Internal parasites in ruminants constitute a problem that returns periodically in almost all livestock herds. The use of pharmaceutical dewormers is only a short-term solution. Animals that graze are always exposed to parasites and are thus constantly being reinfected. A serious pest control program for the goat producer begins with a good understanding of parasites and the use of preventive measures in combination with deworming medications.

 

General knowledge of the life cycle and characteristics of parasitic worms is helpful for the producer. Most parasites, whose host is the goat, have a direct life cycle. This means they only require one host (your goat) to complete their life cycle. There are a few exceptions, the liver fluke for one. It spends part of its cycle in certain snail species. Hence the lower occurrences of liver flukes in dryer parts of the country. Species that require more than one host are said to have an indirect cycle.

 

The cycle of the parasite in general terms begins with:

At this point it is interesting to note that goats are NOT grazers by nature. They are browsers. This means in effect that they will choose to stand on their hind legs to eat leaves and woody substance given the choice over grasses. When goats are kept in browsing conditions the parasite factor is greatly lowered, as the worms eggs are deposited on the ground, not in the trees. Unfortunately we the producers in the United States don't always have access to this type of "pasture"

Pasture management that is designed to reduce internal parasites requires long-term planning.

 

The first factor is animal density.Overpopulation increases the concentrations of parasites.

Pasture rotation consist of dividing the pastures into parcels of land called paddocks and frequently moving the animals from one paddock to another to optimize grass use. From a parasitic point of view, the objective is to not put the animals back into the same field until the risk of infection has diminished. Theoretically this means that parasitism will decrease if the number of parcels of land is increased or the rotation time is increased. Unfortunately, in practice, it appears difficult to diminish the parasitic load with intensive grazing. The lifespan of the L3 larvae is in fact always greater than the time required between grazing periods for maximum grass use. Therefore, if one waits six weeks before returning animals to a lot, the quality of the grass decreases as well as the quantity of grass ingested by the animals, whereas the level of parasites only diminishes slightly

About 80% of parasites live in the first 2 inches of vegetation. Thus Parasite infections are reduced by letting animals graze on grasses that are a minimum of 4 inches from the ground.

The drier the grass, the more parasites will stay at the base of the plants as parasites need moist conditions to survive. In moist conditions the larva can be found as high as 12 inches up the grass stem. The larva of the parasites also prefers low light conditions. Such as night, cloudy days, sunrise sunset. They avoid strong light conditions, intense dry heat and extreme cold.

Producers who have more than one animal species (cattle and goats) can graze the two different animal species together, although not fool proof this method can help to break the parasite cycles. Several parasite species cannot infect two different animal species. By grazing two species together part of the parasites will be ingested by a host that is not friendly to the parasite, ending its life cycle.

Fertilizers can and do change the mineral and ph balance of the soil creating a less than idea environment for the parasite

 

In the loafing areas where there is little to no grasses simply a resting or sheltered area we use hydrated (or barn) lime. Put down at a dept of approximately 6 inches. Lime is a very good drying agent and as seen parasites need moisture. It also serves to eliminate ammonia odors. It is not recommended to be put on pastures in this heavy of a concentration. For the pastures we use Urea, as it has a tendency to "clean" manure. Meaning it causes the manure to be less hospitable to the parasite. Composting of manure also accomplishes this. The internal temperature of composted manure should reach approximately 140 degrees F. Parasites are destroyed in as little as one hour at 122 degrees F.

 

Lastly but certainly not least is burning off of the pastures in late fall. While this does not eliminate all the larva it will certainly hinder more than a few. Consequentially burning the pasture requires the goats be moved to another area.Hopefully their winter pasture and the remaining parasites on the burn site will have to try and survive another season with out a host.

Veterinary offices conduct fecal analyses. These consist in identifying the species of parasites present in the animal and counting the eggs of the parasites per gram of stool. Results of the analyses are often expressed by the terms of: absence of parasites, low, average or high levels. In all cases, it is important to identify the parasite, so the appropriate dewormers can be used. Your veterinarian can assist you in this. I offer here two articles on parasite reductions. The first is authored by

 

Sue Reith
Carmelita Toggs
Bainbridge Island WA

 

and has been used with permission. I have used with good success her method. As with many producers though, I am unable to follow her method to the letter. In my instance I do not have a closed herd. Many of my goats are shown by 4 H kids also, goats are brought into my herd for breeding purposes, yet still I incorporate her method into my herd with good success. Each producer has unique situations and must monitor their own individual herds using what works for them and perhaps tweaking those methods that don't .What works for one may not be as effective for another due to individual circumstances. What we as producers CAN do is to acquire as much valid information as possible and apply what we have learned to our own situations.

 

The second article is written by

 

Dr Deb Mangelsdorf DVM

Konza Veterinary Clinic

Konza Kids Dairy Goats and meat goats

 

The article offers further advice on parasite management. Again it has been used with permission. I would like to thank both of these ladies for their articles.

 

Dawn Rush