eChapters

Immunity

Immunity is the resistance of body against extraneous etiological factors of disease, which is afforded by the interaction of chemical, humoral and cellular reactions in body. This is an integral part of the body without, which one cannot think of life. During the process of evolution, nature has provided this defense mechanism in the bodies of all living creatures particularly of higher animals and man, that protects them from physical, chemical and biological threats. It can be classified as natural or paraspecific and acquired or specific immunity.

Natural/paraspecific immunity

There are some species which are resistant to particular diseases due to presence of natural resistance against them e.g. horse, pig, cat are resistant to canine distemper virus; dogs are resistant to feline panleucopenia virus, chickens are resistant to anthrax. Even within species, there is natural resistance that protects some individuals while others are susceptible e.g. Indian deshi cattle Zebu (Bos indicus) is quite resistant to piroplasmosis in comparison to Bos taurus. Besides, there are the mechanisms or barriers in body provided by nature.

Inflammation

Inflammation is a complex process of vascular and cellular alterations that occur in body in response to injury. The term inflammation has been derived from the Latin word inflammare, means to set on fire. Inflammation is considered as an important event in body that activates the existing defense mechanisms in circulating blood to dilute, naturalize or kill the irritant/ causative agent. Thus, it is said that immunity is the resistance of body, while inflammation is the activation of that immunity. It is beneficial to body except when chronic or immune origin. Inflammation starts with sublethal injury and ends with healing.

Etiology

• Any irritant/ injury.

• Bacteria, virus, parasite, fungus etc.

• Trauma. • Physical or chemical injury.

Necrosis

Local death of tissue /cells in living body is known as necrosis, It is characterized by the followings.

• Pyknosis is condensation of chromatin material, nuclei become dark, reduced in size and deeply stained.

• Karyorrhexis is fragmentation of nucleus.

• Karyolysis is dissolution of nucleus into small fragments, basophilic granules/fragments.

• Chromatolysis is lysis of chromatin material.

• Necrobiosis is physiological cell death after completion of its function e.g. RBC after 140 days.

Necrosis is further classified into coagulative, caseative, liquifactive and fat necrosis which are different from apoptosis (Figs. 5.1 to 5.3).

Cloudy Swelling

Swelling of cells occur with hazy appearance due to a mild injury. The cells take more water due to defect in sodium pump leading to swollen mitochondria which gives granular cytoplasmic appearance. It is the first reaction of cell to the mildest injury. Cloudy swelling is a reversible reaction (Figs. 4.1 & 4. 2).

Etiology

• Can be caused by even mildest injury.

• Any factor causing interference with metabolism of the cell like bacterial toxins, fever, diabetes, circulatory disturbances etc.

Macroscopic features

• Organ becomes enlarged and rounded.

• Weight of organ increases.

• Bulging on cut surfaces.

• Amount of fluid increases in organ.

Microscopic features

• Swelling of cells, edges become rounded.

• Increased size of cells.

• Cytoplasm of the cells becomes hazy/cloudy due to increased granularity.

• Can be seen in liver, kidney and muscles.

Congestion/ Hyperemia

Hyperemia is increased amount of blood in circulatory system. It is of two types, active and passive. In active hyperemia blood accumulates in arteries while in passive hyperemia the amount of blood increases in veins (Figs. 3.1. to 3.4).

Etiology

• As a result of inflammation.

• Obstruction of blood vessels.

Macroscopic features

• Organ becomes dark red/cyanotic.

• Size of organ increases.

Etiology

Etiology is the study of cause of disease. It gives precise causal diagnosis of any disease. Broadly, the cause of diseases can be divided into two

a. Intrinsic causes.

b. Extrinsic causes.

Intrinsic Causes

Those causes which determine the type of disease present within an individual over which he has no control. These causes are further divided into following subgroups:

Genus

Specific diseases occur in a particular genus or species of animals. e.g. Hog cholera in pigs, Canine distemper in dogs

Definitions

Pathology

Pathology is the study of the anatomical, chemical and physiological alterations from normal as a result of disease in animals. It is a key subject because it forms a vital bridge between preclinical sciences (Anatomy, Physiology, Biochemistry) and clinical branches of Medicine and Surgery (Fig.1.1). Pathology is derived from the Greek word pathos = disease, logos = study. It has many branches, which are defined as under:

General Pathology

General Pathology concerns with basic alterations of tissues as a result of disease. e.g. fatty changes, thrombosis, amyloidosis, embolism, necrosis (Fig. 1.2).

Systemic Pathology

Systemic Pathology deals with alterations in tissues/organs of a particular system. e.g. respiratory system, genital system etc. (Fig. 1.3).

Key Points

• Animal euthanasia is the act of humanely killing animals, most commonly with injectable drugs.

• Euthanasia techniques vary by species, age, and the health status of the individual animal.

• Death must be confirmed before disposal of any animal remains.

• Animal remains must be disposed of in a legal manner that does not contaminate food sources or the environment.

Introduction

Euthanasia is the act of inducing humane death in an animal by a method that induces rapid loss of consciousness and death with a minimum of pain, discomfort, or distress. Euthanizing agents cause death by three basic mechanisms: (1) direct depression of neurons necessary for life function, (2) hypoxia, and (3) physical disruption of brain activity. Because loss of consciousness resulting from these mechanisms can occur at different rates, the suitability of a particular agent or method will depend on whether an animal experiences distress before loss of consciousness. Unconsciousness, defined as a loss of individual awareness, occurs when the brain’s ability to integrate information is blocked or disrupted. Ideally, euthanasia techniques cause rapid loss of consciousness, followed by cardiac or respiratory arrest and death.

Key Points

• With the aid of microorganisms, ruminants typically use NPN to synthesis proteins for nutritional needs.

• When there is an excess of urea in the body, ammonia is produced excessively, which can be harmful.

• The majority of clinical indicators are neurological in nature, and their severity varies depending on a number of variables.

• Ruminal environment acidification to stop excessive ammonia generation and absorption; symptomatic therapy is advised.

Introduction

In addition to being a widely utilized fertilizer for crops, urea is frequently used in animal feeds as a low-cost protein substitute [1]. The previously mentioned explanations explain the reports of urea toxicity in ruminants. These animals may use non-protein nitrogen (NPN) like urea to create ammonia, which is subsequently used to synthesize proteins that partially meet their nutritional needs. This is made possible by the urease enzyme and ruminal microorganisms. On the other hand, rapid overconsumption of NPN leads to excessive ammonia generation and toxicity. This chapter aims to provide an overview of some of the most frequent causes of urea poisoning, clinical symptoms to watch out for, and associated treatments.

Key Points

• It might be necessary to administer oxygen or perform artificial respiration. Giving tranquilizers is not a good idea.

• Precaution: It's crucial to always follow the label's instructions on how to use pesticides since they provide information on how to do so. Warnings against using on unapproved species or in testing conditions must also be included on labels. A maximum of care should be made to prevent drift or drainage to neighboring fields, pastures, ponds, streams, or other properties outside the treatment area. In no case should amounts larger than those specifically recommended be utilized.

Introduction

It has been determined that a number of plant species are poisonous to animals. These plants not only posed a health risk to humans and animals, but they also significantly reduced cattle productivity. Many plants contain chemicals that can be dangerous or even lethal to animals. The degree of toxicity varies based on the animal species, the quantity of plant material ingested, and the particular poisonous compounds in question. In general, there are two categories of dangerous plants: those that are known to be toxic and contain toxic compounds, and those that are normally non-toxic but can turn hazardous in certain circumstances. Here are some typical plant toxicities, along with information on managing toxicity and clinical signs.

Key Points

• When pesticides, which are chemicals used to manage a pest, impact non-target organisms like humans and animals, it's known as pesticide poisoning.

• Pesticides have the ability to contaminate the surrounding area and the ecosystem.

Introduction

Pesticides are chemical chemicals that are applied to destroy pests. These insecticides have the capacity to contaminate the surrounding area and the ecosystem. Pesticides can also be hazardous to a wide range of other creatures, including fish, birds, beneficial insects, and non-target plants, in addition to having a toxic effect on insects and weeds.

Etiology

Today's society faces several issues due to the overuse of pesticides in fields and food. Products may deteriorate if they are kept in partially filled containers for extended periods of time or exposed, whether intentionally or unintentionally, to high temperatures. It is dangerous to store chemicals anywhere other than their original container since the identification and label instructions are lost. These products can have severe effects on people or animals if they come into unintended touch with them. It can be extremely risky to mix substances or use them in unapproved combinations. In order to increase the efficacy of certain pesticide formulations, such as pyrethrins, pyrethroids, and d-limonene, piperonyl butoxide is added. It lessens the chemical's breakdown in the body of the insect or animal, but it also increases the pesticide's toxicity to both the pest and the host animal.

Key Points

• It is frequently reported that metal, non-metal, and metalloid components cause toxicity in farm animals.

• The type of element causing toxicity affects both the treatment and the clinical indications of toxicity.

• The best course of action for managing toxicity is to treat symptoms f irst, then, if the causal toxin is known, use targeted antidotes.

Introduction

Animal diets contain a variety of environmental components, including metals and non-metals. Certain substances are necessary for the animal and only become poisonous when consumed in excess, while others simply endanger the animal's health. However, a number of variables, including the absorbed dose, the exposure route, the period of exposure (acute versus chronic), and others, affect how toxic the substance is, and these variables must be taken into account when diagnosing, treating, and managing clinical cases. Given the multitude of factors affecting these metals' toxicity. An attempt is made in this chapter to present a streamlined synopsis of the toxicity of metals, non-metals, and metalloid elements that are frequently encountered.

Key Points

• Dogs can be fed a wide variety of chocolate and cocoa-based goods, particularly during holiday seasons, such as candy, cakes, cookies, brownies, and chocolate chips.

• Dogs that eat chocolate usually become very sick, but they also seldom die from it.

Introduction

Caffeine and theobromine are found in chocolate. Dogs' metabolisms of caffeine and theobromine differ from humans'. Because they contain more theobromine and caffeine, darker, bitter chocolates are considered to be more dangerous.

When a dog consumes too much chocolate goods, it can lead to major health problems like seizures, heart failure, and muscular tremors. In extreme situations, the dog may even pass away from cardiac or respiratory failure. Due to the fat and sugar content, it induces vomiting and diarrhoea even in non-toxic doses. Numerous substances found in chocolate are hazardous to animals. Although chocolate poisoning can affect a wide variety of animal species, including dogs, cats, horses, and rodents, it most frequently affects dogs. Theobromine and caffeine are the main harmful ingredients in chocolate. The amount of caffeine and theobromine in chocolate varies with kind. Dogs' metabolism of theobromine and caffeine differs from that of humans. Dogs are more sensitive because of this. Dogs who consume chocolate may become seriously unwell, even though it rarely results in death. When a dog eats too many chocolate-containing foods, such as cakes, cookies, brownies, candies, and chocolate chips, it might become poisoned.

Key Points

• Drug poisonings can be acute or chronic and result in the development of clinical signs and symptoms that may lead to animal disability or death, as well as extreme physiological and/or psychological changes.

• Drugs are substances that are used to prevent, treat, diagnose, and relive disease conditions by changing the physiology and/or psychology of the individual.

• Certain veterinary drugs have a specific antidote to counteract poisoning cases, while other veterinary drugs do not, and supportive therapy is required to counter these poisonings.

• Over-the-counter (OTC) medications, which are defined as human drugs or nutritional supplements that are available without a prescription, have potential risks for use in animals due to their increased toxicity.

Introduction

Many veterinary medications, which are used to treat both animals and birds, have the potential to poison the species to whom they are provided. These medications' toxic effects are mostly caused by giving them to the wrong species, at the wrong doses, or in the wrong combinations of medications. Certain medication poisonings can be identified due to patient individuality and eccentricities. As a result, there are many cases of these poisonings. This chapter discusses the poisoning caused by frequently and carelessly used veterinary medications, such as the toxicity of antibiotics and antibacterials, the toxicity of antiparasitic drugs, the toxicology of analgesics, the toxicity of cough treatments, the toxicity of the digestive system, the toxicity of vitamins, and the toxicity of topical preparations.

Key Points

• Electrolyte Imbalance: Regularly monitor and rectify imbalances in potassium, sodium, and other electrolytes dependent on the individual situation. Prompt management requires early detection of metabolic emergencies.

• Fluid Management: To restore intravascular volume and prevent dehydration in many metabolic emergencies, adequate fluid replacement is essential.

• Continuous monitoring of vital signs, laboratory values, and clinical status is essential for evaluating the efficacy of interventions and making necessary modifications.

Introduction

A class of disorders known as "metabolic emergencies" affect metabolism and physiology abnormally in both congenital and acquired forms. Among these ailments are endocrine disorders, thyrotoxicosis, inborn metabolic inefficiencies, and illnesses linked to electrolyte imbalances. Hypercalcemia, hyponatremia, hypoglycemia, hyperglycemia, and diabetic ketoacidosis, as well as hyperuricemia, hyperuremia, and hypercreatininemia due to renal failure, lactic acidosis, hyperammoniemia, and adrenal failure, are metabolic emergencies that pose a life-threatening risk.

Key Points

• The most commonly cystitis and pyelonephritis occurs in farm and companion animals after parturition.

• Hematuria, pyuria, and stranguria are common presenting clinical symptoms;

• In acute situations, a prolonged course of treatment (two to four weeks) with the administration of the proper antimicrobials is usually successful.

Introduction

Both farm animals and companion animals frequently suffer from urinary infections, which are difficult to diagnose. In cows, urine testing is more helpful in excluding the illness if it shows any pus or germs (in females), and f inding the urethral calculus that is causing the urinary obstruction can be done by palpating the bladder using a rectum examination and palpating the urethral tube (in males). Because of the shorter urethra in females and the associated uterine infection that occurs during or after parturition, females are more likely to get urinary tract infections.

Key Points

• Dogs exhibit respiratory distress symptoms more frequently than cats.

• Respiratory distress might have overt or covert clinical symptoms.

• The thorax and belly move paradoxically in cases of severe respiratory distress.

• Immediate intubation is the first step in managing a respiratory emergency: opening the airway.

Introduction

The telltale symptoms of "oxygen hunger" include tachypnea, stretched head and neck, abducted elbows, flare of the nares, cyanosis, open-mouth breathing, anxiety, and inability to lie down or relax. It is more usual for dogs than cats to exhibit symptoms of respiratory distress. Tachypnea and conspicuous breathing motions when in a sternal recumbency position are the only indications of respiratory dysfunction in cats, who often mask the severity of their illness. Despite their seeming stability, these patients are often extremely vulnerable and can rapidly decompensate when under stress.

Key Points

• The main objective of managing open fractures is to neutralize further damage to the surrounding tissue while executing prompt, stable osteosynthesis and immobilization.

• Discomfort management should be considered because musculoskeletal diseases can cause severe discomfort.

Degenerative Myopathies

It is a degenerative disease of the musculature. Endocrine imbalances (hyperadrenocorticism, hypothyroidism, and hyperthyroidism), hypokalemia in cats, ischemic myonecrosis in recumbent cattle, post-exercise rhabdomyolysis, chemical agents, poisonous plants, and drug-induced degenerative conditions are some of the possible associations with it.

Key Points

• In diary animals, the health of the mammary gland (udder) is paramount.

• Any udder or teat disease state has a direct impact on milk output.

• Common udder/teet affections include: abscess, mammary gland hematomas, udder cleft dermatitis, udder edema, intramammary hemorrhage, teat damage, ulcerative mammillitis, udder dermatitis, and more.

Introduction

Mammary gland (udder) health is a crucial factor in animals used for production. The state of the udder determines the dairy industry's economics. The output of dairy animals is directly impacted by any udder ailment. Due to selection, breeding, genetic engineering, and animal management, animals under production pressure are more susceptible to a variety of diseases. More safety measures should be implemented in order to shield the udder from illness-causing factors. The many udder and teat affections and their therapeutic management are briefly discussed in this chapter.

Key Points

• Dystocia, uterine prolapse, obstetrics, and torsion of the uterus are among the common obstetrical issues in dairy animals.

• These reproductive abnormalities cause dairy farmers to suffer significant f inancial losses.

Introduction

Every instance of obstetrical complications needs to be handled right away. Along with taking the case history, a general clinical assessment and examination should be performed. Dystocia is one of the various obstetrical problems that is more common in cattle.