What’s the best way to assess boar stud performance?

“There are as many ways to do this as there are types of boar studs and points of view of managers and consultants performing the assessment,” says Chris Kuster, DVM, MS, PhD, Kuster Research and Consulting, Geneseo, Ill. His remarks were made in a presentation during a seminar on “Boar Stud Issues” at this year’s American Association of Swine Veterinarians annual meeting in Toronto.


Looking at semen collection technique also is an important aspect   of boar-site audits.

Site audits
To fully understand the operation and challenges of individual boar studs, regular contact in the form of site audits is critical, says Kuster. “During these visits, every area of production should be reviewed, with special emphasis on current challenges and recent issues.”

This would include assessing:

  • The boars.
  • Boar housing area.
  • Semen collection technique.
  • Semen quality screening.
  • Semen processing, including equipment calibration, packaging and shipping.

Kuster adds that most boar studs are capable of producing doses of semen that meet designated quality criteria part or most of the time. However, knowledgeable and dedicated personnel with sufficient training in proper techniques, equipment selection and use are required to do this consistently, he says.

Adoption of Standard Operation Procedures (SOP) also can be helpful, says Kuster. Among other things, these procedures can:

  • Provide continuity between individ-uals performing the same tasks on different days.
  • Be used for training new personnel.
  • Serve as documentation of specific changes implemented in response to problems.

“Regular review of SOPs as a method of measuring compliance is recommended. Site visits are also a good time to review the nutrition program, feeding management, health and biosecurity protocols and to address issues related to sanitation and hygiene. Ensuring that all of these components are in place provides the basis for future performance reviews.”

Quality monitoring
Monitoring the quality of the end product is one important aspect of measuring boar stud performance, says Kuster. He recommends a complete
semen analysis that includes:

  • Dose volume.
  • Sperm concentration.
  • Total sperm per dose.
  • Objective motility assessment.
  • A full morphology differential.
  • Aerobic culture.

A broader picture of boar stud performance can be determined by charting complete semen analyses over time and benchmarking against comparable boar studs in the industry.

“Routine third-party assessment of randomly selected doses of extended semen provides feedback to the boar stud personnel, management and their veterinary consultants on the current performance of that site,” says Kuster.

Access to the records of these assessments can also reassure customers that the boar stud is diligently self‑policing and addresses deficiencies quickly.

How often these third party assessments are done depends on whether the boar stud is interested in simply spot‑checking performance or if a true monitoring program is desired, according to Kuster. Spot-checking might include quarterly or semi-annual assessments, he says.

“Depending on the size of the boar stud and their collection schedules, a monitoring program may require sample submissions on a monthly, bi‑weekly or even weekly basis,” Kuster says. “A bare minimum would be considered five doses per site per month, with some systems choosing to increase surveillance levels to detect if even a very small percentage of doses do not meet their quality guidelines within a defined confidence interval.”

Interpretation of results generated by third party analysis is important in determining when and what interventions are necessary, according to Kuster.

“For individual reports, measures of expected statistical variation, such as standard error or confidence intervals, can be used as a guideline when reviewing sperm concentration and total sperm per dose parameters.

“Motility is often interpreted with the age of the sample and extender taken into consideration, with a generally accepted cutoff value of 60 percent at the time of insemination. A full sperm morphology differential will reveal the percent of normal cells as a fraction of the total sperm in the sample, in addition to reporting sub classifications of specific abnormalities.”

Guidelines are available to determine classification on an individual sample basis, with 70‑75 percent normal morphology as the generally accepted cut‑off range, according to Kuster.

“Aerobic culture of the extended semen is recommended to monitor bacterial contamination, particularly for isolates known to possess spermicidal activity,” says Kuster.

“A broader picture of boar stud performance can be obtained by charting their complete semen analyses over time, preparing formal statistical process control charts, and benchmarking against comparable boar studs in the industry.”

Customer feedback
Boar studs that have access to the production records of sow farms that use their product can use this information to monitor the stud’s performance, says Kuster.

“Consistent trends in reproductive efficiency over time across multiple sow farms or sudden dramatic dips in performance should be heeded as warnings to the boar stud.”

These warnings should trigger an investigation as to the potential cause and a plan for corrective action.

Kuster cautions that these reports should be used responsibly and interpreted in light of all pertinent information by both the sow farm and the source boar stud to make rational assessments. “The most common complaint is for the sow farm to withhold details relating to management changes, disease pressure, and other information  that must be considered in addition to semen source.”

Sample size also is important, says Kuster. “Statistically speaking, smaller units with lower breeding targets may appear to have more variation in their results when measured over the same period as larger units utilizing the same source of semen. Whenever possible, the boar stud should manage their product distribution in such a way that fairer comparisons are possible.

“Simple procedures, such as splitting an individual sow farm's order between two or more batches of semen and sending each batch to at least two different sites is one small way to achieve these goals.

“Routine monitoring of dose temperature during delivery and of the sow farms’ semen storage units is another way for boar studs to monitor their product once it is out of their
direct control.”

Production efficiency
Measures of boar stud production efficiency are only as good as the records maintained by that stud, Kuster says.

“Since semen is a perishable product, boar studs produce what they
need to fill orders, which may not reflect their true production capacity. This fact should always be kept in mind when reviewing any boar stud efficiency measure.”

An example, Kuster says, is using doses per boar per week as a commonly cited boar stud statistic.

“This factor can be misleading when compared across studs or even within the same system. The target number of sperm per dose is an integral part of this equation, and other factors contribute as well, including boar age, genetic line, and semen collection frequency.

“A more useful measure would be to calculate the total number of sperm collected per boar on a monthly or weekly basis, instead of relying solely on doses per boar. This can be further broken down by genetic line and age, or other factors pertinent to the individual situation.”

Other important parameters to assess include ejaculate discard rate and semen collection frequency, according to Kuster.

Ejaculate discard rates vary seasonally and can range from more than 13 percent in the summer to 8 percent or less the rest of the year. “If this is not the case for a particular stud, they either have impeccable environmental control and a stable group of boars, or they are not being as critical as some of their contemporaries.”

Discard rates can also be impacted by quality standards, culling frequency and semen collection strategies.

As far as semen collection frequency, Kuster says that it can be tailored to boar age and past history.

“The most consistent production is generally observed if boars are routinely collected once a week,” he says. “Although it is often possible to temporarily increase dose production for a given boar when measured over a week or month time period, reducing the resting period between collections in order to meet targets will eventually result in depleting the epididymal reserves.”

This can lead to a disproportionate amount of labor required to achieve the same dose production.

Sources of production efficiency targets include genetic suppliers, published reports and individual experience. (See the accompanying table).

Economic efficiency
Boar stud performance also needs to be assessed in terms of economic efficiency, says Kuster. “Although commercial boar studs are in business to generate revenue, ultimately all boar studs are cost centers whether viewed from the perspective of an integrated system or from an industry standpoint as a whole.

“ Seeking to operate in a cost‑efficient manner is a positive goal, as long as the boar stud's impact on sow reproductive performance and producer profitability are also taken into consideration. Reducing costs at the boar stud may seem large in relation to the boar stud's budget. However, these savings may be relatively minor when measured against the operating cost of an entire system, and in fact could have negative repercussions that are magnified for the  producer in pounds of pork ultimately produced.”

Kuster says that when comparing costs, it is vitally important to be honest in the assessment. “It takes more than feed and extender to produce a dose of semen, so attention to details such as start‑up cost associated with site preparation, building values, equipment and other factors must be accounted for as well.

“Sometimes labor is shared, as is often the case with delivery drivers and AI supervisors, and the correct portion of their wages should be attributed to the boar stud. Out‑ sourced
labor should also be included where appropriate.”

Boar studs considering expansion or negotiating contracts that expand current productio, should break down their fixed and variable costs and determine the marginal cost of each additional dose produced under their current system, says Kuster.

Assigning costs to a production unit, such as dose of semen, rather than accepting the variability associated with batch purchasing at intervals that may not correspond to the time periods being analyzed helps to further fine‑tune these types of estimates, according to Kuster.

“For example, while labor cost may fluctuate on a weekly basis in close association with dose production, expenditures for insurance may be annual or quarterly, while two lots of extender may be purchased in one month and none the next. Spreading these costs out over the period of time they were actually used, rather than in the week or month they occurred, can simplify financial reviews.”

The cost of production, Kuster says, can be measured in multiple ways, including cost per dose produced, per boar space, per boar inventoried and other measurements. (The accompanying table  summarizes various values that have been quantified. )

Kuster emphasizes that when analyzing a boar stud budget, labor is generally near the top of the list from a cost standpoint. Using labor as an efficiency measure, such as doses produced per hour of labor, can make sense under certain situations, such as calculating employee bonuses or determining staffing levels. For commercial boar studs, global efficiency measures such as return on equity can be used to assess financial performance as a business entity.