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  • Dr Enoch Bergman, Swans Veterinary Services

2023 Results: Bull Preputial Breakdown PDS


Bull sales are well and truly under way - it’s time to think about preparing your virgin bulls for joining. An important factor is attempting to reduce the incidence of balanoposthitis, a common cause of bull preputial breakdown, or balanoposthitis. Balanoposthitis is latin for inflammation of the penis and prepuce.  Affected bulls often progress to catastrophic preputial and penile injury if not removed from mating situations.


Preputial damage caused by balanoposthitis.

Swans Veterinary Services and ASHEEP & BEEF are once more running our Meat & Livestock Australia Producer Demonstration Site (PDS) project on preventing bull preputial breakdown by vaccination, giving producers access to some free Bovine Herpesvirus vaccine and covering most of the cost of bull preputial breakdown investigations.  Zoetis has kindly provided Rhinogard vaccine for the project in the past and is generously agreeing to assist the project this year.


Preputial damage caused by balanoposthitis.

By either vaccinating twice with Bovilis MH + IBR (Coopers), once with Rhinogard (Zoetis) intranasally, or using both vaccines, we believe we can reduce the incidence and severity of this crippling syndrome which seems to prey primarily on virgin bulls.


Within the Esperance district last year, our producers’ bulls suffered a lot of balanoposthitis. Surprisingly, even some of Swan’s clients whose bulls were vaccinated still suffered significant amounts of preputial breakdown. In the end, the incidence of breakdown was less amongst vaccinated bulls overall by close to 5%, however we still feel  we should be able to widen that margin with more data. There has been discussion of using both vaccines concurrently, and also of the potential benefit of exposing new bulls to cull cows prior to the breeding season. Obviously, exposing new bulls to cull cows carries risk, not only of STDs but also of the bulls injuring themselves, other bulls, or the cows.  Regardless, any intervention which can be shown to reduce the incidence of this critical syndrome has merit.  


The project’s Lead Producer Simon Fowler (Chilwell) commented, “local producers have been vaccinating bulls for over ten years and have anecdotally seen a large reduction in balanoposthitis. I certainly expect the PDS to show a more significant reduction in injuries to vaccinated bulls.”


Dr Enoch Bergman demonstrates a bull breakdown investigation.

We will keep working in this space, but what was apparent is that producers who vaccinate perceive that it helps, with survey participants giving an average score of 9.5 out of 10 when asked if they believe vaccination helps in the prevention of bull preputial breakdown.


Contact Swans (08) 9071 5777 to become involved in the project and to organise a preventative program including herpesvirus vaccines for your virgin bulls prior to this year’s mating season.


Summary of Key Project Findings 2023

Following is a summary of key data collected in the Preventing Bull Preputial Breakdown by Vaccination PDS project during the 2023 season.


Producers in the region were surveyed post-breeding, 48 individual properties were surveyed.

  • 19 (40%) of the properties surveyed vaccinated their bulls prior to joining.

  • 7 properties requested bull breakdown investigations.  All cases were confirmed as balanoposthitis.  100% of the bulls blood tested had antibodies to bovine herpesvirus on 6 of the properties.  On the remaining property only 2 of the 6 bulls screened had antibodies to herpesvirus.

  • 1107 total bulls and 347 virgin bulls were present on the 48 properties.

  • 540 total bulls and 161 virgin bulls were present on the 29 properties which did not vaccinate their virgin bulls prior to joining.

  • 567 total bulls and 186 virgin bulls were present on the 19 properties which vaccinated their virgin bulls prior to joining.

  • 51.2% of the total bulls surveyed were present on properties which vaccinated.

  • 53.6% of the total number of virgin bulls were present on properties which vaccinated.

  • Virgin bulls represented 32.8% of the bulls present on the total number of properties. The proportion of heifers on individual properties averaged 32.9% but ranged from 0% to 100% of the proportion of total bulls present.

  • Of the total surveyed data set, 16.7% of the virgin bulls and 9.5% of the experienced bulls broke down during joining.

  • On the unvaccinated properties, 20.5% of the virgin bulls broke down during joining, 3.1% of the total due to lameness, 17.4% due to balanoposthitis.

  • On the vaccinated properties, 13.4% of the virgin bulls broke down during joining, 0.5% of the total due to lameness, 12.9% due to balanoposthitis.


Producers were asked “On a scale of 1 to 10, with 1 being very unlikely and 10 being very likely, do you intend to vaccinate your virgin bulls prior to joining with Rhinogard or Bovilis MH + IBR to help reduce the incidence and severity of balanoposthitis.”

  • From the producers on the 19 vaccinated properties, responses ranged from 7 to 10 with an average of 9.4.

  • From the producers on the 29 unvaccinated properties, responses ranged from 1 to 10 with an average of 7.4.


Data will continue to be collected and collated. 


The following observations have been made: 

  • Exposing virgin bulls to sexual experience (commingling with cull cows) prior to joining may help reduce the incidence of balanoposthitis.

  • Wet conditions may contribute to the incidence and severity.  45.2% of producers who reported no virgin bull breakdowns reported wet conditions whilst 64.7% of those who reported virgin bull breakdowns reported wet conditions.  We will continue to monitor this in years 2 and 3 of the project.


Simple Economic Analysis:

One of the project objectives is to model some of the economic impacts of balanoposthitis.  Modelling the syndrome is complicated as there are a number of circumstances which will change the outcome.  Some of these include:    

  • Time of onset of the syndrome.

  • Time to recognition by the producer.

  • Access to replacement bulls.

  • Purchase value of affected bulls.

  • Salvage value of affected bulls.


If a producer were able to purchase and replace a virgin bull early within the joining process, without any disruption to either the pregnancy rate or calving distribution, the cost would simply be the purchase price minus the cull value of the bull. Assuming the bull was fit to load, the cull value of a young bull in today’s market in Western Australia would range from $1,000 to $1,500.  Recently our local sales averaged slightly over $10,000 per bull. So, quite simply the cost of a bull being culled early in its reproductive life could be $8,500. At this rate, any procedure which could reduce the incidence of failure leading to premature culling by a single percent would generate a return of $85.


From our survey work collected so far, and likely to change as we move forward, we found a 4.5% reduction in the proportion of virgin bulls which broke down within the properties which had vaccinated their bulls prior to joining.  This equates to a $382.50 return on investment for intervention with vaccination.


Potentially of greater additional cost, bulls which are either not identified early, cannot be removed in a timely fashion, or that fail to be replaced can result in a higher proportion of animals preg tested empty at pregnancy diagnosis and/or a disrupted calving histogram (more calves born late in the calving season). 


Pregnancy testing season is under way and in coming weeks we will be able to collect data from one of our core producers that suffered a significant amount of balanoposthitis.  We will develop a case study from that core producer’s experiences and will be able to use some of the data to calculate the potential cost to their production system from the outbreak of balanoposthitis.

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