These notes are intended to provide clients with the basic information they require prior to having a colt castrated. If you have any questions not addressed in these notes please speak to your usual vet who will be happy to assist you.

When to castrate

Traditionally this takes place in the spring of the yearling year, but there is no reason why they should not be castrated either earlier, as a foal, or later. There is no evidence to suggest that horses left entire develop any differently to those castrated earlier. Indeed foals that are castrated whilst still suckling on their dam seem to get over the operation best of all age groups.
Castrations are normally carried out in spring and autumn. This is to avoid the flies of summer and the mud of winter. It should be borne in mind that they will benefit and recover faster if they are allowed exercise in the days following the operation and this should be considered when planning the date.

Both testicles must have descended into the scrotum and there should be no other material (e.g. herniated intestine) in the scrotum before castration is carried out. If there is suspicion that other material may be present within the scrotum then the horse should only be castrated in a hospital environment. If only one testicle is present there is then a choice of either waiting until the testicle appears later, if it does, or castrating the ‘rig’ in hospital. This may involve considerably more surgical intervention as the retained testicle may be present within the abdomen thus necessitating a surgical laparotomy or laparoscopy.

Prior to general anaesthesia the horse should be in good condition, have been wormed regularly and without any recent respiratory infection. Ideally he should have been previously vaccinated fully against tetanus but if not he can receive antiserum at the time of castration.

Where to castrate

The operation may be carried out either at the owner’s own property or at the hospital. The advantage of carrying it out at your own property is the lesser inconvenience caused to you and your colt by traveling. Providing you have adequate facilities then this may be your preferred location.

If castrated at home a competent experienced handler will be required, preferably one who does not mind the sight of blood! Clean, warm water will also be required.

The horse will also need to be starved overnight because, as with humans, it is considerably safer to anaesthetise a patient who has not eaten for eighteen hours. They are allowed access to water.

Remember that your horse will have to be anaesthetised and will as such will need to lie on the ground, which should be danger free (i.e. no stones, barbed wire, tree stumps etc.)
Again, ideally the weather should be dry and warm so that he is not lying in dust or mud, and not standing in the rain.

Castration within a stable is seldom desirable, as there are often hard protuberances on the walls that may damage your horse either when being anaesthetised or during recovery. However, in certain circumstances the attending veterinary surgeon may consider this a suitable place bearing in mind the options available for that horse.

It is often preferable to castrate colts in the standing position, using sedation and local anaesthetic rather than general anaesthetic.

If carried out at the hospital the colt will be admitted the day before in order to allow him to settle and get used to his surroundings. We find colts that are relaxed are better subjects for anaesthesia the next morning. He will then be castrated in the operating theatre, which offers the highest standards of sterility and anaesthetic equipment. Usually he will stay overnight following the anaesthetic and go home the following morning. However, you may discuss this with your veterinary surgeon.

The Procedure

Castration involves the removal of both testicles through surgical incisions into the scrotum. The connections of blood vessels, tubes etc. from the testicle to the body internally must also be crushed and cut.

There are two methods. The “open” technique incises open the scrotum and, having removed the testicles, the wound is left open for postoperative drainage. The “closed” technique involves suturing the various layers, once the testicles are removed, to prevent herniation of intestines through the castration site. The latter takes longer and it is not usually possible to do this under field anaesthesia.

Standing castration without general anaesthetic but by the ‘open’ technique is usually suitable for horses which are well handled and have fully descended testicles. Again, it is usually better with professional handlers as many handlers go a little weak at the knees whilst watching this technique!

The Risks

The administration of any general anaesthetic or surgical procedure does carry an element of risk and, although we will do all we can to minimise this, it must always be borne in mind. As well as preparing the horse by starving etc. the subject will undergo a pre-anaesthetic check. In very rare cases where there is an adverse reaction, the emergency resuscitation equipment that is available at the hospital will offer your horse the best chance of recovery. Unfortunately, this equipment is not mobile enough to be carried to the owners’ premises.

Other risks involve herniation of the abdominal contents through the wound. This is more common in foals and in those operated on by the open technique. This risk is minimised by using the closed technique (which has to be done in hospital conditions). Infection acquired at the time of surgery or from mud and dust contamination subsequently is also a risk. This emphasises the importance of hygiene wherever the horse is castrated.

The preferred choice of the practice is the ‘closed technique’ carried out at the hospital but we understand the economic reasons why some owners may not elect to have this option. Your vet will be happy to discuss the options.

The Costs?
To help our clients budget and choose which technique they should have performed we now carry out castrations on a “fixed fee” basis. For an up to date quotation please telephone the Reception at the practice.