sexual e parâmetros reprodutivos em touros da raça Nelore criados em sistema extensivo. Rev. Bras. Zootec. 39: 503–511.121 121 Menegassi, S., Barcellos, J., Peripolli, V. et al. (2011). Measurement of scrotal circumference in beef bulls in Rio Grande do Sul. Arq. Bras. Med. Vet. Zootec. 63: 87–93.
122 122 Smith, B., Brinks, J., and Richardson, G. (1989). Estimation of genetic parameters among breeding soundness examination components and growth traits in yearling bulls. J. Anim. Sci. 67: 2892–2896.
123 123 Beef Improvement Federation. (2010), Guidelines for Uniform Beef Improvement Programs, 9th edn. Available at http://www.beefimprovement.org.
124 124 Casas, E., Lunstra, D., Cundiff, L., and Ford, J. (2007). Growth and pubertal development of F1 bulls from Hereford, Angus, Norwegian Red, Swedish Red and White, Friesian, and Wagyu sires. J. Anim. Sci. 85: 2904–2909.
125 125 Chase, C. Jr., Chenoweth, P., Larsen, R. et al. (1997). Growth and reproductive development from weaning through 20 months of age among breeds of bulls in subtropical Florida. Theriogenology 47: 723–745.
126 126 Fields, M., Hentges, J. Jr., and Cornelisse, K. (1982). Aspects of the sexual development of Brahman versus Angus bulls in Florida. Theriogenology 18: 17–31.
127 127 Rocha, A., Carpena, M., Triplett, B. et al. (1995). Effect of ruminally undegradable protein from fish meal on growth and reproduction of peripuberal Brahman bulls. J. Anim. Sci. 73: 947–953.
128 128 Silva‐Mena, C. (1997). Peripubertal traits of Brahman bulls in Yucatan. Theriogenology 48: 675–685.
129 129 Freneau, G., Vale Filho, V., Marques, A. Jr., and Maria, W. (2006). Puberdade em touros Nelore criados em pasto no Brasil: características corporais, testiculares e seminais e de índice de capacidade andrológica por pontos. Arq. Bras. Med. Vet. Zootec. 58: 1107–1115.
7 Breeding Soundness Evaluation: Comparative Review of Different Standards
Scott T. Norman
Kallangur Veterinary Surgery and Oakhill Assisted Animal Breeding, Kallangur, QLD, Australia
Introduction
The overarching goal for a bull breeding soundness evaluation (BBSE) is to provide a standardized, unambiguous report on the suitability of a bull to be used in a breeding program. A secondary goal may be to utilize the data to facilitate genetic selection for fertility traits. The evaluation process needs to be repeatable, reproducible, efficient, and safe for both the bull and the clinician. There also needs to be flexibility in the process to accommodate differing managerial requirements. Within each managerial situation there needs to be consistency in the process of data collection, data interpretation, and classification of the evaluation outcomes, with results readily understood by the end user. Such consistency helps to maintain the credibility of the BBSE, assisting veterinarians, cattle producers, and researchers alike.
Foundations for the knowledge that underpins the current practices used in the assessment of bull fertility are attributed to research performed in the first four decades of the twentieth century [1]. Seminal research into specific aspects of bull fertility arose out of the USA [2, 3] and Sweden [4]. Following the understanding that many individual factors affect bull fertility, there was a progressive realization of the need to assimilate this knowledge to enable the development and application of minimum standards for each fertility parameter. The assimilation of fertility parameters into a bull fertility evaluation process formed the foundation of BBSE procedures. The earliest documentation in western literature of standardized procedures, interpretation, and reporting for BBSEs was described in 1954 by a group called the Rocky Mountain Society for the Study of Breeding Soundness of Bulls. Following several iterations, this group evolved in 1974 into the American Society for Theriogenology (SFT), with the basis for current protocols, data recording, and reporting being developed [5].
Following on from these initial developments, BBSEs are now conducted by veterinarians throughout the world to estimate the potential for a bull to sire calves under a range of management conditions. These conditions vary from the assessment of bulls pre‐sale for seed‐stock producers; commercial producers using natural mating in multi‐sire or single‐sire situations; assessment for the ability to collect and process frozen semen; and assessment for insurance purposes. These varied contexts coupled with differing production goals mean that the processes for determining and reporting the suitability of a bull for breeding have evolved with a degree of autonomy in different regions. While there are many similarities, there are also variations in the techniques employed, interpretation of the findings, reporting of results, and systems for oversight of the processes within the veterinary profession.
General Concepts
Based on cattle industry requirements for efficiency, financial viability, and reliability, the defined needs for veterinary BBSE include [6]:
1 A system for breeders/vendors to provide assurance that bulls have a high probability of being fertile at the point of sale.
2 A system for buyers/users of bulls to understand evaluation reports and to have confidence that bulls have a high probability of being fertile at the point of sale.
3 A system whereby veterinarians can meet industry needs that is consistent with their own professional opinions, enables them to produce professional reports, and enables electronic reporting and storage of data.
4 A system that is flexible enough to suit bull transactions, insurance examinations, and routine screening of herd bulls.
5 A system that is applicable to wide variations in geographical, cattle genotype, and management situations throughout the world, and equally applicable to dairy and beef bulls.
The early iteration of the BBSE developed by the SFT set the general template for the procedures, data recording, interpretation, and reporting of results. The details of these procedures are described in Chapters 8 and 9, but in summary the BBSE process can be condensed into the following seven categories:
1 General physical examination
2 Reproductive physical examination
3 Measurement of scrotal circumference (SC)
4 Semen evaluation – bull‐side
5 Semen evaluation – morphology and other laboratory evaluations
6 Serving ability or capacity
7 Testing for specific infectious or genetic diseases may be carried out on an as‐needed basis.
Of these seven aspects of the BBSE, the first three are considered compulsory in systems investigated in all regions. The remaining four categories may be variably included depending on the managerial situation, or the geographical location. While all BBSE systems agree or imply that full semen evaluation is desirable, some systems allow for semen evaluation to be either truncated to just a bull‐side,
