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On the face of an outbreak of a disease, collection of right clinical specimens in proper preservative, their transportation to the laboratory under ideal conditions and quick processing of specimens in the laboratory to identify the causative agent are crucial to successful control of the disease. This attains more importance when a highly contagious disease appears.

Collection of specimens from a virus-infected host is the first step for demonstration or isolation of a virus. Specimens for virus isolation should be collected at the time when the maximum amount of virus can be expected to be present. i.e. collect the specimens as early as possible after the onset of clinical symptoms. In many viral diseases maximum viral production occurs before the patient becomes ill so that it is ideal to collect the specimen at an even early time.
The nature of the specimen taken in any particular instance is determined by the patient’s clinical syndrome and previous history. They are best considered under three main headings.

1. Specimen for virus isolation/antigen detection/ nucleic acid detection
2. Specimen for serological investigation
3. Specimen for direct examination

Location and Layout
• As the laboratory will be handling materials hazardous to human and animal health, it must be isolated as much as possible from livestock yards, poultry farms and quarantine stations and should not function in or near establishments handling healthy animals, food products for human or animal consumption or near vaccine production laboratories.
• Animal houses, garages, workshops, stores, water tanks, residential accommodation, administrative blocks have to be constructed as per the need of ideal microbiological laboratory. Expansion possibilities should
also be kept in mind. The building can be arranged in 5 main groups:
• Administrative / laboratory rooms
• Decontamination and disposal area
• Animal house facilities
• Workshops / stores/garages and
• Residential accommodation for the staff, hospital, schools, playgrounds, parks, shops etc. • The laboratory building may be rectangular in blocks, arranged in L, T or U shapes and may be of one or several stories. The temperature, wind velocity, rainfall,

Introduction

Poultry is one of the most widespread food industries worldwide. Chicken is the most common type of poultry in the world. The term broiler is applied to chickens that have especially been bred for meat; they grow rapidly. Broiler strains are based on hybrid crosses between Cornish White, New Hampshire and White Plymouth Rock. In broiler production there are two main production phases – keeping of parent stock and production of day-old-chicken (DOC); and growing and finishing of broilers.

The primary purpose of any enterprise is to maximize return on investment over the long-term. It is therefore necessary to market poultry, meat products, and eggs at a price which allows farmers or integrators to maintain profitability in a competitive market. Cost-effective programs of biosecurity and vaccination are required to prevent or limit the impact of disease. It is emphasized that the incremental return in the form of enhanced egg production, hatchability, liveability, growth rate, and feed conversion efficiency must exceed capital and operating expenditures on disease prevention.

In avian medicine, because clinical signs in birds can be vague, veterinarians must rely on additional clinical tests to accurately diagnose and treat conditions. These tests, including hematology, urine analysis and others, are essential for understanding diseases early and tailoring effective treatments. Clinical hematology is qualitative and quantitative assessment of blood and other blood component for the treatment of clinical patient. In comparison to mammals, bird’s erythrocytes are oval and nucleated cells, nucleated thrombocytes, heterophiles instead of neutrophils. RBCs of birds have relatively short life span and regenerate more quickly than mammals. The preferred vein for blood collection in birds varies with the species. In most species the wing veins is preferred site. Both EDTA and heparin have been used in avian clinical haematology as anticoagulant. The average blood volume of most birds is approximately 10% body weight. Avian plasma samples frequently are yellow due to carotenoid pigments, not bilirubin. Uric acid is the major nitrogenous waste product of birds it is relatively inert and substantially less toxic than ammonia or urea. Both BUN and creatinine levels are normally low in birds and may be below the minimum detectable limit of the assays in the laboratory. It may be useful to evaluate BUN and uric acid together to differentiate among dehydration, postprandial effects and renal pathology.

All infectious agents, toxins, and nutritional imbalances have an impact on the performance of the farm and consequently on the local poultry industry. Additionally, poultry can be infected with common diseases like endoparasites, ectoparasites, infectious bronchitis, Marek’s disease, fowl cholera, salmonellosis, infectious coryza, fowl pox, avian encephalomyelitis, etc.

Controlling infectious diseases is vital for poultry health and diagnostic methods are an indispensable feature to resolve disease etiologies and the impact of infectious agents on the host. Although the basic principles of disease diagnostics have not changed, the spectrum of poultry diseases constantly expanded, with the identification of new pathogens and improved knowledge on epidemiology and disease pathogenesis. In parallel, new technologies have been devised to identify and characterize infectious agents, but classical methods remain crucial, especially the isolation of pathogens and their further characterization in functional assays and studies.

In poultry medicine, the diagnostic process originally shifted from the traditional veterinarian approach centered on individual animals to the health assessment of entire flocks. Flocks are commonly classified as “healthy” if they perform according to their genetic potential and are considered free from clinical disease. On-farm, diagnostic activities comprise routine sampling and investigations in line with health control programs; nationally and/or internationally adopted control programs for certain Mycoplasma and Salmonella species represent examples of paramount importance. Samples may be investigated immediately on site (e.g., rapid antigen test for avian influenza) or sent for further processing to a laboratory (e.g., ELISA and PCR). Field veterinarians further implement diagnostic surveillance in order to provide epidemiological data for flock management purposes. The periodical collection of samples (e.g., feces, serum samples, and swabs from mucosal surfaces) is primarily used to confirm the infection (free) status of a flock or to monitor vaccine response. Altogether, generated data facilitate objective judgment and decision making in order to optimize flock health and production.

Paracelsus recognized more than 400 years ago that it is “the dose that makes the poison.”Deliberate or inadvertent over dosages may cause illness, and a misplaced decimal in water or feed medication concentrations frequently results in toxicity. A general feature of modern complex poultry rations, feed mill equipment, and feed delivery to poultry farms is that any component included in a ration may at some time be mistakenly included at a higher than desired rate. This may occur through human or mechanical error. For example, sulfaquinoxaline poisoning occurs in meat-type chickens, even at recommended doses, because of high water intake in warm buildings, particularly in hot weather, or because of poor feed mixing.

Poisonous substances are widely distributed in nature. Poisoning occurs more frequently in free-range and backyard flocks and in village poultry where birds forage in neighboring gardens and fields or receive household waste and weeds cut from roadsides and fields. Some of these poisonings are malicious. Contaminated litter on the floor and in nest boxes is an added source of toxins in chickens not raised on wire.

Nutritional deficiencies can result from a lack of specific nutrients in the diet, adverse interactions between nutrients in seemingly well-balanced diets, or the influence of specific anti-nutrients. The latter two scenarios are particularly challenging to diagnose because dietary analysis may suggest that nutrient levels are adequate. Micronutrients such as vitamins and trace minerals are typically added to diets through standalone micro premixes, making classic signs of individual nutrient deficiencies rare. Instead, the effects are often a combination of various metabolic conditions. Accurate diagnosis often requires comprehensive information about the diet and management practices, clinical signs in affected birds, necropsies, and tissue analyses. However, tissue analysis, especially of the liver and serum, can be misleading. Following the onset of a deficiency, birds may sequester nutrients in the liver, leading to falsely high liver assay values even when the diet is deficient. This effect is particularly significant for minerals such as copper. A diet that appears to contain sufficient levels of certain nutrients based on analysis may actually be deficient in those nutrients to some extent. Stressors such as bacterial, parasitic, or viral infections, as well as extreme temperatures, can interfere with nutrient absorption or increase the nutritional requirements. Toxins or microorganisms may destroy or render unavailable specific nutrients that appear to be present in adequate levels according to conventional chemical or physical assays. Consequently, many trace minerals and vitamins are included in the diet at levels significantly higher than the actual requirements to account for these potential issues.

Metabolic disorders are classed as illness associated with a failure in one of the body hormone or enzyme systems, storage disease related to lack of metabolism of secretory products because of the lack of production of a specific enzyme, or the failure or reduced activity of some metabolic function. There are numerous genetic, metabolic disorders in poultry but these are rare in commercial poultry. In poultry it is usual to include under the heading of metabolic disorders those conditions associated with increased metabolism, rapid growth rate or high egg production that result in the failure of a body system because of the increased work-load on that organ or system. Metabolic disorders that result from an increase production of, or deficiency of or failure in the production, synthesis, or transport of an enzyme, hormone or secretary mechanism. Metabolic disorders that result from high nutrient intake, rapid growth, high metabolic rate, pulmonary or systemic hypertension, and high egg production or a rapid increase in egg production. Other conditions that could be classed as metabolic disorders related to: (a) management defects; (b) nutritional deficiency or excess; (c) infectious agents; (d) toxins.

Introduction

Disorders of the hemopoietic system in poultry can significantly impact the health and productivity of these birds. The hemopoietic system is responsible for the production of blood cells, including red blood cells, white blood cells, and platelets. Disorders within this system can lead to various health issues, including anemia, immunodeficiency, and impaired blood clotting. Some of the common disorders of hemopoietic system include:

1. Anemia: Anemia is a condition characterized by a decrease in the number of red blood cells or hemoglobin in the blood. In poultry, anemia can be caused by various factors, including nutritional deficiencies (such as iron deficiency), infectious diseases (such as avian malaria or chicken infectious anemia), and parasitic infestations (such as blood-sucking parasites like leucocytozooncaulleryi, ticks, lice and mites).

2. Avian Leukosis:Avian leucosis is a viral disease caused by avian leukosis virus (ALV). It primarily affects young birds, causing tumors in various organs, including the spleen, liver, and bursa of Fabricius. Avian leukosis can lead to immunosuppression, anemia, and increased susceptibility to secondary infections. The avian leucosis diseases include lymphoid leucosis (affecting lymphoid cells), myeloid leucosis (affecting myeloid cells), osteoptrosis, etc. and can result in immunodeficiency, increased susceptibility to infections, and other systemic symptoms. It also affects blood-forming tissues, including the bone marrow and lymphatic system, leading to an overproduction of abnormal white blood cells.

Introduction

Eye

Avian ocular apparatus includes eyeball, optic nerve, and accessary structures e.g., eyelids, lacrimal glands, and muscles etc. The eyeball is composed of three tunics namely the f ibrous (cornea and sclera), vascular (choroid, iris, ciliary body) and nervous tunic (retina). The histological structures of all these tunics are similar to mammals except the Bowman’s membrane (the basal lamina of corneal epithelium) is not distinct. Similar to the mammals, they also have three refractive media viz., aqueous humour, lens, and vitreous humour. The cornea does not refract light.

There are some important diseases and disease conditions of eye in poultry birds. The common aetiology of eye diseases in poultry birds has a wide range and includes heredity, nutritional deficiency, infections (microbial and parasitic) and managemental failure. Some of them are not seen often in the modern intensive rearing systems like the deficiency diseases while others are seen associated only with the intensive system housing of birds like the ammonia burns. The infectious diseases of only eyes, are not encountered in poultry birds. The diseases like the colibacillosis, pasteurellosis and Marek’s disease can affect eyes along with other body systems. Understanding of eye diseases of poultry birds requires basic knowledge of ophthalmic anatomy, concepts and terminology of eye associated pathological changes. The affected birds generally show ocular lesions and loss of condition due to starvation as they are unable to search for feed and water. Some conditions are reversible while others may be irreversible according to the extent of damage. Nutritional and managemental diseases in most cases are relatively easy to diagnose and manage, while infectious and hereditary diseases may require deeper investigation. Some diseases like endophthalmitis, eye notch syndrome and ophthalmopathy have been recorded but their causes could not be found out.

The skin of the birds provides a physical barrier between the birds its environment, protecting the birds from bacteria and physical injury. The health of the bird can be compromised, and the value of the end-product can dramatically decrease. Bird’s skin differs from that of mammals by its thinness, by the presence of feathers instead of hair, and by the absence of sebaceous glands (sweat glands), although the overall histological structure is similar. Bird’s skin is composed of an epidermis separated from a dermis by a basal membranes to protect the body from infection. The integumentary system consists of the skin, the feathers and the appendages (claws and beak). The skin covers the majority of the body and contains glands in the outer ear canal and the preen gland at the base of the tail, that the bird uses to preen its feathers. The integumentary system is very important in providing protection to the bird from a number of potentially dangerous situations. The functions provided by the integumentary system include: A barrier between the external environment and the internal systems and organs thus provides support and protection from infection by microorganisms and from physical injury. Excellent thermal insulation to help regulate body temperature in a variable environment. Numerous nerve endings for the senses to enable the bird to be aware of potentially harmful situations. Pigments for display and protection from the elements. The compounds capable of conversion into vitamin D when exposed to sunlight. Avian skin is relatively thin with the epidermis consisting of only 2-10 cell layers. There are no sweat glands; instead heat is lost via the respiratory tract and by radiation from featherless areas. The brood patch is a featherless area that can occur in both sexes and is either seasonal or permanent depending on species.

Introduction

Pain management in poultry is an important aspect of animal welfare and overall production efficiency in the poultry industry. Poultry birds, such as chickens and turkeys, can experience pain due to various reasons including routine management procedures, injuries, and diseases. Managing pain in poultry is crucial not only for ethical reasons but also because pain can lead to decreased productivity and increased susceptibility to diseases. For the better management First step is identification of pain in birds which can only be possible with the thorough knowledge of their behaviour. Second step is the selection of appropriate analgesics and their dosing’s as there are various species of birds. Commonly used analgesics for birds includes, NSAID’s, opioids etc.

1. Routine Management Procedures: Many routine procedures in the poultry industry, such as beak trimming, toe clipping, and wing clipping, can cause pain and distress to birds if not done properly. Beak trimming, for example, is often performed to reduce feather pecking and cannibalism in crowded conditions but can cause acute pain if not done correctly. Proper techniques and pain management strategies must be employed during such procedures to minimize pain and distress in birds.

Introduction

The reproductive system is fundamental to poultry production, playing a crucial role in both the quantity and quality of eggs laid. Its importance goes beyond mere biology, impacting the profitability and long-term sustainability of poultry operations (Abbasi et al., 2024). Central to this is the egg, the ultimate product of avian reproduction. The reproductive system coordinates complex processes to ensure eggs meet high standards. Any disruption to this delicate balance can have far-reaching effects on the economic and environmental aspects of poultry farming. Disorders affecting the avian reproductive system pose significant challenges to the poultry industry. Whether they are minor disturbances or major disruptions, these disorders can undermine the foundation of successful production. They can lead to reduced egg production and compromised egg quality, affecting productivity, efficiency, and ultimately, profitability. In today’s poultry management landscape, where efficiency is paramount, the impact of reproductive disorders cannot be overstated. Beyond economic concerns, these disorders also affect sustainability and environmental responsibility. A healthy reproductive system is not only crucial for financial success but also for upholding ethical and responsible poultry practices. As such, ensuring the reproductive health of poultry is of utmost importance. It requires dedicated effort, attention to detail, and a comprehensive approach. By strengthening the reproductive system against various threats, poultry producers can secure not only the current success of their operations but also a legacy of responsible stewardship for future generations (Habibi et al., 2024).

Poultry, encompassing a wide range of domesticated birds, plays a crucial role in agriculture, providing meat and eggs to populations worldwide. The health and well-being of poultry are of paramount importance for sustainable and efficient production. One aspect that significantly influences poultry health is the condition of their wings. Wings serve various purposes for birds, including flight, balance, and protection. Disorders affecting poultry wings can arise from a multitude of factors, ranging from nutritional imbalances to infectious agents and environmental stressors.

Understanding and addressing poultry wing disorders require a comprehensive approach that encompasses both preventive measures and therapeutic interventions. This comprehensive understanding involves recognizing the various disorders that can afflict poultry wings, their causes, symptoms, and potential treatments. In this exploration, we delve into 50 multiple-choice questions and answers covering a diverse array of poultry wing disorders, providing insights into the complexity of avian health management.

The Significance of Poultry Wing Health

Maintaining the health of poultry wings is not merely a matter of ensuring their ability to f ly; it is intrinsically linked to the overall well-being of the bird. Poultry wings are vital for performing a myriad of daily activities, including foraging, preening, and maintaining social hierarchies within flocks. Additionally, the condition of the wings often reflects the bird’s general health status, making them an essential diagnostic indicator for avian health professionals.

Introduction The urinary system of poultry, consisting of the kidneys, ureters, and cloaca, is essential for removing waste products and maintaining fluid balance. However, this system can be susceptible to various disorders that can impact the health and productivity of the flock. This chapter will discuss some of the most common urinary system disorders in poultry.

Urinary system disorders can have significant negative impacts on poultry health and productivity (Klybeck, n.d; Mississippi State University Extension, n.d; Poultry Hub, n. d.). Some of the key ways these disorders affect poultry include:

1. Gout: Renal diseases often lead to gout in poultry, which is a metabolic disorder resulting in hyperuricemia and deposition of uric acid or urates in tissues (Klybeck, n.d.). This can further damage the kidneys or other body systems.

2. Reduced productivity: Gout has a direct effect on productivity by lowering weight gain, increasing feed conversion ratio (FCR), and causing mortality which may reach 11-30% (Klybeck, n.d)

3. Organ damage: Accumulation of uric acid can lead to swelling and damage of kidney cells, as well as visceral gout where whitish deposits are found on the surface of organs like the heart, liver, intestines, and lungs (Klybeck, n.d; Mississippi State University Extension, n.d.).

4. Mortality: Severe kidney damage and dysfunction can quickly lead to debilitation and death in poultry (Poultry Hub, n.d.). Acute septicemic coliform infections may also cause sudden death (Mississippi State University Extension, n.d.)

5. Respiratory issues: Infectious bronchitis virus can affect both the respiratory and urinary systems, causing inflammation and damage to the kidneys (Mississippi State University Extension, n.d.).

Introduction

Musculoskeletal diseases in poultry are often exhibited as lameness or leg weakness. Numerous factors, including those related to diet, animal husbandry, infections, or heredity, might contribute to musculoskeletal problems. Lameness can be exhibited due to disorders in the central or peripheral neurological systems, reproductive system, trauma or infection in the foot, leg, hip, spine, or just a generalised sickness. Less frequently, musculoskeletal anomalies can affect the bird’s beak, neck, or wings. The diseases can also be classified as infectious origin (bacterial, viral) or non-infectious origin (congenital deformities, nutritional, trauma or neoplasia). Modern poultry production lines put a lot of strain on the musculoskeletal system due to factors like growth rate in broiler chickens and egg output in laying hens. As a result, poor nutrition and husbandry practices frequently lead to musculoskeletal disorders. Thus, musculoskeletal disorders in poultry can be controlled by choosing proper genetic selection, efficient vaccinations, adequate nutrition and proper husbandry practices.

Introduction

Hepatocytes are tiny cells that constitute the primary structural unit of the liver. Periportal hepatocytes, the first to receive blood from the portal system, are particularly vulnerable to hepatotoxins and endotoxins. Periacinar hepatocytes, placed further away from the portal blood supply, are more susceptible to hypoxia, toxic metabolites and hypoperfusion. Inflammatory cells are drawn to injured hepatocytes and biliary epithelium due to the release of cytokines and inflammatory mediators. This causes additional hepatocyte necrosis and fibrosis. The liver has exceptional regenerative abilities as hepatocytes can be replaced even if only 12% remains intact.

Hepatocytes exhibit colour changes when they are laden with fat or pigments. In their f irst week of life, young turkeys and chickens typically have a lot of fat and pigments (carotenoids) deposited in the liver due to the ability of intestines in mobilizing the yolk content. It is typical to find fat vacuoles (microscopic fat deposits) within the hepatocytes at this point. A bird's liver will typically turn mahogany-brown after about seven days of life. Because of the influence of oestrogens, the hormones that are present in large concentrations once maturity is attained, the quantity of fat in the liver of adult hens increases before the age of lay. Because a large amount of fat and pigments are transferred from the liver to the oviduct for yolk formation in eggs, the majority of laying hens in a flock will typically have a pale brown or yellowish liver. When liver seems pale or yellow, histopathology is a crucial technique that can be used to establish a differential diagnosis.

Introduction

The digestive system of the birds has modifications to facilitate the easy flight. Length of intestine in birds is relatively shorter compared to mammals. Also, they lack teeth and jaw muscles which are replaced with light weight beak. Food grains are swallowed as whole and ground in the gizzard with the help of powerful muscles. In the mouth, tongue is used to manipulate the food and also aids in swallowing the food. Chickens have as many as 300 taste buds. The elementary system in birds consists of gastro intestinal tract and the accessory glands, the course of the elementary starts with Mouth, oesophagus, crop, proventriculus (glandular/true stomach), gizzard (mascular stomach), small intestine (duodenum, Jejenum, ileum), large intestine (colon and caeca) which lastly opens into cloaca. For fast growing poultry species elementary system is very important. It plays vital role in digestion, absorption and also provides protective immunity. Poultry intestines harbours diversified microflora which aids in enhanced availability of nutrients to the bird. Intestinal wall contains four layers: mucosal, submucosal, muscle tunic, and the serosal layer. As intestine is involved in important functions like digestion & immunity, any change in intestinal integrity / microflora balance impacts the bird performance in terms of body weight gain in broilers and egg number in layers. Some bacteria, viruses and also fungi produce different diseases / conditions in poultry birds. The ban on the use of antimicrobial growth promoters has pushed poultry producers from use of AGP’s to alternatives to AGP’s such as prebiotics, probiotics, essential oils and some herbals. Maintaining good gut health in the absence of AGP’s and anticoccidial drugs is a challenging situation for the poultry farmers across the globe. Poultry gut contains diverse community of bacteria, fungi, protozoa and viruses. The recent data suggests that gastrointestinal tract of a broiler chicken colonizes by an estimated 600 – 800 species of bacteria. The abundance and diversity of microbiota varies along the GI tract. After the hatch GI tract colonizes within 3-4 days. Small intestine of broilers mainly contains lactobacilli although enterococci, E.coli, eubacteria, clostridia, propionibacteria and fusobacteria can be found.

Introdcution

Poultry have a nervous system made up of the brain, spinal cord, sympathetic nerves that govern their viscera, and branches that go to their ears and eyes. The structure of the brain and spinal cord is very similar to that of mammals. However, there are also significant structural variations between many bird brains and many human brains, including the following:

1. Absence of cortex: According to Cobb (1960), the cortex is “a peripherally placed coating (pallium) of cells arranged in layers,” yet it is completely absent in birds. However, other authors have compared the hyperstriatum to the mammalian cortex (Haefelfinger, 1957; Stingelin, 1958).

2. Presence of hyperstriatum: The functions of the hyperstriatum are comparable to those of the mammalian cortex. In pigeons and chickens, the hyperstriatum may be involved in the visual and hearing systems’ functions.

3. Birds have highly developed optic lobes.

4. Turkeys and vultures are the only birds with a well-developed olfactory system.

Introduction

Ante mortem diagnosis of cardio vascular diseases in avian patients is a challenging to the physician. Compare with the mammals, few anatomical and physiological features are unique in birds. The avian heart is anatomically similar to mammals, although birds have a proportionally larger heart size relative to a comparably sized mammal. Heart size in mammals remains equivalent to body mass, while larger birds have a proportionally smaller hearts in relation to body size than smaller birds. The apex of the heart is enclosed between the right and left hepatic lobes and lies along the sternum and parallel to the thoracic spine in the cranio ventral coelom. The avian cardiovascular system is adapted to the high aerobic requirements for flight, running or swimming. Efficient oxygen transfer to the tissues is facilitated by a lower total peripheral resistance, higher heart rate, higher arterial blood pressure and more rapid myocardial depolarization. The clinical signs seen in birds afflicted with cardiac disease can be vague and non-specific which are mimicking many other disease conditions. Similar to mammals, birds may present with lethargy, weakness, exercise intolerance, syncope, dyspnoea, coughing and even sudden death. On physical examination cardiac disease may be suspected based on the presence of arrhythmia, murmur, muffled cardiac sounds, poor peripheral pulses, cyanosis and coelomic distension. Pulmonary oedema, hepatomegaly, ascites and enlarged jugular veins with pulsation may be seen in cases of congestive cardiac failure. Pericarditis can occur with primary infectious agents or secondary to disease occurring in adjacent tissues, such as mycotic pulmonary granulomas. Visceral gout due to hyperuricaemia may also affect the pericardium. Congestive heart failure and systemic manifestations of disease, such as hypoproteinaemia, may result in effusions within the pericardium. Myocardial ventricular hypertrophy can occur with any condition that results in an elevated preload on the heart, including pulmonary hypertension and atherosclerosis. Myocarditis has been observed in cases of chlamydiosis, polyomavirus infection and proventricular dilatation disease from bornavirus. Heavy metal toxicosis has been associated with cardiac neural dysfunction and myocardial infarction. Vegetative endocarditis and resultant valvular insufficiency can occur with bacteraemia from chronic bacterial infections involving other organ systems.