleeding from the nostril but this should be minimal and transitory and stop soon after the tube is removed.                REF:    Handbook of Stock Diseases; Monnig and Veldman    www.equidblog.com