bulls, these modalities will be of more interest to researchers than to clinicians for the foreseeable future.
Summary
Diagnostic ultrasound is a safe, non‐invasive method for acquiring additional diagnostic and prognostic information in cases of infertility in the bull. Clinical competence with bull genital ultrasonography can be readily achieved by routinely imaging the genital tract of normal healthy bulls. This will provide the frame of reference necessary to identify and interpret pathologic changes as they are encountered. The common lesions are seldom subtle and are readily detected by systems providing average or better image quality. We recommend ultrasonography as an adjunct to the BBSE for all cases of subfertility in artificial insemination (AI) sires and valuable natural service sires. Routine screening of young sires as part of a pre‐purchase evaluation should be done with caution as the most common ultrasound change encountered is a fibrotic lesion or foci in the testes. These lesions have been shown to have little or no effect on semen quality in young bulls. Advances in ultrasound diagnostic capability, especially as it relates to assessment of blood flow in the scrotum or tissue density measurement, may enhance our ability to discriminate between fertile and infertile bulls in the future.
References
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11 Management of Breeding Bull Batteries
E. Heath King
Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Starkville, MS, USA
Introduction
The purchase and maintenance cost of the bull battery represents a significant expense to the cow calf producer. Improper management of this investment can have negative economic consequences through both a reduction in herd productivity and the loss of bulls due to injury or death. A reduction in the size of the calf crop or loss of the calf crop is easily noticed by the producer, but many subfertile bulls are capable of inefficiently producing offspring and this may go unnoticed in some herds. This inefficiency leads to delayed conception, which has been estimated to cost 23–27 kg of weaning weight for every 21 days a cow remains open during the breeding season [1]. In an attempt to compensate for poor bull management, producers will often increase the stocking density of bulls within their herd. The expense of purchasing and maintaining excess bulls can also limit the profitability of a herd.
The management of breeding bulls will vary somewhat between herds, but the overall goal should be to provide a group of disease‐free,