The welfare of docking and castrating lambs

There is a growing public debate pertaining to routine animal husbandry practices performed on livestock farms. In sheep production, docking and castrating are practices which are increasingly being questioned by animal welfarists and other interested persons. Scientists in Europe, New Zealand, Australia, and the United States are trying to address these concerns through research and education.

That we should consider the welfare of docking and castrating requires a paradigm shift for most U.S. sheep producers. Reasonable people are not suggesting that we do not do these practices (when necessary), but suggest that producers have a moral and ethical obligation to minimize the pain, stress, and distress that farm livestock experience while they are in our care.


Tail docking (intentional removal of part of the tail)

Justification
It is not difficult to justify the need for docking lambs. We do it for reasons of health and hygiene. We do it to improve the welfare of sheep and lambs, not detract from it. Fecal matter accumulates more easily on the hindquarters (breech) of a sheep or lamb if it has a long, woolly tail. Wet wool can become a breeding ground for flies. Blow flies lay their eggs in the soiled wool (or open wounds) and the eggs develop into maggots, which feed on the living flesh of the animal. This is called blow or fly strike. A serious case of flystrike is far more painful than docking. It can be a cruel way for a sheep to die. Research has shown that docking protects sheep and lambs from fly strike, while having no effect on lamb mortality and production.

Ease of shearing, crutching, and dagging are other important reasons for tail docking, especially for replacement stock. In some flocks, females are docked while tails are left on male lambs. Lambs raised in extensive production environments, such as the hill country of Great Britain, are often not docked. Abattoirs prefer to process lambs without long tails, especially when those tails have collected fecal matter. The more fecal matter that enters the processing chain, the more potential there is for e. coli and other contaminants.

Charollais ram
A docked Charollais ram.
 

Contrary to what many people may say, tails are not docked to make sheep look better. Nor are they docked to facilitate mating. A ewe's tail does not interfere with coitus or lambing, though some producers find it easier to manage their flock during lambing if the ewes don't have long tails.

Methods
Common methods of tail docking include the rubber ring (elastrator), cautery (docking with a hot iron), emasculator, and cutting the tail off with a knife. The elastrator [image] is a tool for bloodless docking. It is used to apply a rubber ring to the tail. The ring cuts off blood supply to the tail, eventually causing it to shrivel and fall off. Some producers cut the dead tail off with a knife. Lambs that are banded are more prone to tetanus since the band (ring) creates an aneurobic environment which is conducive to the tetanus organism. Immunity from tetanus is important.

An electric docking iron [image] cuts and cauterizes the tail simultaneously. Cutting the tail off with a knife causes excessive bleeding. Application of a hot iron to the stump, will cauterize the tail stump in the same manner as the electric docker. An emasculator [image] has both a crushing and cutting mechanism. The crushing mechansim seals the blood vessels on the remaining tail stub, while the cutting mechansim removes the tail. A Burdizzo [image] has a crushing, but not cutting mechanism, so a knife must be used to cut off the tail.

Docking is considered to be a good health management practice. It is a standard practice in the Western world, though not throughout the world. Twenty-five percent of the sheep in the world are of the fat-tail or fat-rump type [image]. Lambs from these breeds are usually not docked. Approximately ten percent of the world's sheep population is comprised of hair sheep [image], and they are usually not docked. Many Northern European breeds have short, thin tails [image] that generally do not require docking. Found mostly in Scandinavian countries, they comprise approximately three percent of the world's sheep population.

According to a 2009 NAHMS study, over 90 percent of lambs in the U.S. were docked. Sheep operations in the eastern states were less likely to dock their lambs than farms in other regions of the country.


Extreme or ultra-short tail docking

Extreme tail docking (leaving a lamb with little or no tail structure) is accomplish by applying the rubber ring very close to the body or using various unsavory "surgical" techniques. It has become a fad among show sheep in North America, as it gives the "illusion" of a squarer docked, more heavily muscled lamb. The practice, when combined with concentrate feeding, has been scientifically linked with an increased incidence of rectal prolapses. Some states have adopted policies requiring lambs that are exhibited by 4-H youth to meet minimum standards for tail length. These policies have met with minimum success, and extreme tail docking remains a blight on the purebred and club lamb sectors of the sheep industry.


Castration (removal or destruction of the testicles)

Justification
Castration prevents unwanted and early pregnancies. It gives the breeder genetic control over his animals. Castration allows male and female lambs to be reared together, enabling later more natural weaning. It eliminates agressive male behavior during feeding and pasturing, lessening the risk of injury to animals and people.

Wether lambs are easier to slaughter than ram lambs. More force is required to remove the pelts from ram lambs versus wether lambs. There may be a slight taint to the meat from sexually mature rams. As a result, ram lambs are often discounted in price, despite their superior performance and conformation. Rams have more aggressive behavior and should be neutered, if they are going to be kept as pets or used strictly for fiber production, vegetation control, or training herding dogs.

Methods
There are three main methods of castration in ram lambs: 1) rubber ring (elastrator); 2) emasculator; and 3) open or surgical method. The rubber ring is applied to the scrotum, above the descended testes, with care taken not to cover the lamb's rudimentary teats. The ring (band) disrupts blood supply to the scrotum, causing it to die and eventually drop off. Sometimes, the testes are pushed up inside the body wall and the ring is applied below the testes to produce a "short scrotum." A short-scrotum ram produces testosterone, but not sperm, thus he'll mate ewes, but not impregnate them.

The Burdizzo [image] is another method of bloodless castration. It is used to crush the spermatic cords, causing irreversable damage to the vessels supplying the scrotum. Each cord is clamped separately. Sometimes, the Burdizo results in incomplete castration. Small lambs are harder to do. The Burdizzo can also be used in combination with an elastrator. The cords are clamped immediately before or after the application of the ring. With the combination method, each cord may be clamped separately or the Burdizzo may be applied across the neck of the whole scrotum.

The testes are completey removed in the surgical method. The bottom one-third of the scrotum is cut off with a knife or scalpel and the testes are pulled out. The wound is allowed to drain naturally. The open surgical method of castration puts the lamb at the greatest risk for infection. This method should not be used during fly season.

So far, non-surgical methods of castration (e.g. chemical) have not proven to be effective or practical for castrating lambs or other livestock.

Compared to docking, castration is a less common management practice worldwide and on U.S. sheep farms. According to the 2009 NAHMS study, 68.5 percent of U.S. sheep operations castrate ram lambs. The likelihood of castration increased as flock size increased. The average age for ram castration was 24.7 days. Only 38.3 percent of operations castrated lambs when they were 7 days of age or younger. Banding was the most common method of castration, employed by 87.5 percent of U.S. sheep operatoins. Large (more than 500 ewes) and range operations were more likely to use a knife for castration.


A review of the scientific literature

In 1994, British researchers (French et al.) published a study in The Veterinary Record in which they had examined the effects of tail docking on lamb health and productivity. Over 3,000 docked and undocked lambs from seven farms were utilized in the study. The incidence of blowfly strike was strongly and consistently higher in undocked than docked lambs. The incidence of fecal soiling on the breech was slightly higher in undocked lambs. Fecal soiling on the breech is an important risk factor for blowfly strike. Both the mortality and production parameters were similar for docked and undocked lambs. The researchers concluded that tail docking protected against flystrike, with little evidence of a detrimental effect on lamb mortality and production.

Pain

Since they cannot talk, there is no definitive way to measure pain in animals. Even comparing pain in humans can be difficult. For animals, the tools used to evaluate pain are usually the behavior changes and physiological responses that occur as a result of a husbandry practice or other stress. Based on observations of lambs that have been docked and/or castrated, researchers have determined that restlessness is an indication of pain, that lateral recumbency is more indicative of pain than vertical recumbency, and that extension, rather than flexion of the hind limb generally indicates more pain. Abnormal standing or walking indicates more pain, while standing or lying still may reduce pain. Increased vocalization has also been associated with an increase in pain.

Baby lamb
How do we measure
pain in animals?
 

With regard to physiological responses to management practices, plasma cortisol has been demonstrated by several investigators to be indicative of pain and distress in farm animals. Cortisol is a corticosteroid hormone produced by the adrenal gland. It is a vital hormone that is often referred to as the "stress hormone" as it is involved in the response to stress. It increases blood pressure, blood sugar levels, and has an immunosuppressive action.

Scientists are in agreement that all methods of docking and castration cause pain and distress to the lamb, though the severity and extent varies by lamb, sometimes breed, and methodology. The scientific literature pertaining to the pain and distress caused by castration and tail docking is lengthy and complex. Studies have been conducted in different countries, with different species, breeds, ages, methods, and methodology. Results and conclusions are not always in agreement, though some general recommendations can be gleaned from the scientific literature.

Research shows that surgical (knife) docking is the most painful. The addition of a clamp to ring castration is beneficial compared to use of the ring alone.Most studies confirm that surgical (knife) castration is the most painful method of castration. The next most painful method is the rubber ring (alone). The Burdizzo method, while still painful, is considered to be the least noxious procedure. The combined method of the rubber ring + Burdizzo method causes the least amount of pain. Pain can be reduced is a local anesthetic is injected into the scrotal neck Short-scrotum castration is considered to be less painful than castration.

Tail length
Scientists have begun investigating the welfare aspects of shorter tail docking.As previously stated, it is a common practice to dock show lambs extremely short. U.S. researchers examined the relationship between dock length and rectal praplses. Short-docked (concentrate-fed) lambs experienced a higher incidence of rectal prolapses than medium and long-docked lambs. The same relationship was found in a similar study conducted in Minnesota, while a more recent Texas study failed to establish link between dock length and rectal prolapses in feed lot lambs.

In New Zealand, it is a common practice to dock lamb tails shorter than the recommendations of the country's Animal Welfare Advisory Committee, which stipulates that the tail stub be left long enough to cover the vulva of a ewe and be an equivalent length in the male lamb. New Zealand researchers found that half of no-tail, short, and medium-docked lambs showed evidence of neuroma and degenerative nerve damage compared to few long and undocked lambs, while long and undocked animals require additional effort at shearing and dagging (removing soiled fleece). In another experiment, restlessness, an indicator of pain and distress in rubber ring docked lambs, was more pronounced the shorter the tail was docked.


Breeding sheep with shorter tails

Breeding sheep with shorter tails that do not require docking is one possibility for addressing the welfare concerns of tail docking. According to researchers, breeding for short tails should be easy. This is because the tail length of groups of offspring appears to be halfway between the parents. Heritability of tail length varies by breed, but has been reported as high as 0.84. Researchers are in agreement that tail length is a moderate to highly heritable trait.

There are many breeds of short-tailed sheep that can be used in crossbreeding programs to produced genetically-docked tails. Tail length appears to be an index of degree of domestication. Wild sheep like the Mouflon(believed to be the ancestor of most modern sheep breeds) or North American Bighorn have short tails.

A breed called "No Tail" was developed over a 50 year period at South Dakota State University. Fat-rumped sheep with no tails were imported from Siberia and mated to Shropshire, Hampshire, and Cheviot ewes with the ultimate goal of producing a tailless breed with good meat and wool qualities. However, it was not until the 5th generation that the first tailless lamb was born.

Taillessness proved to be a multiple factor trait, thus never became fixed in the flock. After 50 years of breeding, only 40% of the lambs were tailless at birth. Another 20% had short tails (< 2.5 cm) and the remaining had long tails (up to 15 cm in length). When a No Tail ram was bred to long tailed ewes, all of the offspring had long tails. The tailless trait had a deleterious effect and was associated with paralysis of the hindquarters. The flock was sold in 1965.

In the 1970's and 1980's, New Zealand researchers encountered the same problems as the American researchers. The homozygous (for taillessness) embryos had reduced viability. In fact, research efforts to breed sheep with shorter tails seemed to parallel the lethal effect of the Manx gene in cats, in which homozygous cats die before birth and heterozygous cats [image link] have severely shortened tails, but many die before they are 12 months old, due to skeletal and organ defects. The small percentage of tailless lambs that are born to long tailed breeds almost always have serious bodily defects.


Alternatives to current practices

Don't dock

Look what I can do with my tail!
An undocked hair
sheep (Katahdin) lamb.
 

It is usually not necessary to dock the tails of hair sheep lambs. This is because hair sheep breeds usually have shorter, thinner tails with less wool on the underside. North American hair sheep breeds include, but are not limited to Katahdin, St. Croix, American Blackbelly, Barbados Blackbelly, Damara, Pelibüey, Wiltshire Horn, and Royal White. Dorpers, while generally considered a hair sheep because they shed their coats, have thicker, woollier tails and are typically docked by their breeders. Hair sheep are gaining in popularity due to their ease of management, including the lack of need for shearing, crutching, or docking or frequent deworming.

It is usually not necessary to dock lambs from the various short or rat-tailed breeds of sheep. These include, but are not limited to Finn Sheep, East Friesian, Shetland, Gotland, Soay, and Icelandic. Fat-tailed sheep are prized for their long, pendulous tails. Sheep-tail fat ("allyah" in Arabic) is still eaten and used as a cooking oil in some cultures. Fat-tailed sheep are seldom docked, though researchers have studied docking as a means of improving the productivity of these animals. The only fat-tailed sheep in the U.S. is the Karakul, and it is different from the breed raised in Central Asia.

If the hindquarters can be kept free from manure, it may not be necessary to dock the tails of lambs from the conventional wooled breeds. This possibility will vary by feeding, management, and breed. Grain feeding promotes looser stools, but grazing lush spring pastures can also cause feces to become more liquified. Stomach worms (besides the barber pole worm) and coccidia can cause scouring, so these diseases must be adequately controlled to prevent the hindquarters from becoming soiled on tailed lambs. An intermediate strategy would be to dock replacement sheep, but leave market animals undocked.


Don't castrate

Castration is deemed unnecessary if ram lambs are marketed before they reach puberty and if they can be reared separately from female lambs. Intact males exhibit superior growth, feed efficiency, and carcass yield. Short-scrotum rams offer the same advantages of ram lambs, while producing heavier carcasses, due to higher dressing percentages. Some of the negative aspects of ram carcasses can be overcome if lambs are treated with zeranol (Ralgro®) implants.

Many ethnic markets prefer intact males. In fact, it is customary for Muslims to sacrifice a ram for Eid-ul-Adha (the festival or feast of sacrifice). Some religious markets require or prefer unblemished lambs. An unblemished lamb would not have had its tail, testicles, or horns removed.

Immunization of male lambs against GnRH (gonatotropin-releasing hormone) or LH (luteinizing hormone) is being evaluated as an alternative to physical or surgical castration. In a study reported in 2000 in the Journal of Animal Science, the procedure resulted in the retention of some positive carcass attributes associating with feeding intact males and reduced sexual behavior.


Minimize pain and distress

Researchers are in agreement that lambs should be docked and castrated as soon as possible, though not during the first 24 hours of life, as this may interfere with colostrum consumption and make the lamb more susceptible to watery mouth (e. coli scours). It is generally recommend that lambs be docked within the first week. Lambs born on pasture should be docked and castrated as soon as they can be mustered. UK law forbids ring castation beyond seven days of age, but some researchers suggest modifying the law to allow ring castration up to six weeks, as this method would be preferable to the open castration (knife) method for older lambs.

According to research results, the hot iron or electric docker is probably the most humane method of tail docking, followed by the elastrator (rubber ring method). Pain can be reduced if the rubber ring method is combined with the use of the Burdizzo and if smaller bands are used.

It is the recommendation of the American Veterinary Medical Association (AVMA), American Association of Small Ruminant Practioners (AASRP), and the American Sheep Industry Association (ASI) that tails be docked no shorter than the distal end of the caudal tail fold. Animal welfare code in other countries (England, Canada, New Zealand, and Australia) stipulates that the tail be left long enough to cover the ewe's vulva and be a similar length in male sheep. Pain is more pronounced the closer the band is placed to the body. When combined with concentrate feeding, shorter docks result in an increased incidence of rectal prolapses, especially among female lambs.

Though researchers are not in complete agreement, the rubber ring method is considered to be the least painful method of castration. Pain can be reduced if the rubber ring method is combined with the use of the Burdizzo and if smaller bands are used. Short-scrotum "castration" is less painful than full castration.

The pain of docking and castration can be reduced by use of a local anaesthetic (e.g. lidocaine); however, this is not practical for most sheep producers, as lambs must be handled twice and there is a time interval between application of the anaesthetic and docking/castrating. It is more difficult to inject a local anaesthetic near the tail. In addition, producers must have a veterinary prescription to purchase and use lidocaine.

Some researchers recommend that open surgical castration not be be permitted without both anesthesia and analgesia (pain relief).


Created or last updated by Susan Schoenian on 18-Aug-2012 .

Copyright © 2008.


Resources/Additional Reading
Tail docking and welfare of sheep - BC Sheep Federation

Lamb tail docking: a controlled field study of the effects of tail amputation on health and productivity
Pain in farm animals - Sustainable Animal Production: Visions for the 21st Century
Understanding Pain and its Relevance to Animals - Alberta Farm Animal Care
Abstracts pertaining to recognition and assessment of animal pain [UK]
Breeding sheep with bare britch and belly - R&D Brief, Meat and Wool New Zealand
Genetic reduction of tail length in New Zealand sheep
Assessment of Acute Pain in Farm Animals Using Behavioral and Physiological Measurements
Reconciling the differences between the length at which tails are commonly docked and animal welfare recommendations
Gonadal function, sexual behavior, feedlot performance, and carcass traits of ram lambs actively immunized against GnRH
Growth and slaughter characteristics of ram and wether lambs implanted with Zeranol
Pain and its control in routine husbandry procedures in sheep and cattle [Australia]
Length of docked tail and the incidence of rectal prolapse in lambs | PDF
The effects of dock length on the incidence of rectal prolapse in lambs
Pain prevention in lamb castration and docking