Parasite Control Program
Link to article on equine parasite control published in the Horse magazine, Feb. 2010, Grass-Roots Parasite Control. This is an ongoing study of the effect of rigorous pasture management on deworming frequency in our mustang horses.
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Raw data and plot of eggs counts per gram (EPG, strongyles) for the period August 8, 2007 to September 24, 2009. Detection level is 25 EPG. A "zero" entry in the table indicates that no eggs were observed at this detection level. Target egg count for deworming (200 EPG) was reached on 5/24/2009. As of March 2015, egg counts are "0" and 50 EPG for Mesteño and Nevada, respectively.
Normally egg counts peak in September-October as the horse ingests infective larvae in the pasture during the spring and summer months. In our case, the high egg counts in April-May are consistent with the overwintering of encysted L3 larvae that produce egg-laying adult worms in the spring. The web site published by the School of Veterinary Medicine at the University of Pennsylvania has some good information on the seasonal variation of strongyle egg counts
(http://cal.vet.upenn.edu/projects/merial/Strongls/strong_10b.htm).
Since May 2009, neither of these horses has been dewormed. Mesteño is negative at the 25 EPG detection level and Nevada's egg count has remained essentially constant at about 50 EPG. Our parasite control program is effective because of the highly controlled environment on our farm. Manure is regularly removed from pastures and not returned to the pastures as fertilizer until it has been composted for 1-2 years. In addition, we have a closed system, i.e., at present, horses do not leave or enter the farm. This is not a practical strategy for most horse farms. However, our results show what can be achieved under ideal conditions and, as such, provide important baseline information for other parasite control programs.
For more information on parasite control refer to the guidelines from the American Association of Equine Practitioners (AAEP) and the recent online source from the Horse magazine "Equine Parasite Control:Deworming and Beyond" by Christa Lesté-Lasserre.
Normally egg counts peak in September-October as the horse ingests infective larvae in the pasture during the spring and summer months. In our case, the high egg counts in April-May are consistent with the overwintering of encysted L3 larvae that produce egg-laying adult worms in the spring. The web site published by the School of Veterinary Medicine at the University of Pennsylvania has some good information on the seasonal variation of strongyle egg counts
(http://cal.vet.upenn.edu/projects/merial/Strongls/strong_10b.htm).
Since May 2009, neither of these horses has been dewormed. Mesteño is negative at the 25 EPG detection level and Nevada's egg count has remained essentially constant at about 50 EPG. Our parasite control program is effective because of the highly controlled environment on our farm. Manure is regularly removed from pastures and not returned to the pastures as fertilizer until it has been composted for 1-2 years. In addition, we have a closed system, i.e., at present, horses do not leave or enter the farm. This is not a practical strategy for most horse farms. However, our results show what can be achieved under ideal conditions and, as such, provide important baseline information for other parasite control programs.
For more information on parasite control refer to the guidelines from the American Association of Equine Practitioners (AAEP) and the recent online source from the Horse magazine "Equine Parasite Control:Deworming and Beyond" by Christa Lesté-Lasserre.
Setting up your own parasitology lab
Basic lab for determining fecal egg counts using the McMaster technique. Other than a microscope, you will need a standardized fecal solution for floating the eggs, McMaster slides, an assortment of glassware, a strainer and funnel, and some exam gloves. More accurate results can be obtained by centrifugation of the fecal solution, although this method is more time consuming. Photo by GA Lager
Update on parasite control program(October 6, 2011)
ELISA tapeworm antibody test
Blood serum for the antibody test was collected from Nevada and Mesteño and submitted to the University of Tennessee (UT) Immunology Laboratory, College of Veterinary Medicine. I thought the ELISA results would be interesting for a number of reasons: 1. As noted above, Nevada and Mesteño have very low egg counts (Mesteño, negative; Nevada, 50 EPG strongyles, as of Jan. 2012) and have not been dewormed since May 2009. The interval between deworming is significant because high antibody titers can be observed 6-8 months after tapeworms have been cleared from the gut. 2. Based on results from Dr. Craig Reinemeyer’s work, about 70% of the horses in the Kentucky-southern Indiana area have been exposed to tapeworms. In his study, blood serum collected for Coggins’ tests from laboratories around the country was analyzed using the ELISA method developed at UT. 3. Are the results from the antibody test consistent with the negative obtained in my small home lab using centrifugation/floatation of a large fecal sample (40 g)? For a discussion of the merits of centrifugation/floatation versus ELISA for detection of Anoplocephala perfoliata tapeworm infection see the paper by KJÆR et al. (2007) published in the Equine Veterinary Journal.
The results of the test indicate that no IgG(T) antibody reactive with A. perfoliata antigen was detected for either horse, which is strong evidence for lack of infection. Note that the positive control sera used in the test are from horses confirmed at necropsy to have equine tapeworms. The positive control value was set as 100% reactivity (Dr. Stephen Kania, Director of Immunology Lab, pers. comm.).
ELISA tapeworm antibody test
Blood serum for the antibody test was collected from Nevada and Mesteño and submitted to the University of Tennessee (UT) Immunology Laboratory, College of Veterinary Medicine. I thought the ELISA results would be interesting for a number of reasons: 1. As noted above, Nevada and Mesteño have very low egg counts (Mesteño, negative; Nevada, 50 EPG strongyles, as of Jan. 2012) and have not been dewormed since May 2009. The interval between deworming is significant because high antibody titers can be observed 6-8 months after tapeworms have been cleared from the gut. 2. Based on results from Dr. Craig Reinemeyer’s work, about 70% of the horses in the Kentucky-southern Indiana area have been exposed to tapeworms. In his study, blood serum collected for Coggins’ tests from laboratories around the country was analyzed using the ELISA method developed at UT. 3. Are the results from the antibody test consistent with the negative obtained in my small home lab using centrifugation/floatation of a large fecal sample (40 g)? For a discussion of the merits of centrifugation/floatation versus ELISA for detection of Anoplocephala perfoliata tapeworm infection see the paper by KJÆR et al. (2007) published in the Equine Veterinary Journal.
The results of the test indicate that no IgG(T) antibody reactive with A. perfoliata antigen was detected for either horse, which is strong evidence for lack of infection. Note that the positive control sera used in the test are from horses confirmed at necropsy to have equine tapeworms. The positive control value was set as 100% reactivity (Dr. Stephen Kania, Director of Immunology Lab, pers. comm.).
Alternative deworming methods (April 15, 2015)
We are currently trialing the herbal dewormer Verm-X. Updates on this new deworming program will be forthcoming. In the meantime if you would like to learn about herbal remedies in general link to these presentations (part 1 and part 2) by UK holistic veterinary surgeon Dr. Nick Thompson on "Intelligent use of herbs in animal husbandry". Originally developed in the UK, Verm-X products are now available to horse owners in this country through Amazon.
We are currently trialing the herbal dewormer Verm-X. Updates on this new deworming program will be forthcoming. In the meantime if you would like to learn about herbal remedies in general link to these presentations (part 1 and part 2) by UK holistic veterinary surgeon Dr. Nick Thompson on "Intelligent use of herbs in animal husbandry". Originally developed in the UK, Verm-X products are now available to horse owners in this country through Amazon.
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