Woolshed 1: castration

Showing posts with label castration. Show all posts

October 11, 2011

Sheep husbandry - Castrating lambs with rubber rings

By Dr Clive Dalton

Castrating lambs with rubber rings
Using rubber rings is the best way to castrate lambs in both large and small flocks. It is bloodless and research has shown that the intense pain only lasts a short time. Lambs should be castrated using rings before they are 6 weeks old - the younger the better.

The main concern is to make sure the ring is placed in the correct position, so the ram will become a proper wether.

If the testicles are missed, then the lamb will be a 'cryptorchid' where one or both testicles can be felt under the skin along the belly, or squeezed back up into the body cavity. These sheep are usually infertile, but there is always the risk of an odd animal being an effective ram.

Cryptorchids grow faster than wethers due to the testosterone produced by the testicles.

Objective
The procedure must be done so that the scrotum, along with both testicles, is captured when the ring is released. The ring must be above scrotum and testicles, and below the rudimentary teats.

Method

1. Get an assistant to catch the lamb and sit it on its rear end on a board or rail at standing height.

2. Grab the end of the scrotum and pull it through the open ring.

3. With the ring fully open and resting on the lamb's body, use your fingers and thumb to locate the testicles and press down to squeeze them through the ring. Hold them there and release the ring.

4. Before flicking the pliers off the ring, make sure there are two testicles now in the scrotum.

5. Double check - testicles in - teats out!

January 15, 2009

Cattle farm husbandry - dehorning & castration

Cattle, farming, husbandry, dehorning (disbudding), castration

By Dr Clive Dalton

What use are horns ?

A horn very close to growing into an animal's
head which needs urgent attention.

Horns were designed by nature for cattle to fight with and for dams to protect their calves from predators. They damage hides, they bruise meat (which is not seen until the beast is skinned at the meat works) and they injure people. There is no place for them in today's farming systems.

Dehorning (disbudding)

The cauterising iron in action. Note how the firmly the calf needs to be held.

Disbudding means removing the small horn “bud” on a calf when it is soft and is best done before it is 6 weeks old.
When you do it really depends on the size of the horn bud. In Holstein Friesians the bud will be big enough long before 6 weeks, but in some Jerseys you may have to wait a bit longer.
The horn bud should be smaller than the cup on the end of the cauterising iron which can be heated by gas or electricity, so you get a complete cauterised ring around the base of the bud which is where the growth occurs.
The calf should be given an injection to block the nerves to the horn bud. Contact your veterinarian who may allow you to do this under their supervision. Your vet can also give the calf a tranquilising injection to further ease any pain.
The anaesthetic takes a few minutes to act so plan your work to consider this.
It is now not acceptable to do calves without anaesthetic as blocking pain is such an easy process.
To test to see if the iron is hot enough, try it on a piece of wood to make sure it will produce an even and complete circle of burning after 2-3 seconds of burning.
The calf must be held firmly in a headbail.
Inspect the calves after half an hour and cauterise any that may still be bleeding.
Do not use caustic paste, no matter how handy it is. It’s corrosive and the discomfort to the calf lasts a long time, and can be rubbed on to other animals – e.g. from calf’s head on to cow’s udder. It’s easy to end up with a badly disbudded calf.
In some horned breeds the small buds may be very pointed, and not round. Dexter calves are a good example of this, and the best practice is to cut these pointed buds out with the horn scallops and then cauterise the bud.

A pointed horn bud from a Dexter removed by scallops

Dehorning

This refers to removing any horns that will not fit in to the cup of a cauterising iron.
There is a range of tools on the market from debudding scoops to cut our small horns, to massive guillotines for mature cattle.
Do not use these devices without consulting your veterinarian because law changes involving the use of an anaesthetic in dehorning are about to change. Dehorning a large animal is a dangerous and painful operation that requires professional expertise.
The mature horn is part of a beast’s skull, and the hole on the end of a severed horn goes right inside the sinuses of the beast’s head next to the brain. Cattle can get infections and die.
To avoid this gruesome operation, never buy horned cattle and tell the stock agents and vendors why.

This is not 'dehorning'. These horns can still inflict damage.

Castration

The first question is whether you need to castrate at all? If calves are going for the bull beef market, then it’s not a consideration.
Testicles produce testosterone which is a great natural growth stimulant so the longer you delay the operation, the more free growth booster you get.
So there is a trend to delay castration to the point where you can just get the testicles through the standard rubber ring. There are now larger rubber rings and applicators available for delayed castration, but these have some animal welfare concerns.
For the animal’s welfare, calves should be castrated with rubber rings before they are 6 weeks old. Make sure this is done correctly so both testicles are left inside the scrotum below the ring, and the calf’s rudimentary teats are above the ring.
If you fail to get the testicles and only cut off the scrotum you’ll be able to feel the testicles under the skin as the animal ages, in front of where its scrotum was. You have created a “cryptorchid” or partial castrate, and this may fool some buyers as they’ll have a steer that behaves like a bull! You had better inform any buyers of your missed target.
With large testicles left under the skin, seek veterinary advice as the animal will need surgery to cut the testicles out.
On large cattle stations, calves are still “cut” (castrated) at about 2-4 months old by experienced operators using a knife. Many old stockmen argue that when the dog has eaten the removed testicles, they know there will be no problems with rogue bulls on the property!
Before you consider using emasculator pliers that crush the spermatic cord but doesn’t cut the skin, talk to your vet about its operation and effectiveness.

Animal welfare issue
Mixing horned and polled cattle that are not mates at saleyards and during transport can cause great pain and suffering to the beast being attacked. Even if they have been long-term mates, and sorted out their social order, the confined space does not allow the lower-ranked beast to escape - as seein in the picture below.

There is also a big financial loss incurred by the owner, as although the gore marks may not look much, once the slaughtered animal is skinned, there are massive bruised areas where the meat has to be condemned. The gored beast because of stress would also have very high pH in the carcass which would also be bad for meat quality.

The situation in the picture below shows very poor saleyard management and ignorance of the MAF Saleyard Code of Practice.

Terrified cow (with small horns) being gored by cow with large horns in saleyard pen.
The gored cow's hide and carcass meat will be ruined. The cow's owner will suffer the penalty but it's the fault of the saleyard operators - who will not stand the loss.

January 2, 2009

Sheep Farm Husbandry - Castration and Tail Docking

Castration, tail docking, age, methods, welfare issues

By Dr Clive Dalton

These procedures have been carried out for centuries, castration to reduce the number of males on the farm, and docking tails to avoid the growth of dags that attract blowflies. So the term “docking” for both these operations, done at the same time.

Both involve animal welfare issues as they are done by farmers (and not by veterinarians), and no anaesthetics are used

Castration
At what age?

Ram lambs grow much faster and are leaner than castrates (wethers) and so make more money in the meat trade. So don’t castrate them if you don’t need to and if you have a good market for them.
On large farms the risks of stray ram lambs disappearing and turning up again to mate ewes before they are discovered is a real one, so castrating all unwanted males is sound management.
It’s recommended that castration should be done after maternal bonding has been completed (i.e. 12-24 hours) and before 6 weeks of age.
Under current law it is an offence to castrate any sheep over 9 months old unless it is done by a veterinarian who will use some form of anaesthetic.

Methods
Rubber rings

Using rubber rings is the most humane method.
A ring is stretched with special pliers and placed around the neck of the scrotum.
The rule is simple – make sure that before the ring is released that both testicles are below the ring and the rudimentary teats are above it.
Hold the testicles down with your free hand in the scrotum while you release the ring to make sure they don’t escape back above the ring.
It’s best to do the lambs between 7-10 days old.
Lambs feel pain as judged by them lying down and kicking from 5-15 minutes but then they show no more obvious distress.

Two nicely docked lambs. Tails will drop off in about 10 days. They are marked on the tail to help check on mothering up

Knife

This used to be the standard method before rubber rings were invented.
It is not recommended now because it’s slow and the risks of infection, bleeding from the wound, hernias and blowfly attack is very possible.
The bottom of the scrotum is cut with a sharp knife or scalpel and the testicles pulled out or “drawn”.
They are slippery and hard to hold and pull out. Old shepherds used to draw them with their teeth!
Research has shown it is much more painful than the rubber ring method.
Surgical castration should only be done by a veterinarian using pain control.

Emasculator pliers

These pliers (called the Burdizzo emasculatome) crush the spermatic cords making the ram infertile.
They are slow and clumsy and are not used much now.
There is always doubt about the result too as you cannot see the end result of the action.

The cryptorchid procedure

This is also called the “short scrotum method” and is where a rubber ring is put around the scrotum so it will eventually drop off, leaving the testicles up against the body wall.
The higher temperature this creates makes the sperm infertile while the ram gets the growth benefit of the male hormones while being infertile.
Be warned though – an odd cryptorchid may not be completely infertile and may be able to get females pregnant.

Tail docking
At what age?

The minimum standard says tail docking must only be done if there is a significant risk of faecal or urine contamination, or blowfly strike that will lead to poor hygiene and health. So if you cannot justify it – then don’t do it.
Without pain relief - dock lambs as young as possible, and not older than 6 months of age.
Beyond 6 months you must use pain relief which may mean the costs of a veterinarian.
Generally docking should be done after maternal bonding has been completed (i.e. 12-24 hours). But some farmers dock with rubber rings when tagging the lambs and claim it does not affect bonding.

What length to leave the dock?

The tail dock (the bit left) should be long enough to wag!
A good guide is that the dock should cover the vulva of a ewe lamb and be the equivalent length in males down to the bald bit on the underside of the tail. This is clearly stated in the MAF Sheep Code of Practice.
If the lamb is able to raise it’s dock when defaecating, it lifts the supporting tissue around the anus (the caudal folds) so can direct any diarrhoea which is common on New Zealand pastures away from the body.
If the dock is too short, the dung runs down its legs and into it’s crutch.
Leave the tail on any ram lamb that you cannot locate the testicles – it’s a good visual sign when drafting. It’s a ‘long tailer” and hence a cull.

This ram's tail dock is far too short, and you can see
the damage done to the tail ligaments. The
MAF Sheep Code of Welfare has been ignored

Methods Rubber rings

Use rubber rings when lambs are 7-10 days old, and the tail should drop off 10-14 days later.
Don’t cut the tail off below the ring as the blood can attract blowflies.
Check the scar on the tail stump incase it has gone septic and attracts blowflies. This does not often happen.

Cauterisation

Here a gas-heated iron is used to both cut and cauterise the tail in one action.
Correct pressure on the iron is important to make sure the stump has been cauterised during the cutting action. A steady slow action is needed.
You soon learn to get it right if you have to hold a bleeding tail stump between your fingers, and cauterise it with the hot iron while the lamb is kicking with the pain!
Check that no docks are bleeding before returning lambs to their mothers. Any that are bleeding will have to be re cauterised.
Blowfly repellant can be applied to the dock if flystrike is a problem.
Don’t dip the lamb’s backside in a drum of sheep dip as the fluid rapidly becomes contaminated with blood and dung over time and does more harm than good.