Ryegrass Staggers - an issue of awareness and management.
Authors: Nic Cooper - Southern Alpacas Stud, Lisa Collier - Collier
NZ Alpacas
For many years, rye grass has been a basic component of New Zealand pastures,
especially in the middle and lower latitudes.
Rye grasses suffer from attack by insects such as Argentine Stem Weevil
and black beetle, which curtail their production life. As a result commercial
varieties have been developed that have a symbiotic relationship with
a fungus, an endophyte, that lives inside the grass, concentrating in
the seed-head and the lower stem. The endophyte gains nutrition from the
grass, and also releases toxins (chemicals) that protect the rye grass
from insect attack.
There are 3 main chemicals produced - Peramine (a natural insecticide),
Ergovaline, and Lolitrem B. It is Lolitrem B that causes major stock problems,
particularly the infliction called "Rye Grass Staggers".
Generally endophyte rye grasses will last a long while, whereas nil endophyte
rye grasses last only a few seasons before needing re-sowing.
RESEARCH:
There has been quite some research done in New Zealand on Rye Grass Staggers,
and its effect on the more usual farm animals such as deer and sheep and
much of this work has been concentrated in Canterbury. Whilst there has
been a lot of translation of effects and cures from sheep and horses to
alpacas, no research has yet been done specific to alpacas.
Recently, in a school project, Lisa Collier (alpaca owner in Canterbury)
conducted some research into this topic and this forms the basis of this
article, which tries to draw some conclusions for alpacas and alpaca management.
The research took the form of a literature search, a wide web search,
talking to scientists noted for their work on rye grass staggers in other
animals, and conducting a limited survey of alpaca owners.
It should be noted that the small population sampled does not allow definitive
conclusions, but it does allow areas to be identified for possible future
study.
 DO
ALPACAS GET RYE GRASS STAGGERS?
The answer is emphatically YES. In fact the scientist specialist involved,
Lester Fletcher from AgResearch, said he was "convinced that alpacas
are more susceptible than other animals" to ryegrass staggers. Some
alpacas seem more susceptible than others. In particular the younger animals
appear to be more susceptible. This research project has indicated that
this is so, with the vast number of responses being in relation to alpacas
under 12 months of age.
Even cria only weeks old can display symptoms, although whether this
is passed through dam's milk, or ingested directly, is unclear.
Research has been done in sheep that indicates that there is a strong
genetic susceptibility to ryegrass staggers, particularly a genetic link
from the sire. This formed the basis of a question in the alpaca owner
survey. With this research being from a small database it would be hard
to draw definite conclusions. However the research does show a correlation
that indicates further work on this linkage might be fruitful.
It has also been hypothesised that susceptibility to staggers is linked
to colour, particularly to the presence of a lightener gene. [The lightener
gene lightens browns to various shades of light fawn, very close to white,
and lightens blacks to greys].
This information gathered is again from a small database
The high proportion of whites and fawns reporting staggers is not in
line with survey population proportions, so this area may also warrant
some further investigation.
 WHAT
DOES RYE GRASS STAGGERS LOOK LIKE?
It is sometimes hard to notice the early stages of ryegrass staggers.
It usually begins with a slight tremor of the head that is most noticeable
when an animal is stressed. It can worsen quite quickly and a noticeable
shake may soon appear. In bad cases an animal will stagger violently,
trip over and even fall down.
The symptoms of the damage become exaggerated when the alpaca is under
any form of stress, including management, and
even movement.
Rye grasses only create staggers in stock in certain conditions. It tends
to be present from late spring through to late autumn, and is more prevalent
during drought, and particularly in the flush of grass growth following
drought. Staggers, therefore, tends to be minimal in the lower South Island
where moister, cooler summers are the norm, but more prevalent further
north.
Staggers tends to affect alpacas grazing the seed heads, as the endophyte
concentrates in the forming seed heads, and it can infect the seed gathered
for later sowing. It also concentrates in the base of the stem, which
means the staggers effect is more pronounced in pastures that are heavily
grazed.
What actually happens when susceptible alpacas graze on high endophyte
concentrations is that the toxin in the endophyte has a specific damaging
effect on the cells of the part of their brain that co-ordinates movement.
The damage can quickly become permanent. It can be prevented, and mitigated
by pasture and animal management, and treatment in its early stages. It
cannot be cured.
One Australian breeder believes he can always pick an alpaca that has
had ryegrass staggers by the look in its eye!
It is worth noting that Rye Grass is not the only grass to create "staggers-type"
symptoms. In sheep, staggers symptoms have been noted to a very extreme
extent on Phalaris grass pastures, and similar "rye grass" symptoms
can be seen in animals suffering from a magnesium deficiency.
PREVENTION AND MANAGEMENT:
Prevention is by far the best way of managing this problem, and prevention
starts with pasture management.
Either do not have endophyte rye grasses in your pastures, or have some
paddocks that are free of endophyte rye grass to keep your most susceptible
animals in at the high-risk times of year. However, because most basic
farm paddocks are primarily endophyte rye grass, for most of us that means
spraying out and re-sowing paddocks - an expensive, time- consuming, and
not always successful process.
If starting from scratch, maybe the question of using a rye grass at
all should be asked (after all I remember some research somewhere indicating
rye grass was not the alpacas favourite grass!). But if you do want to
use a rye grass, there are a number of nil endophyte rye grasses available
(from our experience the low endophyte grasses are not effective with
alpacas). And this season a new endophyte rye grass has been introduced
that produces (the good) Peramine, but not (the bad) Lolitrem B or Ergovaline.
These are called "AR1" cultivars. If re-sowing is not attractive,
at least a top sow (direct drill) of other grasses and herbs will dilute
the endophyte effect for a couple of seasons. [This is not a place for
discussing alpaca friendly pasture mixes. Traditional pasture mixes are
focused to the needs of other stock, that are very different from those
of alpacas, and pasture development for alpacas is a vital issue for the
industry in the next few years.]
Next, if you have rye grass paddocks, practice regular topping of these
paddocks to avoid seed head creation. Avoid these paddocks if they are
well eaten down during drought, and especially in periods of lush growth
following drought.
If you do have alpacas that develop rye grass staggers, there are a number
of early stage mitigation techniques, but the most important is to remove
the affected alpacas immediately and entirely from the rye grass. Because
stress exaggerates the staggers effect, taking a couple of companion animals
along as well for company will minimise the stress of being isolated form
the herd. Move them onto a specially sown paddock, or feed hay. But remember
that hay made from toxic endophyte rye grass will itself retain the toxicity,
as hay!
Anecdotally, we have found that the following can assist in aiding an
alpaca in the early stages of rye grass staggers:
- Cocktail Vitamin B (e.g. mulitject - B) or Thiamine (B1), or "B
Calm" injections.
- Drenching with EHE (a horse mix of Cider Vinegar, Manuka Honey and
Garlic) -- alpacas actually really love this mixture!
- Drenching with Bio-Mos, a Nutritech product used for staggers in
horses, that is supposed to actually stimulate excretion of
the toxin.
We have found nothing to cure staggers once it has truly set in.
Prevention is truly better than cure.
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