Methods of Marking Lambs and Precautions to be Observed

New Zealand Journal of Agriculture, Volume 81, Issue 3, 15 September 1950, Page 197

Methods of Marking Lambs and Precautions to be Observed

By

A. D. M. G. LAING,

Assistant Director, Livestock Division,

Department of Agriculture, Wellington. THE marking of lambs on a sheep farm is an important annual operation and unsound methods or any relaxation in the usual precautions can cause substantial loss. This article summarises methods in use at present and makes suggestions for minimising losses. It is emphasised that practical instruction from experienced operators in all lamb-marking operations is essential, and knowledge gained from literature can never eliminate the necessity for such instruction.

LAMB marking consists of three different operations: The placing of a distinguishing mark in one or both ears, the amputation of tails, and the castration of male lambs. The order in which the operations are done is immaterial and is suited to the convenience of the owner, but it is desirable, for obvious reasons, that double catching should be avoided and that lambs should be returned to their mothers as quickly as possible; for these reasons everything necessary is carried out in succession on each lamb. Lambs are usually marked at between 1 to 6 weeks of age; 3 weeks is probably the ideal age. Systems vary according to the type of farm; for example, on high-country properties only one mustering will be convenient for this purpose. It should be remembered that the double operation, triple in the case of male lambs, is a strain on a young weakly lamb and lambs should not be marked when very young. Preliminary Arrangements Lamb-marking operations, even on quite a small scale, must be carefully organised. It is essential that clean yards should be used. If the sheep yards have concrete floors, very thorough washing down will make them suitable. On most properties, however, a convenient and clean part of

the paddock where the ewes and lambs are running is selected and temporary catching yards are put up. Hurdles and wire netting are suitable materials.

A diagram of such a temporary yard is shown below. The board used for resting the rump of the lamb on when operating must be clean, and the use of a new piece of planking for this purpose is justified; 6in. is a good width. The board should be washed down frequently while operations are in progress. It is important to choose a suitable, day for docking operations. In very hot weather there may be trouble from fly strike and, if the causative organism (Erysipelothrix rhusiopathiae) of arthritis or swollen joint exists on the farm, cold, windy weather may cause cases of this trouble in the lambs operated on, because of their lowered resistance to germ infection. So that lamb marking can begin reasonably early in the morning ewes and lambs should be mustered the day before. It is important that marking should be completed by early afternoon so that all lambs can be properly mothered up before nightfall. Careful attention must also be given to all instruments which are to be used in lamb-marking operations. These should be thoroughly cleaned, boiled for at least 10 minutes in water in which 5 per cent, of washing soda has been dissolved, and then wrapped in clean cloths. Clasp knives, which have numerous crevices where dirt may collect, are quite unsuitable, and a one-piece knife of suitable size should be used. It should be sharpened before it is sterilised. These remarks also apply to any special-shaped earmarking pliers which may be used, as there have been instances of infection from dirty instruments of this type.

A clean box, up-ended to hold the instruments and antiseptic, should be placed at a convenient point beside the plank on which the lambs will be rested when being marked. It is sound practice to cover this with a clean towel or old piece of sheet. A small basin filled with . methylated spirits should be available and in this all instruments used should be placed when not in the operator’s hand. It is desirable to apply antiseptic to the operation wounds, and it is far better to use a small pressure oil can which has been sterilised to squirt on antiseptic than to employ swabs, which rapidly become fouled. The operator and catchers should wear reasonably clean clothing or sacking overalls. Catching and Holding Lambs should be caught as gently as possible and around the body. The use of some form of suitably sized shepherd’s crook may help to prevent rough handling, as with it the lamb can be caught from behind in front of the chest. Swollen joints, bruising, or even dislocations may easily result if lambs are caught by the legs. The catcher places the lamb with its rump on the plank which has been erected across one end of the catching pen, and its back against his body, with the fore and hind legs on either side held together. This allows complete control of the lamb with a minimum of force and leaves the parts to be operated on, the ears, the' tail, and the purse, within easy reach of the operator. Earmarking • It is probably best to do earmarking first, as it is less drastic than the other two operations. An earmark, or a metal clip affixed to the ear, is defined as a “brand” within the meaning of Section 61 of the Stock Act, 1908, in which an earmark is described as: “An earmark distinctly and plainly made by cutting, splitting, or punching the ear, but so that in no case shall more than onefourth of the ear be removed”. It is obligatory under Sections 61 and 62 of this Act that all lambs shall be branded before April 30 in each year, though it is obviously more convenient and suitable to do this work a few weeks after the lambs are born. Earmarking is carried out with special pliers and with the Usual reasonable antiseptic precautions. If ear tags are used, they should be inserted half-way along the ear with the tag hanging down. It is desirable to useantiseptic solution on the site before and 'after the operation. Docking or Amputation of the Tail The tail should be amputated level with the lower tip of the vulva ' (the external genital orifice) in the case of female lambs, and a stump of. the same length should be left in male lambs. It is immaterial whether the cut is made at a joint or through one of the tail vertebral bones. The younger the lamb is at docking, however, the more rapidly will the wound heal. There are three common methods of docking tails: By using the knife, the searing iron, or the rubber ring.

Use of Knife Docking by use of the knife is the recommended method, and a one-piece, easily sterilised knife should be used. The operator holds the tail in one hand, squirts antiseptic solution on the place where the cut will be made, presses the skin upward toward the body, and with a clean, sharp cut with the knife severs the tail. The object of pushing the skin back is to allow for more satisfactory healing and prevent protrusion of the cut bone. The tail may also be bent with the tip toward the lamb’s body and cut through at the bend by the operator drawing the knife toward him. This method leaves an overlapping flap of skin which is stated to assist. healing. When the operation has been completed some antiseptic should be squirted into the wound. On many farms it is customary to place the ewe lamb ■: tails in one heap and the wether tails in another to make counting easy, Docking by Searing Iron Docking by the searing iron is quite efficient if carefully carried out, when it appears to prevent unfortunate sequels . such as arthritis infection (inflamed joints). It is, .however, inconvenient, and operators must be thoroughly experienced in the method. The procedure is similar to that for amputating the tail with a knife, but the tail must be held quite straight and , never folded. . The searing or docking iron, must be at . “black heat”, not red ■ hot. It is impossible to describe the correct degree of heat and it can be ' learnt, only by experience. Four, six, or more searing irons are necessary and a small brazier for the ■fire is preferable.' Searing irons with internal heating by methylated, spirits are available.

METHODS OF MARKING LAMBS

The searing iron is pressed lightly on the tail at the desired point, the skin being pressed toward' the. body as in the knife method, and with gentle pressure the whole structure is seared through. There is no haemorrhage, a light scab will form over the wound, and healing will be fairly rapid. If the iron is too hot, however, tissue damage will be considerable and pus will form under a thick scab. A purulent wound of this nature may result in death from septic poisoning or tetanus. Therefore, though the searing iron method of docking can give very good results and is, in good hands, excellent on arthritis-infected farms, it leaves little or no margin for error. Antiseptic should be used both before and after the operation. Docking by Rubber Rings The use of small rubber rings, made in different sizes and put on the tail at the point desired for. amputation, has increased greatly. The skin should be pressed toward the body as with the other methods, and the rings should, if possible, be placed over a joint, though this is not easy. After some days the stoppage of circulation of blood results in gangrene, and the decayed portion of the tail drops off. An open, ragged; dirty wound is left, and in areas where tetanus infection exists there . have been ■ fairly heavy losses from this disease in lambs of all ages docked by this method. From a surgical point of view amputation by ligature of a portion of .the animal body with a bony core is not a sound procedure. . ' : ■ Castration of Male Lambs Castration is effected by the removal or destruction of the testicles. The knife, one of the types of instruments

known as bloodless emasculators, or rubber rings may be used.

Whatever method is used, the lamb should be held as described in the section on docking, and castration should be the final operation of the three necessary for male lambs. Use of Knife Antiseptic should be applied freely to the site both before and after the operation. The tip of the purse should be held in one hand and the lower third either cut off completely or slit by a free incision from front to back. Either method should give that free drainage from the site of the operation which is so essential to healthy healing. The testicles may now be forced out of the slit in the purse by gentle pressure from above. Many farmers still use the old-fashioned method of grasping the testicle with the teeth to pull it out. Specially designed forceps of several types are also available for this purpose and these can be kept with the knife in the methylated spirits basin placed beside the operator. The withdrawal of the testicles must be done gently and no risk must be taken of breaking the cord internally. The knife may be used to scrape through the cord, but special emasculating pincers which cut and crush the cord and reduce haemorrhage are recommended. The pincers must also be kept in the methylated spirits basin when not in use. Animals with only one testicle in the purse should be suitably marked for early disposal, as they are rigs and will develop male characteristics. Emasculators or Bloodless Castrators Several types of emasculators or bloodless castrators are available. They work on the principle that, owing to the difference in the structure and elasticity of the skin and the structures forming the cord, it is possible with the jaws of a very carefully constructed and adjusted pair of pincers to sever the cord without more than lightly crushing the skin within which it lies.

All points mentioned about castration with the knife, including the use of antiseptics, apply to the use of emasculators. Users should note, however, that crushed skin is less resistant to infection than a clean wound with good drainage. Points to remember are:— 1. See that the jaws close on the cord well away from the testicles; that is, up the neck of the purse toward the abdomen. If the testicle is crushed, then trouble will ensue, abscess formation or even death resulting. 2. See that the cord does not slip out of the jaws of the instrument as they close. The fingers and thumb of the free hand may be used for this. It is a good plan when the jaws are closed very gently to push the severed end of the cord up and away. The jaws of the instrument should be kept closed for the period advised by the makers.

METHODS OF MARKING LAMBS

If there is doubt about the operation being satisfactory or if lambs are older than the usual age for castration, the cord may be crushed a second time higher up. Do not neglect to swab antiseptic solution on the crushed skin after completing the operation. There may be some swelling of one or both testicles, but it soon subsides and the organs wither away. Rubber Rings Castration by ligation, that is a tight ligature or clam around the testicles, has been practised from very ancient times. The rubber ring placed around the neck of the lamb’s scrotum or purse is a modern adaptation of this method. General points are the same as for the two previous methods and the use of antiseptics to counter the crushing and irritation of the skin which ensue must not be neglected. The purse eventually drops off. One drawback to this method is the extent to which lambs on which it is used rub the ligated part on the soil with resultant dirt contamination. With both the bloodless emasculator and the rubber ring methods of castration there can be no doubt that more care should be taken, on some properties at least, than there is at present. At one meat export works during the past season 8 per cent, of wether lambs were classed as stags; that is, as imperfectly castrated. When emasculators are used imperfect castration is due to one cord slipping and being imperfectly crushed. When rubber rings are used for castration care must be taken that both testicles are well below the rubber ring when it is closed. If one or both are not, then sufficient testicular tissue will be left functioning to create a “staggy” carcass, and very considerable unnecessary pain will be caused to the lamb. The attention of all sheep farmers is drawn to the fact that complaints about the proportion of “staggy” New Zealand wether lamb carcasses have been received recently from the United Kingdom.

METHODS OF MARKING LAMBS . . .

Procedure after Lamb Marking 3 Care after marking is by no means the least important part of the operation. Important points are:1. The lamb must be placed very gently on its feet on the ground, As far as possible the wounded parts should not become soiled. 2. The ewes should be kept handy to the docking yard and the lambs allowed to them as soon as possible ‘ for a drink of milk. A. long run to the ewe should be avoided, as this may increase bleeding. 3. Do not move the ewes until all the lambs have mothered. • . -vxtu v, urun 4 ’ freshlymarked lamb? to their Sack ' dock careful to take dock dLiv them along very slowly and quietly. Possible Troublesome Sequels to Possible Troublesome Sequels to Lamb Marking „ . „ j . . , Arthritis or swollen inflamed joints: These are due to infection gaining entrance into a wound, and harsh weather conditions undoubtedly play a part by lowering body resistance. The type of inflammation with heat and pain but relatively little swelling passes fairly quickly and most cases, apart from those which have setbacks, recover uneventfully. Where there is pus formation and swollen joints a wasted limb or limbs and consequent rejection lor export on slaughter may ensue P on siaugmer may Proper antiseptic precautions ■ and other measures already outlined, will

prevent the trouble. Penicillin treatment m the very early stages of arthritis, if economically justified, will give good results. Acute septic poisoning and/or blackleg: Symptoms are sudden death occurring in 1 to 4 days after marking. This trouble is due to a breakdown in the cleanliness of the marking procedure, use of dirty ground for the docking yards, etc. It can be prevented by careful attention to all precautions and, if the farm is badly contaminated, by the use of a preventive vaccine on the ewes about 3 weeks before they' are due to lamb and the carrying out of marking of lambs as soon as possible after birth, The advisability of such vaccinations should always be discussed first with a veterinary surgeon or a field officer of the Livestock Division, Department Tetanus lockjaw: The lamb Tetanus or lockjaw: The lamb becomes rigid, lies flat, and is in great pain. The symptoms appear 1. to 9 days after infection. If lambs are approached or touched, their rigidity increases. The head may be bent right back. Humanity dictates immediate slaughter, as the pain is intense, „ i • - , a u n Docking methods such as the use of rubber rings should be avoided m areas where tetanus infection is known to exist. If[it is considered essential to use rubber rings for docking m tetanus areas, and tetanus cases occur, swabbing out of the dirty wounds where the tails have dropped off with hydrogen peroxide, the oxygen of which is effective against the tetanus germ, may help to prevent further

cases. It must be emphasised that as long as there is an open, dirty wound, infection may take place; tetanus cases can and do occur in the circumstances described weeks after marking has taken place. .Tetanus symptoms appear 1 to 10 days after the tetanus germ has gained entrance. They are due to a poison or toxin produced by the germ, which affects the nerves, producing muscle convulsions. If it is economically worth while, inoculation can efficiently prevent tetanus infection. Antiseptics for Use at Lamb Marking Methylated spirits, pure or diluted with one quarter of its bulk of boiled water, is an excellent antiseptic, as are the antiseptics known as the quaternary ammonium group. Hydrogen peroxide, diluted with .2 or 3 parts of boiled water, is also excellent for wounds. There are, too, many excellent proprietary preparations available.