Tool 11.12 Prevention of clostridial diseases and cheesy gland

Disease

Conditions when likely to occur

Clinical signs

Vaccination strategy

Clostridial Diseases:

Tetanus

Penetrating wound (including marking wounds)

stiff-legged gait followed by convulsions initially stimulated by sound or touch and gradually progress in severity

Young lambs:

Vaccinate ewes 4–6 weeks before lambing.

Lambs:
Vaccinate at marking and give a booster 4–8 weeks later (usually at weaning)

Older stock:
Annual booster timed before high-risk period or pre-lambing. Vaccination for pulpy kidney may be required more frequently in high-risk situations, such as grain feeding in drought or grazing high-quality fodder crops

New stock:

Implement vaccination procedures as for normal stock. If history of vaccination known, implement flock program. If vaccination history not
known, give an initial dose, then booster 4–8 weeks later.

Sudden changes in feed quality, particularly where sheep move rapidly onto high quality pasture from supplementary or dry feed and vice versa, increases the risk of pulpy kidney.

If stock have not been vaccinated in the three months prior to the feed change, vaccination at least 10 days prior to exposure to the new feed is advisable, as well as minimising the risk of stock gorging on the new feed by allowing them access to it in the afternoon when they’ve had a chance to fill up on the feed they’ve been on throughout the morning.

Black leg

Muscle bruising, growing animals

severe lameness, swelling of affected leg, very depressed, fever, skin dry and cracked, often sudden death

Black disease

Liver fluke infestation

depression and abdominal pain, sudden death

Malignant oedema

Wounds

contaminated wound, often associated with lambing, local swelling, fever, severe toxaemia and death

Pulpy kidney

Lush pasture, heavy grain feeding, change of feed

convulsions, sudden death

Please note:

• Consider the local risk based on previous district and property history for all clostridial diseases.
• Clostridial diseases require veterinary assistance to aid in diagnosis with necropsy, bacteriology and histopathology.
• Intensification is likely to increase risk of clostridial diseases such as blackleg and pulpy kidney.

Cheesy gland

Infection commonly through shearing cuts or directly through freshly shorn skin, in count out pens by sheep coughing on each other or dipping immediately after shearing. Can also be spread by rubbing and contamination of wounds and broken skin when animals are in close contact, for example when sheep are held in small yards or closely grazed on contaminated grass or in feed troughs. Infection is widespread and does not cause serious production losses on farm but is a major cause of economic loss to the meat industry due to condemnations and carcase trimming.

Abscesses develop in lymph nodes around the body
Abscesses are obvious in freshly shorn sheep
Sometimes sheep will cough if abscesses are present in the lungs

Cheesy gland vaccine is incorporated in clostridial vaccine, either as 3-in-1 or 6-in-1. Initially two doses are required to provide protection, and then an annual booster is necessary to maintain it. Sucker lambs do not need vaccinating against cheesy gland as they are sold before abscesses develop. Dipping hygiene is important and sheep should only be dipped if attempting to eradicate lice. Sheep should be carefully shorn to avoid shearing cuts and not dipped until cuts have healed.