Nasal bots menace in sheep and goats

A MAJOR problem confronting sheep and goat farmers all over the world is the menace of nasal bots. These are the larval forms of sheep nasal fly, namely Oustrus ovis''. These are non-biting flies found in all places whereever sheep and goats are kept. They are brown in colour and are a centimeter long and covered with short hairs. They are active during day time. The female flies deposits its larvae around the nostrils of the animals. On sensing the flies the animals become restless.

The larvae are white in colour and crawl into the nasal passages attach themselves to the inner lining by their oral hooks. They irritate the mucosa which results in copious secretion of mucous on which they feed. After growth, they pass on to frontal sinuses and develop into the next stage larvae. There they turn dark brown in colour and measure about 3 cm. Then they crawl back to the nasal passage and are expelled out when the animals sneeze. The larvae burrow into the soil and pupate. Flies come out in a months time. The entire life cycle is completed in six months and at times even nine months depending on climatic conditions.

Rarely, the larvae move to abnormal locations and cause erosion of some skull bones. Similarly, they may get into the brain in which case, animals show in coordination and high stepping gait. It is for this reason that this condition is also known as ``false gid'' in them. At times, these flies deposit their larvae on the eyes and mouths of people who take care of these animals. They migrate into near by tissues and cause discomfort.

When there are one or two larvae, they may pass out unnoticed with mild symptoms. Symptoms are dependent on the number of these larvae present in their nasal cavities. The common symptoms are sneezing, cough and jerky movements of heads. Animals become dull and do not feed well. There is a marked in decrease growth rate in young and in the adult the body weight is decreased. In moderate and heavy infestations animals may deteriorate in and die.

Several drugs are available in for curing this crease. Treatment should be repeated at six month intervals for nasal bots. When there are liver flukes and ruminal flukes and intestinal strongyles rafoxanide is preferred. Nitroxynil can also be given.Medication of nasal passages for prevention or for curative treatment is not practicable and also endangers them. Flies can be killed by various trapping devices like peromone traps or other. Frequent white washing of sheds, with lime is helpful in controlling the past.

K. James Christopher

Lam farm, Guntur-522034. A.P.

Send this article to Friends by E-Mail

Section  : Science & Tech
Previous : Ideal for juice and coloured wine
Next     : New route to the Net