Code of recommendations and Minimum Standards for the Welfare of Sheep

Code of recommendations and minimum standards for the welfare of Sheep

Animal Welfare Advisory Committee
c/o Ministry of Agriculture
P O Box 2526
Wellington
New Zealand

Code of Animal Welfare No. 3 (Revised)
ISBN 0-477-08550-4
ISSN 1171-090X
July 1996

1. Introduction

New Zealand’s temperate climate and topography are ideal for the extensive grassland farming of the country’s approximately 50 million sheep. Because of these favourable conditions and the freedom to range and graze good quality pasture, New Zealand sheep enjoy a high standard of husbandry. In addition, the country’s geographical isolation, effective border control, strict quarantine systems and the absence of major insect disease vectors ensures that the sheep are free of many of the serious debilitating and fatal diseases which affect sheep in other countries.

However, under some circumstances, grassland farming may put the welfare of sheep at risk as they may be exposed to inclement weather. Unless care is taken the health of individual animals may be compromised in the interest of general flock welfare.

World-wide, welfare considerations are becoming increasingly important for the keeping and farming of animals. Practices that were once considered acceptable are now being reassessed and modified or abandoned according to new knowledge and changing attitudes in society.

New Zealand agricultural products are of a very high quality. Increasingly, our access to international markets depends on our ability to provide quality assurance. Demonstrably high animal welfare standards are a vital part of that assurance.

2. The Purpose of the Code

This Code complements legislation by outlining the minimum standards which are currently acceptable to the informed New Zealand public and it makes recommendations to ensure good sheep welfare.

It is a practical guide for those involved in sheep production, and it is intended to encourage the adoption of the highest standards of sheep husbandry.

As with all Codes produced by the Animal Welfare Advisory Committee it takes account of 5 basic requirements:

  • from thirst, hunger and malnutrition
  • provision of appropriate comfort and shelter
  • prevention, or rapid diagnosis and treatment of injury, disease or infestation with parasites
  • from distress
  • ability to display normal patterns of behaviour.

Good sheep welfare depends upon competent handlers. Therefore, appropriate technical training is necessary for those involved in the husbandry of sheep. Ignorance is no excuse for inappropriate handling and management of animals as expert advice is readily available, and should be sought if the handler has any doubt about correct procedures.

The Code also provides interested parties in New Zealand and overseas with evidence of the high sheep welfare standards in this country and demonstrates the commitment of the industry to continued improvement of these standards.

2.1 The Scope of the Code

The Code provides the owners and managers of sheep with principles for their care and use. It encompasses all aspects of the farm husbandry of sheep but does not deal with transportation, meat-plants, saleyards and experimentation. These are dealt with in the Codes of Recommendations and Minimum Standards for the Transportation of Animals in New Zealand, for the Sea Transport of Sheep, for the Slaughter of Stock in Licensed Premises, for the Welfare of Animals in Saleyards and for the Care and Use of Animals for Scientific Purposes.

2.2 Preparation and Revision of the Code

The Code is a comprehensive revision of the Code of Recommendations and Minimum Standards for the Welfare of Sheep published in 1992.

It was written by a working group established by the Animal Welfare Advisory Committee. It was extensively reviewed by leaders and representatives of the sheep farming community including farmers, veterinarians, advisors, scientists, teachers and welfarists.

This code is based on the knowledge and technology available at the time of publication and may need to be updated in the light of future knowledge.

Comments on the content are invited and should be addressed to the Secretary, Animal Welfare Advisory Committee, P O Box 2526, Wellington.

3. Legal Responsibilities and Definition of Terms

3.1 Legal Responsibilities

It is an offence, under the Animals Protection Act 1960, to allow animals to suffer unnecessary or unreasonable pain or distress. The breach of a code provision, whilst not an offence in itself, can nevertheless be used as evidence in tending to establish the guilt of anyone accused of causing an animal suffering under the Act.

Specifically, the Act indicates that an offence is committed if anyone;

  • ill-treats any animal
  • to provide any animal with adequate shelter or proper food and water sufficient to maintain its live weight within the normal physiological range for its species, type, age and sex
  • an animal so that it suffers unnecessary pain or distress
  • brands, mutilates, confines, conveys or carries any animal in such a manner or position as to cause it unnecessary pain or suffering
  • leaves alive any animal which is in such a condition that to keep it alive is cruel
  • any sheep over the age of 9 months, unless the castration is performed by a veterinarian
  • any animal over the age of 20 months unless during the whole course of the operation the animal is under the influence of a general or local anaesthetic sufficient to prevent the animal from feeling pain.

The owner or person in charge of the sheep is responsible for the health and welfare of the sheep in his or her care. They are accountable for implementation of the legal requirements and standards set out in the Code.

3.2 Definition of Terms

The interpretation of the words shall, must and should is as follows:-

Shall means there is a statutory requirement.

Must indicates a minimum standard.

Should denotes a strong recommendation.

4. Feed, Water, Shade, Shelter and Climate

4.1 Feed

Sheep shall be given appropriate feed in sufficient quantities to maintain their body weight within the normal physiological range for their type, age, production status and sex, and their diet should be adequate to prevent disorders caused by faulty nutrition.

Generally sheep should not be deprived of feed for longer than 24 hours and they must not be deprived of feed for longer than 48 hours.

The feed requirements of sheep vary with factors such as age (stage of growth), size, pregnancy, lactation, amount of exercise, wool cover and prevailing environmental conditions.

Tables 1 and 2 in the Appendix show recommended daily pasture requirements and recommended minimum pasture length and dry matter quantities for sheep in grassland farming systems.

As a general guide, a ewe requires a daily intake of metabolisable energy of 8 to 10 megajoules (MJ) to maintain its body weight, 16 to 20 MJ in late pregnancy and up to 30 MJ in early lactation.

Average hay has about 8 MJ per kg and an average hay bale weighs 20kg to 25kg. Concentrates usually provide 13 MJ/kg or more. Sheep which are housed and fed a concentrate diet may require a pellet with relatively less energy, about 9 MJ/kg, and more roughage.

Sufficient feed should be provided to maintain the sheep in good health with a body condition score of 3, as shown in Appendix Figure 1. The use of body condition scores is recommended as an integral part of sheep husbandry.

Generally, extra feed should be provided for sheep for at least 3 weeks after shearing (see Shearing), as during this period their maintenance requirements may increase by up to 40% or up to 32% if cover combs are used. (Cover combs do not shear close to the skin but leave a short length of wool.) Supplementary feed must be provided for newly shorn sheep if sufficient good quality pasture is not available. Some of the energy produced by digestion in the rumen (forestomach) is released as heat and this may help prevent cold stress.

The feed requirement of ewes increases with pregnancy and lactation, as indicated in Appendix Tables 1 and 2.

Pasture generally provides a balanced diet. If a single crop is fed for more than a few weeks there may be a risk of certain diseases developing (see Diseases Related to Feeding), and appropriate precautions should be taken and expert advice sought if necessary.

Grazing conditions can become very muddy under crops fed during wet weather. Under such circumstances sheep should have access to a relatively dry area on which they may rest.

When sheep are to be fed high energy feed such as grain or concentrate pellets, training to the feed should take place over a period of time. They should have free access to small amounts at first and gradually the daily amounts should be increased until the full ration is available. Generally this takes about 2 weeks. When sheep become accustomed to new feed in this way it helps prevent overeating by some (e.g. grain overload) and food avoidance by others.

Supplementary feed such as hay or silage should not be fed if it is mouldy.

In controlled grazing systems e.g. rotational grazing, break feeding and strip grazing, available pasture is subdivided into small lots for grazing at a relatively high stocking rate with frequent shifts of the sheep. Shifts may be as frequent as twice a day. The amount of pasture available on each break should be sufficient to meet the needs of the sheep during the time they are on that break. There should be enough reserve feed to allow more frequent shifts if it is very wet and the fodder grazed becomes trampled and muddy. When pasture growth is not as good as expected, extra feed should be provided to meet the nutritional requirements of the sheep.

Overfeeding can cause problems. A full rumen may contribute to bearings (prolapses of the vagina) in heavily pregnant ewes. Obesity also predisposes to bearings and to casting, especially of sheep in full wool.

Information about the quality and quantity of feedstuffs which should be fed is available from veterinarians and agricultural consultants.

4.2 Water

Sheep shall be given sufficient good quality water to maintain body weight within the normal physiological range for their type, age and sex.

Sheep should not be deprived of water for more than 48 hours, and in hot weather for no more than 24 hours. Water sources should be reliable and the water clean.

Factors which increase water requirement include lactation, pregnancy, hot and dry weather, sparse and dry feed. If these conditions apply, individual sheep may drink up to 6 litres of water daily.

In hot weather sheep pant, and the evaporation of moisture from nose and mouth has a cooling effect. This increases their water requirement. Water supplies should be checked more frequently during hot weather.

When feed is lush and the weather cool, sheep generally require little or no drinking water. Nevertheless water should be available at all times.

4.3 Shade

Shade should be provided for sheep especially in hot, sunny weather. Activities such as mustering, transportation and prolonged yarding should be avoided in such conditions.

Newly shorn sheep may require shade to prevent sunburn.

In areas where facial eczema occurs and particularly when signs of the disease are present, and after shearing, there is a greater requirement for shade.

4.4 Shelter

Shelter should be provided for sheep especially in cold, wet, windy weather, at lambing and after shearing. Very young lambs are particularly susceptible to hypothermia in cold wet weather. It should be noted that unless ewes at and soon after lambing are adequately fed, they may choose to graze rather than shelter thereby exposing their lambs to the effects of the inclement weather.

There should be sufficient shelter at lambing to provide the ewes and their lambs with effective protection while allowing the shepherd to inspect the flock from an appropriate distance without disturbing lambing ewes

When three or more lambs are born in a litter, they tend to be relatively small and particularly susceptible to chilling. In flocks where multiple births are common there is a greater requirement for shelter at lambing.

For at least 2 weeks and up to 4 weeks after shearing, sheep are susceptible to hypothermia and they should be pastured so that they can readily be brought into covered yards or to other effective shelter during this period. They should also have sufficient feed in the weeks after shearing (see Feed) to provide adequate energy to prevent cold stress and death.

Sheep which are shorn just before lambing have a particular requirement for good shelter (see Prelamb Shearing).

Effective protection from cold, wind and rain can be provided by low level shelter such as tussock, shrubs, flax, windcloth or other artificial material. Trees may diffuse rain and wind but without shelter to the ground sheep may still be unprotected in bad weather. Some paddocks provide natural shelter in the form of banks and gullies.

4.5 Climate

Heavy rainfall, unseasonal snowstorms and droughts can cause significant distress and losses in livestock. To lessen these effects, farms susceptible to climatic disasters should have contingency and action plans as follows;

In areas subject to floods the farmer should:

  • heed weather warnings
  • ensure that sheep can be moved quickly to safe higher ground
  • ensure ready access to stock
  • move sheep to higher ground as soon as possible
  • ask for assistance if needed from the local District Council or Flood Committee
  • hold sufficient stored feed at accessible sites
  • clear access tracks of slips promptly.

In areas prone to winter storms the farmer should:

  • heed weather warnings
  • choose lambing and shearing dates judiciously
  • use blade shears, cover combs or snow combs when shearing in late autumn, winter or early spring or when sheep are to be grazed at high altitudes following shearing
  • ensure good track access to stock
  • move stock to more sheltered or lower land as soon as possible
  • ask for assistance if needed from the local District Council or Disaster Committee
  • ensure access for equipment that can clear tracks
  • clear tracks of slips and snow promptly
  • hold sufficient stored feed at accessible sites
  • where possible train sheep in advance to eat the supplementary feed likely to be offered.

Farmers should be aware that in some snow storms, turbulence can result in drifts in the lee of shelter and this can trap sheep seeking shelter. However, well fed sheep may survive under snow drifts for several days. Often they can be detected by ventilation holes created by their breath.

In drought-prone areas, farmers should:

  • ensure that there are good sources of water not immediately dependent on rainfall such as bore water and reservoir water
  • make provision to obtain water from outside the area during prolonged droughts
  • secure access to grazing land outside the drought-prone area
  • if unweaned lambs are over 8 weeks old and ewes are losing condition, wean the lambs
  • ask for assistance if needed from Federated Farmers or agricultural consultants
  • hold reserve stocks of hay, silage or other supplementary feed
  • accustom sheep in advance to eat the supplementary feed likely to be offered
  • provide shade as this can reduce the water requirement of stock
  • move the sheep to areas where water and feed are available or sell, slaughter or have slaughtered sheep which cannot be given adequate feed and water.

5. Other Husbandry Practices

5.1 Restraint

Sheep should not be caught, dragged or lifted by the wool. They should not be lifted by the horns and they should not be dragged by the horns unless the horns are very sturdy. Generally sheep should be handled or restrained by means of an arm under the neck and an arm around the rump. Propping the sheep on its rump so that it leans back on the handler’s leg is a convenient method of restraint for many quick procedures such as foot trimming and shearing.

The techniques used to restrain sheep should not cause injury or unnecessary distress. Sheep should not be kept on their side or back for more than a few minutes at a time especially if the rumen is full or if they are heavily pregnant.

Sheep must not be tethered unless they can be adequately monitored. If they are tethered, sufficient feed and water must be available at all times. A collar which fits comfortably should be used and if it causes chafing or other injury it should be removed. Any sheep which continues to resist tethering after reasonable training has been undertaken should be released.

As a general rule, sheep should not be kept isolated from other sheep for any longer than necessary because they become distressed if left alone.

5.2 Cast Sheep

Sheep in full wool, especially if heavily pregnant, are liable to become cast, especially on flat country. Cast sheep become distressed and can die within a short time if not rolled back into a normal position. When back on their feet they may need to be supported for a few minutes before release to ensure they are steady. At risk sheep should be kept where they can be viewed readily and if heavily pregnant they should be inspected at least once daily until they have lambed.

5.3 Rams

Because rams may lose weight over the breeding season they should be healthy and have a body score around 3 or 4 (see Appendix Figure 1) before mating commences. Their feet should be healthy. Harnesses fitted to mark ewes should fit comfortably and should be inspected frequently to ensure that they do not cause chafing of the skin. They should not be left on longer than necessary. They should be removed if they cause injury and adjusted if they appear to be causing discomfort.

5.4 Lambing

The main cause of neonatal lamb mortality is starvation and/or hypothermia and/or mismothering (failure of the ewe to bond with her lambs). Keeping losses to a minimum entails forward planning and the provision of appropriate supervision and shelter during the lambing period as well as the provision of appropriate feed during pregnancy so that ewes are in good body condition at lambing.

Farmers should choose sheltered paddocks for lambing, that is paddocks with natural shelter (for example gullies or scrub) or planted shelter belts, or artificial windbreaks in the form of wind netting or a similar material. Very steep land is generally not suitable for lambing ewes, particularly for ewes likely to have two or more lambs.

The requirements for shepherding at lambing time vary from flock to flock depending on the ease of lambing of the particular breed of sheep or strain within the breed, the topography and the expected lambing percentage. In other words the intensity of shepherding should be appropriate for the environment and should depend on how well the breed or strain of ewes is suited to that environment.

A compromise should be sought between insufficient supervision such that ewes and lambs suffer unnecessarily as a result of lack of assistance at lambing and overzealous supervision which can result in dystocia (difficult birth) and disruption of ewe-lamb bonding.

Ewes select a lambing site up to 3 days before lambing and may separate themselves from the flock at lambing. The ewe and lamb(s) may remain on the birth site for 12 hours or more. Management practices that allow ewes to remain on the birth site during this time will increase the chances of both bonding and lamb survival.

In the most extensive farming systems, it is strongly recommended that breeds or strains be used which generally lamb successfully without assistance. When unaccustomed to daily shepherding it may be better to leave them undisturbed or observe them from a distance using binoculars if necessary. If the stocking density is low other sheep are less likely to intrude on the birth site. Unnecessary interference may cause ewes to move from birth sites and this in itself can lead to an increase in dystocia cases and mismothering. Where ewes are seen to be in difficulty they should be assisted and they can be marked for culling from the flock along with their progeny at a later date. Genetic selection for ease of lambing and mothering ability are crucial for natural lambing in these systems.

For intensively farmed flocks, more frequent shepherding is indicated during the lambing period. The most intensively farmed flocks generally have a high rate of twins or multiple births and are accustomed to the regular presence of humans, dogs and vehicles. Assistance should be given if ewes experience difficulty during lambing. Assistance should also be given to small weak lambs, particularly in bad weather. The assistance may take the form of artificial rearing, fostering, moving ewes with small lambs or 3 or more lambs to more sheltered paddocks or onto better pasture. Weak lambs may be given assistance to obtain their first feed of colostrum from the ewe. Portable pens can be used to confine ewes and lambs to aid mothering-on. Once bonding has occurred woollen or plastic lamb coats can be used to prevent hypothermia in cold wet weather, but they should be used judiciously as they may increase the risk of mismothering.

Prelamb shearing may help prevent metabolic disease and ewes becoming cast, and may encourage ewes to use available shelter with their lambs (see Prelamb Shearing).

If the wool of the ewe is relatively long, prelamb crutching and bellying (removal of wool from around the tail and udder and from the belly) will help ensure that lambing is uncomplicated and that the lamb has unimpeded access to the teats (see Crutching).

Dogs used during lambing must be under strict control.

If a ewe requires help from the shepherd at lambing, the hands of the shepherd should be clean and the fingernails clean and short. Where dystocia is present efforts to correct the placement of the lamb should not cause unnecessary damage to the uterus and vagina. Undue force should not be used. In most cases, the use of obstetric lubricant or soap and water is strongly recommended. The lamb should be in a normal position for delivery with its forelegs extended in front of its head in the birth canal. Some lambs may be delivered successfully in the posterior position provided care is taken to prevent the lambs tail-head injuring the dorsal wall of the vagina. If this is not the case and if the lamb’s position cannot be corrected with firm but careful manual assistance, expert help should be obtained. As a general rule only dead lambs should be dismembered for removal. If attempts to lamb a ewe are unsuccessful, expert assistance should be obtained or the ewe should be killed humanely.

Lambing in autumn, winter and early spring carries a risk of nutritional and cold stressunless appropriate provisions are made. If necessary, supplementary feed should be provided for ewes and there should be sufficient effective shelter for ewes and lambs.

Pregnancy testing by ultrasonic scanning of ewes at around 50 days to 80 days’ gestation may allow ewes carrying two or more lambs to be identified and separated for preferential treatment in late gestation, at and after lambing.

Dead (slink) lambs should be buried or burned or disposed of in offal pits. If they are to be collected by a slink skin operator, they should be covered or placed in a covered container while awaiting collection.

5.5 Breeding from Young Ewes

If ewes are to be mated before they are a year old they should be well grown for their breed, well fed during winter and carefully supervised at lambing.

Use of sire breeds with relatively low single lamb birth weights is recommended.

Unwanted mating of ewe lambs should be avoided by running them separately from all fertile male sheep from the time they are about 4 months old.

Generally ewes reach puberty at 6 to 9 months of age and can conceive from this age. If they conceive when they are not well grown there is an increased risk of dystocia because of relatively large lambs. There is also a risk that the ewes themselves may not reach their full potential body size.

5.6 Fostering/Artificial Rearing

If a ewe seems unable to raise her lamb(s) successfully, they should be fostered onto other ewes if possible, hand-reared or humanely killed.

To provide them with sufficient energy, newborn lambs should receive 150 to 250 ml colostrum per kg body weight in the first 24 hours after birth. The volume required depends on environmental temperature. To help protect them from infectious diseases they require at least 200 ml of colostrum within 24 hours of birth. Ewe colostrum is best. Cow colostrum is also useful but it can cause anaemia in some lambs. Home made "colostrum-substitutes" are of limited value as they do not contain the antibodies present in true colostrum. Colostrum can be frozen if not required immediately, preferably in 100 ml lots. It should be slowly warmed to blood temperature before feeding (but not in a microwave oven because this may denature antibodies).

As feeding lambs by stomach tube requires care to avoid insertion of the tube into the windpipe it should only be carried out by or under the supervision of people skilled in the technique.

Pens used for fostering or artificial rearing should be kept clean and dry.

The mother of a dead lamb is more likely to accept an orphan if it is covered with the skin of her own lamb. There are also mothering aids available such as sprays for the ewe’s muzzle to mask the smell of a strange lamb.

If any lamb less than a few days old is penned for fostering or artificial rearing its navel should first be sprayed with disinfectant to prevent bacterial infection.

Where tethers are used to restrict ewe movement while she is trained to adopt a foster lamb or lambs the ewe and lambs must be inspected frequently to ensure they do not get caught up in the tether and to see that the lambs are not being unduly rejected (i.e. butted) by the ewe. The tethers should fit comfortably so that they don’t cause chafing. If chafing occurs the tethers should be removed.

The fostering process should cause as little distress as possible. Lambs should be removed if the process is not succeeding.

The best artificial feeding systems generally use self-help feeders which offer ready access to milk from teats attached to a container of milk. Bottle-reared lambs should be fed as frequently as possible, up to four times daily and at least three times daily for the first week of life, thereafter twice daily. Lamb milk powder can be purchased readily, and the manufacturer’s feeding instructions should be followed. Generally this is a better option than feeding a formulation based on cows’ milk.

All equipment used to provide milk in artificial rearing systems should be kept clean, with periodic disinfection including daily disinfection of teats and bottles if possible, particularly when large numbers of lambs are involved.

If lambs have not received sufficient colostrum early vaccination against clostridial diseases is recommended.

Artificially reared lambs should have access to good pasture or hay from about 3 to 4 weeks of age to aid development of the rumen in preparation for weaning.

5.7 Weaning

As a general rule lambs should not be weaned before 6 to 8 weeks of age. The water supply of ewes whose lambs have been newly weaned should not be restricted. Ewes should not be put onto lush pasture after weaning as the incidence of mastitis mayincrease. To minimise distress, groups of newly weaned ewes and lambs should be out of sight and sound of each other.

5.8 Tail Docking

The docking of lambs’ tails is carried out to help prevent faecal dag formation and flystrike and to facilitate shearing

5.8.1 Age

Tail docking should be carried out after maternal bonding has occurred (i.e. after 24 hours of age). Sufficient time should be allowed after docking for ewes and lambs to be reunited before dark.

If tails are to be docked, the procedure should be carried out before the lambs are 6 weeks of age and must be carried out before they reach 12 weeks of age unless the procedure is carried out by a veterinarian using anaesthesia.

5.8.2 Technique

New Zealand research indicates that to minimise stress in the lambs, the techniques of choice for tail docking are the application of a rubber ring or the use of a hot searing iron.

To minimise the risk of infection, the operating area, equipment used, the lambs themselves and the operator’s hands should be clean. The use of temporary yards which can be moved from paddock to paddock is wise as it helps prevent build-up of contamination in the operating area.

The procedure should not be carried out on wet lambs or in wet weather, because this increases the risk of infection.

Docking with an unheated knife carries greater risks of haemorrhage and infection of the wound and requires extra precautions to control bleeding and to prevent infection of the stump.

5.8.3 Length of Tail

There is some evidence to indicate that the rubber ring should be placed so that the tailis left long enough to cover the vulva and the equivalent length in males. This may help ensure that when the tail is lifted for defaecation the caudal folds on either side are raised and the faeces directed away from the body, thereby helping prevent faecal contamination of wool and helping prevent blowfly strike. If tails are very short the caudal folds are not raised and soft faeces are more likely to soil the area below and on either side of the tail.

5.9 Castration

Castration is traditionally carried out for management reasons to prevent unintended mating. Castrated lambs are known as wethers. Farmers should give serious consideration to whether or not castration is necessary. It should not be carried out unless it has significant management advantages, e.g. it may not be necessary in ram lambs that are to be slaughtered before 6 months of age. There is no "ram taint" in the meat of prepubertal lambs.

5.9.1 Age

If lambs are to be castrated the procedure should be carried out after maternal bonding has occurred (i.e. after 24 hours of age) and preferably before 6 weeks of age.

It should be noted that under the existing Animals Protection Act it is an offence to castrate any sheep over the age of 9 months unless the castration is performed by a veterinarian. This age standard is inappropriate in the light of current knowledge.

Accordingly it is strongly recommended that if rubber rings are used the lambs should be under 12 weeks old, and if surgical castration is carried out, the lambs should be under 6 weeks old, unless these procedures are carried out by a veterinarian using anaesthesia.

5.9.2 Technique

The best method of lamb castration is the application of a rubber ring to the neck of the scrotum using an elastrator, i.e. an applicator made for the purpose.

Surgical castration by laypeople is not recommended. It is likely to cause greater and more prolonged distress than other methods, together with an increased risk of adverse consequences following the operation, such as excessive bleeding, hernias (prolapse of intestine into the scrotum) and infection of the wound. If surgical castration is to be carried out by a layperson, veterinary advice should be obtained to ensure that the correct method is used to keep pain and distress to a minimum, and that the operation is carried out as hygienically as possible to reduce the risk of wound infections.

Castration by crushing of the spermatic cords using the Burdizzo emasculatome is rarely practised in New Zealand.

The area where castration is carried out, the equipment used, the lambs themselves and the operator’s hands should be as clean as possible and lambs should be dry. The elastrator and rubber rings can be dipped in dilute antiseptic before application.

5.9.3 Short-scrotum Technique

In the short-scrotum (sometimes colloquially known as "cryptorchid") technique, rubber rings are applied to the scrotum below the testes so that the testes are pushed towards the abdominal wall. The increased testicular temperature usually renders the lamb sterile. The recommendations are as for conventional castration using rubber rings.

5.10 Mustering and Yarding

Sheep should not be yarded for periods of more than 24 hours unless feed and water are provided. Yarding for more than a few hours can precipitate metabolic diseases such as sleepy sickness (pregnancy toxaemia) and milk fever (hypocalcaemia) in ewes in late pregnancy, and it can predispose to infectious diseases such as salmonellosis. Sheep should not be left unsupervised in races.

If heavily pregnant ewes or ewes and their unweaned lambs are mustered or yarded, every effort should be made to move them quietly and without crowding, to minimise distress caused by separation of ewes from their lambs. The time spent in the yards should be kept to a minimum, preferably not more than 4 hours and less in hot weather.

In hot weather sheep should be mustered in the cool of the early morning or evening especially if their wool is of medium length or longer. Access to water should be provided.

Use of dusty yards should be avoided, particularly in hot weather as they may predispose to pneumonia. The prior damping of dusty yards with water sprinklers is a useful procedure during hot weather.

Dogs should not be used excessively. Dogs which bite repeatedly must be muzzled when in use.

Sheep should be moved slowly and quietly. There should be sufficient competent dogs to head off potential smothers. Smothering occurs when sheep pile on top of one another in corners or at gateways especially when moving downhill. It tends to occur in large groups of sheep if they move too rapidly and especially when sheep areforced into corners or through narrow gateways or when they rush to feed.

When unaccustomed to yarding, lambs are susceptible to smothering, especially after weaning.

Sheds and yards must be designed, constructed and maintained to minimise the risk of injury to sheep and should take advantage of behavioural characteristics to facilitate the flow of sheep.

If sheep are moved on foot they must not be forced to proceed at a pace likely to cause exhaustion and heat stress.

5.11 Injuries

When a sheep has been injured and appears to be distressed, in pain or handicapped as a result, immediate steps must be taken to provide relief. Appropriate treatment should be given or obtained from a veterinarian. If the injury is so severe that it would be cruel to keep the sheep alive, euthanasia must be carried out (see Humane slaughter). If the sheep is to be shorn it should be killed before it is shorn.

5.12 Crutching, Dagging and Face-Wool Removal (Eye Wigging)

Wool under and to either side of the anus can become laden by clumps of wet or dried faeces (faecal dags). These dags should be trimmed off as they can cause discomfort and inflammation of the underlying skin and they may attract blowflies.

Wool growing around the eyes of sheep should be trimmed if it obscures their vision.

Before lambing wool around the udder should be trimmed if necessary to allow the lamb unimpeded access to the teats. Wool around the vulva should be trimmed to facilitate lambing.

5.13 Shearing

It is strongly recommended that sheep be shorn at least once a year.

Shearing sheds and equipment must have regular maintenance checks, and shearing equipment should be clean.

Sheep should not be shorn if the forecast is for cold wet weather.

Shearing must be carried out skilfully and/or carefully to ensure that shear cuts are kept to a minimum. Sheep should not be handled roughly. Extensive or severe cuts must be treated as soon as possible. Care should be taken to avoid accidental shearing cuts to teats and prepuces.

Avoid leaving freshly shorn sheep in dusty yards, as any cut may be a potential access site for the bacteria which cause "lympho" or caseous lymphadenitis.

As sheep with a full rumen may suffer distress when shorn, those which have been on lush pasture should be rested off pasture for a minimum of 6 hours before shearing.

The use of cover combs or blade shears is strongly recommended in districts in which there is little or no natural shelter and in areas subject to very cold weather.

Provision should be made for extra feed and for appropriate shade and shelter for sheep after shearing (see Feed and Shelter). Newly shorn sheep require up to 40% more feed for 3 weeks or more after shearing to sustain body temperature and maintain body condition. Maintenance requirements may be increased for 6 to 8 weeks after shearing. There should be ready access to covered yards or effective shelter for several weeks after shearing in case of cold wet weather.

After shearing sheep may be keen to get back to pasture, but without their wool they can be injured by crowding through gateways. Care should be taken not to hurry newly shorn sheep out of the yards and through gateways.

5.14 Prelamb Shearing

In the more intensive farming systems, shearing 4 to 6 weeks before lambing may encourage ewes to use available shelter with their lambs. If prelamb shearing is carried out effective shelter must be available. The ewes must be well fed because if they are hungry they may graze rather than shelter with their lambs. The use of blade shears, cover or snow combs is strongly recommended. Prelamb shearing should be carried out early enough in the day to give ewes time to feed and find shelter before dark.

5.15 Marking and Tagging

Marking to aid identification of the sheep may involve applying raddle in the form ofchalk, crayon or spray. Raddle marks are generally applied to the head or wool of the body and persist for a period from several days to several months before they wear or wash off. This is the least stressful means of identification and is the recommended practice for short term identification.

Permanent marking can involve removing a portion of the ear. This is not recommended unless there is no practical alternative method, as ear tissue is sensitive. The pain caused and the risk of infection should be kept to a minimum by ensuring that the implement is clean and sharp. The amount of tissue removed should be kept to a minimum, and must not exceed a fifth of the ear.

Ear tagging involves inserting a plastic or metal tag into the ear by punching a hole then clipping the tag into the hole or by clipping the tag directly through ear tissue. The number of tags used should be kept to a minimum, preferably not more than two per sheep.

When ear cutting or ear tagging, care should be taken to avoid cartilage ridges and blood vessels.

Lambs should not be tagged within 24 hours of birth because of the risk of mismothering. If it is important to identify newborn lambs, a temporary raddle mark should be applied and every effort made to minimise disturbance of ewe and lamb.

5.16 Dehorning

Most New Zealand sheep are naturally polled and in horned breeds there is usually no valid reason for disbudding or dehorning. However, if horns curl round in front of the eyes or are likely to grow into the head, partial or complete dehorning is necessary. Removal of the insensitive horn tip may be carried out by a layperson, but it is strongly recommended that cutting into sensitive tissue in the core of the horn be carried out only by or under the supervision of a veterinarian, using anaesthesia.

5.17 Teeth Clipping/Breaking

The crowns of the incisor teeth of lambs must not be forcibly removed by forceps, pliers or any other instrument. The procedure is likely to cause considerable pain and it does not benefit the lambs.

5.18 Preparation of Sheep for Meat Processing Plants

There is a meat processing plant (licensed slaughter premises) requirement that sheepare presented clean for slaughter. Dirty sheep are cleaned in the meat plant yards by spray washing or swim washing and occasionally by removing dags and dirty wool, and this contributes to preslaughter stress. The farmer has an obligation to ensure that sheep which leave the farm for slaughter are clean and free of dags. Their wool should be 10 mm to 20 mm long, so they should not have been shorn in the previous 3 weeks. Their wool should not be long, since sheep with long wool are more difficult to clean and dress. Prior to transport sheep should be held off pasture for at least 6 hours, preferably overnight but for no longer than 24 hours, with access to drinking water, to minimise the risk of faecal contamination of fleece in the transporter.

5.19 Transport of Injured and Pregnant Stock

The farmer or delegated manager of sheep is responsible for the selection of fit and healthy sheep for loading onto road vehicles.

If a sheep is unable to stand on all four legs or is so injured that transport is likely to increase any pain it may be experiencing it is unfit to travel. It must be treated or killed humanely on the farm (See Injuries). Under certain conditions the animal may be killed on the farm by a veterinarian or licensed pet food operator for use as pet food (see the Animal Welfare Advisory Committee’s Code of Recommendations and Minimum Standards for the Welfare of Animals Transported within New Zealand).

Sheep that are likely to give birth during transportation must not be transported.

5.20 Feedlots and Housing

In New Zealand, sheep may be kept in feedlots to facilitate adaption to concentrate feed before sea transport, and occasionally sheep are housed indoors for short periods after shearing or in winter or for specialised wool production. In these systems each animal should be provided with sufficient good quality feed and water to maintain optimal body condition (body score 3, see Appendix, Figure 1). Concentrate diets should be formulated to avoid copper poisoning and urinary calculi. Feedlot sheep should have shade and windbreaks available at all times. Housed sheep should have fresh air, sufficient room to move around freely and dry areas to lie on. The house should be well lit during daylight hours.

Sheep in feedlots or kept indoors should be examined at least once daily and any sheep which is losing weight or has become ill should be given appropriate treatment or removed.

6. Diseases and their Control

Sheep farmers should be familiar with the normal behaviour of sheep, they should be familiar with the common diseases in their area and should observe their stock carefully for signs of disease or distress. Early recognition of ill-health helps to determine the cause and control the disease effectively.

Every sheep farmer should have an animal health programme, preferably documented, and developed in consultation with a veterinarian. This should incorporate preventive measures to guard against internal and external parasitism, diseases of the feet and trace element deficiencies. The animal health programme should include appropriate vaccinations against endemic diseases.

Diseases can compromise welfare by causing discomfort, distress and/or pain. The signs include listlessness, blindness, weakness, diarrhoea, loss of appetite, teeth grinding, weight loss, lameness, aimless wandering, abnormal posture or frequent lying down, loss of wool, coughing or panting and often separation from the flock.

All sheep in which injury or disease is or seems likely to be causing severe or persistent pain, or distress, severe malaise or emaciation must be treated. If the appropriate treatment is not known or not available, a veterinarian must be consulted or the sheep be humanely destroyed without delay.

6.1 Internal and External Parasitism

6.1.1 Internal Parasitism

Gastrointestinal parasitism is a threat to production in grazing sheep throughout New Zealand. Control is essential to ensure good health, production and welfare.

Sheep in their first year of life are particularly susceptible and generally require regular drenching with an effective drench. Thereafter an age-related resistance tends to develop, but parasitism may still occur.

Monitoring of the intestinal parasite status by egg counts is an important part of all parasite control programmes.

A drenching programme for internal parasite control should be established preferably in consultation with a veterinarian, since anthelmintics should be used strategically to maximise productivity while minimising the risk of drench resistance.

Drenching requires skill on the part of the operator to prevent the drench being forced into the lungs. Care must be taken to avoid damage to the throat by rough handling and drench guns with rough or damaged nozzles should not be used.

Rumen anthelmintic capsules provide control of worms for 3 to 4 months, but their administration requires particular skill since they are relatively large and may damage the lining of the mouth and throat if inserted roughly. Excessive force should not be used. They should only be administered to sheep over the age specified by the manufacturer and they should only be used with the manufacturer’s applicator.

6.1.2 External Parasitism

Parasites such as lice, keds, ticks and blowflies can distress sheep by causing irritation and itchiness. They can also limit production while severe infestation by blowfly larvae can be fatal. Lice tend to build up over autumn and winter.

There are various repellents and insecticide treatments for external parasite control, some of which may be effective for up to 14 weeks. Preventive treatments should be given when the wool is short. Pour-ons should be applied as soon after shearing as is practicable and saturation products (in plunge dips or saturation showers) should be used at the time recommended by the manufacturer, usually 6 to 12 weeks after shearing.

There is no longer a legal requirement that sheep be treated for external parasites annually but nevertheless sheep should be regularly inspected and any early infestations treated promptly.

Pour-ons are less stressful than plunge dips and saturation shower dips.

Those responsible for sheep during plunge dipping should ensure that the sheep are as calm as possible. Their heads should be submerged for a minimal time to avoid inhalation which can result in drowning or deaths later from pneumonia. Sheep must not be plunge-dipped if they are panting. There must be at least one stock handler beside the plunge bath to supervise sheep as they are put through to ensure that no sheep is distressed unnecessarily.

Likewise sheep which are given saturation showers should be kept as calm as possible. They should not be showered if they are hot or panting. They should not be packed so tightly that there is risk of smothering.

Ewes and their unweaned lambs should not be plunge-dipped or showered. Likewise sheep with recent cuts such as shearing cuts should not be plunge-dipped or showered.

Insecticides should be used according to the manufacturer’s instructions.

6.1.3 Flystrike

Flystrike can cause extreme animal suffering

Blowflies generally lay eggs on soiled damp wool. The larvae live in and on the flesh beneath the dirty wool. This flystrike causes the sheep considerable distress as a result of ulcers, inflammation, infection, and discomfort. This may lead to reduced appetite, weight loss and sometimes death. Flystrike can occur at any time of year in some localities but generally summer/early autumn is the period of highest risk.

In recent years the establishment of the Australian green blowfly (Lucilia cuprina) has increased the risk of flystrike over much of New Zealand.

Reasonable steps must be taken to control flystrike. Control measures include:

  • frequent inspection of sheep to identify early strike cases
  • prevention or early treatment of injured or diseased skin which might attract blowflies, e.g. lumpy wool (dermatophilosis), foot rot and ram fight injuries
  • tail docking (as outlined earlier)
  • strategic crutching/dagging or shearing before and/or during the risk period
  • dipping/showering/topical application of insecticide/repellent at strategic intervals throughout the period of risk (long-acting insecticide may act for 8 to 12 weeks)
  • effective control of internal parasitism and pasture control to prevent the soiling of faeces that can follow access to lush feed and which results in faecal soiling of the breech
  • moving sheep to areas which are cool and windy or to relatively high altitude pastures where blowflies are not present or are less active
  • mulesing and pizzle-dropping (see Special techniques).

Longer term reduction of risk can be achieved by implementing biological controls such as use of parasitic wasps and fly traps to reduce blowfly numbers.

6.2 Trace Element Deficiencies

Many of New Zealand’s soils and pastures are deficient in the vital nutrients cobalt, selenium and/or copper. Cobalt deficiency results in ill-thrift especially in growing lambs. Selenium deficiency can result in poor growth, white muscle disease in lambs and infertility in ewes. Copper deficiency is less common but occurs occasionally causing hind-limb weakness (enzootic ataxia) or fragile bones (osteoporosis). In some areas, iodine deficiency may result in increased neonatal mortality because it increases susceptibility to hypothermia. With guidance from a veterinarian or other animal health consultant, farmers should monitor the trace element status of their sheep and provide supplements as appropriate.

6.3 Diseases Related to Feeding

The metabolic diseases milk fever (hypocalcaemia) and sleepy sickness (pregnancy toxaemia or acetonaemia) are diseases which occur in late pregnancy. Milk fever may occasionally occur during lactation. Grass staggers (hypomagnesaemia) can occur in ewes in early lactation. A nutritional check is often a precipitating factor. The risk of metabolic diseases may be minimised by ensuring a rising plane of nutrition in the last few weeks of pregnancy and avoiding prolonged yarding. However, a sudden spell of inclement weather can interrupt feed intake and precipitate disease. To detect early cases, stock should be observed closely for abnormal behaviour such as dullness or agitation. To be effective treatment should be administered as soon as possible.

Many crops provide good nutrition in the short term; however, with some of them there is a risk that nutritional deficiencies may occur or harmful amounts of damaging substances may be eaten. Among the diseases that can occur are brassica redwater, brassica white muscle disease, brassica goitre in neonatal lambs, rape scald and, on a variety of green feeds, nitrate poisoning.

Silage should be of good quality with a pH of less than 5 otherwise there is a risk of circling disease (cerebral listeriosis) and possibly abortions. Silage and hay should not be mouldy.

Digestive disorders can result from overconsumption of any new feed particularly high energy feeds such as concentrates and grain (see Feed).

If there is any doubt about how to prevent, detect or treat diseases associated with feeding, advice should be obtained from a veterinarian or other animal health consultant.

6.4 Diseases of the Feet

Lameness is a relatively common condition and can be a significant animal welfare issue. There are a variety of causes including arthritis, but most frequently the site of lameness is the foot. Arthritis may occur in newborn or recently docked lambs.

The horn of the feet of sheep tends to overgrow and curl under the foot if it is not worn naturally through abrasion. Excess horn should be trimmed from feet as appropriate to prevent overgrowth. Foot-trimming should be carried out carefully to avoid unnecessary bleeding.

Footscald and footrot are common causes of lameness. If footrot is present, overgrown and underrun horn should be trimmed off. Both conditions should be treated by standing affected sheep in a footbath of 10% zinc sulphate or 5% formalin for 5 to 10 minutes to kill bacteria. If footrot is left untreated, arthritis in the foot joints or foot abscesses may develop and these are very difficult to treat effectively.

Sheep which are persistently lame should be treated or humanely destroyed.

Long-term solutions for problem flocks may include the use of footrot vaccine, selection for breeding of sheep with sound feet and culling problem sheep. With an appropriate combination of preventive measures, footrot eradication is possible.

6.5 Tooth Faults

Tooth faults may be a cause of or may contribute to ill-thrift in sheep and examination of the incisors should be included in investigations of ill-thrift.

If the lower jaw is relatively long or relatively short in comparison to the upper jaw, or if incisors are excessively worn or very long or very loose or if incisors are missing the sheep may not be able to graze short pasture effectively. Very loose incisors can be painful and should be removed manually. Sheep with severe faults should be given preferential grazing or culled.

Mechanical grinding of teeth to reduce their length must not be carried out. There is no evidence that this practice has any beneficial effects.

6.6 Facial Eczema

With the exception of the southern part of the South Island facial eczema occurs in much of New Zealand.

Facial eczema is caused by a fungus in the pasture. Toxins in the spores damage theliver and predispose the sheep to an exaggerated form of sunburn called facial eczema or hepatogenous photosensitisation.

In summer and autumn, habitats known to favour high spore counts such as northfacing slopes, ridges and near hedges should be avoided. Stock should be moved to safer pasture or crops. Frequent drenching with zinc solutions can help prevent liver damage and pasture can be sprayed with fungicide.

Shade should be provided to help prevent sunlight damage and sheep should be housed in darkness while they are sensitive to sunlight.

The degree of risk can be monitored using spore counts to aid selection of grazing for stock.

If there is any doubt about prevention and treatment of the disease advice should be obtained from a veterinarian or agricultural consultant.

Minimising the disease in the long term may involve breeding resistant strains of sheep.

6.7 Ryegrass Staggers

This disease is common in summer and autumn in all but the southern part of the South Island. It is caused by a fungal endophyte in ryegrass but there is no practical way of measuring the amount of fungus in pasture. To a limited extent the risks can be assessed using local knowledge.

The signs are tremor of the head then the rest of the body, staggery gait and inco-ordination. Sheep which show these signs are susceptible to misadventure and should be moved onto low risk paddocks of low endophyte or endophyte-free ryegrass pasture, onto a crop or they should be fed hay. They should be moved slowly and left undisturbed as much as possible. Paddocks with natural hazards such as ponds, ditches and bluffs should be avoided.

Affected animals usually recover spontaneously when no longer exposed to the toxin.

6.8 Bearings and Bearing Retention

Vaginal prolapses ("bearings") may occur in ewes in late pregnancy. Predisposing factors include lush feed, a full rumen, pregnancy especially with two or more lambs in utero, overfatness, lack of exercise and hilly ground. Avoiding as many of these factors as possible will reduce the risk of bearings. Food intake should be moderate and regular.

Early action is essential if treatment is to be successful. Remedies include cleaning and replacing the prolapse and partially closing the vaginal opening. In early cases it may be sufficient to tie wool across the vulva. Generally more radical treatment is necessary such as use of a purpose-made vaginal retainer inserted into the vagina and tied to the wool or use of sutures or pins to close the vulva after replacement of the prolapse. Sutures and pins used to retain bearings must be removed when lambing is imminent, but some retainers are designed to allow ewes to pass them. Whatever method is used to prevent vaginal prolapses, every effort must be made to minimise any additional pain or discomfort caused by their use and if there is any doubt about the method or technique, a veterinarian should be consulted.

Ewes must be destroyed humanely if the bearing has dried out, if it has been badly damaged or if it is not successfully retained.

Because there is evidence this trait may be passed on to progeny, affected ewes should not be retained for breeding.

6.9 Johne's Disease

Johne’s disease is a bacterial disease which impairs digestion in the intestine. Affected sheep progressively lose weight even if treated until they become emaciated and die. Prevention by vaccination is an option on problem farms. Veterinary advice should be obtained regarding diagnosis and control. Affected sheep should be euthanased as early as possible both for welfare reasons and to help reduce the spread of infection.

6.10 Plant Poisoning

A variety of native and introduced plant species have the potential to poison sheep. Some appear to cause considerable distress and pain and may be fatal. Sheep should not be given garden plants or garden trimmings unless it is certain that the plants are not poisonous. Sheep should not be allowed access to native shrubs and trees unless the shepherd is confident that there are no poisonous species present.

6.11 Vaccination

A number of infectious diseases can be prevented by vaccination. These diseases include some clostridial diseases such as pulpy kidney disease, blackleg, black disease and tetanus. Other diseases are toxoplasmosis abortion, Campylobacter abortion, scabby mouth, salmonellosis, Johne’s disease and footrot. The vaccinationprogramme for each farm should be devised in consultation with a veterinarian.

To reduce the risk of infection at the injection site farmers should follow the vaccine manufacturer’s instructions carefully when vaccinating sheep as injection site lesions, if found at slaughter, may cause carcase downgrading or rejection.

6.12 Diseases in Organic Farming Systems

Successful organic farming systems require high levels of husbandry to avoid the stock health and welfare problems that can occur without the regular use of conventional vaccines and other animal remedies.

Veterinary and other appropriate expert advice should be obtained if organic remedies are ineffective in relieving pain and distress caused by disease or injury.

6.13 Breeding for Resistance to Disease

The susceptibility to many diseases may be partly hereditary. Gastrointestinal parasitism, facial eczema and footrot are among the most common diseases in New Zealand and susceptibility to these diseases can be reduced by selective breeding. This has the potential to enhance the welfare of sheep through reducing disease and therefore the need for mustering and yarding for preventive treatments and remedies, while not significantly lowering their productivity.

However, breeding for resistance to these diseases in certain populations of sheep means it may be necessary to allow the disease to express itself in these sheep. The clinical disease should not be allowed to persist for longer than is necessary to demonstrate the degree of susceptibility. Any sheep which develops clinical signs of disease in a breeding programme should be treated appropriately or culled.

Selecting rams for resistance to facial eczema involves dosing with a specified amount of sporidesmin (the facial eczema toxin) and measuring its effect on the liver by blood tests. The animals should be tested indoors or allowed free access to shade and the clinical disease should not be produced. The procedure must be carried out only under veterinary supervision.

7. Special Techniques

7.1 Mulesing

Merinos have folds of skin around the perineum (the hairless area under the tail) which can become soiled by urine and faeces particularly soft faeces, thereby predisposing the sheep to blowfly strike.

Mulesing is a surgical procedure in which the wooled skin immediately adjacent to the naturally hairless skin above and on either side of the anus is removed. The resultant scars extend the area of woolless skin so that faecal and urine soaked dags cannot accumulate at these sites. Consequently the risk of breech flystrike is significantly reduced.

Mulesing is performed on some Merino sheep on a relatively small number of farms where sheep are farmed in very extensive systems and where there is a high risk of breech flystrike.

7.1.1 Chemical Mulesing

Chemical mulesing has been trialled overseas but has not proved to be a satisfactory procedure.

7.1.2 Surgical Mulesing

There are several surgical techniques each of which involves the removal of specific areas of wooled skin around the perineum. In New Zealand the technique used is one in which strips of skin are removed from either side of the perineum and from each side of the tail, and the tail is docked to a length that covers the vulva or the equivalent length in males.

7.1.3 Advantages and Disadvantages

Disadvantages of mulesing are that it causes pain both at the time it is carried out and during the healing process, there is a risk of infection and flystrike of the mulesing wound itself and the mulesing operation and healing process are unsightly.

Advantages are that mulesing can significantly and permanently reduce the risk ofbreech flystrike in Merino sheep otherwise well adapted to the high dry country in which they are generally farmed and in which they may subsequently be farmed for 10 years or more. As well as being at less risk of flystrike, Merinos which have been "mulesed" are spared the frequent and often protracted mustering for flystrike preventive treatments necessary in alternative systems of control. Requirements for reducing insecticide residue concentrations in wool add additional constraints to the use of insecticides in flystrike control.

7.1.4 Standards

Non-surgical (i.e. chemical) mulesing must not be carried out.

Surgical mulesing must not be carried out unless all the following conditions are met:

  • the sheep are Merino or Merino-dominant types
  • the sheep are destined to be farmed in extensive farming systems in areas where there is a high risk of flystrike
  • it is probable that no other flystrike preventive measure or combination of measures is likely to be effective
  • the procedure is carried out by competent operators using clean sharp mulesing shears
  • no more skin is removed than is necessary.

Even under these conditions mulesing may be carried out only until practical and effective non-surgical methods of flystrike control become available.

If sheep are to be mulesed, the procedure should be carried out before they are 12 weeks of age.

Antiseptic should be applied to the wounds and insect repellent around them

7.2 Pizzle-dropping

Pizzle rot (balanoposthitis) is a bacterial infection of the end of the prepuce. Merino wethers on good pasture are most at risk. The high protein feed results in urine with a high ammonia content which can scald the skin at the end of the prepuce, predisposing to pizzle rot and increasing the risk of flystrike. Close supervision of high-risk groups is necessary so that lesions can be detected and treated early. Treatment involves restricting the diet to hay with free access to water. More advanced lesions may require veterinary treatment. To prevent the condition the wool around the prepuce should be kept short but the hairs at the end of the prepuce which assist drainage of urine should not be removed. Pizzle-dropping is a surgical preventive procedure which facilitates urine drainage from the prepuce.

Pizzle-dropping is carried out on Merino wethers on a very few farms in the South Island where pizzle rot is a recurring problem. The skin that holds the prepuce against the belly is cut with modified mulesing shears for a length of 6 cm to 7 cm from the free edge so that the end of the intact prepuce hangs free of the abdomen. No skin is removed and as the skin which is cut is poorly supplied with blood vessels and nerves, the procedure appears to cause little distress. Healing is generally uneventful and complete in 2 to 3 weeks.

Pizzle-dropping must not be carried out unless all the following requirements are met:

  • the sheep are Merino or Merino-dominant types
  • it is probable that no other combination of disease-prevention measures is likely to be effective
  • the sheep are destined to be farmed in systems in which there is a high risk of pizzle-rot and flystrike
  • the procedure is carried out by competent operators using clean sharp implements.

Even under these conditions pizzle-dropping may be carried out only until practical effective non-surgical methods of disease control are available.

Antiseptic and fly repellent should be applied.

The sheep should be monitored closely for 3 weeks after pizzle-dropping or until the wounds have healed.

7.3 Laparoscopy, Embryo Transfer, and Electroejaculation

Laparoscopy, transcervical insemination and embryo transfer must be carried out only by veterinarians, or by trained and competent operators under veterinary supervision, using sedatives and anaesthesia as appropriate.

For semen collection from rams, use of an artificial vagina is the technique of choice for welfare reasons. If this is not practicable or if semen is required for diagnosticpurposes, collection by electroejaculation may be an option. Electroejaculation must be carried out only by veterinarians or by trained and competent operators under veterinary supervision.

8. Home Killing/Humane Slaughter

When sheep are killed on the farm for home consumption or for dog food or because they are old, injured or diseased, the most humane method available should be used.

Sheep must be slaughtered in a humane manner by a competent person.

Whenever possible the sheep should be shot with a rifle or captive bolt pistol (see Figure 2).

In an emergency, if no rifle is available, slaughter by exsanguination may be carried out as follows. For right-handed people the sheep should be restrained gently but firmly, standing or on its left side with its chin in the operator’s left hand (and vice versa for left-handed people)

The wool over the throat should be parted and using a large very sharp knife a deep cut should be made across the front half of the neck so that both main arteries, both main veins, the windpipe and gullet are severed. The sheep will lose consciousness in 3 to 8 seconds and should be held gently but firmly until then.

Attempts to break the neck and sever the spinal cord do not hasten death and only add to the distress suffered.

Newborn lambs may be killed by a heavy blow to the skull so that the lamb dies instantly.

The signs of an effective kill are immediate collapse, dilation of the pupils of the eyes and cessation of rhythmic breathing.

If there is any doubt about the efficacy of the attempt it should be repeated immediately.

All reasonable efforts should be made to prevent distress in sheep awaiting slaughter.

Appendix

Figure 1: Body Condition Scoring of Sheep

(From MAFF, UK Leaflet 787 1984)

Body condition is assessed by palpating the backbone in the region between the ribcage and the pelvis, using the fingertips. The sharpness of the vertical spines of the vertebrae as indicated in the diagrams is determined together with the prominence and degree of cover at the horizontal processes. Then, by pressing the fingers into the area between the vertical spine and horizontal processes, the amount of eye muscle and its fat cover can be assessed.

Taking all these into account it is usual to score the ewes on a 0-5 basis as below.

Grade O

Emaciated. No muscle or fat can be felt between skin and bone. Sheep in this condition are very weak and may have to be destroyed unless preferential treatment can be given. They are unfit to travel, unsuitable for human consumption and must not be sent to a meat processing plant.

Grade 1

Poor condition. The vertical spine and horizontal processes are prominent and sharp. There is no fat cover but muscle can be felt although it is wasted. Sheep in this condition are unsuitable for human consumption and require preferential treatment and should not be sent to a meat processing plant.

Grade 2

The bones of the spine feel rounder, and are not as prominent. The muscle feels fuller but there is still little fat cover. Sheep in this condition are at the minimum acceptable standard for slaughter at a meat processing plant for human consumption.

Grade 3

The bones of the spine can be felt only by pressing firmly, and feel smooth and well covered. The muscle is full and rounded and there is a moderate depth of fat cover. Sheep in this condition are approaching the optimal level for meat processing plants.

Grade 4

Bones of the spine are difficult to detect but with pressure they feel like a hard line between the fat-covered muscle areas. The ends of the horizontal processes cannot be felt. Muscles are full and thickly covered by fat. Sheep in this condition are close to becoming fat.

Grade 5

Bones of the spine are undetectable even with firm pressure and there is a depression between the layers of fat where the spinal column would normally be felt. The horizontal processes cannot be felt. The muscle is very full with a very thick fat cover. There are often accompanying heavy deposits of fat in the rump area. Sheep in this condition are overfat and require careful feed management.

Figure 2: Recommended Positions for Captive Bolt Stunning and/or Destruction of Sheep Using A Firearm

Note:

  1. Captive bolt pistols are held against the head when fired whereas rifles and shotguns must be held 10-25cm away from the head when fired.
  2. Normally, if an animal does not resume breathing following captive bolt stunning, it will die of its own accord. However, as absence of breathing cannot be guaranteed, it is recommended that captive bolt stunning be followed by immediate pithing or bleeding (throat cut or thoracic stick) to ensure the animal does die.
  3. Only those with current firearms’ licences should use a rifle or shotgun. Great care must be taken to ensure that there is no danger to themselves, to other people, or to other animals.
  4. The shooting position is particularly critical when low velocity and low calibre bullets or captive bolt guns are being used.
  5. The selection of the captive bolt pistol and cartridge strength must be appropriate for the particular class of animal (in this case sheep). The manufacturers recommendations can be considered the minimum requirements; the use of higher cartridge strength would also be appropriate.

    For polled sheep the correct site is in the midline on the highest point of the head aiming straight down towards the angle of the jaw.

    For horned sheep, the correct site is in the midline just behind the bony ridge between the horns aiming towards the back of the throat. It is particularly important to bleed sheep promptly when using this shooting position as they have been known to regain consciousness quickly.

Table 1: Recommended Livestock Daily Feed Requirements

Daily pasture dry matter (PDM) requirements in kg for lambs and 1-year-old sheep

  For maintenance plus liveweight gain per day
Liveweight Maintenance 50 g per day 100 g per day 200 g per day
20 kg 0.6 0.7 0.9 1.1
30 kg 0.8 1.0 1.2 1.5
40 kg 1.0 1.2 1.4 1.9

Daily PDM required in kg for ewes

Liveweight Maintenance Late Pregnancy Lactation
40 kg 0.74 1.1 2.2
45 kg 0.80 1.1 2.3
50 kg 0.86 1.2 2.4
55 kg 0.92 1.3 2.5
60 kg 0.99 1.3 2.6
70 kg 1.12 1.4 2.8

Note: In comparison with pasture which gives approximately 11 megajoules of metabolisable energy (MJME)/kg DM, average pit silage gives 8.5 MJME/kg, and average hay 7.5 MJME/kg whereas good quality hay and silage give approximately 10 MJME/kg.

Table 2: Recommended Minimum Pasture Length and Dry Matter

Quantities for Sheep Production

Sheep Type Pasture Length (cm) Pasture DM (kg/ha) Feed Intake (kgDM/day) Growth Rate
EWES
Mid pregnancy (winter)
6 weeks pre-lamb
Ewes with lambs (spring)
Post weaning (summer)
Mating (autumn) 		 
1 - 2
2 - 3
4 - 5
1 - 2
2 - 3 		 
400 - 500
600 - 800
1400 - 1600
900 - 1000
1200 - 1400 		 
1.0
1.3
1.8
1.0
1.4 		 
Maintenance
60-80 g/d
180-200 g/d (lambs)
Maintenance
120 - 150 g/d
LAMBS
Weaned - Spring
Weaned - Summer
Weaned - Autumn
Weaned - Winter-spring 		 
3 - 4
2 - 3
2 - 3
3 		 
1200 - 1400
1400
1200
1100 		 
0.8
1.0
1.2
1.2 		 
160 - 200 g/d
130 - 150 g/d
80 - 100 g/d
100 - 120 g/d
1 YEAR-OLDS 2 - 3 1400 1.3 60 - 80 g/d

Adapted from tables provided by Agriculture New Zealand consultants

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Animal Welfare Group

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Phone: 04 894 0366
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