Health
Natural management of parasites
By Av Singh, Agriculture Canada
Jul 22, 2003, 17:21

Parasitic diseases are one of the more serious problems facing livestock producers, often causing economic and production losses. For those farmers interested in organic or natural production of meat, synthetic dewormers such as anthelmintics or parasiticides are restricted and, in some cases, prohibited. Also, increased resistance to dewormers, growing concerns regarding parasiticide residues in meat, and harm to non-target species such as those that help decompose manure have producers looking for alternatives.

The following are some of the innovative practices being used to limit parasite infestation.

Grazing animals are often exposed to parasites and the likelihood of being reinfected is greater than with confined animals. Internal parasites therefore pose a greater challenge for organic livestock producers because of a higher reliance on pastures.

For most organic or natural producers, a “zero tolerance” approach to internal parasites is not a desirable goal. Preventative practices may not be economically feasible and many producers want their animals to have controlled exposure to parasites to help build immunity. Ideally, the objective is to develop an animal production system where parasites may be present in small numbers, but do not affect animals’ health or performance.

Herd management
An animal can resist or tolerate internal parasites better when its living condition are good. In barns, animals should be fed from feeders rather than from the ground to avoid contamination.

Vitamins and minerals can play a key role in affecting ruminant susceptibility. Vitamins A, D and B complex are integral in developing immunity to parasites, while iron and cobalt, which are used to synthesize vitamin B12, are essential minerals.

Pasture management
High stocking rates have a direct correlation with increased parasite load. If parasite infestation is a problem, lower stocking densities are recommended. This reduces the amount of manure in a given area and the residual grazing height is often higher.

Leaving a residue greater than four inches will lower the probability of parasite infection significantly, considering 80 percent of parasites live in the first two inches above the ground.

The risk of infection is also lowered by waiting to put animals out to pasture after the dew has lifted, or until the grass has dried after a rain. Drier conditions force parasites to stay at the base of plants where they are less likely to be eaten.

Pastures that have been harvested for hay, silage or small grain crops can generally be considered safe. Pastures grazed by other species for a season or longer are considered safe because only a small amount of cross infection occurs between the species.

The type of forage growing in a pasture may also determine parasite loads. Generally, grass-dominant pastures contain more parasite larvae than pastures containing forbs such as chicory, or legumes such as alfalfa and birdsfoot trefoil, mainly because of the increased levels of condensed tannins.

The common practice of harrowing pastures to break dung pats is not recommended. Dragging manure pats across pastures may scatter parasite eggs and larvae, making it difficult for animals to selectively graze away from infected areas. Harrowing may be beneficial just before a dry period, or when a pasture will be rested for a long time.

Alternatively, dung-burying beetles and free-ranging chickens help break down dung pats, reducing the environment for parasite infestation.

Alternative dewormers
As a last resort, organic livestock producers can carry out deworming treatments. All treatments involving natural products should ideally be preceded by a fasting period and followed by a laxative period. Many of these natural dewormers can be considered poisons. Therefore, it is essential to follow indicated dosages.

Most botanical dewormers can be also found as homeopathic preparations, which are free of side effects and do not require a fasting or laxative period.

Common botanical dewormers include garlic in pills or powders, fresh tinctures such as wormwood or Aretmisia spp., wild ginger or snakeroot, goosefoot, conifers, mustard, squash or pumpkin seeds, carrot and fennel seeds, and pyrethrum, a plant extract from chrysanthemum.

Other products used as dewormers include diatomaceous earth and charcoal, which are often added to the ration, and peroxide, copper sulfate and Shakelee’s Basic H surfactant, which are added to water. (Certain organic certifying bodies may not accept Shakelee’s Basic H surfactant).

Despite access to synthetic parasitides, organic farmers continue to rely on fine-tuning their nutrition regimes, herd and pasture management, and field and soil practices so they can learn to coexist with parasites.


© Copyright 2003 by Deerfarmer.com
Deer Farmers' Information Network
www.deerfarmer.com