by Deb Maxwell, ParaBoss Operations Manager

August 2015

 

It's been a year since the limited release of the Barbervax® vaccine in 2014, and it's now time to ask “is this vaccine going to help solve the barber’s pole worm problems?”

When asking this question it is important to consider if Barbervax is effective, value for money, reasonably convenient and easy to use. So how does this new vaccine—which is only for barber’s pole worm, not scour worms—measure up?

How it works

This is not a knockdown product, like a drench. A vaccine relies on priming doses to stimulate the sheep’s immune system to produce antibodies that kill barber’s pole worms. It takes three priming doses to achieve protection, which is one more dose than for other vaccines that we are used to using, and its protection lasts for six weeks after each dose.

When a sheep first receives Barbervax, three doses of the vaccine are required to reach an effective level of antibodies. But for sheep already primed the previous year, effectiveness occurs about ten days after the first vaccination of the season. Subsequent doses are given each six weeks through summer and autumn until barber’s pole worm is no longer a risk.

Editor's note (December 2015): Barbervax is now registered for use in sheep of any age. See the Barbervax program.

Effectiveness

Yes, it is effective—but only if you follow the directions; a hard lesson already learned in the last year by those trying to take short cuts.

Once the immune system is primed and effective levels of antibodies are being produced, sheep can kill most, but not all, of their existing and incoming barber’s pole worms. Worm egg counts due to barber’s pole are generally kept below 500 epg—a safe level, and well below that causing production effects.

The Barbervax vaccine works where drenches fail against barber’s pole worm due to drench resistance, and the history of other vaccines indicates that worms are unlikely to become resistant to it.

Value for money

The Barbervax vaccine retails for 64c per dose (excluding GST), but it cannot be used as a one-off treatment. Priming doses are essential before it becomes fully effective, so it needs commitment to a ‘season’s-worth’ of treatment—usually five doses for lambs/weaners. This equals $3.20 per sheep (regardless of bodyweight).

You should also factor in the possibility of needing to use conventional drenches if scour worms are a problem or there is already a high barber’s pole worm burden during the priming stage of using the Barbervax vaccine. For lambs, a weaning drench is still essential because:

1. Scour worms may be present.
2. Weaning generally coincides with the start of the high barber’s pole risk time and if rains fall in late October and early November immunity from the vaccine may not have had time to kick in.

In comparison, existing worm control costs vary markedly across properties (see Table 1 at the bottom of this article for some current drench prices). Consider not just the drench costs but costs from sheep deaths and whether the drenches are effective on your property.

When Barbervax is properly used, there should be no deaths or illness from barber’s pole worm. There will always be a tiny proportion of animals that do not respond to a vaccine, even when correctly given. The flock immunity will keep the worm challenge low and these few sheep, unless they are particularly susceptible to barber’s pole worm, will generally stay healthy.

A single dose of Barbervax is quite a bit cheaper than a long acting drench and the newer knockdown (short-acting) drenches, but requires a commitment to five doses, usually. It is reasonably priced considering its prolonged effect, and will be even better value in the second and subsequent years it is given to each mob as the primer doses are not required.

Ease of use

It’s a subcutaneous injection—not as easy or fast as a drench, but not rocket science. It pays to be attentive and careful when administering, just as for other vaccinations and injectable products such as long-acting moxidectin.

Convenience

Here is where the vaccine certainly has some pros and cons.

On one hand, Barbervax has no Withholding Period or Export Slaughter Interval, so it can be used without concern before animals go for slaughter.

On the other hand, it’s not an annual one-shot vaccine. With five doses usually required in the first year and only six weeks sustained effectiveness after the third and each successive dose, extra labour requirements to muster and treat might be significant. Whether this is an inconvenience for you depends on how many drenches you would have given over the same period.

If you have out-of-control barber’s pole worm and are drenching every month or so during summer and early autumn in most years, then this product is a superior alternative. 

Barbervax will fit into existing WormBoss programs along with other tools like grazing management and breeding worm resistant sheep. For some people (like myself, even in the worm-heaven of Guyra, NSW), the WormBoss Program for summer rainfall areas is a God-send. I now only drench two or three times a year by religiously following the fairly simple grazing management process and I breed my sheep for worm resistance.

The Barbervax program is not a complete alternative to drenching or conventional worm management. Some drenches are still required as is worm testing to check progress—though with time, and a continued vaccination program, monitoring needs may decrease.

So, is the Barbervax vaccine for you?

I believe you should consider it strongly if you:

1. Are the type of person who can commit to a program and follow it.
2. Want a low risk effective program, where you can follow a recipe and know it will work.
3. Are currently drenching lambs/weaners four or more times per year for barber’s pole worm.
4. Are experiencing occasional deaths each year from barber’s pole worm (where there are a few deaths, there will also be less obvious, but nonetheless significant production losses).
5. Have few effective drenches left on your property or want to preserve the effectiveness of your drenches.
6. Like the idea of an organic/natural approach to worm control or are a prime lamb producer who wishes to use a product without a Withholding Period or an Export Slaughter Interval.

Further information:

• The Barbervax vaccine program
• More about the vaccine and its development
• Where to buy Barbervax—currently it is available through Grazag

Table 1. Typical costs of drenches (prices from Landmark Guyra, August 2015)

Drench product	Drench resistance in barber’s pole worm	Length of protection	Cost per sheep
			30 kg	50 kg
Levamisole e.g. Nilverm	Moderately common	1–2 days	4 c	7 c
Benzimidazoles e.g. Valbazen	Very common	1–2 days	8 c	13 c
Naphthalophos e.g. Rametin	Very rare, though effectiveness is not 100% on immature worms	1–2 days	10 c	17 c
Closantel e.g. Closicare plus Se	Very common	28 days	15 c	25 c
combination drench: BZ/LEV e.g. Duocare LV with Se	fewer than with single actives	1–2 days	8 c	14 c
combination drench: BZ/LEV/ML e.g. Triguard	fewer than with single actives	1–2 days	28 c	47 c
combination drench: BZ/LEV/ML/CLOS e.g. Q-Drench	fewer than with single actives	1–2 days	29 c	48 c
Monepantel e.g. Zolvix	Rare	1–2 days	64 c	107 c
Derquantel (+ abamectin) e.g. Startect	None reported	1–2 days	59 c	99 c
Long acting moxidectin e.g. Cydectin LA	Common, also resulting in shorter duration than the claimed 91 days	91 days (shorter against scour worms)	83 c	138 c