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Preface Basic sciences like veterinary physiology, serve as the foundation upon which a veterinary graduate student builds his or her understanding of the veterinary sciences. The knowledge of veterinary physiology serves as a cornerstone for understanding pathophysiology, animal productivity, and treatment strategies. Hence, an effort has been made to prepare a comprehensive handbook of veterinary physiology covering all practical’s (experiments) to be conducted in hematology, cardiovascular system, digestive system, respiratory system, excretory system, endocrinology, physiology of reproduction, animal growth, environmental physiology & climatology, and animal behaviour, consulting different textbooks of veterinary physiology, research & review articles, as well as relevant websites, and the same has been acknowledged in the reference section. All the analytical techniques have been written in a simplified language with brief importance, the normal physiological value of various parameters and interpretation for each experiment so that undergraduate students will have better insight into the subject. This handbook aims to serve the function of a manual as well as a practical textbook where all the pertinent experiments are compiled together for easy reference. Being the first of its kind, any suggestions, ideas, and comments from the readers are highly appreciated for improvement in future editions.

Introduction Hematology is the study of blood and its constituents. Blood is a specialized fluid connective tissue, which consists of plasma (55-70%) and the formed elements (30-45%) that flow all over the body in the vessels of the cardiovascular system. Plasma comprises water (90-92%), proteins (6-7%), enzymes, hormones, lipids, and organic & inorganic constituents. The three major classes of plasma proteins include albumin, globulin, and fibrinogen. The organic elements include non-protein nitrogen (NPN) compounds (like urea, uric acid, creatine, creatinine, amino acids, glutathione, and xanthine), glucose, neutral fats, phospholipids, cholesterol and others. The inorganic constituents include calcium, phosphorus, magnesium, potassium, sodium, chlorine, sulfur, iodine, iron, copper, cobalt, manganese, zinc, selenium, and molybdenum; they contribute about 1 percent of the plasma. Blood performs various functions by its constituents. The constituents of the blood are highly dynamic, and they inter shift from their reference values very quickly in any adverse condition. This is why; studies of blood cells and complete blood count (CBC) are important for accessing general health, diagnosing various diseases, and providing prognostic information when coupled with a thorough physical examination. The blood examination is performed routinely to diagnose hematological diseases, including certain hereditary diseases of the blood, and to determine the body’s ability to respond to a hematological insult. The key parameters evaluated in the hemogram are ESR, PCV, Hb, TEC, MCV, MCHC, TLC, and DLC.

Introduction The cardiovascular system is comprised of the heart and blood vessels (arteries, capillaries, and veins). The heart pumps blood to blood vessels which allow blood to flow throughout the body. Both heart and blood vessels are work together to keep the blood circulating, ensuring the interchange of O2, CO2, electrolytes, and nutrients between the blood and the tissue fluids & cells, and removing waste products from the body via the excretory system. The purpose of the study of the cardiovascular system is aimed at understand the pathophysiology of the heart and vascular system. A physical examination, arterial blood pressure, and electrocardiography are routinely employed to examine the cardiovascular system. The physical examination of the heart includes palpation, percussion, and auscultation.

Introduction The digestive system and its auxiliary organs main functions include digestion and the absorption of nutrients required for cell metabolic processes. Digestion is the mechanical and chemical or enzymatic breakdown of large nutritional macromolecules into simpler molecules that cells can absorb. It takes place in the aqueous milieu of the digestive system and is secreted by the salivary glands, stomach and mucosal glands, pancreas, and liver. Digestive enzymes are secreted almost throughout the digestive tract. Salivary enzymes such as lingual lipase and α-amylase initiate the breakdown of fat and carbohydrates in the mouths of young animals (e.g., calves) and omnivores (e.g., rats, pigs, and humans).The optimum pH for oral digestion is 6.7 (6.2-7.6). The gastric juice contains pepsinogen, HCI, and intrinsic factors. The pepsinogen enzyme is secreted by the stomach’s chief cell. Pepsinogen is converted to pepsin at acidic pH ranges of 2.0 to 3.5 and initiates the digestion of proteins in the stomach of monogastric animals. Also, the stomach’s parietal cells secrete HCI and intrinsic factors. Cyanocobalamin, is a synthetic form of vitamin B12 requires an intrinsic factor in ruminants to be absorbed. The abomasum of young ruminants secretes proteolytic enzymes such as rennin or chymosin. Rennin acts on milk at a pH of 6.5.

Introduction The main function of the respiratory system is to exchange O2 and CO2 between the atmosphere, blood, and cells, which are necessary for animal survival. The circulatory and respiratory systems work together to provide oxygen to cells while eliminating CO2. O2 consumption and CO2 production are determined by cell metabolic activity. Respiratory volumes or lung volumes refer to the volumes of gas in the lungs at any given point during the respiratory cycle. These volumes vary according to the animals’ physiological state, ambient factors, and health status. This is why; measurements of lung volumes are helpful in understanding the pathophysiology of the respiratory system.

Introduction The kidneys play a vital role in maintaining water and electrolyte balance (such as chloride, potassium, calcium, hydrogen, magnesium, and phosphate ions). It also regulates the acid-base balance of the blood, arterial blood pressure, and osmotic pressure of the nd water-soluble waste products, which are removed from the bloodstream by the kidneys and excreted as urine. Normally, the kidneys receive about 22% of the cardiac output. According to Arthur Cushny (1866-1926), there are three steps involved in urine formation in the nephrons: glomerular filtration, tubular reabsorption, and tubular secretion. When the kidneys are injured, their regulatory activities are disrupted, resulting in a change in the quality and quantity of urine. Urine is composed of the following components: This is the reason why a urine analysis is a common test to evaluate the pathophysiology of the urinary system in general and the kidneys in particular, as well as to aid in the differential diagnosis of certain diseases.

Introduction Endocrinology is the study of the endocrine system, which includes the glands and their secretions known as hormones. Hormones are essential for animal behaviour, growth and development, metabolism, lactation, reproduction, excretion, and reabsorption of inorganic ions. Therefore, if a certain hormone concentration in blood or another body fluid is detected, it provides the pathophysiology of the representative endocrine gland. Endocrine glands, the cells or tissues they govern, and the secretory substances (hormones) they produce are investigated using a number of methodologies. They are as follows: Surgical methods (e.g., hypophysectomy, gonadectomy, etc). Chemical ablation or impairment (e.g., alloxan or streptozotocin agents that selectively destroy the insulin-secreting beta-cell, etc). Hormone replacement therapy (e.g., estrogen during menopause to reduce the risk of bone fracture related to osteoporosis, etc). Immunological neutralization of hormone activity (e.g., contraception both male and female, injection of antibodies against NGF resulting in failure of sympathetic nervous system development, etc). Tissue extraction and purification (e.g., progestin is a synthetic hormone that mimics progesterone, etc.). Histological-cytological studies (e.g., employment of a battery of histological stains to characterize each pituitary cell, etc). Bioassays (e.g., oxytocin-induced contraction of rat uterine myometrial tissue strips, etc).

Introduction Reproduction is the biological process that results in the formation of new progeny or individual organisms. Male and female gametes unite to form a zygote, which develops or produces offspring.

Introduction Growth is the irreversible gain in body weight, size, length, and circumference. It is accomplished by two fundamental processes: hypertrophy (increase in tissue, cell volume and progressive accumulation of intercellular substances) and hyperplasia (growth as a result of cellular multiplication by mitotic division). Animal growth is influenced by both genetic and environmental factors. Animal body growth and weight gain play a critical role in reproductive performance. It also acts as one of the traits to evaluate the breeding value, optimize management & feeding practices, and prepare the correct dose of therapeutic pharmaceuticals to treat animal diseases. As a result, measurement of body growth is essential for the selection of superior germplasm, feeding & housing management, health care management, and optimizing other environmental conditions that have an impact on animal growth for an economically viable animal industry.

Introduction Climate change induces significant and long-lasting shifts in the statistical distribution of weather patterns over periods ranging from decades to million years. It is believed to be the cause of long-term temperature changes, changes in rainfall patterns and volume, prolonged summer seasons, increasing sea levels, and increased frequency and intensity of floods, droughts, and heat waves, etc. Animals are intimately and inseparately associated with their physiological and chemical environments from conception until death. As a result, climate change has an impact on animals both directly and indirectly. Since, animals have had to alter their behavioural and physiological mechanisms in order to maintain homeostasis. Climate change has emerged as a serious threat to the livestock industry. It reduces animal productivity by lowering growth, milk yield, meat production, egg production, wool production, reproductive performance, and health. About 20 to 30 percent of plant and animal species would likely be at risk of extinction with an increase of 1.5 to 2.5°C, which will result in severe consequences for food and nutritional security in developing countries. This is why; measurements of meteorological variables are needed for effective scientific management of livestock and poultry to cope with the negative impacts of climate change while enhancing growth and productivity.

Introduction Animal behaviour is the study of how animals interact with one another, other living things, and their environment. Animals display a variety of behaviours in response to both external stimulus and their own pathophysiological state. Almost all domestic animals express a variety of behavioural responses throughout their lifespan, like feeding, sexual behaviours, etc. But every species responds to the same stimuli in a different way. This is why; the study of animal behaviour helps in efficient breeding, feeding, and reproductive management. It also serves as a reliable indicator of overall health and well-being.

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