Poultry Health and Management

359 Pages·2006·9.45 MB·English

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Poultry Health and Management
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by

Dr. Joseph J. Giambrone

[email protected]

http://www.ag.auburn.edu/poultry/facultypages/giambrone.html

Professor
Poultry Science Department
201 Poultry Science Building
260 Lem Morrison Drive
Auburn University, AL 36849-5416
Preface

The purpose of this Poultry Health and Management book is to provide an up-to-date
accessible source of information about poultry diseases and other aspects of poultry
health and management. The book is divided into subsections, each of which will deal
specifically with single or related topics.

Introductory chapters provide a variety of information such as anatomy and physiology,
clinical and postmortem examination, disease prevention and control measures, which
include sanitation, disinfectants, vaccination programs, and other pertinent information
useful for creating and maintaining sound poultry health programs.

Various chapters deal with diseases caused by a particular type of agent including
bacteria, virus, fungi, protozoa, parasites, etc. Another section is devoted to
"miscellaneous diseases" conditions in which the exact cause is not known or is not in a
single entity group. The mention of any drug or vaccine in this handbook, whether by
trade or by chemical name, is not to be construed as an endorsement of that product

Acknowledgments

The following individuals and companies are thanked for their photo contributions: Drs.
F. J. Hoerr and Haroldo Toro, Auburn University, College of Veterinary Medicine; Dr.
Kenny Page, University of Georgia, College of Veterinary Medicine; Lohmann Animal
Health, Gainesville, Ga; Fort Dodge Animal Health, Overland Park, KS; Schering Plough
Animal Health, Kennilworth, NJ; and Intervet Animal Health, Millsboro, DE. Kajun Guo
is thanked for his work in editing the manuscript and transferring the MS word document
to adobe.

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Poultry Health and Management

by

Dr. Joseph J. Giambrone

[email protected]

Poultry Science Department
Auburn University

1.- Anatomy and physiology 4
2.- Clinical Examination 24
3.- Laboratory diagnostic procedures 34
4.- Post-mortem examination 40
5.- Pathology 56
6.- Causes of avian diseases 59
7.- Disease prevention and control 67
8.- Disease diagnosis 92
9.- Vaccination procedures and the immune response 100
10.- Antibiotics, probiotics, and prebiotics for disease control 118
11.- Bacterial diseases 136
12.- Viral diseases 178
13. Fungal diseases 229
14.- Mycotoxins 235
15.- Protozoan diseases 244
16.- Toxicity 260
17.- Nutritional diseases 271
18.- External parasites 290
19.- Internal parasites 308
20.- Miscellaneous conditions 322
21.- Environmental diseases and Vices 336
22.- Tables of equivalents 340
23.- Management surveys 342
24.- References 350
25.- Glossary 352

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1. Anatomy and physiology

Before you can treat a disease, one must make an accurate diagnosis. Diagnosis requires that you
know the normal anatomy of the fowl (figure 1.0). This chapter will provide a general overview
of avian anatomy and physiology.

Figure 1.0. Normal anatomy of the domestic chicken

The skeletal system

The bones of birds are rich in calcium salt and are dense. In many bones, the marrow is displaced
by air spaces, which are connected with the respiratory tract. These hollow bones help lighten the
skeleton to aid in flight (figure 1.1).

Skeleton of the wing

Scapula, coracoid, and clavicle compose the shoulder. The scapula, long, narrow and slightly
curved, lies dorsal (back of) to the ribs. It articulates (connects) with the coracoid at an acute
(severe) angle. The coracoid is the largest bone in this group and articulates by its proximal
(close to its center of origin) end with a facet (a small smooth surface on the bone) on the
sternum. This proximal end presents a foramen (aperature or perforation), which connects with
the anterior (above) thoracic air sac. The distal (away from the center of the body) end of this
bone has a hook-like process, which together with the proximal ends of the humerus and scapula,
forms a ring of bone (Foramen triosseum) through which passes the tendon (connects muscle
with bone) of the supracoracoid muscle. This is an elevator of the wing. Anterior to the coracoid
is the clavicle, which by its proximal end articulates with the coracoid and humerus and by its
distal end meets its fellow to form a forked bone (furcula, wish bone). A ligament (connects bone
to bone) unites the furcula to the rostrum (beak-shape structure) of the sternum.

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The humerus is present on the medial side of the proximal end, a Foramen pneumaticum, which
connects with the anterior thoracic air sac. In the adult bird, a radial and an ulna compose the
bones of the carpus. There are the second, third, and fourth incompletely developed metacarpal
bones. The second metacarpal bone is very short and is attached to the fused proximal ends of
the third and fourth. The latter two are also fused at their distal ends. Of the digits corresponding
to the metacarpal bones, the second and third are each composed of two phalanges (long bones
of the digits), and the fourth has one phalanax (singular of phalanges).

Figure 1.1. Skeleton of the domestic fowl (left) and psittacine bird (right).

Skeleton of the leg

Ilium, ischium, and pubis bones compose the pelvic girdle (belt). The ilium and ischium are
fused with the regional vertebrae, and in the concavities (depression) of the ventral surfaces of
these two bones the kidneys are lodged. A large sciatic foramen perforates the ischium posterior
to the acetabulum. The pubis is a long, slender bone beginning antero-ventral to the acetabulum
by a knob and extending posterior with its free end projecting beyond the ischium. Slightly
postero-ventral to the acetabulum, it is separated by the obturator foramen from the ischium.
There is attachment between pubis and ischium for a short distance posterior to the foramen,
beyond which the shaft and extremity of the pubis are free.

The femur, patella, fibula, and tibia closely resemble those of mammals. Since the tarsal bones
fuse early with the tibia and metatarsal bones, there are no separate tarsal bones. The tarsal joint
is a ginglymus, or hinge joint, composed in the adult of the fused bones on the distal end of the

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tibia and those on the proximal end of the metatarsus. The metatarsus is composed of a shortened
first metatarsal bone connected by a ligament (connects bone to bone) to the medio-plantar
border of the fused second, third, and fourth metatarsal bones. Very close and proximal to the
first bone on the medial side of the shaft of the fused mass of the male is a hooked process. This
is the base of the spur. The distal end of the metatarsus has three condyles (articular surface on
the bone), which articulate with the first phalanges of the second, third, and fourth digits. In the
chicken the first digit of the foot is directed posterior and carries two phalanges. The second,
third, and fourth digits are directed interiorly and have, respectively, three, four, and five
phalanges.

Muscular system of fowls

The pectoral muscles (figure 1.3) are highly developed in birds that can fly. There is a superficial
one, which depresses the wing, and a deeper one, the supracoracoid muscle. This latter one has a
tendon of insertion, which passes through the Foramen triosseum at the shoulder joint to be
inserted on the humerus near its head. The supracoracoid muscle is an elevator of the wing. The
abdominal muscles are very thin sheets of muscle. The thigh muscle (figure 1.2) is also well
developed in avians.

Figure 1.2. thigh muscle

Figure 1.3. Breast Muscle

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The digestive system

The beak

The beak, both upper and lower segments, is composed of a superficial epidermis (superficial
portion of skin). This has the four typical strata (layers) ordinarily ascribed to it. Derma or
corium intervenes between epidermis and periosteum. This layer contains blood vessels and
nerves, and some touch corpuscles. The bone of the upper beak is the Os incisivum (premaxillae)
and the lower is the Os dentale (Corpus mandibulae). Since birds have no teeth, the beak serves
to pick up food.

Cavity of the mouth

The lining membrane is similar to that of the mammals. Many posterior directed papillae (nipple-
like projections) are present in the mucosa of the hard palate, which presents a median cleft.
Lymphoid tissue is present in the Lamina propria of older birds. The food is swallowed
immediately when taken into the mouth.

The tongue

The dorsum of the tongue has a mucous membrane, which although uneven, is devoid of papillae
except posterior where there is a transverse row. The epithelium on the dorsum is highly
keratinized. It continues over the tip to the ventral side where soon it becomes less cornified and
smooth. Lymphoid tissue may be present in this part of the tongue of older birds. The muscles
are poorly developed and are arranged about the arrow-shaped end of the entoglossal bone,
which is the anterior end of the hyoid bone.

The salivary glands

The salivary glands all have a similar structure. The tubules of each lobule open into a central
cavity, which is continuous with an excretory duct. Amylase is present in the saliva of the hen.
Lymphoid tissue may be found both interlobular and intralobular in most of the salivary glands
of adult birds.

The pharynx

The posterior-most transverse row of palatine papillae and the row on the base of the tongue may
be taken as a division line between mouth and pharynx. The mucous membrane of the pharynx is
similar in structure to that of the mouth. Dorsally on the median plane is a slit, which provides a
common opening for the pharyngeal ends of the eustachian tubes. Continuity with the nasal
cavity is through the cleft of the hard palate.

The esophagus

The structure of the esophageal wall is similar to that of mammals. The thick epithelial layer of
the mucosa is highly keratinized (scleroprotein). Extending through this layer and into the

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Lamina propria are large mucous glands. Some lymphoid tissue may be found in the Lamina
propria. This organ serves as a tube for passage of food from the mouth to the crop (figure 1.4).

The crop

The esophagus of ducks and geese has, in its cervical portion, a long spindle-shaped dilatation. In
pigeons and chickens a ventral diverticulum (a sac-like opening from a tubular structure) marks
the junction of cervical and thoracic portions. In the chicken this crop, or ingluvies, has a
structure similar to that of the esophagus with the exception that it is glandless in its greater part,
and its greater curvature has a sparse blood supply. The crop serves as a food reservoir and
moistens (softens) the food. The crop contains some mucous glands and produces some amylase.
The crop of the pigeon has two lateral lobes.

The structure of the wall is similar to that of the esophagus. In the female pigeon, which has been
setting eggs for 8 days, hypertrophy (increase in size) of the wall has already begun. This
remains until several days after hatching. The most marked change is in the increased number of
cells of the epithelial (avascular covering of surface) layer, which becomes markedly folded. The
superficial cell-layers of the epithelial layer become laden with fat and are desquamated (scaled
off) into the lumen to form pigeon "milk" for feeding the young.

The proventriculus

The proventriculus is the glandular stomach of the fowl. It differs from the similar mammalian
structure, in that its lumen is scarcely larger than that of the esophagus. Its storage capcity is
limited. There are the four typical layers in its wall. In the center of each lobule is a cavity, which
receives the glandular secretion and is continuous with an excretory duct. Several excretory ducts
empty into the lumen of the proventriculus through large papillae. The free ends of the cells of
the tubular glands are directed toward the central cavity and do not touch adjacent cells, thus
giving a separated appearance to the glandular epithelium. The glands of the proventriculus
secrete gastric juice, which contains mucus, pepsin, certain salts, and hydrochloric acid for
digestion of nutrients.

The gizzard

The gizzard (ventriculus) is a spheroidal organ, flattened in the lateral direction. Its two lateral
sides are biconvex discs. There is a dorsal and a ventral muscular mass. These muscular masses
are of a red color, but non-striated. The lumina (spaces in the interior of the structure) of the
glands contain a material with cellular debris, which forms the so-called horny layer of the
gizzard. It has wavy lines parallel to the surface and wider lines perpendicular to the surface. The
gizzard has a mechanical function; it serves to crush grain.

The small intestine

The intestine of the fowl, although similar to that of mammals, differs markedly in some parts. It
is about five to six times the length of the body. The duodenum, which does not have glands of

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Brunner, presents a loop supporting the pancreas, and is generally considered to terminate at the
entrance of the bile and pancreatic ducts. The jejunum and ileum are supported by a mesentery,
and bounded by air sacs, which separate them from the abdominal wall. There is often a
diverticulum (pouch) on this portion of the intestine, which is a remnant of the yolk stalk. The
propria (sensory area) contains considerable lymphoid tissue and lymph nodules. Crypts of
Lieberkühn open into the lumen of the gut between the bases of adjacent villi. The small intestine
is the primary organ where digestion and absorption of nutrients takes place. Digestion takes
about 10 hours to complete in the chicken.

Figure 1.4. Digestive System

The ceca and large intestine

Beyond the small intestine, the bowel presents two retrograde (going backward) portions (the
ceca) and a continuing portion (the large intestine). The paired ceca extend interiorly for some
nine inches parallel to the ileum. The ceca are attached by peritoneal folds. The villi are well
developed near the mouths of the sacs, shorter and broader in the mid-portions, and in the fundus
(lowest parts of the sac) the villi are low and blunt. The glands of Lieberkühn are poorly
developed. In older birds, lymph and much lymphoid tissue are present in the propria. The large
intestine has numerous villi for absorption of nutrients. The ceca absorb water from the stool.

The rectum

The rectum is that portion of the bowel between the cecal orifices (openings) and the beginning
of the cloaca. The structure of the rectal wall resembles that of the small intestine. The glands of
Lieberkühn are, however, much smaller and fewer. A slight constriction is usually present to
mark the termination of the rectum.

The cloaca

Usually, definite circular folds delineate the three portions of the cloaca (the coprodaeum, the
urodaeum, and the proctodaeum). The coprodaeum is the passageway between the rectum and
urodaeum. The urodaeum continues the passageway between the coprodaeum and the
proctodaeum and, in addition, receives the ureters and genital tubes. Between the urodaeum and

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the proctodaeum, the limiting fold on the dorsal side guards the entrance to the bursa of
Fabricius. The wall of the cloaca has a structure similar to that of the rectum and small intestine.

The bursa of Fabricius

The bursa (of Fabricius) cloacae in the chicken, extending dorsally from the roof of the
proctodaeum, attains a maximum size in four to five weeks, and at about six months has
disappeared. The mucosa is much folded, and these folds contain great numbers of lymph
nodules. The nodules have a typical lymph-follicle structure (dense periphery with a lighter
center). The bursa produces immature (B) cells, which later develop into plasma cells. Plasma
cells secrete antibody into circulation. The bursa also produces B cells, which cede to other
lymphoid organs such as the spleen, cecal tonsil, and gland of Harder (small gland located
behind the eye). The bursa atrophies at sexual maturation. These other lymphoid organs take
over the bursa’s function at this time.

The anus

The structure of the anus resembles that of mammals. A sheet of cross-striated muscle, making
its appearance at the level of the bursa of Fabricius, extends in the fused propria and submucosa
to the borders of the dorsal and ventral anal lips. The end product of protein digestion (uric acid)
is voided together with other digested material. The urates are white in birds, the intestinal void
is green, and the cecal excrement is light brown.

The liver

The liver (figure 1.5) is the largest gland of the body, and plays an important part in generation
of energy. The liver is involved in the following: formation and secretion of bile; formation and
storage of glycogen and regulation of glucose content in circulation; deamination of amino acids;
desaturation of fatty acids; detoxification of poisonous substances brought to the liver by blood;
and aiding the destruction of erythrocytes. The microscopic structure of the liver varies little
from that of mammals. A cystic duct and a hepatic duct both empty into the intestine, near the
terminations of the pancreatic ducts. The bile produced by the liver and stored in the gall bladder
serves as a medium of excretion and as a digestive secretion.

Figure 1.5. Liver

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