Genetic and Skin Diseases

By D. Scott Adams.

Genetic diseases are those inherited by the lamb and kid from their dams and sires. They may be primarily structural (involve the way the body looks) or metabolic (chemical). While most result in early death of the fetus, some may not be particularly serious.

This chapter will discuss only conditions which affect productivity or survival. A great many more inherited problems are described in sheep than in goats.

Jaw Defects. The mandible (lower "jaw") is either too short or too long. Rectal Prolapse. The tissue inside the anus comes out. This condition is most common in black-faced sheep. Inverted eyelids (entropion). Usually the lower eyelids turn in and cause the eye to be sore and runny. They may be surgically corrected.

Cryptorchidism. One or both testicles of male lambs and kids not present in the scrotum (sac) but retained in the abdomen. Skin folds. Wrinkled skin which lowers productivity and is associated with lowered fertility.

Face Covering. Ewes with fleece covering the face are less productive than those with short hair on the face. Fleece Defects. Several abnormal types of fleece can be inherited: Poor quality with a tendency to break, hairy or fuzzy lambs, and high belly wool.

Infertility

Infertility in Polled (hornless) Goats. Breeding of hornless bucks and does leads to hermaphrodism (intersex and infertile) and small infertile testicles in male offspring. Hornless females should be bred to horned or disbudded males.

Mannosidosis of Nubian Goats. Kids are born unable to rise and have flexed front legs and straight rear legs. Myotonia Congenita of Goats. Upon being startled the goats become very rigid for about 30 seconds.

Genetic diseases are caused by breeding animals carrying genes which when found together in the same offspring produce abnormal or undesirable characteristics.

These diseases are transmitted through certain types of breeding practices, particularly inbreeding. Breeding male offspring to their dams and dams to their sires are examples of inbreeding.

Very little can be done in the way of treatment in most cases, but a veterinarian should be consulted for advice.

For prevention, seek professional advice, avoid inbreeding when possible, and do not breed animals known to be carriers of genetic diseases.

Skin Diseases

The skin is the body's largest organ and first line of defense in many diseases. For these reasons, diseases which involve the skin and cause damage to it are many and varied. Generally speaking, conditions which affect sheep also occur in goats.

Parasitic skin diseases mostly are caused by insects lice, ticks (keds), mites (mange and scabies), maggot infestations (fly strike).

Lice causing itching, loss of hair or wool, licking, biting at affected areas, and anemia (thin blood) in severe cases.

The small insects can be seen on the affected areas and nits (eggs) can be found attached to hair and wool. Sheep keds are large (1/4 in.), tick-like insects found mostly on sheep and in large numbers cause irritation.

Mange and scabies are contagious diseases which result in hair loss, intense itching, crusty scabs, and redness. Maggots are small rice-like worms hatched from eggs of blowflies which cause irritation, damage and holes in the skin under the wool particularly around the anus and vulva.

Lice, keds, and mites are spread mostly by direct contact, and strike is spread by blowflies. All can be treated with insecticides approved for use in sheep and goats. Consult your veterinarian for a specific diagnosis and treatment.

Prevention lice and keds can be better controlled by treating after shearing. Animals with certain types of scabies must be quarantined and treated. The incidence of strike can be reduced by shearing the area around the anus and vulva.