FARM AND GARDEN.

King Country Chronicle, Volume V, Issue 333, 1 February 1911, Page 6

FARM AND GARDEN.

THE HORSE BOT-FLY. PREVENTION AND TREATMENT. Many so-called remedies have been placed on the market for the bot-fly, but most authorities are agreed that prevention is better than cure. There is a very general opinion that; no form of drenching or dosing is effective in dislodging the bots. Some proprietary mixtures have on occasion succeeded in expelling bots, and in others the same treatment has proved fatal to the animals, setting up all the symptoms of acute poisoning. We cannot do better than cull from some notes on this pest by Professor Douglas Stewart, M.R.C.V.S., published when he occupied the position of Chief Inspector of Stock in New South Wales. The fiy exists in its perfect state in this country from September to March. The female fly buzzing about the horses during the warmest hours of the day, hovers about for a few seconds over the place where it seeks to deposit its eggs, drops an egg on it, and immediately flies away, but soon returns to lay a .second egg, and repeats the operation so often that hundreds of eggs may be found on the same horse. The eggs are usually deposited under the jaw on the neck, breast, shoulders, and forearms. They are yellowish white in colour, and conical in shape, and about onetwentieth of an inch long. They are transversely striated, and adhere to the hair by the small end, in the same manner as the "nits of the louse." They hatch in a few days, and the larvae escape, while the empty shell remains clinging to the hair. The larvae are vivacious, and begin to craw] on the skin, causing a slight itching, which impels the horse to lick and bite the part. In this way the larvae gain the mouth, and from there pass with the food into the stomach, where they attach themselves by means of ho r klets arranged about their mouthpieces, and subsist on the inflammatory products secreted by the mucous membrane. The bots remain in the horse's stomach for about 10 months, by which time they have reached their maturity. They then detach themselves voluntarily, and, passing along with the alimentary matter, become expelled with the faeces.

As regards the ill effects the larvae may have on the health of their hosts, many divergent opinions exist. Certain authorities have attributed most serious consequences to them, but when we reflect on the extreme frequency of the gastric larvae, the multitude of horses infested with them, and their frequently being present in enormous numbers in the stomach without even being suspected during life, owing to the absence of an apparent disturbance we might be led to believe that they are altogether inoffensive. Still one cannot examine the numerous sores they produce on the interior lining of the stomach without admitting that the functions of that organ must have been interfered with by the excessive irritation that had been going on. Interference with the function of the stomach produces indigestion, which often leads to colic of a fatal kind. Affected horses commonly have a hide-bound, emaciated appearance, notwithstanding the fact that they possess capricious, though irregular, appetites. They sometimes give rise to inflammation, followed by perforation, leading to peritonitis and death.

There are a great many remedies used, many having gained a reputation through being administered at a time when the larvae were naturally leaving their host. The most common and safe remedy is from one to two ounces of turpentine mixed with the white of an egg, and given one to two pints of raw linseed oil on an empty stomach. Though not wholly efficacious, its administration is often followed by the expulsion of a number of bots. Bisulphide of carbon given in half ounce doses in capsules frequently dislodges a number of stomach bots. The following treatment has been reported to have given good results in Mew South Wales: —After starving the animal for at least 24 hours, give one quart of molasses or dissolved sugar in a quarl of milk, and in SO minutes give two ounces of alum dissolved in one quart of water followed in about an hour by a quickacting laxative, such as half a pound of Epsom salts, or two pints of raw linseed oil.

The difficulty of removing' the hot from the stomach of the horse accentuates the necessity of exercising preventive measures in a thorough manner. A piece of rag saturated in some anti fly-strike preparation and suspended from the throat-strain is often of considerable benefit. Jt is necessary to frequently examine the horses running loose on pastures and repeat the dressing as required.