News Updates

The African Horse Sickness Trust
Reg IT 2043/2005 PMB

Outbreak Notification
Date 13th February 2008

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Hi there

Subsequent to my last report on the 4^th there has been a substantial increase in cases reported.  In the last 9 days 39 cases have been reported. Today have been the worst with 14 reports so far. The areas particularly worst hit are: Eastern Cape ( the area from Grahamstown to PE, Gauteng, and specifically north of the R28 ( no confirmed cases in the south of Gauteng yet) North West  Province ( the areas just north of Gauteng) specifically Skeerpoort, Brits and Pretoria West.

We are trying to get better samples to do virus isolations and typing but we are not getting tissue samples – please if a horse dies we need fresh samples of lung and spleen. To date the only typing achieved is a 7 and 2.  It is critical that we map the serotypes throughout the country.

I have only included the reports from the last 10 days in this mail. 
Please insist that all cases you hear of are reported on the website: www.africanhorsesickness.co.za

Regards,
Douglas Welsh

Outbreak status 2007/8:

Reported cases                 87           All cases reported on the website
Approved cases                84           All cases confirmed by vet and or sample results pending
Confirmed cases               30           All cases confirmed by DOA to end  Jan 2008 

Herewith the case locations from 4th to13th Feb :

EXTRACT FROM WAHO RULES IN CONNECTION WITH EMBRYO TRANSFERS 

RULE 18:          EMBRYO TRANSFER AND OVUM TRANSFER

Each Registering Authority Member has the authority to allow or not allow the use of Embryo Transfer or Ovum Transfer within their area. 

The following registration rules have been designed to allow the Registering Authority to monitor this process effectively from the initial request of the Embryo or Ovum Transfer Permit to the registration of the resultant foal. They are the minimum rules required.  The amount of fees or any additional requirements are at the discretion of WAHO Registering Authority Members.

1.         IMPORTED HORSES PRODUCED BY EMBRYO TRANSFER OR OVUM TRANSFER

It is a mandatory rule that all WAHO Registering Authority Members must register imported horses produced by this method.

2.         NUMBER OF FOALS PER YEAR PER DONOR MARE

Registration Authorities may, at their discretion or following legal advice, choose to place a specified limit on the number of foals they will register per donor mare per year according to the laws and culture of that country.  They may also, at their discretion, allow multiple foals per donor mare.  Whichever they choose, every Registering Authority Member must furnish WAHO with a copy of their Embryo Transfer or Ovum Transfer rules.

3.         EMBRYO TRANSFER OR OVUM TRANSFER PERMITS FOR DONOR MARES 

An Embryo Transfer or Ovum Transfer Permit is required for each mare to be used as a donor for Embryo Transfer or Ovum Transfer.  The following mandatory WAHO Embryo Transfer or Ovum Transfer Permit rules must be complied with:-

An Embryo Transfer or Ovum Transfer Permit must be issued for each mare to be used as a donor for embryo transfer or Ovum Transfer. By signing the application form, the signatories fully accept and agree to be bound by and abide by the procedures and rules established for Embryo Transfer registration or Ovum Transfer registration by both WAHO and by the Registration Authority and by any relevant Government regulations.  A permit may be issued for a donor mare if the following requirements are met:

a)       An application for an Embryo Transfer Permit or Ovum Transfer Permit, on a form provided by the
          Registration Authority, must be completed, signed and submitted to the Registration Authority by the
          recorded owner(s) or authorized agent(s) of the donor mare with her name, full registration details and
          location;
b)      The donor mare must be registered with the Registration Authority of the country of domicile;
c)      The DNA of the donor mare has been placed on permanent record with the Registration Authority;
d)      The required fee (if applicable) has been paid;
e)      Once issued, the Embryo Transfer Permit or Ovum Transfer Permit will be valid until the recorded
          ownership of the donor mare changes or the mare is exported; 
f)        If a stallion named in the Embryo Transfer or Ovum Transfer permit is replaced, for any reason, by
          another stallion, the Registration Authority must be notified and, if necessary, a replacement Embryo
          Transfer or Ovum Transfer permit will be issued free of charge; 
g)      Embryo Transfer or Ovum Transfer Permits are issued to a specific named donor mare and are not
          transferable. 

Here then some thoughts on ET and its advantages and disadvantages:

Embryo transfer (ET) is a procedure that is becoming more and more popular in the equine world for obtaining foals. This technique involves recovering embryos from bred (donor) mares and placing them in a recipient mare who, in turn, carries the foal. There are several reasons for the use of this procedure. Multiple foals can be produced from one mare (possibly genetically superior) in a breeding season. It can be used to produce foals from mares that cannot take time off from racing or showing. Embryo transfer can also be used to produce foals from sub fertile mares that are unable to successfully carry a foal to term. Young fillies that can produce viable embryos but are not yet able to carry them may be used as donor mares. Older mares no longer capable of carrying a foal also make good candidates for embryo transfer. Embryo transfer also cuts down on breeding injuries and the spread of venereal diseases to the horses. However, this is not an accepted method of breeding for all breeds of horses.

As it is becoming more popular, the demand for qualified veterinarians is increasing. This technique can be done by the private practitioner on the farm, which makes it very accessible to most clientele. Selecting the mares, synchronizing, flushing the embryo and then transferring it all take time, but the rewards of success will be well worth the wait when a mare unable to carry a foal for various reasons is able to produce a viable offspring. 

AN INTRODUCTION

The last few years have seen a growth in the use of Artificial means for breeding horses. More specifically sport horses, however, the use of these techniques is allowed in certain countries for breeding racing and show  horses.
In very simple terms the process involves removing a 6-8 day old embryo or embryo’s from a donor mare and transferring them to a recipient mare or storing for later use.
In horses as distinct from cattle, the production of one viable embryo is more normal than the super ovulation often seen in cattle.

Advantages
·         Provide opportunity for breeders to have access to a better or more extensive genetic pool
·         Allows the owners of good competing mares to breed into these bloodlines without having to limit the 
          mare’s competition career unnecessarily.
·         Provides lower cost alternative to importing or exporting genetics of certain lines into a country,
          compared to the transport costs of a live horse.
·         Protects the bloodlines in the event of an accident to the mare, in much the same way as frozen semen
          does with the stallion.
·         Allows the breeding of a mare that may have an inability to carry the foal to full term or indeed is unable
          to conceive due to physical injury.
·         Potentially allows the breeding of a sub-fertile mare.

Disadvantages or concerns
·         The process is expensive and relies on the provision of donor mares
·         The percentage of live foals born is relatively low
·         A highly skilled team of stud workers and veterinary surgeon are required
·         The Thoroughbred industry will not allow ET at all.

We can break the topic down in to several sections:
·         Selection of the donor mare
·         Selection of the recipient mare(s)
·         Synchronising the mares cycles
·         Transferring the embryo to the recipient

Selection of the Donor Mare

The donor mare will be by nature the donor because of one or more of a number of reasons:
·         She is sub fertile
·         She aborts before term on a regular basis
·         She fails to conceive despite ovulating
·         She is a performance horse and needs to remain in competition
·         She is a very young horse who is unable to carry a foal herself.

The mare will undergo a complete examination paying attention to the size and tone of the cervix and uterus are taken and analysed to ensure the mare is disease free.

It would be normal for the donor mare to be examined for at least two cycles before the procedure is initiated if she is unknown to the stud.

Selection of the recipient

There are many factors to be considered in the selection of the best recipient mare for your foal. The most import initial considerations is that they are of similar build and quality to the donor. It is certainly true that many of the characteristics of a foal are inherited from the mother (not applicable in this case), however, surely some are acquired through the behaviour of the mare. Foals often turn out to move very much like their mothers, as well as having a great deal of the temperament. Although there is no research known to the author about these characteristics, it would be better to play it safe. Do not breed a top competition foal out of a shire donor mare. You might end up with a superb horse that moves like a shire. Although this is ideal when breeding shires, it is not ideal when breeding a dressage horse.

The recipient should be completely disease free and of a similar size.

The Synchronisation Process

Ideally the donor and recipient should ovulate within 24 hours of each other so that the reproductive tracts are in the same physiological state and the recipient can carry on where the donor stops.

The difficulty comes in the prediction and control of ovulation. Although oestrus may begin on the same day, this is no guarantee of the same pattern of ovulation.

Normally hormones are used to accomplish this, in the form of Prostaglandin (PG), which advances the onset of oestrus.

The added use of Luteinising Hormone to bring about ovulation along with the use of PG allows for the cycle of the recipient to be brought into line with the donor should they be different.

The use of the above along with extended lighting, will encourage the mares to cycle earlier in the year.

The use of a teasing stallion on both mares is essential to establish whether they are ready for insemination.

It is essential that the hormone levels of the recipient be monitored, with attention to the progesterone levels. If these are not at the correct level, the pregnancy may not be maintained in the early stages. Once established, the uterus takes over production of Oestrogen from the corpus lutea.

Removal of the embryo from the donor mare

When the donor mare is ready to be covered or inseminated, this proceeds as normal. Scanning of the mare will reveal an embryo and this is then removed by one of two means, either surgical or non-surgical.
Antibiotics are administered as a precaution.

Maintenance of the pregnancy

It is essential to monitor the progesterone levels of the mare to ensure the pregnancy holds and supplement these levels by injection if necessary.
When everything is confirmed, treat the mare as a normal in-foal mare.

The Future

The field of research is extending into other areas, such as the recovery of an oocyte prior to ovulation. This procedure is useful for a mare that can not maintain an embryo long enough for it to be harvested.

Furthermore in a discussion at the Registrar’s meeting at the 2007 WAHO Conference in Syria some countries expressed their concern at the well being of the donor mare, as in some cases some serious health problems of the donor mare have been experienced concerning hormone imbalance. The ethics around creating donor mares only because the mare must be shown year in and year out for personal gain and ego satisfaction of the owners was also tabled, as well as the moral principles surrounding the fact that the perfectly healthy and normal mare is never allowed to carry a foal full term or to raise such a foal naturally.

As the procedures of embryo transfer advance, ethical issues will arise.  Naturally, a mare produces one foal per year, yet this technology significantly increases that figure.  Combating Mother Nature with man-made technology always creates problems.  Unfortunately, the consequences are still unknown.  Without regulation, ET could create a large impact on the gene pool and horse population.   In certain cases, ET is used to produce foals from reproductively unsound mares.  That scenario potentially harms the next generation by passing on the genes for the unsoundness.  Additionally, the surgical method is a highly invasive procedure.  Is it justifiable to force an unnecessary surgery on a recipient mare simply to produce a foal without donor mare depreciation?  The current actions of the equine industry say “yes”, but ultimately the answer depends on personal interpretation and motivation.

Over the past 20 years, embryo transfer made a significant impact on the equine industry.  The procedure has provided many additional opportunities for horse breeders and enthusiasts.  Financial advantages and disadvantages of the procedure do exist, as well as genetic and scientific gains and losses.  Although it is a valuable technique of assisted reproduction, its efficiency is limited by unreliable or ineffective methods to super-ovulate mares.

Researched, compiled and written by Marie-Louise van Wyk.