for sperm morphology will be reduced or the real‐world fertility may not reconcile with the anticipated fertility. It therefore seems reasonable for a producer to expect that standards are being applied in an equitable way regardless of the personnel performing the evaluation.
The Use of Vital Stains
In all systems except that of the ACV, the use of nigrosin‐eosin staining is one of the recommendations for preparing samples for morphological examination. None of the regions recommends incorporating the Live/Dead aspect of vital staining into the BBSE assessment. The ACV does not recommend the use of vital stains for morphology assessment due to the recommendation of utilizing an endorsed morphologist for the assessment process. In this scenario, the morphologists unanimously prefer samples in fixative such as formal buffered saline (FBS) solution as this enhances the detection of defects under phase‐contrast or DIC microscopy. There is also concern that the osmolality of the vital stain may vary widely if not stored carefully, adversely affecting sperm morphology.
White Blood Cells in Semen
The ACV and SFT manuals both describe the detrimental effects of white blood cells (WBCs) in the semen. The ACV suggests that if more than several WBCs are identified per high‐power field or if purulent material is observed grossly in the ejaculate, the veterinarian should use clinical judgment regarding treatment and prognosis, with a Q or X applied to the category.
Discussion
While exploring the evolution of the BBSE throughout the world, it is apparent from all regions that variation in the early processes of assessment, interpretation, and reporting of results led to uncertainty in the outcomes of the testing. There was a perception from seed‐stock producers and their veterinarians that bull sale opportunities may not be equitable if some bulls were placed under more or varied scrutiny compared to contemporaries. In most regions this variation was arguably the biggest driver toward a standardized BBSE procedure. Regardless of other reasons for performing a BBSE, the requirement for a process that provides equitable comparison of all sale bulls is critical to the integrity of the BBSE. The understanding is that the primary driver to standardizing the approach to BBSE may not necessarily be the science behind the ideal of improving bull fertility, but more the necessity to make the collection and interpretation of data on which bulls are compared when presented for sale as equitable as possible. If this goal is not achieved, then the credibility of BBSE will be reduced to the point of it no longer being considered by producer bodies to be relevant.
When reviewing BBSE standards from different regions, most provide clear guidelines on what aspects are compulsory and what aspects are suggested recommendations. Ideally these compulsory and suggested processes can be tailored to different bull management scenarios. The South African and BCVA systems have addressed this requirement by stipulating “Use Classes” (Figure 7.5). On similar lines, the ACV system works on a risk assessment format where non‐compulsory aspects of the testing can be included or removed depending on the management scenario or breed society requirement. While the SFT system doesn't explicitly provide the option for tailoring the evaluation, there is room to provide comments on options for bulls that fall into the decision‐deferred category.
What is not so clear from the standards of different regions is the process of interpreting some aspects of the findings. This is not surprising, as cattle veterinarians are in the unenviable position of having to apply clinical judgment to the continuum of a biological system, while cattle producers are expecting clear “yes/no” answers. To assist with standardized interpretation and reporting it seems there are two requirements: (i) a standardized data recording and reporting system, which all regions provide; and (ii) CPD to ensure there are standardized data collection techniques and interpretation. While two of the regions have provided comprehensive manuals to assist with CPD, other regions appear more dependent on undergraduate training providing a sound knowledge base. Yet, with the knowledge surrounding BBSE constantly evolving, there is a need for experience and on‐going training to attain and retain competency. For example, anecdote from the ACV suggests there can be 2‐ to 5‐cm differences in the SC measurements between experienced and inexperienced operators. Similarly, there can be confusion and variable recommendations when conditions such as hocks with joint effusion, interdigital fibromas, aberrations in leg conformation, or neutrophils in the semen are encountered. Assessing extremes in these conditions is not difficult, but standardizing the interpretation of mild to moderate presentations appears less straight‐forward. One way to reduce this variation is to provide supervised training, recurrent updates, and where relevant, abnormality scales with exemplars.
For the BBSE to maintain integrity, it is essential that producers have a clear understanding of what to expect when they have their bull assessed. The corollary to having a clear process to follow is that veterinarians will need ready access to CPD in order to maintain currency in the process. The SFT in the USA has taken the lead in the CPD area for close to 50 years, as evidenced in their current and prior manuals for the breeding soundness evaluation of bulls [10]. But perhaps the most extreme evolution of CPD identified in this review is the BBSE Accreditation scheme developed by the ACV in Australia. This scheme provides veterinarians with the opportunity to submit themselves for compulsory postgraduate education and assessment in order to receive accreditation. The accreditation provides them with the commercial advantage of marketing themselves as having industry‐recognized skills and competency in the BBSE process.
For credibility of the BBSE process to be maintained, the following points seem important:
1 The system must have standardized data collection processes.
2 There must be standardized data interpretation.
3 There must be standardized reports to allow the end users to easily interpret the findings in order to compare bulls.
4 It seems suitable to move away from a system that places veterinarians in the position of having to “pass” or “fail” bulls using a system that is based on incomplete science – particularly when there is limited opportunity for a detailed assessment and there is incomplete understanding of all factors affecting future fertility. To this end, using a reporting system that simply states the findings for each category and allows for interpretive comments may be a good option.
5 There must be continuing professional education in the processes of BBSE for veterinarians so that producers have confidence in the outcome for their bull.
6 Consideration should be given to an accreditation program for veterinarians performing these procedures. This point is particularly important considering the profound influence outcomes from these evaluations can have on the financial viability of seed‐stock producers.
Considering points 5 and 6, the three parameters that commonly concern bull producers are the measurement of SC, the individual motility percentage, and the assessment of sperm morphology. Effective, worldwide extension surrounding the influence of these three parameters on bull fertility means that poor results can lead to a bull not passing the BBSE and either not being able to be sold through normal channels or having a reduced sale price. Alternatively, the bull may have a reduced sale price even if the result meets fertility standards but is lower than contemporaries. Due to the physiologic and economic importance of these parameters and their highly visible nature to producers, it is essential that veterinarians are adequately trained in these techniques to provide consistent results.
A summary of notable variations in the bull evaluation processes from different regions that may help inform future iterations include:
Removal of the word “soundness” from the description of the process.
Provision
