Diseases of the sheep

Sheep may fall victim to poisons, infectious diseases, and physical injuries. There are some obvious signs of ill health, with sick sheep eating little, vocalizing excessively, and being generally listless. In the XXth and XXIst centuries, a minority of sheep owners have turned to alternative treatments such as homeopathy, herbalism and even traditional Chinese medicine to treat sheep veterinary problems. The need for traditional anti-parasite drugs and antibiotics is widespread, and is the main impediment to certified organic farming with sheep.

Many breeders take a variety of preventative measures to warn off problems. The first is to ensure that all sheep are healthy when purchased. Many buyers avoid outlets known to be clearing houses for animals culled from healthy flocks as either sick or simply inferior. This can also mean maintaining a closed flock, and quarantining new sheep for a month. Two fundamental preventative programs are maintaining good nutrition and reducing stress in the sheep. Handling sheep in loud, erratic ways causes them to produce cortisol, a stress hormone. This can lead to a weakened immune system, thus making sheep far more vulnerable to disease. Signs of stress in sheep include: excessive panting, teeth grinding, restless movement, wool eating, and wood chewing. Avoiding poisoning is also important, common poisons are pesticide sprays, inorganic fertilizer, motor oil, as well as radiator coolant(the ethylene glycol antifreeze is sweet-tasting)

Common forms of preventive medication for sheep are vaccinations and treatments for parasites. Both external and internal parasites are the most preva- lent malady in sheep, and are either fatal, or reduce the productivity of flocks. Wormsare the most common internal parasites. They are ingested during graz- ing, incubatewithin the sheep, and are expelled through the digestive system. Oral anti-parasitic medicines known as drenchesare given to a flock to treat worms, sometimes after worm eggs in the feces has been counted to assess infestationlevels. Afterwards, sheep may be moved to a new pasture to avoid ingest- ing the same parasites. External sheep parasites include: lice, sheep kids, nose bots, sheep itch mite, and maggots. Kids are blood-suckingparasites that cause general malnutritionand decreased productivity, but are not fatal. Maggots are those of the bot fly and the blow-fly. Fly maggots cause the extremely destructive condition of flystrike. Flies lay their eggs in woundsor wet, manure-soiled wool, when the maggots hatch they burrow into a sheep's flesh, eventually causing death if untreated. In addition to other treatments, crutching is a common preventative method. Nose bots are flies that inhabit a sheep's sinuses, causing breathing difficulties and discomfort. Common signs are a discharge from the nasal passage, sneezing, and frantic movement such as head shaking. External parasites may be controlled through the use of backliners, sprays or immersive sheep dips.

A wide array of bacterial diseases affects sheep. Diseases of the hoof, such as foot rotand foot scaldmay occur, and are treated with footbathsand other remedies. These painful conditions cause lamenessand hinder feeding. Ovine Johne's disease is a wasting disease that affects young sheep. Bluetongue disease is an insect-borne illness causing fever and inflammation of the mucous membranes. Ovine rinderpestis a highly contagious and often fatal viral disease affecting sheep and goats.

A few sheep conditions are transmittable to humans. Scabby mouth, contagious ecthyma or sore mouth) is a skin disease leaving lesions that is transmitted through skin-to-skin contact. More seriously, the organisms that can cause spontaneous enzootic abortion in sheep are easily transmitted to pregnant women. Also of concern are the prion disease scrapie and the virus that causes foot-and- mouth disease (FMD), as both can devastate flocks. The latter poses a slight risk to humans. During the 2001 FMD pandemic in the UK, hundreds of sheep were culled and some rare British breeds were at risk of extinction due to this.

Date: 2016-01-03; view: 1475