Saturday, March 09, 2013

Tapeworms in working donkeys in Ethiopia

Tapeworms are a potential problem amongst working donkeys in Ethiopia research has revealed.

The work, carried out by Dr Mulugeta Getachew formed part of his PhD studies and was funded by the Donkey Sanctuary.

He conducted a serological survey of donkeys from four different geographical regions of Ethiopia. Blood samples were collected from 797 donkeys, that had been naturally exposed to tapeworm infection. None had never been treated for tapeworms.

The tapeworm ELISA test, developed for use in horses, was used to detect parasite-specific serum antibody, IgG(T), in the serum of donkeys. A pilot study had confirmed that the test was suitable for use with donkey sera.

Dr Getachew found substantial serological evidence that donkeys were potentially infected with the tapeworm Anoplocehala perfoliata.

Overall, most animals harboured few parasites and a few donkeys were infected with
large number of parasites. The results indicated that 26% and 8% of the donkeys were moderately and highly infected, respectively. The remainder had low infection intensity or were negative for A. perfoliata infection.

He found a marked difference between results from different regions of the country. Bereh, a mountainous region, had significantly more moderately (51.2%) or highly (23.5%) infected donkeys, than the other midland or lowland regions.

He explains that, in contrast to the other regions studied, Bereh is characterized by pastures that are low-lying and wet, with wide areas of permanent pasture specifically kept for animals and for haymaking.This is likely to result in favourable environmental conditions for the survival and development of both the oribatid mites that are the tapeworm's intermediate host and the tapeworm eggs.

He concludes: “The finding of high sero-prevalence of cestode (tapeworm) infection, which is consistent with the results of coprological and post-mortem findings clearly indicates that cestodosis is one of the major parasitic problems in the donkey population of Ethiopia.”

These results indicate a risk of intestinal disorders, particularly, colic, associated with A. perfoliata infection in donkeys.”

Wednesday, March 06, 2013

Effect of composting on Parascaris equorum eggs

The eggs of the large roundworm of horses, Parascaris equorum, are particularly resistant to extremes of climate and may survive for many years in stables and on pasture. Composting is becoming a popular method of dealing with waste from equine premises. How likely are P. equorum eggs to survive in composted manure?

A study carried out by researchers from the University of Kentucky Department of Animal and Food Sciences on a central Kentucky horse farm investigated the viability of P. equorum eggs in manure subjected to windrow composting.

For the purposes of this study, a single windrow approximately 42.3m in length, 2.7m in width, and 0.9m in height was built. It contained equine manure, soiled bedding and other waste material, which came from stables occupied by adult stallions and mares. Temperature and carbon dioxide levels within the row were monitored daily. The compost would be mechanically turned and aerated as necessary to maintain optimum conditions. Previous experience had shown that it took 10-12 weeks for the windrow to decompose completely.

Sentinel chambers were used to expose 3g samples of feces to the composting process. The faeces, collected from a weanling foal, had an average of 2216 P. equorum eggs per gram.

The chambers were made of mesh that kept the P. equorum eggs inside, whilst allowing liquids and bacteria to pass through.
 
Chambers were exposed to one of three treatments.
  1. Constant exposure. These were placed within the centre of the windrow. Each day after the windrow had been turned, the chamber was placed back in the centre of the windrow.
  2. Intermittent exposure. The chambers were placed in the centre of the windrow. On alternate days, after the windrow had been turned, the chamber was placed back in the centre, or placed on the outside of the windrow.
  3. Control chambers were kept at 4°C.
Every two days, one chamber from each group was removed and incubated at room temperature for 21 days, at which stage the eggs were examined microscopically to assess if they were viable. (Viable eggs contained larvae.)

Chambers treated with constant exposure contained about 10% viable eggs on day 2 and 0% by day 8. Intermittent treatment resulted in 16% viable eggs on day 2 and 0% by day 6. In contrast , control chambers had average P. equorum egg viabilities of 79% throughout the 18 days of the study.

The researchers concluded that not only was the windrow composting system effective in eliminating viable P. equorum eggs, it did so rapidly. 

Monday, March 04, 2013

Information sought on saddle slip

Can you spare a few minutes to complete a questionnaire to help research into saddle slip? Scientists at the Animal Health Trust are trying to understand more about the reasons for a saddle to slip persistently to one side in some horses.

To this end they have devised a questionnaire to examine the interactions between horses, saddles and riders.

Saddle slip is a problem seen in all sorts of horses and ponies and can contribute to back pain. It may also be a sign of hindlimb lameness.
A recent study by Line Greve and Sue Dyson at the Animal Health Trust Centre for Equine Studies in Newmarket, found that that saddle slip is not necessarily due to an ill-fitting saddle or asymmetric shape of the horse’s back.

Sue Dyson said: “Detection of saddle slip provides an opportunity for the owner, riders and trainers to detect low-grade and subclinical lameness, with important welfare consequences.”

Greve and Dyson are continuing their investigations, trying to understand more about the reasons for a saddle to slip persistently to one side in some horses. To this end they have devised a questionnaire to examine the interactions between horses, saddles and riders.
The questionnaire should only take a few minutes to complete, and will help reveal the frequency of occurrence of saddle slip and the risk factors involved.  Follow the link for more details...

Saturday, March 02, 2013

Maggot wound therapy

Maggots might be the last thing you'd want to find in a horse's wound. But a recent study assessed the efficacy of maggot debridement therapy in a range of equine lesions and found it was beneficial in 93% of cases.

Over a four year period, Dr Olivier Lepage and colleagues treated forty-one cases (35 horses, 4 donkeys, 2 ponies ) in France and Mali.

The maggots used were sterile common green bottle fly maggots, which have been used in human medicine to clean long-standing, infected or necrotic wounds. Maggots digest fibrin and necrotic tissue, along with bacteria, and secrete proteolytic enzymes and antimicrobial agents into the wound.

Interestingly these are the same species of fly larvae that are the most common cause of fly strike in rabbits and sheep. In horses (and humans) it appears that healthy tissue is able to inactivate the proteolytic enzymes so that only diseased tissue is digested. In contrast, sheep and rabbits can not inactivate the enzymes.

Maggots were applied either directly onto the wound or retained within a polyester net containing small pieces of foam. They were kept in place with cohesive, but not occlusive, bandage – maggots need oxygen.

Between 300 and 900 maggots were used for each wound, depending on its size. They were left in place for three days. In 5 cases the response to the initial MDT was inadequate and so a second treatment was applied for a further 3-4 days.

Conditions treated included limb lacerations, deep seated foot infections and soft tissue abscesses and abdominal incision breakdown. Within just one week a favourable outcome was recorded in 38 of 41 cases. Wounds that did not respond well were those involving neoplasia or a bone sequestrum.

No more than 2 MDTs were needed in this series of cases, in contrast to other reports. The clinicians suggest that this was likely due to the light surgical debridement that was carried out in most cases in this series, before the maggots were applied.

Lepage and colleagues conclude that maggots can be recommended in horses, ponies and donkeys for debridement of wounds and for their potent antibacterial effects – including their use against difficult to control infections such as MRSA and other multibacterial resistant bacteria.

They advise against its use in cases where neoplasia is present. In this study, melanoma and squamous cell carcinoma continued to deteriorate after MDT.

 Read more: www.equinescienceupdate.com

Developmental joint disease in Norwegian Standardbreds

A research project carried out at the Norwegian School of Veterinary Science has revealed that 50.7% of Norwegian Standardbred yearlings suffer from loose bone fragments and lesions in their joints.

Developmental orthopaedic disease is well recognised in the horse, and can result in lameness or poor performance. It can appear in various forms such as: osteochondrosis (OC)/osteochondrosis dissecans (OCD), palmar/plantar osteochondral fragments (POF or “Birkeland fractures”), ununited palmar/plantar eminences (UPE) and dorsoproximal first phalanx fragments.

The aim of the study, led by Sigrid Lykkjen, was to assess the prevalence, development and interrelation of the various forms of developmental orthopaedic disease (DOD) affecting the tarsocrural, metacarpophalangeal (MCP) and metatarsophalangeal (MTP) joints in Standardbred trotters.

The work formed the basis of her PhD thesis entitled “Genetic studies of developmental orthopaedic joint diseases in the Standardbred trotter”. The research was carried out as a collaborative project between the Horse Clinic and Department of Disease Genetics at The Norwegian School of Veterinary Science, the University of ├ůs and the University of Minnesota.

Tarsocrural and MCP/MTP joints of 464 Norwegian Standardbred yearlings, born in 2006 and 2007,were examined radiographically. Lykkjen assessed the prevalence of osteochondral lesions and also looked at the interrelation between affected sites.

She found osteochondral lesions in 50.7% of the horses. OC/OCD of the tarsocrural (hock) joint occurred in 19.3%. Of the lesions in the hock joint, OCD of the distal intermediate ridge of the tibia (DIT) was the most common. The prevalence of OC/OCD in MCP joints was 3.6%, whereas the prevalence of POF and UPE in MCP/MTP joints was 23.1% and 3.9%, respectively. 
 
It was common for horses to have similar lesions on the opposite leg. There was an association between OCD of the distal intermediate ridge and OCD of the lateral trochlea ridge, and between POF and UPE.

The high prevalence results for tarsocrural OC/OCD emphasise the need for breeders to take account of these diseases in planning their breeding programme.

Read more at: www.equinescienceupdate.com/articles/djdns.html

Friday, March 01, 2013

Good and bad news for donkey lice

Lice can be a problem for donkeys, especially in older or debilitated animals.

Lice are obligate parasites, passing their whole life cycle on the host. This makes them easier to control, but only if they are susceptible to the anti-parasitic products used to control them. Unfortunately, recent work suggests that donkey lice may be developing resistance to commonly used treatments.

Lauren Ellse, Faith Burden and Richard Wall studied the value of pyrethroid-based insecticides on a population of donkey lice. They found a high level of pyrethroid tolerance in the lice tested, and suggested that this was likely to reflect the development of resistance.

In laboratory tests, they assessed the effect of cypermethrin and permethrin on chewing lice (Bovicola (Werneckiella) ocellatus ) collected from donkeys.

They compared the efficacy with that of diazinon, an organophosphate compound to which the lice were unlikely to have been exposed previously.

Neither permethrin, nor cypermethrin, (at concentrations recommended for use on animals) had any significant effect on mortality of B. ocellatus. Combining cypermethrin and permethrin with piperonyl butoxide (which may enhance their activity) did not make them any more
effective.

In contrast, 0.04% diazinon caused 70% mortality within 4 hours and 100% mortality after 24 hours exposure.

Another study raised the possibility of using essential and non-essential oils in the control of biting lice.

Rose Talbert and Richard Wall examined the toxicity of six essential plant oils to the chewing louse, B ocellatus collected from donkeys,

They found that tea-tree, lavender, peppermint, eucalyptus and clove bud showed high levels of toxicity to lice.

They suggest that these botanical products may offer environmentally and toxicologically safe, alternative veterinary treatments for the control of ectoparasitic lice.