Congenital Right-side Rib Agenesis in a Male Lamb: A Rare Case Report

Sheep play a vital role in agriculture, contributing to Gross Domestic Product (GDP) through meat, wool, and leather. The number of ribs in sheep is an important economic trait, particularly for meat production, as a higher rib count correlates with increased mutton yield. However, the congenital absence of ribs is a rare condition scarcely documented in veterinary field. This report presents the first known case of rib aplasia in a lamb, highlighting its clinical presentation, diagnosis, and implications. A two-day-old male co-twin lamb exhibited symptoms of ataxia, anorexia, and dyspnea. Physical examination revealed missing ribs on the right side and scoliosis at the thoracic vertebrae level. Chest X-rays confirmed the absence of the 9th and 10th ribs and thoracic scoliosis. Despite explanations of the poor prognosis, the lamb collapsed after two days, and no post-mortem examination was conducted. This case underscores the need for further research to identify genetic factors contributing to congenital rib agenesis in lambs, given its economic importance in the sheep industry.