Joint Ill
Joint ill, also known as infectious polyarthritis, is a common condition in young lambs. It is caused by bacterial infections that typically enter the body through the navel shortly after birth or through wounds from tagging, docking, or castration. This condition can cause significant discomfort and mobility issues for affected lambs, impacting their overall health and growth.
Symptoms and Diagnosis 🩺
Lambs with joint ill often appear dull and may have one or more swollen, painful joints. The infection can also spread to the spine, leading to paralysis of the hindlimbs or all limbs. Lameness usually becomes noticeable a few days after infection, typically around 5-10 days old. The affected joints are swollen, hot, and painful, and the lambs may exhibit muscle wastage due to lack of use of the limb.
Diagnosis: Diagnosing joint ill is primarily based on clinical signs. In lambs less than one month old, any lameness and swollen joints should be considered septic until proven otherwise.
Treatment 💊
The treatment of choice for joint ill is procaine penicillin, which is effective against the common bacteria causing the infection, such as Streptococcus dysgalactiae and Erysipelothrix rhusiopathiae. Penicillin should be administered once daily for at least five consecutive days during the early stages of lameness. However, some degree of lameness may persist due to inflammatory changes within the joint.
If lambs continue to show moderate to severe lameness after two courses of antibiotic therapy, they may not grow well and could represent a major welfare concern. In such cases, euthanasia may be necessary for welfare reasons.
Prevention 🛡️
Preventing joint ill involves several key practices:
- Colostrum Intake: Ensure all lambs receive adequate colostrum (at least 50 ml per kg body weight) immediately after birth and 210 ml/kg in total within the first 24 hours. Colostrum quality can be assessed using a handheld Brix refractometer.
- Navel Care: Treat the navels of newborn lambs with a strong 10% iodine solution as soon as possible after birth and again within six hours to prevent bacterial entry.
- Hygiene: Maintain clean and dry bedding and ensure good hygiene practices to reduce the bacterial challenge in the environment.
- Outdoor Lambing: Turnout to pasture for outdoor lambing during the late high-risk period can reduce the number of lambs affected by joint ill.