Scouring, poor weight gain, poor coat quality, bottle jaw, lethargy, death. These are all words that come to mind when thinking about internal parasites in farmed animals. Worms can be a silent killer for any animal that grazes pasture and alpacas seem to be particularly prone especially under high stocking rates. As soon as crias begin to graze, they are likely to be ingesting worm larvae. Most animals don’t develop much immunity against worms until they are 1 year old and peak immunity is obtained around 18months. This means that adult animals are still eating larvae but less are allowed to develop in the gut and produce eggs. Young stock are most at risk of parasitic disease due to a lack of this immunity. There are many ways to reduce the effects of parasitism including drenching, lowering stocking rates, cross-grazing, resting paddocks and supplementary feeding.
Drenching is the only effective way to eliminate current parasite burdens and some drenches will also prevent re-infection. There are a lot of products available that contain different ingredients that have unique strengths and weaknesses. This is a vast subject and not all drenches are created equal so please ask for assistance from a vet when deciding on which drench is best for your animals. For instance, drench choice can be affected by: age and type of stock, time of year, finances, drench resistance and species of worms to be killed. To check for drench resistance a faecal egg count reduction test is performed. This can easily be carried out at your vet clinic- please ask for more details. Every time we use a drench, resistance can develop so it is important to use drenches sparingly and know the resistance status of your property.
The worm that kills sheep, goats and alpacas most often is Haemonchus contortus (Barber’s pole). It is found in the abomasum (4thstomach) and sucks blood. This causes severe anaemia even in adult animals and results in weakness, fluid accumulation under the jaw, pale membranes in the eyes and mouth and can ‘suddenly’ lead to death. Using a long acting drench such as Genesis ultra will provide protection against this worm for 56 days. This is a good drench to use from January through to about May as this worm thrives in hot, humid conditions. Performing faecal egg counts before drenching will give an indication of whether or not your animals need treating.
By lowering stocking rates, there will be more pasture available and animals will graze away from faecal matter thus reducing intake of larvae. Most larvae are in the base of the sward so longer grass equals less ingestion. Alpacas and cattle don’t share the same worms in general (alpacas and sheep/goats do). This means that grazing the two together or following a mob of cattle with alpacas will reduce the viable larvae on the grass. The alpacas will eat the cattle worm larvae and destroy them in the gut (and vice versa).
Resting of paddocks is not very practical in NZ (especially around Auckland) as temperatures are high enough all year to allow larval development. To effectively rid a paddock of larvae, it must realistically be re-sown or put into crop. By grazing crops and feeding hay/grain, animals are grazing less and therefore have a lower parasite challenge.
Please monitor your animals closely for signs of parasitism before deaths occur, as you could not only be saving money but also lives.