Simple Needle Test Revolutionizes Early Diagnosis of Calf Anorectal Atresia

Needle aspiration technique as a supportive tool for clinical diagnosis of anorectal atresia in calves

Ahmed Abdelrahiem Sadek and Kamal Hussein

Background

Anorectal atresia is among the most frequent congenital intestinal abnormalities in newborn calves, characterized by an absent or obstructed anal opening that prevents defecation and causes abdominal distension and discomfort. Traditional diagnosis relies on history, physical inspection, and radiography. However, in cases lacking visible perineal bulging, these methods may be inconclusive. The study evaluated needle aspiration as a supplementary diagnostic tool under field conditions to support accurate diagnosis and guide surgical decision-making in calves with anorectal atresia.

Methods

The study included 116 male calves (6 hours–5 days old) examined at Assiut University Veterinary Teaching Hospital between 2018 and 2024. Clinical, needle aspiration, and radiographic assessments were performed. A blind needle aspiration technique was conducted using an 18G needle and a 20 mL syringe inserted aseptically under the tail base to determine the proximity of the blind rectal pouch to the perineal surface. Radiography confirmed the anatomical position of gas-filled rectal ends, and surgery was performed based on diagnostic findings—either perineal anal reconstruction or right flank laparo-typhlostomy.

Results

Clinically, 62 calves exhibited perineal bulging indicative of atresia ani, while 54 calves without bulging were diagnosed with atresia ani et recti. Needle aspiration yielded positive fecal material in all calves with bulging and in 46.3% of non-bulging calves, indicating that their rectal end was within 5 cm of the skin. Negative aspiration results occurred in 53.7% of non-bulging calves, corresponding to a rectal end located deeper than 5 cm. Radiographic findings correlated closely with aspiration outcomes. Surgical correction by perineal opening was successful in calves with near-surface rectal ends, while laparo-typhlostomy was required for deeper lesions. All operated calves survived for at least three months post-surgery.

Limitations

This study only included male calves, which may limit applicability to females with rectovaginal fistulas. The accuracy of the needle aspiration method may vary depending on the surgeon’s experience, fecal consistency, and concurrent anomalies. Long-term outcomes beyond the three-month follow-up were not assessed.

Conclusions

Needle aspiration is a quick, safe, and effective field technique that complements radiography for diagnosing anorectal atresia in calves, particularly when perineal bulging is absent. The method enables veterinarians to determine the rectal pouch’s proximity to the perineum, facilitating informed surgical planning between perineal and laparotomy approaches. This practical diagnostic aid enhances decision-making, reduces procedural delays, and improves prognosis in affected neonates.

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