Alpaca Articles

RYE GRASS STAGGERS

By Nic Cooper Southern Alpacas Stud and Lisa Collier Solitaire Alpacas

The research done in New Zealand on Rye Grass Staggers, and its effect on the more usual farm animals such as deer and sheep, 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.

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. 
 

RYE GRASS

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 affliction 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.

Our thanks to 
Lester Fletcher
for his input 
to Rye Grass background, 
and research work 
in other livestock.
 

Thanks to those 
who participated in the alpaca breeder survey

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.
 

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.

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 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.  Most farm paddocks are primarily endophyte rye grass, so for most of us that means spraying out and re-sowing paddocks. 

The question of using a rye grass at all should be asked. There are a number of nil endophyte rye grasses available (from our experience the low endophyte grasses are not effective with alpacas).

Recently 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. 

In our experience, over a couple of years the AR1 cultivars get infested with the usual rye grass, re-colonising from seeds from nearby paddocks.

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. 

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 them 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 from the herd.

Move 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:

1) Equiguard sprinkled on the alpaca's feed to remove and bind the toxins - one measure per alpaca on chaff or lactating mix or similar chopped feed

2) Cocktail Vitamin B (e.g. mulitject - B) or Thiamine (B1), or "B Calm" injections.

3) Drenching with EHE (a horse mix of Cider Vinegar, Manuka Honey and Garlic) -- alpacas like this mixture!

We have found nothing to cure staggers once it has truly set in.

Prevention is truly better than cure.
 

Updated December 2008