Table Of ContentEQUINE
FORMULARY
Content Strategist: Robert Edwards
Content Development Specialist: Catherine Jackson/Nicola Lally
Senior Project Manager: Beula Christopher
Designer: Christian J. Bilbow
Illustrator: Lesley Frazier
EQUINE
FORMULARY
Second Edition
DEREK C. KNOTTENBELT
OBE, BVM&S, DVM&S, DipECEIM, MRCVS
Philip Leverhulme Hospital
University of Liverpool
Liverpool, UK
FERNANDO MALALANA
DVM, DipECEIM, FHEA, MRCVS
Philip Leverhulme Hospital
University of Liverpool
Liverpool, UK
Edinburgh London New York Oxford Philadelphia St Louis Sydney Toronto 2015
Copyright © 2015 Elsevier Ltd. All rights reserved.
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This book and the individual contributions contained in it are protected under copyright by the Publisher
(other than as may be noted herein).
First edition: 2006
Second edition: 2015
ISBN 978-0-7020-5109-8
EISBN 978-0-7020-5424-2
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
Library of Congress Cataloging in Publication Data
A catalog record for this book is available from the Library of Congress
Notices
Knowledge and best practice in this field are constantly changing. As new research and experience broaden
our understanding, changes in research methods, professional practices, or medical treatment may become
necessary.
Practitioners and researchers must always rely on their own experience and knowledge in evaluating and using
any information, methods, compounds, or experiments described herein. In using such information or methods
they should be mindful of their own safety and the safety of others, including parties for whom they have a
professional responsibility.
With respect to any drug or pharmaceutical products identified, readers are advised to check the most current
information provided (i) on procedures featured or (ii) by the manufacturer of each product to be administered,
to verify the recommended dose or formula, the method and duration of administration, and contraindications.
It is the responsibility of practitioners, relying on their own experience and knowledge of their patients, to
make diagnoses, to determine dosages and the best treatment for each individual patient, and to take all
appropriate safety precautions.
To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors, assume any
liability for any injury and/or damage to persons or property as a matter of products liability, negligence or
otherwise, or from any use or operation of any methods, products, instructions, or ideas contained in the
material herein.
The
Publisher's
policy is to use
paper manufactured
from sustainable forests
Printed in China
PREFACE TO SECOND EDITION
The Saunders Equine Formulary has become a standard “must have in the car”
book for equine practitioners and those who only see a few horses from time
to time. Its distribution has been world-wide and we hope that it will continue to
prove to be a useful aid to high-quality equine practice internationally. We have
maintained its handy nature and its concise format so that information is readily
available and useable advice and support can be easily accessed.
I am particularly pleased to welcome Fernando Malalana to the co-authorship
of the Second Edition. I hope that he will be able to carry the baton of this little
book into the future. I am also very grateful to him for undertaking the update so
enthusiastically and so thoroughly.
Inevitably in the modern world, new drugs have come onto the market and others
have disappeared from production and we have tried to update this aspect of the
book in particular. The process of outdating and new drugs will mean that gradually
there will be changes—the reader is encouraged to deface the book by deleting
things that disappear and writing in new information! The book is there to be used
and it’s best when it is dirty and worn out! Of course, we recognise that many
drugs used in equine practice have no licence for equine use because there is no
commercial logic in seeking a licence for a minority species. It therefore becomes
even more important that their use is fully understood and that they are used
correctly.
We have also updated the diagnostic tests and procedures sections and the
various appendices which have proven so useful over the life of the First Edition.
We would like particularly to thank the following for their contributions to the
book—without their special help we would really struggle to keep up with all the
changes that have taken place: Alex Dugdale, David Bardell and Caroline Argo
deserve special mention.
The dedication of this book to the memory of Clare Harrison remains—she still
lives within many of us; a happy, outgoing, and energetic veterinary student whose
memory continues to inspire students at Liverpool University. It is little consolation
to Victoria and Roger, I am sure, but Clare remains in my heart to this day, even as
the years roll by and the world keeps turning.
DEREK C. KNOTTENBELT, OBE, BVM&S, DVM&S, DipECEIM, MRCVS
xv
1 VITAL SIGNS, NORMAL
Part VALUES
REFERENCE VALUES
Normal vital signs
SAMPLE COLLECTION
Haematology
Derived values
Plasma and serum biochemistry
(i) Plasma/serum proteins
(ii) Globulins
(iii) Non-protein biochemistry
(iv) Electrolyte and mineral parameters
(v) Vitamins/hormones (excluding sex hormones)
(vi) Acid–base balance
(vii) Enzymes
(viii) Blood coagulation
(ix) Cerebrospinal fluid
(x) Synovial fluid
(xi) Peritoneal fluid
(xii) Urine
(xiii) Faecal analysis
REPRODUCTIVE DATA
Mare
Plasma hormone concentrations
Granulosa theca cell tumour
Urinary hormone concentrations
Prediction of foaling date from service date
Signs of impending parturition
Stallion
Semen characteristics
1
Part VITAL SIGNS, NORMAL VALUES
REFERENCE VALUES
Abnormalities of physiological parameters (vital signs, haematological or
biochemical parameters) are frequently used to assist the diagnosis and
management of disease but there are important considerations to be taken into
account before they can be relied upon. Hitherto, the term ‘normal value’ has been
used to indicate that the measured parameter is within the reference range for
a pool of apparently normal horses. There are always valid criticisms of defined
normal values in view of individual variations within the natural/normal population
distribution. The term ‘reference value’ is now used widely so that the implication
of normality is not emphasised. An apparently normal individual animal may have
values that fall outside the accepted 95% confidence limits and abnormal ones
may fall within the normal range. However, the clinician is usually able to select the
samples required and assess the validity of the results on the basis of the clinical
features and the reference values provided by the laboratory.
Many commercial laboratories have pathologists who may be qualified and able
to provide interpretive assistance, but without provision of a complete range of
information it is unreasonable to expect this. Therefore, all requests for laboratory
testing should be accompanied by as much clinical and historical information
as can reasonably be provided. This also provides the pathologist with added
information, which might bias or alter the tests that are performed. Clinicians can
seldom be effective or convincing specialist pathologists!
Commercial and ‘in-house’ laboratories must ensure that they are subjected to
proper and regular quality control assessments. This serves to ensure the quality
and, therefore, the validity, of the results of assays. Failure to do this opens the
door for misinterpretation at best and litigation at worst. Misleading laboratory
results can also jeopardise the well-being of the patient and are in any case a
complete waste of time, effort and money. Organisations exist to provide quality
control assessments and these provide a vital service to the profession and the
owners of animals who have a right to expect quality and value for their money
(Fig. 1.1).
3
4 Vital signs, normal values
95%
2 × SD 2 × SD
Low Normal High
Mean
Fig. 1.1 Distribution curves for a haematological or biochemical parameter showing
the ‘normal’ reference range in the middle, an ‘abnormally low’ range to the left and an
‘abnormally high’ range to the right. It can be seen that there are (large) areas of overlap
such that a normal horse can have an apparently abnormal result while an abnormal one
might easily have a normal value. This makes interpretation a critical factor in clinical
practice. The more distant the value from the normal the more likely it is to be abnormal,
but these values are unlikely to create major problems for the clinician. It is the subtle
differences that are the challenge. In many cases, the trends in values are more helpful
than the single ‘snapshot’ estimation. This applies, in particular, to conditions where the
clinical signs are not themselves pathognomonic, e.g. liver disease.
Statistical analysis of the results of profile v individual laboratory examinations
shows that where a single test is performed the chances of the result being an
error are low, but where six parameters are measured there is a 50% chance
that one of them will be outside the reference range. The greater the number of
tests performed the greater the chance of abnormal findings (in otherwise normal
horses!).
Notes:
= The reference values shown in this section are those that are accepted in
the Department of Veterinary Pathology, University of Liverpool. The values
may differ from those in other laboratories and may also be varied from
time to time in the light of ongoing developments and experience in clinical
pathology. For example, estimation of creatine kinase (CK) can be made
at different temperatures and so a value that seems low or high from one
laboratory may appear to be normal when compared to the reference range
from another.
= The laboratory should provide their own ‘reference values’ on every report,
although the lab should not report on the findings unless this is based
on a full history and is the opinion of a qualified and experienced clinical
pathologist.
Vital signs, normal values 5
Normal Vital Signs
The normal vital signs for horses will vary according to the circumstances,
e.g. transport, exercise and mental status. External and internal factors may
influence them and due note should always be made of the circumstances under
which they are obtained. There are some circumstances when abnormalities can
be masked by temporary or intermittent physiological alterations in vital signs.
There are physiological/natural variations that are the result of breed, age and
stage of training.
Table 1.1 Reference ranges for the basic vital signs in horses.
Pulse rate Respiration Temperature Capillary refill
(b/min) rate (b/min) (rectal) (°C) time (seconds)
Foal (newborn) 100–128 14–15 38.5–39.5 <2
Foal (7 days) 80–120 14–16 38.0–39.0 <2
Foal (3 months) 60–100 14–15 37.5–38.0 <2
Pony 45–55 12–15 37.5–38.0 <2
Thoroughbred 35–45 12–15 37.5–38.0 <2
(resting)
Thoroughbred 25–40 10–15 37.5–38.5 <2
(fit)
6 Vital signs, normal values
SAMPLE COLLECTION
Not only is the correct anticoagulant essential for accurate laboratory analysis, but
also it is essential that the tubes are filled correctly.
Note:
= Check anticoagulant requirements with laboratory before obtaining samples.
Consider effects of transport on samples, particularly when this involves
postal services.
Table 1.2 Sample collection requirements for the range of parameters
measured from blood.
Tube: Parameter FlO Citrate LiHep Plain Affected by
x
Haematology √ 0 0 ± 0 L H
Clotting 0 0 √ 0 0 L H
Glucose 0 √ 0 0 0 S
Phosphate 0 √ 0 0 ± H
Urea 0 0 ± ± √ H
Proteins 0 0 ± ± √ L H
Fibrinogen 0 0 ± √ 0
Serum amyloid A 0 0 0 ± √ L H
Bilirubin ± 0 ± ± √ H
Cholesterol 0 0 0 ± √
Triglycerides 0 0 0 ± √ L
Creatinine 0 0 0 ± √ L H
Lactate Mixture of FlO + EDTA – check with lab (assay immediately)
x
Copper 0 0 0 ± √ H
Electrolytes 0 0 0 0 √
Blood gases 0 0 0 √ 0 L H
Bicarbonate 0 0 0 √ 0 L H S
Ammonia Special requirements – check with lab first (assay immediately)
Enzymes 0 0 0 ± √ S
Hormones 0 0 0 √ √
H, affected by haemolysis; L, affected by lipaemia; S, immediate separation. Samples
marked: ÷, best; ±, acceptable; 0, unacceptable.
