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Goats

How to use Barbervax® in goats

Barbervax®, used under the prescription and supervision of a veterinarian, has the potential to improve the control of barber’s pole worm in goats in Australia.

In Australia, many goat owners have an ongoing problem with barber’s pole worm due to frequent rainfall and mild temperatures. Many are smallholders who cannot effectively “clean” pastures of worm larvae with grazing management practices.

Drench resistance is very common in goat herds, especially with barber’s pole worms, therefore drench-based control may have poor outcomes where drench resistance is severe. This is common where smallholders use older, single-active drenches that many worms are already resistant to and it accelerates further development of drench resistance.

Barbervax® is a vaccine against barber’s pole worm and is only registered for use in sheep in Australia, but it may be of use in goats. Therefore, the use of Barbervax® in goats is “off-label” and requires a veterinarian’s prescription prior to use.

In sheep, it has shown to be a long-term, easy to use, environmentally friendly solution that suppresses worm egg production and has no withholding period or export slaughter interval and there is no indication that resistance to the vaccine should develop.

Registration of Barbervax® in goats in Australia did not proceed because of poor results from one of the three registration trials, however poor condition of some participating goats may have been a factor (see the MLA report on Barbervax® Vaccine in Goats).

Preliminary overseas trials and off-label use in Australia indicate that the Barbervax® vaccine can be beneficial for goats, with results very similar to those recorded with sheep and lambs.

Because Australian registration trials had mixed results it is strongly recommended that the prescribing veterinarian oversees a monitoring program in association with vaccine use to assess the value of the product in each goat herd.

How to use Barbervax® in goats

Ideally, evaluate the vaccine in a portion of a herd and monitor and compare treated and untreated animals.

A vaccination and monitoring schedule is provided below.

The vaccine is given to goats of any age as a series of subcutaneous injections of 1 ml, at no more than 6-week intervals when protection is required during the barber’s pole worm-risk season. Note that animals in very poor condition or ill-health may not develop the required level of immunity.

In the first season, the first two vaccinations do not provide protection, but they prime the goat’s immune system. Protection occurs about 10 days after the third vaccination, and lasts for up to 6 weeks.

The first 3 vaccinations are generally given 4 weeks apart and further vaccinations no more than 6 weeks apart while there is a barber’s pole worm risk, or more frequently (for instance, each 4 weeks) in those years and situations where animals are exposed to very heavy challenge from barber’s pole worm.

The initial 3 vaccinations can be given as fast as 2 weeks apart if priming and immunity needs to be achieved very rapidly, such as starting a herd on Barbervax® when the barber’s pole risk is already high. Likewise, they can also be given further apart if there is no hurry to develop the immunity, for example, if administered at convenient times during a low barber’s pole risk time of year (so that immunity is ready when the risk increases).

It is likely that, similar to sheep, once goats have received an initial course of vaccine in one barber’s pole worm season, a single booster injection in a subsequent season will typically provide protection from about 10 days post-vaccination for up to 6 weeks without the need for a second priming dose. Subsequent vaccinations are continued 6-weekly (or sooner) during the risk period.

  • Vaccination with Barbervax® in goats causes temporary pyrexia a day later. On average, this rise in body temperature is less than one degree centigrade and lasts for only one day and owners are unlikely to notice any indication of this in their goats. No adverse signs were observed in any of the goat studies.
  • Barbervax® is not a knockdown product, but rather a protective immunising treatment against barber’s pole worm. When used in goats it relies on concurrent monitoring to assess the effectiveness of the vaccine against barber’s pole worm and the level of scour worms (which the vaccine does not affect).
  • The vaccine can be overwhelmed by very high worm challenge, so the use of low worm-risk paddocks is recommended. If such preparation is not possible, more frequent drenching may be required while immunity is building in goats.

Using small amounts of vaccine
The Barbervax vaccine comes in 250 ml and 100 ml packs. It includes a standard statement to use the contents within 12 hours of broaching the pack. However, veterinarians may need to dispense small amounts. The best approach is to use an aseptic technique and divide the entire contents of the pack into sterile syringes (sizes to suit clients) at the same time, keeping them refrigerated—not frozen—until use, but no longer than the pack expiry date.

Vaccination and Monitoring schedules

Start the Monitoring schedule and the Vaccination schedule at the same time.

Monitoring schedule

  1. Conduct a WormTest and larval culture at the time of the first vaccination.
  2. Drench only if the worm egg count exceeds 500 epg, otherwise continue testing at 4-weekly intervals until a drench is required.
  3. Exactly 14 days after drenching, collect a faecal sample and conduct another WormTest and culture.
  4. DrenchCheck: Use the results from just before the drench and 14 days after the drench to calculate the percentage reduction in worm egg count (use culture results to calculate WEC for each species). If efficacy is less than 98%, use a more effective combination next time and DrenchCheck any new drench combinations when used.
  5. Thereafter, WormTest and culture 7–10 days before each Barbervax vaccine is given.
    Drench at the vaccination time if barber’s pole worm count exceeds 800 epg or scour worms exceed 500 epg.
    If WormTests are not feasible in smallholder herds, instead carry out these two assessments on every individual animal and drench individuals (not the whole mob) as required:
    1. Conduct FAMACHA® assessments of eye conjunctiva colour weekly (high-risk times) to fortnightly.
      Drench if conjunctiva is white to medium pink (FAMACHA colours 5, 4 or 3. Do not drench if darker pink, score 2. Goats are rarely the Score 1 red colour of healthy sheep.
      This assessment is cheap, but very subjective. It requires practice and may not identify the need for drenching as early as a WormTest.
    2. Assess Body Condition Score at each vaccination.
      A loss in body condition despite adequate nutrition may indicate scour worm infection (not affected by Barbervax® vaccine).
      Drench if animals are Body Condition Score 2 or less or have dropped a score during the last month.

Vaccination schedule

First season of use

  1. The first Barbervax® vaccination (V1): ideally 2 months before higher-risk periods for barber’s pole worm. First priming dose (protective immunity is not achieved).
  2. The second Barbervax® vaccination (V2): 2­–4 weeks after V1.
    Second priming dose (protective immunity is not achieved).
  3. The third Barbervax® vaccination (V3): 2–4 weeks after V2.
    Protective immunity is achieved about 10 days after V3.
  4. The fourth and further Barbervax® vaccinations: 4–6 weeks apart during times of barber’s pole worm risk. This may be all year in warmer, wetter districts.

Subsequent seasons of use (for animals that have received priming doses in a previous year)

  1. The first Barbervax® vaccination: ideally 2 weeks before higher-risk periods for barber’s pole worm commence. Further priming doses are not required. Protective immunity is achieved about 10 days after V1 in the second season an animal is vaccinated.
  2. The second and further Barbervax® vaccinations: 4–6 weeks apart during times of barber’s pole worm risk. This may be all year in warmer, wetter districts.
Which drench?

Pour-on products can be less effective and their use overseas has led to widespread resistance.  Similarly, long-acting injections should be avoided as they increase the likelihood of drench resistance developing.  Always use an effective, short-acting, multi-active drench. This will help to slow the development of drench resistance. The more actives, the better. Rotating drenches does little to slow drench resistance.

It is better to continually use a combination of 4 actives, where most of the individual actives are fully or highly effective in their own right, than to rotate between less effective or single-active products. However, drench resistance is widespread. Do not assume that 3- or 4-way multi-active commercial products are 100% effective on all properties; do a DrenchCheck to be sure.

You will need to use more than one drench concurrently (not mixed together) to achieve the desired combination effect, as ready-made combination drenches do not have enough required actives for this purpose.

Use at least 4 of these actives with either or both derquantel and monepantel as mandatory inclusions:

  • Monepantel
  • Derquantel
  • Abamectin or moxidectin (ML group) (ivermectin is not recommended as it is less potent)
  • Levamisole
  • Albendazole or fenbendazole or oxfendazole (BZ group)
  • Closantel

Dose rate

BZ drenches (if not in a combination): 2 x sheep dose rate.
All others, including commercial combination products: 1.5 x sheep dose rate.

Prescription

It is recommended that all drenches be used off-label, even those registered for use in goats, because all should be administered at dose rates higher than shown on the label. As such, they all require a veterinary prescription.
Each veterinarian should consider their decision about the withholding period based on:

  • Whether the product is registered for goats and hence has a MRL, but is being used at a higher dose rate.
  • The ability of goats to metabolize drenches more rapidly than sheep.
  • Whether the product is not registered for use in goats and hence needs to be below the Level of Reporting if any is found in meat products.
  • The likelihood of these goats or their products entering the human food chain.
Danger

Startect® and Zolvix Plus® (but not Zolvix®) also contain abamectin. To avoid toxicity from overdosing, do not use them with another drench that also contains abamectin, moxidectin or ivermectin, e.g. Q Drench®, most triple actives, and single-active ML products.

The organophosphate active, Naphthalophos, is not recommended in smallholder flocks due to the risk of fatality from drenching into the trachea.

Scour worm treatments

Barbervax® does not stimulate immunity to scour worms, which can build up over time during a Barbervax® program. When monitoring indicates a scour worm treatment, ensure the drench combination contains at least 1, but preferably 2, of the following actives: monepantel, derquantel or an ML.
Closantel is not active against scour worms and there is widespread resistance of scour worms to BZ and levamisole.

Examples of drenches that could be used concurrently for barber’s pole worm control

  • Zolvix® and Q drench®
  • Startect® and Zolvix® and a Levamisole/BZ combination product
  • Startect® and a Levamisole/BZ combination product and a closantel product
  • Zolvix Plus® and a Levamisole/BZ combination product and a closantel product
  • Zolvix® and a Levamisole/BZ/ML combination product and a closantel product

Startect®, Zolvix® and Zolvix Plus® degrade some plastics and syringes. Veterinarians should ensure they are dispensed in an appropriate container. A copy of the original labels should also be provided with all drenches dispensed.

Product names and actives

Proprietary names have been used above where they are the only commercially available product for that active/s.

  • Q drench®      = oxfendazole (BZ), abamectin (ML), levamisole, closantel
  • Startect®         = derquantel + abamectin
  • Zolvix®          = monepantel
  • Zolvix Plus® = monepantel + abamectin

The other actives are available in a number of commercial single and multi-active formulations.

Dairy goats

Many product labels state that the drench must not be used on animals whose milk may be used for human consumption.  A veterinarian’s prescription cannot override a “DO NOT USE” statement on the label. Labels must therefore be read very carefully.  Some BZs and Caprimec® and Virbamec Oral® are registered for use on dairy goats and have a milk withholding period. In addition, Copper Oxide Wire Particle (COWP) boluses can be used in goats to treat barber’s pole worms and, if combined with a drench, can improve the efficacy of drenches where some resistance may be present.  These are already registered for use in goats for preventing copper deficiency and have a nil withholding period.