Septic arthritis is most common in lambs less than four weeks of age and in flocks housed for lambing. Response to treatment can be poor resulting in chronic lameness and ill thrift. Prevention relies on management practices including effective navel treatment, sufficient timely colostrum intake and good general hygiene. Morbidity has been reported to range from 2 to 20% with up to 50% of lambs affected in severe cases (Watkins, 2007, Rutherford, Jeckel and Ridler, 2015). The latter also reported that around 20% of affected lambs will go on to die. Of 36 flocks surveyed by these authors 39% were routinely using prophylactic antibiotics to try and reduce the incidence of joint ill. In the current climate prophylactic use of antibiotics is becoming harder to justify.
Historically Streptococcus dysgalactiae has been shown to be the most common cause of septic arthritis in lambs. Other causal bacteria include Escherichia coli, Trueperella pyogenes and Erysipelas rhusiopathiae.
As septic arthritis is diagnosable on clinical examination the number of submissions to SAC Disease Surveillance Centres is usually low and will not reflect the true prevalence of this disease. Following lambing 2016 it was anecdotally reported that there had been a greater than usual number of outbreaks, high morbidity and a poor response to both prophylactic and therapeutic treatments.
There is a need for up to date information on which pathogens are responsible for outbreaks of septic arthritis and what is the most appropriate antibiotic to treat them with. For this reason we are offering free post-mortem investigation of septic arthritis cases at all SAC Consulting Veterinary Centres during lambing 2017. The aim will be to examine affected lambs from between 50 and 80 flocks on a first come, first served basis. Lambs should be ≤ 4 weeks of age and between 1 and 3 will be examined per flock. Ideally at least one of the submitted lambs should be untreated.
Rutherford, S.J., Jeckel, S. and Ridler, A. (2015) Characteristics of sheep flocks affected by Streptococcus dysgalactiae arthritis. Veterinary Record, 176, 435-436.
Watkins, G.H. (2007) Arthritis. In Diseases of Sheep, Blackwell publishing, Chapter 41, 288-293.