RADIOGRAPHIC ASSESSMENT OF CRANIAL CRUCIATE LIGAMENT RUPTURE IN THE DAIRY COW

Abstract

Case records and radiographs of 37 dairy cows presented to the University of Illinois Veterinary Medicine Teaching Hospital with a diagnosis of cranial cruciate ligament rupture were reviewed. Signalment, history, duration of lameness prior to clinical presentation, and physical examination findings were evaluated. Survey radiographs were examined and radiographic lesions were documented. Individual cows were classified into groups (A, B, C) based on the severity of radiographic lesions, with Group A cows having minimal radiographic lesions. Cows in Groups A and B had radiographic lesions similar to Class I in beef bulls reported in another study.3,4 An attempt was made to relate the severity of radiographic lesions with age and duration of lameness. Group A animals tended to be younger cows (x̄= 4.58 years) with a short duration of lameness. Group B cows were older (x̄= 7.87 years) with a somewhat longer duration of lameness. Group C cows were slightly younger (x̄= 7.30 years) than Group B cows; however, their duration of lameness was much longer (x̄= 57.2 weeks vs 6.35 weeks for Group B and 2.54 weeks for Group A). The pathogenesis of cranial cruciate ligament rupture and its associated lameness appeared to differ in dairy cows from beef bulls. The majority of animals in this study had radiographic lesions of mild to moderate severity (Groups A and B). In contrast, based on previous work, beef bulls had a greater tendency to be similar to our Group C designation. Beef bulls became lame with cranial cruciate ligament rupture only after severe lesions of degenerative joint disease had already occurred. It has been stated that lameness associated with cranial cruciate ligament rupture in the beef bull is, therefore, secondary to degenerative joint disease. In contrast, the syndrome in dairy cows, as evidenced here, differs, since they often presented with cranial cruciate ligament rupture with little or no radiographic evidence of degenerative joint disease.