Tail Docking
It is quite common to tail dock lambs with the purpose of reducing future accumulations of faeces around the tail and breech area, which favour the occurrence of Blow Fly Myiasis (“Strike”). The blowfly (Lucilia sericata) is attracted to the damp warm conditions of a soiled breech and tail to lay its eggs. The larvae which hatch out burrow into the flesh to feed, leading to tissue damage, distress, loss of condition and even death depending on the severity of the infestation.
Docking tails helps to address food safety concerns, as there is generally a decrease in tag (manure build up) on a docked animal, helping to avoid contact of the meat with bacteria during butchering. Other reasons given for docking include ease of management at mating and lambing and altering the appearance of certain breeds for traditional reasons. Whereas the former may be the case, the latter is not a sound reason for docking. There is a belief that long tails may reduce breeding efficiency in ewes but the evidence does not support this.
However, available evidence does indicate that docking is beneficial to lambs on farms where blowfly strike is a problem, one study revealing an incidence of strike five times greater in undocked lambs compared with docked lambs. In this regard length of tail remaining after docking is important. Very short tails increase susceptibility to strike whereas long docked tails give the lowest incidence of strike.
The tail affords a degree of protection against the elements to the sensitive anus and vulva and perhaps the udder also. Therefore, it is in each farmer’s interest to consider carefully the necessity for docking lambs rather than doing so out of routine. Clearly if scouring is controlled by an adequate pasture management and working program the need to dock should be reduced.
(Note: Some breeds, such as the Icelandic sheep, are naturally tailless.)
Tail Docking Methods
The following is a list of methods available for tail docking.
1. Rubber Ring
This is the most widely used method. Using an elastrator, a constricting latex ring is applied to the tail below the level of the anus in males and the vulva in females. This cuts off the blood supply to the tail beyond the ring resulting in death of those tissues and the sloughing (shedding) of that part of the tail. The actual separation usually occurs at the joint immediately above the ring. This takes about 3 to 4 weeks. Some operators attempt to place the ring on a joint in the belief that this is less painful or more effective. At present, there is no hard evidence to support this although a minority of lambs do seem to react less than others for some reason.
Advantages: effective; cheap; quick; can be performed by single operator; relatively unskilled; relatively safe for operator and lamb.
Disadvantages: infection can occur over the prolonged sloughing period as the ring cuts into the tissues. This can allow bacteria to gain access via the tail resulting in abscesses or, more seriously, Clostridial diseases such as tetanus. Pus formation around the ring is common and may attract flies. Rubber rings may not be used by Law if the lamb is more than 7 days old, timing incompatible with common hill farming practice. Despite its clean appearance, there is a good deal of scientific evidence that this method involves considerable pain in the majority of lambs.
2. Knife
A small majority of farmers use this method. Severing at a joint is easier and therefore swifter. A scalpel or very sharp knife which is not used for any other purpose (other than castration) must be employed. It should be placed in an antiseptic liquid such as povidone-iodine (“Pevidine”) or chlorhexidine gluconate (“Hibitane”) after use on each lamb. Good hygiene is essential. Soiled tails should be cleaned and swabbed with a dilute Pevidine or Hibitane solution before docking and the operator’s hands should be washed and dried frequently. An assistant should catch and restrain the lambs thereby allowing the operator to keep his/her hands free from contaminants. Applying a wound powder or spray (eg. Terramycin aerosol) to the stump may help prevent infection.
Advantages: effective; cheap.
Disadvantages: risk of serious haemorrhage (bleeding), particularly in older lambs, which causes a major set-back or at worst is fatal; leaves an open wound which can allow entry of bacteria, not suitable in fly season; there is scientific evidence that it is the most painful method; two people required if hygiene to be maintained.
3. Burdizzo
A Burdizzo or similar bloodless castration instrument is used to crush the tail, preferably on a joint. It is held in place for 5 or 6 seconds and then usually a knife is introduced below the jaws of the instrument and the tail severed just below the crush.
Advantages: Less likely to bleed severely compared with the knife method; can be used in older lambs.
Disadvantages: slow; some consider this method cruel as it may involve crushing bone; may damage the Burdizzo jaws; effectively leaves an open wound; awkward to perform single-handed; good hygiene requires a handler and an operator.
4. Docking Iron
These instruments (a number of different designs are available e.g. Alfred Cox, Ritchey Tagg) use a blade heated by an integral gas burner to sever and cauterize (sear) the tail in one swift action. The lamb is held by an assistant or a specially designed cradle.
Advantages: As well as severing the tail easily, the heated blade cauterizes the tissues and blood vessels thus minimising or preventing haemorrhage; the heat sterilises the blade; scientific evidence suggests this is the least painful method, as the nerve endings are destroyed by the intense heat; one design can be operated single-handedly and the flame and blade have a guard over them; can be used in older lambs.
Disadvantages: some designs involve the use of two operators with a risk of burns being suffered; fire risk; some scientific evidence suggests that cauterized tails take slightly longer to heal; a different method must be used for castration.
Long term side-effects of tail docking
Various studies have been conducted to see if the different methods of tail docking adversely affect subsequent growth and productivity. No such effects were found overall. Nevertheless, individual lambs which suffer severe haemorrhage or infection are detrimentally affected. There is evidence that if tail are docked too short there may be damage to the rectal and/or vaginal nerves, which leads to a higher incidence of rectal and vaginal prolapse.
Summary
- Only castrate or dock if necessary.
- Avoid castrating or docking lambs less than 24 hours old and older than a week of age.
- Only castrate or dock healthy lambs.
- Ensure lambs to be castrated or docked are protected against the Clostridial diseases.
- Avoid castrating or docking in bad weather or in soiled, muddy surroundings or during the fly season.
- Before castrating check that there is no scrotal hernia and that both testes are present in the scrotum.
- Check afterwards, especially last thing at night, for signs of ill effects such as haemorrhage or excessive discomfort.
- Ensure all operators are trained and competent.
