External Parasites of Horses
http://edis.ifas.ufl.edu/ ( Publisher's URL )
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Permanent Link: http://ufdc.ufl.edu/IR00001429/00001
 Material Information
Title: External Parasites of Horses
Physical Description: Fact Sheet
Creator: Bradley, Melvin
Publisher: University of Florida Cooperative Extension Service, Institute of Food and Agriculture Sciences, EDIS
Place of Publication: Gainesville, Fla.
Publication Date: 1989
Acquisition: Collected for University of Florida's Institutional Repository by the UFIR Self-Submittal tool. Submitted by Melanie Mercer.
Publication Status: Published
General Note: "Date first printed August 1965. Date revised June 1989."
General Note: "section 13 of 14 of 4HHSG01, which supersedes CO 201"
 Record Information
Source Institution: University of Florida Institutional Repository
Holding Location: University of Florida
Rights Management: All rights reserved by the submitter.
System ID: IR00001429:00001


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NAME_________________________________________________________________________________________ ADDRESS_____________________________________________________________________________________ CLUB_________________________________________________________________________________________ 4-H HORSE PROGRAM HORSE SCIENCE This educational material has been prepared for 4-H use by the Cooperative Extension Services of the U.S. Department of Agriculture and State Land-Grant Universities in cooperation with the National 4-H Council and the American Quarter Horse Association. Trade or brand names used in the publications are used only for the purpose of educational information. The information given herein is supplied with the understanding that no discrimination is intended and no endorsement of products or breeds of horses by the Federal Extension Service or State Cooperative Extension Services is implied, nor does it imply approval of products or breeds of horses to the exclusion of others which may also be suitable. This material was originally published by the National 4-H Council, 7100 Connecticut Avenue, Chevy Chase, Maryland 20815. Programs and educational materials of National 4-H Council are available to all persons regardless of race, color, sex, age, religion, national origin or handicap. Council is an equal opportunity employer.


Horse Science: External Parasites Affectin g the Horse Pa g e 3June 1989Have you ever been aggravated by swarms of mosquitoes, irritated by ticks and chiggers, or agitated by fleas? These discomforts and many more are experienced by some horses for extended periods of time because of external parasites. A parasite is defined as a plant or animal living on, in, or with another living organism (its host) at whose expense it derives food and shelter. External parasites of horses usually bite (with the exception of certain flies) and/or suck blood for food, and use body temperature and the hair of the host for comfort and shelter. Foals and young growing horses are especially susceptible to all types of parasites, which may result in temporary or permanent lack of development. External parasites are a problem to many horses. They are often associated with improper nutrition, mild forms of disease, stress, and sometimes conditions of general neglect. External parasites are easier to eradicate or control than internal parasites, but response to treatment may be disappointing unless a total health program is practiced. The most common external parasites are (1) flies, (2) lice, (3) mites, (4) ticks, and (5) a fungus causing ringworm. Both ringworm and mange mites are communicable to man.FliesFlies are a constant source of annoyance to horses, making them restless and ill at ease. The house fly and face fly feed on skin, nasal and eye secretions, or debris, but do not bite. The tenaciousness of the feeding face fly makes its presence particularly annoying to horses. They are commonly found in the northern half of the United States. Horn flies, stable flies, and deer and horse flies are biting insects that suck blood. Since they show a preference, some horses are severely harassed by these pests. Biting flies can be vectors of serious diseases such as encephalomyelitis. Blow flies are common to large areas of the United States, and effect damage by laying eggs in wounds. One type hatches into maggots which feed on dead tissue, retarding healing and enlarging the wound. The other type hatches into screwworms, which feed on live tissue, causing severe damage and sometimes death. Both types are easily eradicated by cleaning the wound and applying a proper medicant.ControlFly control is best effected by removal of waste and decaying vegetable material. Manure should be stored in covered containers or spread thinly (for rapid drying) on fields not used by horses. Remove moist hay, straw, garbage. and grain frequently during warm weather. Use screens when practical.


Horse Science: External Parasites Affectin g the Horse Pa g e 4June 1989Life C y cle TreatmentThe four stages of the life cycle are the egg, the larva, Successful treatment of flies varies from one part of the the pupa, the adult. House, stable, and horn flies commonlycountry to another and will be influenced by the degree of lay their eggs in manure or occasionally in decayingimmunity they have established for a specific product. For vegetation or any moist collection of spilled grain. Face fliesthis rea son a qualified person should be consulted for lay their eggs in fresh manure on pastures. Horse and deerrecommendation in a given area. Regardless of the area, flies deposit eggs in the mud of swamps, salt marshes, or onpesticides should be considered poisonous and should be vegetation near water. regarded with extreme caution. Read the directions carefully HORSE FLY and follow them closely. Do not permit sprays to contaminate feed or surfaces that horses will lick. Do not store them where they may accidentally get into feed. Baits are effective but poisonous and should be placed out of reach of horses because many contain enough sugar to induce their consumption. Strands or cords treated with insecticide and hung in stables are often effective. Daily sponging or spraying may be necessary to give protection from horse flies and face flies. For those insecticides commonly used and recommended for your area, contact your local county agent or veterinarian.LiceLice that infest horses are of both the biting and sucking kind. Long hair is conducive to maximum reproduction and spread of lice, thus they are often observed in poorly groomed and poorly housed horses, especially in early spring. Symptoms include rubbing, biting, general unthriftiness, and patches of skin denuded of hair.Life C y cleThe adult lice attach their eggs to the hair, usually close to the skin (the so-called nits). Here they hatch in from 11 to 20 days. The young lice reach maturity and the female begins laying eggs when she is 11 to 12 days of age. Lice live their entire lives on the host, and can exist only about three days when off the host animal. STABLE FLYBITING LICE


Horse Science: External Parasites Affectin g the Horse Pa g e 5June 1989SUCKING LICEPreventionProper feeding. grooming, and clean stabling will do much to prevent louse infestations. Lice may be carried from one animal to another on harness, saddles, blankets, brushes, or curry combs moved directly from a lousy animal to one free from lice.TreatmentHorses may be dipped, sprayed, sponged, or dustedsources for information regarding the prevailing regulations thoroughly for lice control. The treatment should befor the kinds and use of insecticides. repeated in two to three weeks in order to destroy the lice hatching from eggs not destroyed by the first application. Contact your county agent or veterinarian for the recommended insecticides most commonly used in your area under prevailing regulations.MitesMites are microscopic creatures that cause horse mange. Positive identity is difficult because skin scrapings must be examined carefully under a microscope. Three genera exist: Sarcoptes Psoroptes or Chorioptes Sarcoptic mites burrow under the skin scurf where they lay eggs and reproduce. Chorioptic type may cause foot mange resembling scratches, although all three may cause mange on any part of the body. Symptoms include irritation, itching, inflammation, loss of hair, crusty scab formation, and folding of the skin.Life C y cleFemale mites lay from 10 to 25 eggs during the laying period, which lasts from 12 to 15 days. After this period the female dies in the burrow. Eggs hatch in 3 to 10 days into young mites. After passing through several molts, they reach maturity and are ready to begin egg laying again in from 10 to 12 days.TreatmentMange is difficult to eradicate in any species of animal. Experience indicates that infested animals should be retreated every 7 days in order to gain control. Dusts are not effective. Spraying or thorough wetting with a brushwashing technique is necessary to reach the well-hidden mites. Your county agent or veterinarian are your bestTicksTicks are a problem to horses in many parts of the country. Like other biting insects, they are vectors of some serious diseases. Piroplasmosis recently infected over one hundred horses in the southeastern part of the United States. In 1960, the red tick, carrier of African horse fever, was identified for the first time in this country, in zoo animals in Florida. TICKS MALE


Horse Science: External Parasites Affectin g the Horse Pa g e 6June 1989TICKS FEMALELife C y cleThe four stages include the egg, the six-legged larva orbe carefully disposed of. Children are particularly prone to seed tick, the eight-legged nymph. and the adult. Transitionringworm infections. from one stage to the next occurs by molting. The number ofUnder the best manag ement conditions horses harbor generations produced annually varies from one every two orsome parasites. Their effect is not spectacular or may be more years up to four or five per year, depending on theunnoticed, but they decrease work efficiency and cause species. All ticks attach to the host and feed on blood.discomfort. Heavy infestations render horses useless and total health program should be effected.TreatmentIn areas where ticks are a serious problem, dipping entire animals must be resorted to. If only a few ticks are found, swab them with cotton dipped in alcohol or chloroform. Since ticks breathe by means of spiracles or MAN AND OTHER ANIMALS; PARTICULARLY holes found on the abdomen, this tends to anesthetize or suffocate them. Several insecticides are available. Follow the recommendations of your county agent or veterinarian regarding their use.Rin g wormRingworm is caused by various species of fungi, arranged in circles on the skin. If penetration is deep enough, severe itching results; and secondary infection may lead to abscesses. The lesions are usually covered with greyish crusts through which short hairs protrude.TreatmentIf only a few lesions are present, soften crusts with warm soap and water and remove, dry the area, and paint with tincture of iodine daily for one to two weeks. If lesions are extensive, contact your veterinarian, since there are many new fungicides more effective than iodine. When treating or handling infected horses, use rubber gloves and wash hands thoroughly after treatment. All scrapings should may cause death or permanent damage. For these reasons a PRECAUTIONS MOST INSECTICIDES ARE POISONOUS TO CONCENTRATES PRIOR TO DILUTION FOR APPLICATION. ALL PRECAUTIONS ON THE LABELS SHOULD BE FOLLOWED FOR THEIR USE AND STORAGE. READ THE LABEL CAREFULLY! AVOID CONTAMINATION OF FEED AND WATER WITH INSECTICIDES. RINGWORM OF THE HORSE DUE TOHORSE HAIR INFECTED BY T. EQUINUM TRICHOPHYTON EQUINUM ECTOTHRIX TYPE OF PARASITISM, X522


Horse Science: External Parasites Affectin g the Horse Pa g e 7June 1989NOTES


COOPERATIVE EXTENSION SERVICE, UNIVERSITY OF FLORIDA, INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, Christine Ta y lor Waddill, Director, in cooperation with the United States Department of A g riculture, publishes this information to further the purpose of the Ma y 8 and June 30, 1914 Acts of Con g ress; and is authorized to provide research, educational information and other services onl y to individuals and institutions that function without re g ard to race, color, a g e, sex, handicap or national ori g in. The information in this publication is available in alternate formats. Sin g le copies of extension publications (excludin g 4-H and y outh publications) are available free to Florida residents from count y extension offices. Information on copies for out-of-state purchase is available from Publications Distribution Center, Universit y of Florida, PO Box 110011, Gainesville, FL 32611-0011. Information about alternate formats is available from Educational Media and Services, Universit y of Florida, PO Box 110810, Gainesville, FL 32611-0810. This information was published June 1989 as CO 201, which is superseded b y 4HHSG01, Florida Cooperative Extension Service. 1.This document is section 13 of 14 of 4HHSG01, which supersedes CO 201, one of a series of the 4-H Youth Development Pro g ram, Florida Cooperative Extension Service, Institute of Food and A g ricultural Sciences, Universit y of Florida. Date first printed Au g ust 1965. Date revised June 1989. Please visit the FAIRS Website at http://hammock.ifas.ufl.edu 2.Melvin Bradle y Universit y of Missouri. Debbie Glauer, member of 4-H Animal Science Desi g n Team, Department of Famil y Youth and Communit y Science, Cooperative Extension Service, Institute of Food and A g ricultural Sciences, Universit y of Florida, Gainesville, 32611.