DON T LET DISEASE GET YOUR GOAT

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1 Vet Times The website for the veterinary profession DON T LET DISEASE GET YOUR GOAT Author : GRAHAM DUNCANSON Categories : Vets Date : February 11, 2008 GRAHAM DUNCANSON delivers his verdict on the best ways to diagnose and treat goats suffering from skin conditions THE old-fashioned farm animal practitioner needs to change his mindset. Goats are, in the main, very important to their owners as individuals. The owners expect a very thorough and caring approach, but, sadly, money is often an issue. Therefore, I encourage owners to bring their animals to us, but I suggest that they do not come into a busy small animal surgery. Getting them to come to a large animal treatment room at a set time, when a farm animal practitioner is there to meet them and examine the goat, is preferable. If possible, in-house laboratory facilities are used and more specialised services are obtained from the Veterinary Laboratory Agency. Pictures are taken and the owners are encouraged to further images to monitor progress. Not all cases will be cured, but I aim to give owners a treatment plan and a prognosis, so that lifelong treatment can be given. I consider follow-up photographs, progress reports and telephone conversations to fulfil my obligations of under my care. Therefore, realistic fees are charged for consultations, but other advice is given free of charge. I charge a realistic fee for the medicines, as this invariably requires splitting a pack or opening a bottle. A mark up is entirely justified, as this is not the resale of large amounts of expensive medicines, but individual treatments often supplied at inconvenient times. I issue a prescription free of charge, but insist on examining the animal first. 1 / 11

2 As a routine, I ask the owner how long the signs have been present and tactfully ask if those signs have changed over time or with the use of any home remedies. I always show an interest in home remedies and never denigrate them and try to find out whether there are any other animals in contact with the patient or possible sources of infection from other holdings (such as shows, visiting the billy or others looking after the goats while holidays are taken). I try to get these answers in a very conversational manner, without ever pointing to a source of possible infection. However, if the owner asks a direct question, such as could she have picked up the infection from a show?, I give a direct answer. I also try to find out if there are any other non-dermatological signs and the sequence of events was there initial pruritis or did this follow a secondary infection? Did the majority of the damage result from self-trauma? I examine the goat as a whole, look at the skin in general and, finally, examine the skin lesions. Parasites Mange mites In my experience, the most common mange mite found on goats is Chorioptes equi. However, I suspect that it is actually C caprae, which I am unable to differentiate. On several occasions, I have found goats affected on the same holdings as horses with foot mange. It is moderately pruritic and there is often a secondary bacterial infection. Diagnosis is simple brush the affected areas with a toothbrush and collect a sample into a Petri dish. The mites can readily be seen under low power with the microscope. I find it is quite responsive to treatment, provided you use a belt-and-braces approach of three injections at weekly intervals of doramectin at 33mg/kg and benzyl benzoate topically. I warn owners to take the goat for a walk after treating with benzyl benzoate, to reduce the risk of ingestion, as I suspect it is quite toxic. I also recommend treating all the owner s animals, as it is likely that one animal may be an asymptomatic carrier. Sarcoptes scabei is a much more severe infestation, but it is beyond my experience. It should be remembered that it is zoonotic, but I would treat the condition in the same manner. Goats running with sheep suffering with sheep scab will contract Psoroptes ovis. This causes few problems in goats, with the infestation usually confined to the inside of the ears. Some authorities claim there is a specific psoroptic mite in goats of P caprae and that goats will pick up the rabbit mite P cuniculi. I imagine all three mites would be responsive to doramectin injections. Goats will also become infested with Demodex caprae, but this condition is very rare. I have seen it in two young, bottle-fed kids, which had Pasteurella pneumonia. I euthanised them after 24 hours, as they did not seem to be responding to antibiotic treatment. 2 / 11

3 Harvest mite These are Trombicula autumnalis and are not really a true parasite as they are free living. However, heavy infestation with these red mites causes intense irritation. I use a cypermethrinbased treatment, Deosan Deosect, which is unlicensed, but very effective. Poultry mite These mites are Dermanyssus gallinae, which I call the stick tight poultry mite. They cause irritation to goats and horses. The goats and the chickens both need to be washed weekly with a cypermethrinbased treatment. Lice Goats are unlucky, as they are affected by Bovicola (biting louse from cattle) and Linognathus (sucking louse from sheep). Both types cause intense irritation. I think it is a myth that they come in the straw and, in reality, they probably need very close contact to come about. A weekly Deosan Deosect wash is my preferred treatment. Keds These insects are often called sheep ticks by goat owners; in fact, they are Melophagus ovinus. In my experience, infestations are light and do not cause much pruritis. Again, a cypermethrinbased product can be useful. Ticks The real sheep tick, Ixodes ricinus, affects most mammals. Owners only find the engorged females, which should be removed with care if their mouth parts remain, a small pustule will result. Fleas There is no species-specific flea for the goat, but I have seen goats afford a temporary home for the human flea Pulex irritans. The goats will show intense pruritis. I have never seen kids or debilitated adults killed by heavy infestations, as reported by other authors. Normal topical flea treatments are effective, but I have no experience with spot-on applications. Fly strike This is rare in goats, except following wounds and infected feet. Immediate maggot removal should be carried out, which can be aided by the use of a hair dryer. After this, I apply Battle s Summer 3 / 11

4 Fly Cream. Fungal infections Trichophyton verrucosum is said to be the most common fungal infection, but that has not been my experience. I have found T mentagrophytes more common, which I assume has come from rodents. Either species is a zoonosis and owners should be counselled carefully about this. Diagnosis can be confirmed by growing a skin pluck on a dermatophyte test medium. Enilconazole and natamycin seem to be effective as sprays or washes. However, in my opinion, the most effective treatment is griseofulvin by mouth. Although this is banned in meatproducing animals, goats are rarely sold for meat. Bacterial infections Staphylococcus aureus This infection is common in goats. It can be a primary pathogen on the udder, or secondary to a parasitic infestation. Goat owners tend to erroneously call it goat pox (this virus is not found in the UK). Confirmation of the diagnosis can be made with a gram stain from a skin scraping. In my experience, the organism is not resistant to penicillin, so five days of pen/strep injections are usually effective. Goats should not be given oral antibiotics. Dermatophilus congolensis This infection, also known as rain scald, is said to occur in the UK but, in my experience, it is rare (it was quite common on the Kenyan coast). The organism can be seen on a gram stain and is responsive to five days of pen/strep injections. If there are sore areas on the skin, antibiotic creams are helpful. Like S aureus infections, it is non-pruritic. Corynebacterium pseudotuberculosis This infection, also known as caseous lymphadenitis, is becoming much more common in goats, as well as sheep. Obviously, it is not spread by shearing in goats but it does seem to spread at shows. Goats will develop abscesses, caused by a variety of organisms, but with C pseudotuberculosis, the pus is very thick and literally caseous. Actinobacillosis Also known as a Norfolk wenn, this is a cutaneous form of lumpy jaw. In cattle, it was first 4 / 11

5 described by Alec Dawson in 1935 in Norfolk, on the marshes surrounding the Broads. I have often seen it in cattle, but I have also seen it in goats, sheep and alpacas. It is not penicillin responsive, but it requires a minimum of five days of streptomycin. I recommend a product that is solely streptomycin. However, similar levels can be achieved by using double doses of pen/strep. Viral infections Orf This infection, also known as contagious ecthyma, seems to cause more problems in goats that it does in sheep, in my experience. This is because, except in certain circumstances, it is self limiting. I advise five days of pen/ strep to eliminate the secondary bacteria and I also use Battle s Summer Fly Cream topically. It is a zoonosis and, therefore, owners should wear rubber gloves when applying the cream. Warts This ailment can appear similar to orf. Jackson (1986) describes two viral causes. The clinical picture, in my experience, is that warts in young growing goats seem to disappear spontaneously. In adults, they seem to remain, but rarely grow to a large size. Old-fashioned owners tie horsehair around them. I have used elastrator rings to good effect, and I try only to do this in the winter to limit the fly worry. Tumours Neoplasia affecting the skin of goats is very rare, even though they are often of a considerable age. I have not encountered melanomas, but they have been reported. I have seen a squamous cell carcinoma of the third eyelid; it did not return after removal. I have also seen a very aggressive tumour on the sheath of a billy, which I assume was a squamous cell carcinoma. The animal was euthanised. There was also the case of a tumour in the wattle of an Anglo-Nubian female, which I assume was a wattle cyst. I left it alone and it never increased in size. Miscellaneous I have been confused by a skin condition that appears relatively often in pygmy goats. It manifests clinically as dry, crusty lesions all over the goat, but mainly around the tail, anus and back of the hindlegs. Histologically, it is described as psoriasiform perivascular dermatitis. It seems to be worse in the summer months, as it is then pruritic. 5 / 11

6 In my experience, treatment with doramectin, antibiotics and zinc supplementation is usually unrewarding. Prednisilone at 1mg/kg during the summer helps the pruritis and does not seem to cause other problems. Topical treatments can be useful to avoid fly strike. I am not sure whether this is a pemiphigus condition, but there is almost certainly an inherited predisposition. Reference Jackson P G G (1986). Skin diseases in goats, In Practice 8(1): / 11

7 Possible pemphigus on a pigmy goat. 7 / 11

8 Goats exhibiting signs of Staphyloccocus infection on the ears. 8 / 11

9 A Norfolk wenn, or actinobacillosis. 9 / 11

10 An example of pemphigus with a secondary infection. 10 / 11

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