In any animal herd, culling for parasite resistance can be a beneficial and cost effective practice. Mike McClintock, Boone County Cooperative Extension Agent for the University of Arkansas Department of Agriculture Extension is familiar with the purposes and benefits behind culling for parasite resistance in a goat herd. Internal parasite management, especially of the round worm, nematode and stomach worm, is a primary concern for many sheep and goat producers. These parasites have become more difficult to manage because they have developed some resistance to most available dewormers.
McClintock urges producers to realize that it’s a long term process to cull for natural parasite resistance. This is because there’s a small chance that this trait is passed to offspring. Natural resistance will vary from animal to animal. He continued, “The first step in selection is a complete set of production records, like when you wormed, what and how much and comments on the results.” He also recommended using the worm fecal counts and the FAMACHA systems of diagnosis to determine which animals will need re-treatment of dewormer. The FAMACHA system involves comparing the color of the mucous membrane of the eye against a FAMACHA color chart in order to determine the level of infestation by internal parasites.
“If a producer has exhausted several repeated methods of parasite elimination, it is probably time to send the animal to market,” added McClintock. When determining whether or not to cull an animal, pay close attention to the offspring of an animal that has been heavily infected. If there are indicators that the offspring carries the low-resistance to parasites, that would be reason to cull the offspring as well. McClintock continued with, “Conversely, the goats that seldom require the rigorous regiments of dewormers should be identified. Their offspring will be more likely to have the resistance abilities of the dam. These kids would definitely be keepers as replacements.”
In time, often a few years, the owner should see positive results in the overall health of the herd.
This type of culling is no different than culling for reproductive or production performances.”
"This type of culling is an important practice for producers to follow if they wish to stay profitable in the long run. But in addition to culling, pesticides are important as well. There aren’t many dewormers that are intended solely for goat production.
McClintock recommended developing a relationship with a veterinarian in order to gain access to dewormers that may be prescription only. And he added that many of the problems that have developed in goat herds have come about from a ‘one-size-fits-all’ mentality. Mass worming when not needed, continual use of the same product year after year, and under-dosing are all practices that have contributed to the goat pestilence problem. Just because one method works on your neighbor’s property doesn’t mean it will work on yours. It’s recommended to work closely with your veterinarian to develop a method (which usually should include rotating between different dewormers) that works best for your herd.
McClintock also suggested producers keep an open, yet cautious mind to natural and alternative dewormers. Base your reasoning on research with proven results. As McClintock put it, “There are no magic bullets that only XYZ company knows about.” Usually proven methods and products with a long-standing reputation are your best bet.
