Hypocalcaemia in 23 ataxic/recumbent ewes: clinical signs and likelihood ratios

Twenty-three ewes in a flock of 2000 were identified as having acute onset ataxia and/or having become recumbent in late pregnancy and early lactation. The presence or absence of 15 clinical signs were recorded. Thirteen of the ewes (57 per cent) were hypocalcaemic and 10 (43 per cent) were normocalcaemic. In the hypocalcaemic group, loss of anal reflex, constipation, tachycardia, hyposensitivity, ruminal stasis, ruminal tympany, salivation and tachypnoea were recorded in 50 per cent or more of the cases. In the normocalcaemic group, tachycardia, tachypnoea and ataxia were recorded in 50 per cent or more of the cases. Constipation, ruminal stasis, salivation and hyposensitivity had likelihood ratios of 3 and above for being associated with hypocalcaemia. Ruminal stasis and hyposensitivity had the likelihood ratios of 0.10 and 0.11 respectively for not being associated with hypocalcaemia.