Cryptorchidism in North American cattle: breed predisposition and clinical findings.

The authors analyzed data collected over 26 years from 143 cryptorchid bulls admitted to 23 North American veterinary schools. Breed was found to be a risk factor. The medical records of 41 cryptorchid cattle were also obtained, and the physical examination findings, method of diagnosis, and surgical management were recorded. Polled Hereford and Shorthorn cattle were at significantly greater risk for cryptorchidism; however, polled cattle were not at an increased risk for cryptorchidism. Cryptorchidism was most commonly diagnosed by external palpation of the superficial inguinal rings and by palpation per rectum. Unilateral cryptorchidism appears to be more common than bilateral cryptorchidism. The incidence of cryptorchidism was 69% for the left testis and 31% for the right testis. Sixty-six percent of the retained testes were located in the inguinal canal. Cryptorchidectomy was performed through an inguinal, paramedian or flank approach in 26 bulls. Cryptorchidism appears to be rare in bovine bulls admitted to North American veterinary schools, with 1.7 cases per 1,000 bull admissions. We suggest that cryptorchidism be considered an inherited trait in the Shorthorn and Polled Hereford breeds.