Sheep Health, Husbandry and Disease E-Book

Agnes C Winter

• Herausgeber: Crowood
• Kategorie: Fachliteratur
• Sprache: Englisch

Veröffentlichungsjahr: 2013

Beschreibung

This comprehensive book covers all aspects of sheep health and disease, and sheep husbandry throughout the annual breeding cycle. Through extensive and detailed photographs it highlights the disease and welfare issues that can arise within the great variety of breeds and flock types. Written by two veterinary surgeons closely involved in sheep health, this book takes a veterinary view of husbandry and emphasizes the importance of keeping diseases out of a flock. From practical tasks such as how to check teeth, feet and udders, through to vaccination schedules, injection techniques and parasite control, it covers the whole life cycle of your flock. Topics covered include: Routine procedures; Selecting breeding stock; Internal and external parasites; Tupping time; Pregnancy; Lambing ewes; Lameness. An essential guide to all aspects of sheep health, disease and sheep husbandry through the annual breeding cycle. Invaluable reference for anyone who keeps sheep on a small scale, with one or two as pets, to those with a commercial flock. It will be of interest also to agricultural and veterinary students and shepherds working with valuable pedigree flocks. Considers how to tackle common diseases, the potential problems that can arise and the preventative measures that can be taken. Superbly illustrated with 609 extensive and detailed colour photographs. Agnes Winter is a specialist sheep vet and Honarary Professor of the Veterinary School at the University of Liverpool and Clare Phythian is a full-time veterinary surgeon specializing in sheep health and welfare.

Leseprobe

Fig. 1 Sheep are fascinating animals to keep.

Sheep Health, Husbandry and Disease

A PHOTOGRAPHIC GUIDE

Agnes Winter and Clare Phythian

Copyright

First published in 2011 by The Crowood Press Ltd, Ramsbury, Marlborough, Wiltshire, SN8 2HR

www.crowood.com

This e-book edition first published in 2013

© Agnes Winter and Clare Pythian 2011

All rights reserved. This e-book is copyright material and must not be copied, reproduced, transferred, distributed, leased, licensed or publicly performed or used in any way except as specifically permitted in writing by the publishers, as allowed under the terms and conditions under which it was purchased or as strictly permitted by applicable copyright law. Any unauthorised distribution or use of this text may be a direct infringement of the author’s and publisher’s rights, and those responsible may be liable in law accordingly.

ISBN 978 1 84797 540 9

Contents

Title Page

Copyright

List of Abbreviations

Introduction

1. Keeping Your Flock Secure

2. Routine Procedures

3. Selecting Breeding Stock

4. Vaccination Schedules

5. Feeding Sheep

6. Thin Adult Sheep

7. Internal and External Parasites

8. Tupping Time

9. Pregnancy

10. Lambing Ewes

11. Newborn Lambs to Two Weeks Old

12. Lactating Ewes and Growing Lambs to Weaning

13. Store, Fattening and Replacement Lambs

14. Lameness

15. Notifiable Diseases, Other Important Diseases and Problems

16. Old, Sick, Injured and Dead Sheep and Lambs

Further Information

Index

List of Abbreviations

AED: abomasal emptying defect

AI: artificial insemination

BOHB: beta hydroxybutyrate

BSE: bovine spongiform encephalopathy

BT: bluetongue

CAE: caprine arthritis encephalitis

CLA: caseous lymphadenitis

CODD: contagious ovine digital dermatitis

Defra: Department for the Environment, Farming and Rural Affairs

EAE: enzootic abortion of ewes

EBV: estimated breeding value

ET: embryo transfer

FMD: foot and mouth disease

IGR: insect growth regulator

Map: Mycobacterium avium paratuberculosis

MV: maedi visna

NSP: National Scrapie Plan

OPA: ovine pulmonary adenomatosis

PGE: parasitic gastroenteritis

PMSG: pregnant mare serum gonadotrophin

SAC: Scottish Agriculture College

SCOPS: sustainable control of parasites in sheep

SPA: sheep pulmonary adenomatosis

TB: tuberculosis

vCJD: variant Creuzfeldt Jakob disease

Introduction

Whether you have a flock of 2,000 sheep or simply two pet sheep, they are an endlessly fascinating, rewarding but sometimes frustrating species to keep. The large variety of breeds in the UK means that there is one or more suitable for every situation, from the lush pastures in the lowlands to the high mountains in the west and north of the country. The introduction of a variety of continental breeds has widened the choice even further, and some of these now play a very important role in the sheep industry. Each breed has its enthusiasts, but for the purist there is nothing better than keeping an indigenous breed that has been developed over centuries to fit the particular geographical and climatic area in which you live. However, the objective of keeping most flocks is to make a living, and crossbreds often make a large contribution here. Whatever breed or cross you choose to keep and for whatever reason, we hope that this book provides information of relevance and interest to you.

The aim is to take the reader through the annual production cycle of the sheep flock, covering common husbandry tasks, problems and diseases with the aid of photographs wherever possible. The idea is not to do this in great detail – other books are available where in-depth husbandry or veterinary information is required – but rather, to give an overview in the hope that it will particularly appeal to aspiring or inexperienced sheep keepers, agriculture and veterinary students, although we also hope that it will be of interest to more experienced shepherds and veterinary surgeons, too.

Similarly we have not attempted to cover every possible situation or disease, rather to highlight those that are most common. It is often said that it is every sheep’s ambition to die, but this is really not the case! We hope we have succeeded in helping to show how sheep can be kept healthy, productive and of high welfare status, along with the options available if problems do arise. Throughout the book we emphasize the need to consult experts, your vet or other sheep specialist, to help prevent problems and to assist when things go wrong.

A big part of preventing problems and improving management and welfare for both the shepherd and the flock is to plan in advance. This should be done with the help of your vet or other adviser before the beginning of the breeding cycle by the construction of a flock health plan, covering the whole year, making sure that all the key areas we have identified in this book are considered and included. Each flock is different, so there is no generic plan that fits all, and any plan should be revised each year in the light of experience.

We would like to thank the many sheep farmers and friends who have allowed us to take photographs or helped in other ways. In particular we would like to thank Judith Charnley, Dianna Bowles, Alex Crossley, Peter Blythe, John Parry, Laura Mason, Nigel Jones and Rob Pearson.

Agnes Winter, Clare Phythian May 2010

1 Keeping Your Flock Secure

To some people the title of this first chapter might suggest that it is just concerned with fencing, keeping your sheep in and other people’s out. Of course this is an important part of managing flocks that are kept on enclosed land, but flock security has a much wider meaning, encompassing all the precautions that should be taken to minimize the introduction of costly infectious diseases.

Types of Flock

Flocks can be simplistically classified according to how they are managed, together with the associated disease risks.

Closed purebred flocks: Closed flocks breed their own replacements and have no contact with sheep in other flocks. In most of these flocks there will be the occasional purchase of new rams, and these are the risky animals as far as possible disease introduction is concerned.

Lowland flocks of crossbred ewes: These include Mules, Welsh or Scotch halfbreds, and Greyfaces or other recognized crosses. Unless a hill flock to breed these is in the same ownership, young replacement ewes are likely to be purchased every year, meaning annual opportunities for disease introduction. Terminal sire breed rams (such as Texel, Suffolk and Charollais) are also likely to be purchased annually.

Purebred isolated hill flocks: These graze extensively, but are prevented from mixing with other flocks by fencing or natural geographic features. These flocks may also make occasional purchases of rams, which pose a potential risk.

Hill flocks that graze extensively on land with access by several flocks: These are at risk of picking up disease from each other, and unless there is cooperation from all flock owners involved, it can be extremely difficult to control infectious disease, particularly sheep scab.

Store lamb finishing flocks: In such flocks weaned lambs may be purchased from many sources and mixed together, creating the perfect opportunity for disease spread.

Fig. 2 Closed purebred flocks should be able to achieve high health status, but beware of the risks in bringing in new rams.

Fig. 3 Double fencing makes sure that a closed flock cannot contact neighbouring animals, and keeps stray sheep out.

Fig. 4 Mule ewes with their lambs. This type of ewe is bought in from flocks that breed them by crossing hill ewes with Bluefaced Leicester rams.

Fig. 5 A hill flock grazing on fenced land, but do the sheep have contact with others on the mountain beyond?

Fig. 6 Where flocks belonging to several owners graze extensively on common land, disease risks are high and it needs cooperation from all involved to control them.

Fig. 7 Markets, where sheep from many different flocks come into contact, form a potential source for disease spread, which is why there are restrictions on movements for several days after purchase.

Fig. 8 Showing sheep often allows contact with animals from other flocks so poses potential health risks.

Fig. 9 Sheep scab is one of the most important diseases that can be introduced into a flock via bought-in or stray sheep.

Fig. 10 This ram has a barely noticeable healed scar below the ear indicating it has almost certainly had an abscess as a result of CLA infection. He is likely to have other abscesses elsewhere in his body so could introduce the disease into a previously uninfected flock.

Draft ewe flocks: Draft ewes originate from a variety of sources; they are often purchased through markets, and are probably the most risky of all sheep to introduce into a flock.

Organic flocks: These flocks are run according to organic farming principles, with strict regulations regarding fertilizer and pesticide use. Conventional medicines can be used to treat sick individual animals, but vaccine use is usually based on a known risk of disease on the farm involved.

Milking flocks: Compared with countries such as Spain and Greece, milking flocks make up a very small part of the UK sheep industry. Most milk is made into products such as cheese.

Of course there are many more types of flock than those described above, but the examples serve to show that the more mixing of sheep that occurs, the greater the risk of introducing diseases that can have a serious impact on the welfare and profitability of the flock. There are other opportunities for disease spread, for example:

showing sheepborrowing rams for small hobby flocksacquiring spare lambs from another flock for ewes that have lost their own lambsstraying sheep are put with a nearby group of sheep through an unlocked gate by well meaning passersby.

Two real examples will serve to highlight the possible consequences. In one flock of 500 ewes, two new rams were purchased at the beginning of the breeding season. These were mixed with the resident rams and used to mate the whole flock. After housing for lambing, a number of the sheep were seen to be itching, but the vet was not consulted until part way through lambing, by which time many of the sheep were affected. A diagnosis of sheep scab was made, and this presented a huge problem of how to control it because of all the very young lambs that were now present and continuing to be born. Much money had to be spent on injectable treatments but the situation was not fully brought under control until several months later, after shearing, when all animals could be treated at the same time. Circumstantial evidence was that the disease had been introduced with the two purchased rams.

In another small hobby flock, a spare lamb was acquired to foster on to a ewe that had lost her own lamb. It was noticed that other lambs in the flock of origin had crusty eye discharges. A few weeks later several of the ewes developed runny eyes, progressing to severe eye infection and blindness. Gradually most of the ewes became infected and required repeated treatment before the problem eventually subsided several months later.

Both of these cases show how the introduction of one or two sheep into a new flock can lead to much cost in terms of time and drugs, which could have been avoided with a higher awareness of the risks involved.

There is a huge list of diseases that can be introduced in this way, most of which are covered at relevant places in this book. The following are the most important and common:

sheep scabchorioptic mangelicefootrotcontagious ovine digital dermatitis (CODD)infectious keratoconjunctivitisenzootic abortion (EAE)border diseasecampylobactersalmonella spporfmaedi visna (MV)ovine pulmonary adenocarcinoma (jaagsiekte)caseous lymphadenitis (CLA)Johne’s diseasescrapie susceptibilityanthelmintic-resistant wormsliver flukeringworm.

Fig. 11 Do not buy a group of sheep that has lame ones in it.

For a small number of these diseases, health or monitoring schemes are available so that sheep can be purchased as being certified free of a particular disease or diseases, and it is well worth investing in such sheep if available; but in the overall scheme of things, these sheep form only a small percentage of those traded each year. The diseases covered by these schemes are:

maedi visnaenzootic abortioncaseous lymphadenitisscrapie resistance.

How to Reduce the Risk of Buying in Disease

Always examine animals carefully before purchase. Do not buy groups that contain lame animals, itching animals or coughing animals, or any other obvious problem, however cheap they seem – they will turn out to be expensive in the long run!

Keep a purebred flock which can breed its own replacements. One example of a breed that has flourished in recent years is the Lleyn, originally a numerically quite small breed from North Wales that is now extremely popular as a replacement for the Mule. It has similar characteristics to the Mule, particularly milkiness and prolificacy, and crosses well with a terminal sire such as the Texel, but a proportion of the flock can be bred pure to provide homebred ewe lambs. However, this breed is not suitable for hill areas where hardy breeds such as the Swaledale, Cheviot, Blackface and Welsh Mountain thrive. There will always be a supply of young crossbred breeding ewes from these areas: in fact they form an important part of the income for these farms, and producing them with a high health status will increase their value and reassure purchasers.

Check the disease history of the supplying flock when buying rams for purebred flocks such as above, examine the animals carefully, and quarantine them after purchase (see below).

Buy rams as far as possible in advance of the next breeding season – if necessary buy direct from breeders. One of the main problems in buying rams is that many of the sales do not take place until very near tupping time, which doesn’t allow much opportunity for quarantining them.

Buy straight off the farm, rather than through a market, if replacements are purchased each year, from as small a number of suppliers as possible.

Try to purchase from the same sellers each year if purchasing through a market, if you are happy with their stock.

Never buy sheep of unknown origin, particularly older sheep that have bred before. These have a high risk of bringing some of the common forms of abortion and other diseases into the flock.

Be careful of bringing in spare lambs from another flock for fostering.

Fig. 12 This flock of Lleyn sheep produces its own replacements as well as slaughter lambs sired by Texel rams.

Fig. 13 Hardy sheep such as the Welsh Mountain will always be needed in mountainous areas where lowland breeds cannot manage. The production of crossbred breeding females such as the Welsh Halfbred or Welsh Mule forms an important part of the income for many of these flocks.

Quarantining Purchased Animals

It is good practice to keep newly purchased sheep, both ewes and rams, separate from those already on the farm. The longer they can be kept apart, the better, but at least a month is recommended. This should allow time to check for infectious foot diseases such as footrot and CODD, and to treat for sheep scab, anthelmintic-resistant worms and fluke, if applicable. The best drug combination to cover scab and anthelmintic-resistant worms may be injectable moxidectin (group 3 AV), which will control scab, and a drench of the new group 4 AD wormer, monepantel. Alternatively, dipping in an organophosphorus (OP) dip will deal with scab, lice and chorioptic mange, and drenching sequentially with moxidectin (group 3 AV) and monepantel (group 4 AD) will guard against introducing anthelmintic-resistant worms. For forty-eight hours after dosing, sheep should be kept on yards or in a field not to be used for grazing sheep (for instance, arable) so that all viable worm eggs will have been passed. However, it is always best to take the latest advice on this complicated subject from your vet as part of a flock health programme. See alsoChapter 7.

For breeding ewes, one of the biggest risks is buying in one of the common abortion agents, particularly that causing enzootic abortion (Chlamydophila abortus). If it is possible to manage these ewes as a separate group, preferably lambing after the main group, this minimizes the risk of spreading this disease, should it occur, to others. Vaccination will reduce, although not eliminate, the risk of introducing this infection (seeChapter 4).

Some of the diseases mentioned above have long incubation periods, so it may be several years before it is realized that they are causing problems, by which time much of the flock may be infected. For example, with maedi, it is estimated that 40 per cent of the flock is likely to be infected by the time clinical cases are seen.

Fig. 14 Spare lambs brought in from another flock may seem to be a good idea, but they are risky as a potential source of disease. This lamb has dirty eyes and a dirty nose.

Fig. 15 A good area of concrete or similar hard standing allows sheep to be held after purchase so they can be dosed with wormers to prevent anthelmintic-resistant worms being brought in. Food and water should be provided if the sheep are to be held for more than an hour or two.

Fig. 16 Enzootic abortion is spread from infected to uninfected ewes at lambing time. If possible, lamb replacement ewes separately in their first year in case they bring infection with them.

Safeguarding the Health of Newly Purchased Animals

Remember that new sheep introduced to a farm may not be vaccinated against common diseases such as clostridia, and may be exposed to other diseases to which they have no immunity; examples of these are toxoplasmosis, tick-borne fever and louping ill.

The most urgent task is to carry out any necessary vaccinations, particularly those for clostridial diseases (seeChapter 4 for vaccination schedules). If some of the land is infested with ticks, be careful not to introduce sheep from non-tick areas at crucial times in the reproductive cycle, such as tupping time and pregnancy, as inevitable infection with tick-borne fever causes temporary infertility in rams and abortion in ewes.

Safeguarding the Whole Flock

Keep infection out by enforcing disinfection of visitors to the flock, cleansing your equipment, boots and vehicle tyres after visiting other flocks, markets, abattoirs and so on, and by maintaining good perimeter fences if this is possible.

Fig. 17 Do not introduce new sheep to tick areas at tupping time or during pregnancy.

Fig. 18 Have good washing and disinfecting facilities for yourself and visitors to the flock.

Fig. 19 Keeping fences in good order prevents groups mixing and stray sheep getting in. This fence could do with some attention!

Fig. 20 Keep perimeter gates locked to keep stray sheep out.

2 Routine Procedures

This chapter deals with record keeping and procedures that take place year-round in a sheep flock, from catching and handling animals, deciding what condition they are in and how old they are, to common tasks such as injecting, drenching and dealing with overgrown feet. In most flocks much time and effort goes into collecting sheep and carrying out these various tasks, so they need to be done efficiently, at the correct time of year, and as few times as possible. Advance planning using your flock health programme should help to streamline handling, but events such as bad weather or sudden outbreaks of disease are likely to mean rounding up sheep unexpectedly. Having a good permanent handling system or an easily used portable system makes such tasks less stressful for sheep and shepherd alike.

Fig. 21 A good permanent handling system on a lowland farm. The concrete floor ensures the pens can be kept clean, and the roof means there is some protection for the shepherds in bad weather.

Fig. 22 Record keeping is important for all flocks – this is a well organized set covering movements, medicines, lambing and mortality.

Fig. 23 A permanent handling system in the north of Scotland. Even in this remote location some of the pens have been concreted to make cleaning up easier.

Handling Pens

Fig. 24 A well constructed outdoor system of pens and a race. The race has a concrete floor and the corrugated iron sheets are placed so that the sheep cannot get their feet trapped.

Fig. 25 This handling system has been put together at minimum cost. When old gates and corrugated iron sheets are used be careful that there are no sharp edges that can injure sheep.

Fig. 26 This track leading to some handling pens is very muddy: these conditions could damage the sheep’s feet, and unless there is a cleaner route back to the field, makes foot bathing a waste of time.

Fig. 27 Mobile handling systems are easily moved around so that sheep can be gathered on the field they are grazing. If being used for more than one flock they should be cleaned regularly to prevent the possible spread of disease. Visiting specialist sheep events is an ideal way to see what equipment of this type is available, and to try it out before purchase.

Catching and Holding

An experienced shepherd with a quad bike, a crook and a good dog can often catch an individual sheep in an open field. For the rest of us, catching a particular animal usually means pushing a group of sheep together in a field corner or bringing them into a handling pen.

Keep the sheep in your sight and go quickly into the group, catching it with a crook or getting hold of it under the neck with one hand, using the other hand on the back to steady it. Do not try to catch it by grabbing the wool over the back. In the case of small pedigree or hobby flocks it is often possible to train the sheep to come for feed into a small pen, or to catch a single sheep by carrying sheep nuts or bread (often a favourite treat for pet sheep) in a pocket. A halter may then be used to restrain the animal if necessary.

Note that it is not a good idea to train rams to come for food from the hand – they may become aggressive and dangerous to handle. There are exceptions, but in general, never make a pet of a ram.

Fig. 28 A quad bike has become an indispensable vehicle for many shepherds.

Fig. 29 A good dog can be an invaluable help in handling and catching sheep, and can save the effort of having to round up the whole flock. However, a bad or untrained dog can upset or even injure the sheep.

Fig. 30 For a small flock, training sheep to come to the bucket can make catching individuals possible; however, do not encourage rams to do this as they can become dangerous.

Fig. 31 Having caught your sheep, hold it firmly under the jaw, using the other hand to steady it if necessary; most will stand fairly quietly like this. Holding the animal firmly against a wall or hurdle will give even more control. Do not try to hold it by grabbing the wool on top of the neck, as it will stru ggle and attempt to get away.

Fig. 32 Handling sheep through a race allows for techniques such as condition scoring to be carried out easily without catching the sheep individually.

Fig. 33 A fairly new handling device that holds sheep by squeezing together the sides of a crate placed in the race; the movable side is operated by a foot plate. It restrains the sheep and makes procedures such as drenching or vaccinating easier and safer, single-handedly if necessary.

Condition Scoring

This is a widely used system of determining whether a sheep is in the correct bodily condition for the stage of its production cycle; it is applicable to sheep of any size. Whilst it is possible to estimate body condition in recently shorn sheep by eye, it can be very misleading to look over the gate at fully fleeced sheep and think they look fit. A thick fleece can mask underlying poor condition, and this is particularly dangerous in the later stages of pregnancy. At this stage, excessively thin sheep are very likely to develop pregnancy toxaemia (twin lamb disease), which can be very difficult to treat successfully. Therefore, monitoring body condition by handling the sheep regularly is an important part of keeping a flock healthy and productive. The technique involves feeling over the loin to assess how easily the bones of the spine (the lumbar vertebrae) can be felt, and how much muscle (the eye muscle of your lamb chop!) and fat is present over them. The scale runs from 0 to 5 as follows:

0: Emaciated, at the point of death, just skin and bone.

1: Very thin, each bone is sharp and easy to feel, very little muscle present, which feels hollow.

2: Lean, the bones can be felt individually but are rounded, muscle is present but feels flat.

3: Fit, the ends of the bones can be felt with pressure, they are smooth and rounded. The muscle is full and rounded.

4: Fat, the ends of the bones can only be detected with firm pressure and are covered with a layer of fat. The muscle is rounded and covered with fat.

5: Very fat, the bones cannot be felt and the muscle is covered with fat.

People experienced in the technique often use half scores, particularly 2½ and 3½, but this is not absolutely necessary. The main aim of scoring is to decide whether sheep are too thin, are fit for purpose, or too fat, and then to manage accordingly, for example by separating into groups, or altering stocking density or feeding management.

The key times to condition score breeding sheep are:

A few weeks before tupping time to ensure that both rams and ewes are in optimum condition for mating.During mid-pregnancy to ensure that weight and condition is not being lost too rapidly.Six to eight weeks before lambing is due to start, to ensure that condition has been maintained and to assess how much concentrate feeding is necessary.

Fattening lambs are handled in the same way to check how close to marketing they are, with extra handling over the ribs and the base of the tail to assess muscle development and fat cover.

Fig. 34 It is impossible to tell accurately by eye the body condition of a sheep carrying a full fleece.

Fig. 35 The correct position of the hand over the loin when carrying out condition scoring.

Fig. 36 It is simple and quick to score sheep in a race, and it should be done every time they are gathered. Either hand can be used, but it is best always to use the same one.

Fig. 37 The fleece of this sick-looking sheep masks her extreme thinness. She was in condition score 1.

Fig. 38 This recently shorn sheep is obviously too thin, certainly less than score 2, but perhaps more than 1 (1½ if using half scores).

Fig. 39 This sheep is in fit condition, about score 3. The loin is well covered, but the position of the bones can be seen and they would feel rounded.

Fig. 40 This sheep is too fat, at least score 4. The position of the bones would be difficult to feel because she is carrying a lot of fat over them.

Ageing

The age of a sheep is normally estimated by examining the incisor (front) teeth present in the lower jaw. Apart from in old sheep that have started to lose teeth, there are eight incisors (four pairs), which meet against the dental pad of the upper jaw. There are no incisors in the upper jaw (usually – although one of the authors has seen a Suffolk lamb with two temporary incisors in the upper jaw, but these were not replaced by permanent teeth).

Lambs are usually born with no incisors, but these start erupting soon after birth, and all eight temporary incisors are present within a few weeks. Occasionally lambs are born with some teeth already erupted – these are very sharp, as anyone who has had to assist in lambing one of these will testify! Lambs retain their temporary incisors through their first year. At this stage it is possible for inexperienced people to confuse this age group with three- to four-year-olds with a full mouth, but the general appearance of the animal should confirm whether it is young or older.

The age at which the temporary teeth are replaced by permanent teeth can be quite variable, as indicated in the table. Generally yearlings would have their first pair fully erupted by one and a half years, two-year-olds would have two pairs, and all permanents would be present by three to four years of age. The shape and size of the permanent incisors is very variable, and the age at which these begin to be lost also varies greatly. Short, spade-shaped teeth tend to be retained longer than long, narrow teeth. It is possible that eating food such as turnips or molasses buckets may speed up incisor tooth loss.

Number of permanent teethCommon nameUsual age at eruptionRange2 (1 pair)Two-tooth1yr 3mth1yr–1yr 6mth4 (2 pairs)Four-tooth1yr 9mth 1yr6mth–2yr6 (3 pairs)Six-tooth2yr 3mth2yr 3mth–3yr8 (4 pairs)Full mouth2yr 9mth2yr 9mth–4yr1 or more lostBroken mouthOver 4yr

Fig. 41 This eight-month-old lamb shows typical temporary incisors. These are more triangular than permanent teeth, but it can sometimes be difficult for inexperienced people to distinguish between the teeth of a well grown lamb and an adult sheep with a full set of permanent teeth.

Fig. 42 This yearling has cut one central permanent incisor and has already lost the first and second temporary incisors on the other side. The other central permanent incisor will soon erupt, followed a few months later by the adjacent one.

Fig. 43 This yearling has both permanent central incisors so is about eighteen months old.

Fig. 44 The normal appearance of a two-year-old sheep, which has two pairs of permanent incisors.

Fig. 45 A sheep with six permanent teeth, which would make it between two and a half and three years old.

Fig. 46 A full-mouthed ewe of about four years old, with an excellent set of permanent incisors. These are broad and short and unlikely to be lost prematurely.

Fig. 47 An old, broken-mouthed ewe about to lose another loose incisor tooth.

Ear Tagging and Flock Records

All sheep flocks, even small numbers kept purely as pets, need to be registered with Defra, and a flock register listing movements on and off the farm must be kept. All sheep born after 31 December 2009, which are not to be slaughtered within twelve months, have to have two permanent methods of identification, one of which must be electronic. These will usually be eartags, although rumen boluses as first used in the National Scrapie Plan schemes are also acceptable. The tags must carry the UK flock number and an individual number. For lambs intended for slaughter within twelve months a single batch tag with the flock number visible is required. There are complex rules about tag colour and the application of replacement tags, and about the information that must be kept in the flock register, so you are advised to look for up-to-date information from Defra (www.defra.gov.uk).

There is a variety of design of tags, none of which has been shown to be foolproof, and there will always be sheep that lose tags in spite of manufacturers’ best efforts. This often results in torn or misshapen ears. One answer would be to use microchips placed under the skin as is used for dogs and horses, however these are not approved at the moment as there is a tendency for them to move in the body and therefore a risk of one turning up in your Sunday roast!

Fig. 48 This lamb complies with current tagging requirements: it has a tag in each ear, one of which is electronic.

Fig. 49 A hand-held ‘wand’ for reading electronic tags, together with a variety of tag shapes and colours available. The manufacturers will advise on what is required.

Fig. 50 An electronic tag reader designed to be part of a handling system.

Fig. 51 This sheep has a misshapen ear resulting from tag placement. The tags are better placed rather nearer to the base of the ear, but not so near that they dig into the ear cartilage ridges on the inner side.

Fig. 52 A lamb with a very swollen ear which is filled with blood (a haematoma) following incorrect tag placement.

Fig. 53 This sheep has lost a tag, leaving a large tear in the ear.

Fig. 54 Not a tag injury, but a deliberately made notch as utilized on some farms to provide permanent flock or individual identification.

Storing Medicines and Recording their Use

There are strict regulations about the purchase and use of veterinary medicines. Details of the information required in your medicines’ book can be obtained from your local Trading Standards Office, and records must be kept for five years. Medicines can be expensive and should be stored in a clean, dry, cool (but not freezing) place. A stock of sterile disposable syringes and needles can be obtained from your vet – a suitable selection for sheep is 20ml, 10ml and 5ml syringes, and 19g 1in needles, plus 16g 1in needles for injecting calcium. For lambs, 2ml syringes with 21g ⅝in needles are suitable for most injections. A plastic divided tray with a handle is a good way of keeping these organized and clean. You also need a sharps container for the safe disposal of needles.

Fig. 55 Use a sharps container to dispose of needles and other sharp objects safely.

Fig. 56 A well organized and clean cupboard used for the storage of drugs.

Fig. 57 A tray containing empty and partially used antibiotics with used syringes in far from sterile or even clean conditions.

Fig. 58 All veterinary medicines, syringes and needles should be stored in a clean, dry, cool place away from the light. Some drugs, such as the dark-coloured one on the right, are sensitive to light.

Injecting

The most common reason for injecting sheep is for vaccination (seeChapter 4 for details of schedules). In addition there are injectable products that can be used for scab treatment and control, antibiotics for sheep suffering from diseases such as footrot or pneumonia, and other products such as vitamin and mineral preparations that may be necessary in certain circumstances.

Any injection should be done carefully to make sure the injected material is put cleanly in the correct site. An incorrect or dirty injection technique can result in abscesses developing, and sick or even dead animals. Syringes and needles should be sterile, and needles should be changed regularly and disposed of into a sharps container.

Always read the instructions, which will tell you how the material should be given, and the withdrawal period during which the animal must not be sold for meat, or, for dairy sheep, the length of time that milk cannot be used. The types of injection are:

Subcutaneous (under the skin): The usual site is high on the neck, close to the base of the ear. An alternative is to use the woolless area behind the elbow. The skin is pinched slightly to make a ‘tent’, injecting into the base of this. Mistakes include:

injecting into the wool onlyinjecting straight through both sides of the ‘tent’ of skininjecting too deep so the material goes into the underlying muscle – this can happen if a sheep moves its head suddenly or if sheep are being injected at speed in a race.

Intramuscular (into a muscle): The best site is into the muscles in the mid-part of the neck above the level of the vertebrae. Use a needle no longer than 1in, and stick it in at right angles to the skin. For a young lamb the safest site is into the front thigh muscles – this is painful, so try to use an injection that can go under the skin if possible. Mistakes include:

injecting near a major nerve. This is most likely to happen if you inject into the rump, or particularly the back of the thigh. The result will be temporary or even permanent nerve damage and a paralysed legcausing damage to a high-value muscle mass such as the rump or leg. Some injections are irritant and may leave permanent damage, spoiling an important part of the carcase

Fig. 59 Bluetongue vaccine being given under the skin using an automatic syringe.

Fig. 60 Giving a subcutaneous injection: a fold of skin is held and the injection is given into the base of this.

Fig. 61 Injecting sheep with a full fleece requires care to make sure the material being injected goes under the skin. In this picture the wool high on the side of the neck has been parted and a fold of skin is being held ready for injection. The woolless area of skin inside the front leg is also a suitable site for subcutaneous injection.

Fig. 62 The upper part of the middle of the neck is a suitable site for intramuscular injections, unless the sheep is very thin. This is also a low value part of the carcase.

Fig. 63 Do not inject in the back of the thigh as it is very easy to inject near the main nerve running down the back of the leg, causing paralysis.

Fig. 64 Injecting in the muscle in the front of the thigh is safer, but this is a high value part of the carcase so is better avoided.

Intravenous (into a vein): This method will generally only be used by a vet. Blood samples are also collected from a vein