eChapters

A bioassay, also known as a biological assay, is a scientific experiment used to quantify the impact of a substance on a living organism. According to Finney (1952), bioassay is defined as measurement of potency of any stimulus (physical, chemical, biological, physiological) by means of reactions which it produces in living matter. It is an essential procedure in insecticide development and the assessment of environmental pollutants, as well as the evaluation of the effects of interventions viz. pesticides and herbicides on the environment. In the field of biostatistics, a bioassay refers to a set of techniques used to determine the quantity or intensity of an agent or stimulus based on the response of the subject. Typically, many methods are employed to assess the strength or effectiveness of an insecticide by examining its impact on living organisms.

An insecticide is a pesticide used to kill or eliminate insect pests in agriculture, households, and industries. Judicious use of insecticides may be a factor in the increase of agricultural productivity, but by their nature of having high toxicity to non target organisms and capability to develop resistance through widespread use, most insecticides have high potential to significantly affect and alter ecosystems. Many are toxic to humans and animals (both domestic and wildlife), and can accumulate as concentrates in the food chain and water resources, giving rise to serious environmental contamination and pollution.

History of Chemical Control, Insecticide Toxicology and Properties

History of pest control probably started when the first person swatted a mosquito or pulled off a tick, the battle for the control of our planet didn’t start until organized agriculture, when pests attacked the plants, and we grew to eat and threatened our very survival.

A pesticide is any substance or mixture of substances used to stop, kill, avoid, or lessen the effects of a pest (insects, mites, nematodes, weeds, rats, etc.). This includes insecticide, herbicide, fungicide, and many other substances used to control pests. Pesticide was defined in different ways at different times and in different places. But pesticide is still generally the same: it is a (mixed) substance that is poisonous and effective on target organisms but safe for non-target organisms and environments.

Chemical control, commonly known as pest control, is the use of chemicals to reduce insect populations. Herbicides, fungicides, insecticides, rodenticides, acaricides, nematodes, and fungicides are all examples of pesticides. Insecticides are a class of chemicals used to combat insect pests. A substance or combination of compounds used to kill, repel, or otherwise prevent insects is called an insecticide. When it comes to controlling pests, insecticides are most powerful tools available for management. They have a wide range of positive effects, including high efficiency, speed of healing, general applicability, adaptability to different settings, adaptability to shifting agronomic and ecological conditions, and low cost. When insect pest numbers approach or surpass the economic threshold, insecticides are the sole viable instrument for emergency action in pest management. The usage of pesticides, a widely used method, can be central to such a system. The use of chemical pesticides will remain pivotal in these initiatives. In many cases, chemical control of pests is the best option available. Some people’s view of pesticide use for pest management as an ecological sin is incorrect. Chemical pesticides are a reliable and useful tool for the biologist, so long as they are used in accordance with good ecological principles.

Mercury, a heavy metal, is present vi. Various forms and is well known for its toxic effects especially on human health. Mercury occurs naturally vin the environment through volcanic eruptions, weathering of rocks and forest fires. It can be observed in soil, water and the atmosphere. Human activities such as mining, industrial processes (eg. Coal Combustion, chor alkali production) and improper disposal of mercury containing products contribute to environmental contamination. Mercury can be absorbed through inhalation ingestion or skin contact. Once absorbed, mercury distributes throughout the body, crossing g the blood brain barrier and placenta. Inorganic mercury is partly metabolized to organic forms, such as methyl mercury, by micro organisms in environment. Mercury is excreted via Urine and feces. Mercury disrupts neuronal function by interfering with neurotransmitter signalling pathways, cognitive function, motor coordination and sensory perception Mercury accumulates in the kidneys, causing tubular necrosis. Proteinuria and renal failure. Clinical signs and symptoms are tremors memory loss, nausea, vomiting, hypertension and chest pain. Diagnosis is based on medical history, physical examination, blood, Urine, hair tests and neuro imaging techniques namely MRI or CT scans. Treatment is based on chelation therapy. Finally it is concluded that understanding the sources, toxico kinetics, toxico dynamics clinical manifestations and treatment options is critical for effective management and prevention of mercury toxicity.

An auricle (pinna) and ear canal (external auditory meatus) of external ear play an important rolein the process of hearing. The main function if external ear is to collect vsound waves and divert them towards the middle and inner ear. The external ear I'd prone to different conditions along with inflammation, infections and other disorders. Common conditions of the external ear include otitis external, Carmen impaction. Contact dermatitis, external otitis media. Antibiotics, antifungal, corticosteroids, ear wax softener, analgesics are useful in treating the disordersof external ear. Finally it is concluded that the function of drugs on the external ear is related to a variety of therapeutic approaches aimed atvalleviating symptoms, resolving infections and increasing healing.

Introduction

The external ear, comprising the auricle (pinna) and the ear canal (external auditory meatus), plays a vital role in the process of hearing. While its primary function is to gather sound waves and direct them towards the middle and inner ear, the external ear is also susceptible to various conditions, including infections, inflammations, and other disorders. In such cases, medications are often employed to alleviate symptoms and treat underlying issues. Understanding how drugs interact with the external ear can shed light on their therapeutic mechanisms and potential side effects.

Copper is an important mineral needed fir many physiological activities especially in the human body along with the formation of red blood cells, maintenance of nerve cells and support of the immune system. Whatever it may be, like various substances copper also exhibits toxicity if present in an excessive amounts. Thus article provides an information regarding the intricacies of copper toxicity, exploring it's sources, toxico dynamics, toxico kinetics. Clinical conditions, diagnosis as well as treatment. Copper intoxication can happen through many sources such as environmental as well as occupational. Common sources are contaminated water, dietary sources, occupational exposure as well as medications. Particularly after an ingestion, an absorption of copper takes place essentially in the stomach as well as smart intestine. Now the transportation of copper happens in the blood stream, mostly in bound to ceruloplasmin, a copper _ carrying protein. An elimination of copper occurs primarily through bile secretion into the feces along with a smaller part excreted especially vin Urine. Whatever it may be, in cases of overload, an accumulation of copper takes place in tissues namely the brain, liver and kidneys, resulting in toxicity. Copper toxicity results in the formation of reactive oxygen species ( ROS ), which cause oxidative damage to cellular to cellular structures namely lipids, proteins as well as DNA. Clinical signs and symptoms include gastro intestinal portion, neurological conditions, hepatic abnormalities, hemolytic anemia as well as renal impairment. Lesions of copper toxicity are hepatic lesions, hepatic cellular necrosis, inflammation as well as fibrosis, copper accumulation, biliary changes, neurological lesions, neuronal degeneration, gliosis, de myelination, renal lesions, tubular damage, interstitial inflammation as well as vascular changes

Cadmium, a roxic heavy metal, poses risk in a significant manner especially to human health and the environment. It's wide spread industrial use and presence in various products make exposure a concern particularly for both environmental and occupational settings. Understanding the source, toxico dynamics, toxico kinetics, clinical manifestations, diagnosis as well as treatment of cadmium poisoning is critical in mitigating it's adverse effects especially on human health. Cadmium gains an entry into the environment through natural processes namely volcanic activity as well as weathering of rocks. Whatever it may be, human activities along with mining, smelting, refining of metals and manufacturing of batteries, plastics as well as pigments, are major contributors to cadmium release especially into the environment. Additionally, cadmium is seen in tobacco smoke, resulting in exposure among smokers as well as passive smokers. Once released into the environment, cadmium gains entry into the human body through many routes such as inhalation, ingestion and dermal contact An inhalation of cadmium containing dust or fumes is a prominent route of exposure in an occupational settings especially in industries namely mining, smelting as well as welding. The consumption of contaminated water and food is another general route of exposure especially for the general population. After consumption, cadmium in essential manner accumulates especially in the kidneys as well as liver with a half life of approximately 10 - 30 years in the organs. It also accumulates particularly in bones, where it consists of half life of several decades.

Arsenic is a naturally occurring element that can be observed in various forms in the environment, including soil, water, and air. While arsenic has some industrial applications, it is also notorious for its toxicity to humans. Exposure to arsenic can happen through ingestion, inhalation, or skin contact, with ingestion being the most common route of exposure in cases of poisoning. Here, authors provide information regarding the source of arsenic intoxication, its toxicology kinetics and dynamics, clinical signs and symptoms, lesions, diagnosis, and treatment.

Introduction

In this article, authors provide information regarding source of intoxication also.

Source of Intoxication

Arsenic poisoning can lead to various sources, including:

Contaminated Water

Arsenic contamination of drinking water is a significant concern in many parts of the world, specifically in regions where natural geological formations consists of high levels of arsenic.

Aluminium is a ubiquitous metal and seen in an environment. Source of aluminium happens through dietary souce, food addivitives, packing materials, medications, environmental exposure as well as occupational exposure. Toxico kinetics is related to the interaction of aluminium with biological systems and toxicity also. Toxico dynamics of aluminium is related to the the oxidatve stress, neuro toxicity and bone toxicity. Diagnosis is based on MRI scan and measurement of serum as well as urine. Treatment is dependent on chelation therapy as well as avoidance of exposure. Finally it is concluded that aluminium toxicity leads to health risks in a significant manner along with potential adverse effects on neurological, gastro, intestinal, renal as well as skeletal systems.

Introduction

Aluminium is a ubiquitous metal observed naturally in the environment. It is widely used in various industrial and consumer products including cookware antacids, vaccines, and food additives. While aluminium is normally considered safe in low concentrations and exposure to high levels can lead to toxicity causing a range of adverse effects on human health. In this comprehensive article, authors will provide information regarding its toxicokinetics and toxicodynamics, clinical signs and symptoms, associated lesions, diagnosis and treatment strategies.

Understanding the Toxicity of Macrolide Endectocides

Introduction

Macrolide endectocides are a class of compounds widely used in veterinary medicine to combat internal and external parasites in livestock and companion animals. While these medications have proven to be effective in controlling parasites, there are concerns regarding their potential toxicity and adverse effects on animals and the environment.

Whar are Macrolide Endectocides

Macrolide endectocides belong to a group of compounds derived from naturally occurring macrolide antibiotics, such as avermectins and milbemycins. These compounds have broad-spectrum activity against various parasites, including nematodes, arthropods, and ectoparasites like ticks and mites. Some commonly used macrolide endectocides include ivermectin, doramectin, moxidectin, and eprinomectin.

Toxicity Concerns

While macrolide endectocides are generally safe and effective when used according to label instructions, there are instances where toxicity can occur. Factors influencing toxicity include:

Introduction

Phenothiazines are a class of drugs primarily used to treat psychiatric disorders such as schizophrenia, bipolar disorder, and severe anxiety. While they can be effective in managing these conditions, they also come with potential risks and toxic effects when not used properly. Understanding the toxicity of phenothiazines is essential for healthcare providers and patients alike to ensure safe usage and minimize adverse effects.

Mechanism of Action

Phenothiazines exert their therapeutic effects by blocking dopamine receptors in the brain, thereby altering neurotransmitter activity and reducing symptoms of psychosis. Additionally, they also block other receptors such as histamine and alpha-adrenergic receptors, contributing to their sedative and antiemetic properties.

Types of Phenothiazines

There arevarious phenothiazine derivatives available, including chlorpro mazine, fluphenazine, thioridazine, and promethazine, among others. Each may have slightly different pharmacological properties and side effect profiles, but they share common characteristics regarding toxicity.

Toxic Effects

Extra Pyramidal Symptoms (EPS)

One of the most well-known toxic effects of phenothiazines is the development of extrapyramidal symptoms, which include akathisia, parkinsonism, and tardive dyskinesia. These symptoms can range from mild discomfort to severe motor disturbances and can be particularly problematic with long-term use.

Introduction

Azoles, a class of organic compounds containing a five-membered nitrogen containing ring, have garnered significant attention in various fields, including agriculture, medicine, and industry. These compounds are renowned for their diverse applications, particularly as anti fungal agents in both human and veterinary medicine, as well as in agriculture for crop protection. Whatever it may be, alongside their efficacy, concerns have arisen regarding their potential toxicity and environmental impact.

The Role of Azoles

Azoles play a crucial role in combating fungal infections in humans and animals. They inhibit the synthesis of ergosterol, a vital component of fungal cell membranes, thereby disrupting fungal growth and proliferation. Additionally, azoles are used in agriculture to protect crops from fungal diseases, contributing to higher yields and improved food security.

Toxicological Concerns

While azoles have proven effective in controlling fungal infections, their use raises concerns due to potential adverse effects on human health and the environment. The toxicity of azoles stems from several factors, including their mode of action, chemical properties, and metabolic pathways.

There is no terminal of any kind of research, rather they presence a static snap of the gamut of ecological dynamics and functions.

The following scopes for future research

• To construct modelling on resilience, beyond agriculture like livestock f ishery, forestry.

• To create new Algorithm of prediction in ecological behaviour and dynamics

• Gender and economic factors in resilience study and analysis

• Ecological resilience in different agro climatic zones covering coastal ecosystem, Himalayan ecosystem red lateritic ecosystem etc

• Policy research in ensuring and intriguing ecological resilience as well as social resilience on the common platform of production behaviour

• Importance of ecological resilience in the perspective of climate change and global warming

7.1 Summary

Never ever in the annals of human civilization, the importance of ecological resilience has become so important and imperative as we are perceiving now. Both the need and greed of food economics have driven the resource bases of our ecosystem, to a dilapidated and fragile status. By 2050 the world’s population will touch close to 9.5 billion and we have to scale up our food production 60% more then what it is right now. In India by 2040, we have to cross 450 million tons of our targeted food production to keep rhythm with population growth. By 2035 we are going to cross the population of China. Understanding the cascade of risks for climate change, as well as the vulnerabilities to these risks, is key to frame ways to adapt. Reducing vulnerabilities is key to reducing the net impacts on food security and nutrition and also to reducing long-term effects. Increasing resilience of food security in the face of climate change calls for multiple interventions, from social protection to agricultural practices and risk management..

When population pressure is soaring up, the need to produce more food from less and less available land and water, the issues of ecological resilience are coming up more swashbuckling and humongous. The aftermath of green revolution has contributed to achievement in food security on one hand, the other hand water has been contaminated and depleted, soil has been eroded with a sharp decline of organic carbon. We are losing 15 tons of topsoil per hectare per year and inviting a disruptive agro-ecosystem, the syndrome of which are quite vivid and prominent.

6.1. Data Interpretation and Visualization of West Bengal

Any kind of production management system or decision-making process is being organised in social ecology. No variable cannot behave discrete or free without having any kind of influence as well as impact from the vary operating ecosystem. That is how it is imperative to know and visualize the basic features in terms of its distributive characters. The distribution of features in variables through this networking and interactions ultimately contribute to a holistic visualization of social ecologization under study.

Table 6.1.1 represents the distribution of variables in terms of range i.e. maximum and minimum values, mean, standard deviation and coefficient of variation for Terai Zone, Old Alluvial Zone and New Alluvial Zone of West Bengal.

The average age (x1) of the respondent stands at 49.02. It denotes that so far as responsibility of agriculture and age base livelihood runs at the population so far as the respondent under study is peaks are at the hands of farmers approaching or passing through old ages. On the contrary the absence of young population or withdrawal of young age farmers from agriculture have got a serious implecation near and far. The cv value runs at 25.78 per cent to indicate that the distribution of variable is highly consistant.

The average of functional education (x2) of the respondent stands at 8.20.The variable education charecterization the social ecology speaks that the most of the respondents are having mid level school education.So, this has got spil over effect on the function and operation of other variables i.e. precisely the perception variables.The cv value stands at 43.69 per cent that’s good enough to infer that the distribution of the variable is highly consistent.

5.1 Locale of Research

Based on the All-India assessment report regarding Climate Vulnerability Assessment for Adaptation Planning in India Using a Common Framework which identifies the most vulnerable states and districts in India with respect to current climate risk and the main drivers of vulnerability, the present study has been conducted in two relatively highly vulnerable states of India namely West Bengal (Vulnerability Indices:0.592) and Jharkhand (Vulnerability Indices: 0.674). It specifically comes under Agro-climatic zone III (Lower Gangetic plain region) and Agro-climatic zone VII (Eastern plateau and hilly region) respectively.

On the basis of Vulnerability Indices (Vis) different district of West Bengal classified into three categories i.e. relatively high vulnerability (0.59-0.69), moderate vulnerability (0.49 -0.59), and relatively low vulnerability (0.38- 0.49). Two districts, Malda (VIs:0.690) and Jalpaiguri (VIs:0.627) from highly vulnerable and three district Murshidabad (VIs:0.524), Dakshin Dinajpur (VIs:0.523) and Burdwan (VIs:0.497) from moderate vulnerable category were selected purposively for the present study. For satisfying the purposes three agroclimatic zones of the West Bengal, viz. Terai Zone (Jalpaigudi), Old Alluvial Zone (Murshidabad and Dakshin Dinajpur) and New Alluvial Zone (Burdwan) districts were taken into account for the assessment. Twenty respondents of two Villages from each Block i.e., Alipurduar-I of Jalpaigudi, Hilli and Gangarampur of Dakshin Dinajpur, Old Malda of Murshidabad and Barabani of East Burdwan were purposively picked for the research study.

In any social science research, it is hardly possible to conceptualize and perceive the data and interpret the data more accurately until and unless a clear understanding of the characteristics in the area and attitude or the behavior of people is at commend of the interpreter who intends to unveil an understanding of the implication and behavioral complexes of the individual who live in the area under reference and form a representative part of the larger community. The socio-demographic background of the local people in a rural setting has been critically administered in this section. A research setting is a surrounding in which input and elements of research are contextually imbibed, interactive and mutually contributive to the system performance. Research setting is immensely important in the sense because it is characterizing and influencing the interplays of different factors and components. Besides the investigators must also have the basic knowledge about the socio demographic background of the people so as to have an easy understanding of their knowledge, attitude and behavior.

Research setting refers to the detail information of an area where the study has been conducted. The study area, generally comprises of a particular geographical area viz. a state, district, block, or gram panchayat area selected according to the convenience of the investigator who possess adequate knowledge regarding the location, communication facility etc. of the locality so that he/she can easily approach each and every corner of the area for data collection. Here. in this study the data collection was done mostly over telephone based on the interview schedule due to Covid-19 pandemic situation.

3.1 Conceptual Framework

Aconceptual framework is an analytical tool that is used to get a comprehensive understanding of the study. It embodies the specific direction by which the research will have to be undertaken. It is generally constructed to provide the researcher the element ofattainable and researchable problems and ideas supported by methodology, design, prospective analysis and empirical conclusion. The conceptual framework is often called as the research paradigm.

The subject matter of the present research is Resilience and productivity of agriculture in different social-ecology: the farmers’ perception, status and interpretation. It is expected that the terminologies and concepts used to frame up the topic need to undergo brief explanation for the better understanding of its meaning.

Resilience: Resilience is about anticipating, planning and reducing disaster risk to effectively protect persons, communities and countries, their livelihoods, health, cultural heritage, socio-economic assets and ecosystems. The ideas of ‘bounce back’, ‘spring forward’ and ‘build back better’ are often used in the context of resilience.

Productivity: Productivity is commonly defined as a ratio between the output volume and the volume of inputs. It measures how efficiently production inputs, are being used in an economy to produce a given level of output.

Agriculture: The word agriculture derives from the Latin ager (field) and colo (cultivate) signifying, when combined, the Latin agricultura: field or land tillage. But the word has come to subsume a very wide spectrum of activities that are integral to agriculture and have their own descriptive terms, such as cultivation, domestication, horticulture, arboriculture, and vegeculture, as well as forms of livestock management such as mixed crop-livestock farming, pastoralism, and transhumance. The Oxford English Dictionary (1971) defines agriculture as “The science and art of cultivating the soil, including the allied pursuits of gathering in the crops and rearing livestock; tillage, husbandry, farming.”

This chapter is an extensive survey of all past studies relevant to the field of investigation which gives a knowledge of what others have found out in the related f ield of study. In any scientific investigation or research a comprehensive presentation of review of literature is a statutory requirement. Its main functions are to develop a better understanding of the problem to be investigated, delineate a new area of study and avoid unnecessary duplication, decide on the tools and techniques to be adopted including developing some new ones, also to relate the present study with the previous ones by finding out the areas of agreement and disagreement.

The review of literature of the present study is based on the major concepts related to the f ield of investigation. As direct references on all the item are not in abundance, certain specific references along with some indirect references have been incorporated in this chapter for the purpose of meaningful use.

Review of literature has been organized with a view to provide hard evidences as to clinically justify the reasons, logic, and contemplation leading to heuristically infer the different echelons of resilience issues.This is also catered to isolate the apparently less attempted genre of resilience study and analysis. Climate change, uncertainty, decline of soil organic carbon, fatigued genes on land, loss of biodiversity and fragile ecology of society have only been some of myriad of factors causing the loss of resilience, from ecology and from society as well.

1.1. Background

Once this beautiful planet conceived human civilization with the glory of motherhood, the birds kept on twittering in an ecstasy of joy and freedom; the ripples of pristine rivers, blue and giggling, offered shelter to silvery fishes and pink Amazon Lilies! But human greed has defeated its own needs. So, what had been a means to survive now has turned into tools to triumph, rather, a weapon to destroy her own creation. By this time, we have transformed fertile lands into a barren Arizona, deep forests into a nasty slums and blue rivers into a filthy stream, called Yamuna.

The advent of the Anthropocene, implies that an unprecedented era of human impact on the natural environment, is now so large that the Earth has entered a new geological epoch; it is leaving the Holocene, the environment within which human societies themselves have developed (Gornish and dos Santos, 2016; Reynolds, 2021). Climate change is a prominent sign of human- driven changes to the global environment. There is every reason to be alarmed about anthropogenic climate change, pollution, and biodiversity loss, all of which have been accelerating in recent decades and do pose “existential crisis” (Díaz et al., 2020; Abhilash et al., 2021). Sixth Assessment Report of Intergovernmental Panel on Climate Change (IPCC) released on February 28, 2022, paints a troubling picture as limiting global warming to 1.5oC (a global target in the Paris Climate Agreement) is not safe for all. If warming exceeds 1.5oC, even temporarily, much more severe, often irreversible effects of climate change will occur, land and ocean temperature change, sea level rise and ocean acidification, loss of Arctic Sea ice and ice sheets, stronger storms, longer heatwaves and droughts, abrupt precipitation mainly intensity and seasonal distribution, thawing permafrost and more (IPCC, 2013). On the basis of the Sixth Assessment UN Secretary-General António Guterres said “The alarm bells are deafening, and the evidence is irrefutable: greenhouse gas emissions from fossil fuel burning and deforestation are choking our planet and putting billions of people at immediate risk.” According to the United Nations (2015), there are still 836 million people in the world living in extreme poverty (less than USD,1.25/ day). And according to the International Fund for Agricultural Development (IFAD), at least 70% of the very poor live in rural areas, most of them depending partly or completely on agriculture for their livelihoods. It is estimated that 500 million smallholder farms in the developing world are supporting almost 2 billion people, and in Asia and sub-Saharan Africa these small farms produce about 80 percent of the food consumed (IFAD, 2011). The rural poor often depend partly on forests for their livelihoods (World Bank, 2002). It is estimated that between 660 and 820 million people (workers and their families) depend totally or partly on fisheries, aquaculture and related industries as a source of income and support (HLPE, 2014).

Veterinary ultrasonographer has to write report of ultrasonography in different animals. The proper ultrasound report writing is the moral duty of the vet ultrasonographer. The accuracy of diagnosis must be ensured. The poor resolution/quality of machine may lead to erroneous diagnosis. Therefore, veterinarian must ensure good quality of machine and proper diagnosis. The report might be different in different animals e.g. report writing about uterus will be different in bitch, cows, buffaloes, camel, horse, goat and sheep. However following might be guidelines in writing ultrasound report of uterus. fetus, endometrium

Uterus: Position of uterus, contents in the uterus, shape and size in initial pregnancy and infections, appearance of myometrium, thickening of uterine layers, presence or absence of fluied/pus/masses, left and right horns and their contents. Observations on the images of uterine fluid and its echoicity, membrane appearance in pregnant animals. Special attentions should be paid to endometrium.

Endometrium: Appearance and thickness; any growth on the surface of endometrium. Images of retained portion of placenta can be ascribed in the cases of retained placenta.

Ovary: Ovaries are scanned to assess cyclic structures, size, shape, its Position/ location and internal echo pattern of follicles. This echo pattern will indicate whether follicle is normal, cystic or with any other abnormalities of follclular f luid. Ultrasound reports also include shape and size of corpus luteum. In cows and buffaloes, presence of cavity, looseness/compactness of luteal cells are also mentioned.

Ultrasonography of the GI tract presents problems and challenges for the sonographer. Sonography of the GI viscera was once throught to be impossible because of artifacts created by gas within the lumen but with the technical advancement in the ultrasonography now the problem has been solved. If the animal is kept of feed and adlib water is given to the dog with I/v fluid than ultrasonography becomes helpful in the diagnosis of gastrointestinal tract disorders. Other conditions such as esophageal carcinomas can also been diagnosed by ultrasonographic endoscopy. in human beings.

The normal ultrasonography of the liver, kidney, stomach & spleen in dogs has been standardized and its use in evaluation of pathological lesions has been reported but ultrasonographic evaluation of oesophagus & intestine, both in normal animals and diseased conditions is yet to be established. Therefore normal ultrasonography of the oesophagus & small intestine in dogs and the importance of diagnostic capability of ultrasonography in diagnosis of pathology of these organs have been compiled.

Mammary glands are important part of body which synthesize and store the milk in between milkings or suckling by the calf. Therefore it attains prime importance in any dairy animal. However, it has received little attention in buffaloes till now. Buffalo presents several unique characteristics in terms of milk production, length and shape of teats and arrangement of duct system in the mammary glands. Development of udder may be related to milk production and the knowledge of changes in its structure in relation to different physiological stages may also have practical implication.

Transducer Selection and Preparation of Scanning

Preparation of the site to be imaged will enhance the quality of the image. Therefore, any loose hair and dirt must be clean off. Ultrasound gel is applied to the area of interest. The gel acts as a coupling agent to prevent air from trapping between the transducer and skin. A 7.5 MHz transducer is ideal for imaging the teats. A 5.0 MHz transducer provides an adequate image. The mammary gland should be scanned with a 5.0-7.5 MHz transducer to give adequate penetration. All structures should be scanned in cross section and longitudinal planes.

This paper primarily considers the general principles of ultrasound and instrumentation and its application in camel reproduction.

Ultrasound waves are mechanical pressure waves similar to audible sound waves and must have a medium in which to audible sound waves and must have a medium in which to propagate. The “frequency” (f) is the number of high- or low- pressure regions crossing each area of tissue each second. The frequencies of the sound waves used in medical ultrasound are much higher than the human audible range (20 to 16000 Hz); hence the waves are called ultrasound. Ultrasound instrumentation

The gray scale imaging equipment uses only time delay and echo amplitude information in creating the image. Most equipment contains the same basic building- block circuits; transmitter, receiver, display and scan converter.

Transmitter

The first circuit building block, the transmitter circuit produces either a high- amplitude, short- duration voltage shock pulse or a driving voltage waveform. Then an output control attenuates the amplitude of the shock pulse or the driving voltage wave form before it is applied to the transducer.

Corpus luteum, one of the biological clock of the estrous cycle and pregnancy, is known foremost for its production of progesterone that blocks the pituitary release of gonadotrophins and prepare the uterus for pregnancy. The ovarian follicle wall consists of granulosa cell and theca cells vascularised and luteinize after ovulation to from a corpus luteum. Corpus luteum is temporary steroid- producing gland undergoes marked structural and functional changes far a short time span during its development functional life and regression. During estrous cycle, the corpus luteum undergoes an initial period of growth (metestrus), followed by a period of maximal function (diestus) and finally by a period of regression (proestrus) preceding the next ovulation (Robert, 1986). The most prominent cell in the CL is the large luteal steroidogenic cell.

Ultrasound imaging has been used to detect and measure the corpus luteum throughout the estrous cycle and corpus luteum has been characterized during pregnancy and non pregnancy. Changes in corpus luteum diameter as detected by ultrasonography are highly correlated with progesterone production. A high correlation has been found in the ultrasonographic detection of bovine corpora lutea (Lean et al., 1992) and between luteal tissue area measured ultrasonographically and plasma progesterone concentration (Bergfelt et al., 1989).

Real time ultrasonography provides means to directly image the reproductive tract. An extensive amount of information can be gained from even a single examination, including determination of ovarian (luteal or follicle detection) and uterine status, detection and monitoring of ovarian and uterine pathology, monitoring the post-partum mare, detection of twins, prediction of ovulation, fetal growth and development and determination of sex of fetus. When first introduced the use of ultrasonography was primarily limited to early pregnancy diagnosis only, with advancement of knowledge and interpretive skills, the diagnostic ultrasonography has a much more application in reproduction. Some of the applications are discussed in this lecture.

Procedure

The procedure and precautions for intrarectal ultrasonographic examination are similar to those for rectal palpation, and no additional restraint is required. The transducer should be protected by the examiner’s hand to prevent trauma to the rectal wall, and the transducer should be well-lubricated. Care should be taken to avoid fecal material attaching to the transducer. After evacuating fecal material from the rectum, the probe is introduced and moved across the reproductive tract in the following pattern: uterine body, right uterine horn, right ovary, right uterine horn, uterine body, left uterine horn, left ovary, left uterine horn, uterine body then cervix. Good contact must exist between the transducer and rectal wall. Air in the rectum or a gas or fluid-filled loop of bowel will result in a distorted image. To minimize scanning errors, principally those of omission, it is recommended to conduct the same scanning procedure during each examination.

Ultrasonography in bull is helpful in diagnosis of problems of testis and accessory glands. This can also be used in assessment of development of these organs. Such developmental assessment, when combined with endocrine data, is useful to know age of puberty, sexual development and dimension of these organs. The ultrasonographic images and data are available for testis, bulbourethral gland, prostate and seminal vesicles in the bull. Ultrasonography of testis of bull can be useful to assess developmental changes, testicular dimensions and pathological conditions of the testis viz. tumors, lesions, abscess etc. Epididymis can also be examined for change in lumen, inflammation, granuloma etc. The accessory sex glands can be better viewed in ultrasonographic scanning to assess their dimensions, normal developmental changes and alterations in their morphology. Before, ultrasonography is undertaken, one should thoroughly revise the knowledge of sectional anatomy and location of these organs.

Testis

Location: The testis, in the bull, is located in the scrotum. In abnormal conditions, the testis might be retained in the inguinal canal or abdomen. Before, ultrasonography, location of the testis should be assured. For this, the testis should be palpated to assess their pliability and rule out adhesions with the scrotal wall. In normal condition, the testis should be freely movable in the scrotum, soft of palpation and both the testis should touch the bottom end of scrotum.

Ultrasonographic images of stomach are required to diagnose ingestion of any abanormal materials by dog. When content of stomach are dry or there is gas in stomach then, it is difficult to get proper image of stomach. Offering water to animal or oral administration of water with the help of syring is also helpful in getting the images of content of stomach. Some time, while doing ultrasonography, movement of contents of stomach can be visualized. Stomach can be images between liver and spleen. The size depends upon contents or intake of food by dog. For proper image of gastrointestinal tract including stomach, there should not be gas in GIT. One should remember that ultrasound beam does not travel in gas. The best medium of ultrasound beam is liquid.

Scanning Technique

If possible, fasting for 12 hours is good to diminish the amount of gastrointestinal gas. However, non-fasted dogs, when offered water may show adequate image quality. The water may be administered in quantity of 15 ml per kg of bodyweight. Removing the stomach gas using an orogastric tube has been recommended tto enhance the visualization of lesions of the stomach, however, this is not in practice in India.

The Liver

The liver is a large and an irregular organ of the body, which extends from the sixth to the eleventh intercostal space. It extends much more caudally on the right side as compared to the left side. Its most caudal part is the caudate lobe whose small portion is visualized encircling the right kidney dorsally at the eleventh intercostal space. The liver of a dog is divided into various lobes namely the left lateral, left medial, quadrate, right medial, right lateral and the caudate lobes which are not identifiable ultrasonographically, except when f luid is present in the abdomen. Otherwise, the position of the different liver lobes can only be approximated. The gallbladder is located to the right of the midline between the quadrate and the right medial lobes of the liver.

Proper preparation of the animal is important to obtain images of abdominal orgnas including that of liver. It is better to keep animal off fed for at east six hours prior to ultrasound scanning. This will avoid interference of gases and solid contents of the gastrointestinal tract. If stomach is taken as landmark of scanning then enough fluid should be given prior to scanning to get good images of stomach. The liver can be easily visualized on one side of stomach. One should be liberal in applying good amount of gel over transducer and body for better image of liver.

Introduction Ultrasonography is well-established technique in human sciences, particularly for diagnosis of pre-natal defects of fetus. In veterinary sciences, this technique is emerging an important tool. This tool is being employed in the small animal practices, particularly bitches for diagnosis of various reproductive disorders and estimation of gestational status. In the past, veterinarians had limited assistance for assessing reproductive status of this animal. Pregnancy diagnosis in a bitch was possible either with the use of X-rays or transabdominal palpation, but that too at an advanced stage of gestation. These methods could provide information either about presence of pups in vitro, or their number, but assessment of fetal viability was not accurately predicted with these traditional methods. With the use of X-rays, there was always risk of harmful effects on the health of mother and fetus. As far as reproductive disorders are concerned, most of them remained either undiagnosed due to the lack of proper access to the internal organs or were diagnosed with a guess. Diagnostic ultrasound is a valuable alternative imaging system that can provide more accurate information about the canine pregnancy and reproductive disorders in comparison to traditional methods.

Ultrasonography in sheep is becoming popular in the field of reproduction and replacing the other old-age techniques, viz. abdominal ballotment, recto- abdominal probes, X-rays and radioimmuno-assays. The reasons are numerous such as unsatisfactory results, hazardous effects to animal, operator or environment, high cost, long delay in diagnostic results and requirement of sophisticated labs. The ultrasound system has low operating cost and does not need special labs as it can be done at farm itself. Ultrasonography is considered safe to sheep and the operator and provides quick and reliable results. The popular opinion about ultrasonography is that it is noninvasive imaging system and is rapid, safe and practical means of diagnosis of pregnancy in sheep. The B-mode real time ultrasonographic system particularly portable system is popular among sheep breeders. In sheep, B-mode real time ultrasonography was used in 1971, using 5 MHz frequency transducer. A transducer of switchable frequency between 7.5 to 5.0 is more popular in sheep practice.

Transrectal Procedure in Sheep

The procedure is similar to goat, but sheep remain quite during transrectal ultrasonography than goat. Following are some of the steps to obtain good quality image:

Ultrasonography in goat is becoming popular in the field of reproduction and replacing the other old-age techniques, viz. abdominal ballotment, recto- abdominal probes, X-rays and radioimmuno-assays. The reasons are numerous such as unsatisfactory results, hazardous effects to animal, operator or environment, high cost, long delay in diagnostic results and requirement of sophisticated labs. The ultrasound system has low operating cost and does not need special labs as it can be done at farm itself. Ultrasonography is considered safe to the animal and the operator and provides quick and reliable results. The popular opinion about ultrasonography is that it is noninvasive imaging system and is rapid, safe and practical means of diagnosis of pregnancy and reproductive disorders in sheep and goat. The B-mode real time ultrasonographic system particularly portable system is popular among researcher and practitioners. In goat, B-mode real time ultrasonography was used in 1971, using 5 MHz frequency transducer. A transducer of switchable frequency from 7.5 to 5.0 is more popular in small ruminant research and practice.

The ultrasonography is based on echo-principal i.e. reflection of sound waves. The ultrasound waves, commonly termed as ultrasound beam is generated from the pizzo-electric crystals, under electric stimulation. The sound beam travels and strike to the organs/tissues on its way and get either reflected or reabsorbed by these structures. The reflected beam is received back by the transducer, which are processed and displayed on the monitor of ultrasound scanner. The display of signal is in form of shades of grey scale i.e. from bright to black picture. If these sound beams strike to organ such as bone, then major part of the beam is reflected and it appears bright (white) on screen. If the sound waves strike to fluid, these get absorbed and are not reflected back, therefore, the image of fluid appears as black on the screen. Other organs appear in between black and bright white. In fact, the reflected sound beam is not proportionate to frequency and velocity of emitted ultrasound beam. The strength of ultrasound beam (grey scale) or brightness of the image depends upon the acoustic impedance of organ or tissue. In simple term acoustic impedance is the capacity of tissue or organ to reflect or absorb these sound beams that again depends upon density or composition of these structures. The reflection of sound beams also depends upon, the angle at which the ultrasound beam strikes the structure on its way. The distance of the organ from the transducer also affects image brightness.

Diagnostic techniques are routinely used for diagnosing different surgical conditions. The most frequently used imaging techniques in veterinary practice are radiography and ultrasonography. Radiography and ultrasonography are not suitable for each organ in large animals. In small animals most organs are suited to ultrasound images except bones and gascontaining structures such as lungs etc. Bone and gas reflect ultrasound and do not allow the sound waves to form image therefore radiography gives better diagnostic images for these organs. The liver, spleen, kidneys, prostate, gravid uterus and fluid containing organs like urinary bladder, gall bladder and major blood vessels can be better imaged with ultrasound. In buffaloes in surgical section important clinical conditions relate to urinary and digestive systems, mammary gland and perineal area.

1. Urinary System: In bovine, the cases of obstructive urolithiasis are commonly observed. These types of cases are more common in bullocks and in buffalo calves. In these cases radiography is not so useful. Sonography can be tried to take the image of ruptured urethra in bullock and can be compared with radiography. Due to ruptured urethra there will be accumulation of urine in the s/c tissue of prepuce. Due to fluid density the image will be radioopaque and will appear white and no detail of the organ can be seen. The ultrasonogram (USG) will show images of glans penis and its coverings. Different diameters of urethra and a point of rupture just behind to glans penis can be make out. Due to obstruction, The B.calves either will pass drop wise urine or there will be complete stoppage of the urine. These cases can also be easily diagnosed by ultrasonography.

In Doppler imaging, the reflections are from circulatory vessels, while in 2D ultrasonic image the reflection is from a tissue(s) or organ(s) In 2D ultrasound strength of reflection in B-mode depends upon density of the organ.On other hand the reflection in Doppler imaging depends upon direction of the circulation. If circulaltion is coming towards transducer, the signal will be strong, while it looses its strength while flowing away from the transducer. As shown in the diagram, the position of transducer on curved surface decides the strength or amplitude of signal. If it is positioned on curve end from where circulation is coming, the signal will be of higher amplitude, but when position is changed to other end of curved surface, where circulation is going down the amplitude of signal will decrease accordingly and is shown in reverse direction.

Principle of Doppler

Movement of blood in vessels is detected, which is depicted by color in some ultrasound machines. The flow coming towards transducer is shown above baseline, while flow going down i.e. away from transducer is shown below baseline. If position of transducer is changed from where the arterial flow is going away from transducer then, the arterial flow will be shown below baseline and venous flow that is coming towards transducer will be shown above baseline. Some machine shows red and blue color of the flow. The red color shows flow coming towards and blue color shows flow going away from transcer. A beginner ultrasonographer may think that the red color is from artery and blue is from vein. This is not true, this shows direction of flow. Since ultrasonic image of flow in Doppler is formed from series of pulses returning from vessels, the magnitude of pulse changes with variation in flow. A stationary flow will not show any height of magnitude.

Ultrasonography has an importance place in human practice and veterinary f ield especially in canine practice. Since many years two dimensional ultrasound has been used for scanning purposes both in human and animal practice. But the scenario has changed in human practice with development of three dimensional technology and later four dimensional ultrasonography has developed which shows movements of the objects being scanned especially in the case of fetuses. Nowadays it has been common to use these advanced technology in the human practices. Yet these technologies are in the childhood stage in the veterinary field. High cost of 3D/4D ultrasound equipment, operational difficulties in non sedated animals & lack of specific knowledge about the operation of volume scanning hinder the use of this technology in the veterinary field. Better understanding of the different application of these technologies can be made to use in research areas for the better understanding of the abnormalities, post therapeutics as well in the diagnosis of the diseases

Principle of Three Dimensional and Four Dimensional Ultrasonography

Sound waves of frequency higher than human audible frequency usually ranges from 2-13 MHz are used in ultrasonography. Depending upon on depth of tissue from the scanning surfaces frequency is selected. Three dimensional ultrasonography gives three dimensional images of the volume being scanned .it works on the same principle of 2D ultrasonography but ultrasonographic beams are sent different angles to get three dimensional image of object being scanned. Volume information is obtained either directly using 2D array probe or by reconstructing three dimensional volume from a series of continuous or non- continuous 2D images by using software (Fenster and Downey, 2000). An advancement of 3D technology is 4D ultrasound. Four dimensional ultrasound adds the fourth dimension as time and gives a dynamic real-time 3Dultrasonography of the concerned organ with a continuous volume image acquisitioned rendering process. (Khurana and Dahiya, 2004).

Congenital anomaly of newborn buffalo calves is quite common in new born calves. Most common encountered are atresia ani, rectovaginal fistula etc. Sometimes, developmental defects interfere with physiological processes viz. in urination and defecation. Therefore, such cases, if not corrected well in time can cause death of the patient. In the present report, few newborn calves were brought to the veterinary clinic with the following abnormalities:

Agenesis of Urogenital System Without Anus

Five newborn buffalo calves were brought to the veterinary clinic with the complain of not passing urine and feces. There was no visible external genitalia and anal opening. At the site of vulva, there was only an impression of vulvar lips and below it, a cord like structure was hanging.

There was an impression of round structure below the skin; in some cases it was outside giving appearance of scrotum which was located in between the two thighs. On ventral side of abdomen, preputial sheath was not present, therefore, it was very difficult to decide about the sex of the calves and site of external preputial-orifice. There was an indication of both sexes, but organs were not developed, therefore it was difficult to decide about the sex of the calves. In some cases, impression of the anal sphincter was visible but there was no visible external anal opening. There was slight deviation of the tail from its base also. Intake of milk was normal. Abdomen was distended bilaterally. Respiratory rate was higher than the normal with slight discomfort .Heart rate was elevated. Blood picture revealed increased total blood cell count with neutrophilia. Radiography of the abdomen showed distended urinary bladder at the floor of pelvis indicating formation of the urogenital system without development of the external opening. Barium meal study revealed marking of gastrointestinal tract and stagnation of the barium up to the rectum.

Ultrasound is mainly used for reproductive purposes in bovine, now days it is also used for other applications. Ultrasound is an excellent tool for diagnostic imaging in large animals because it is portable, easy to use in the field, produces results at the time of the examination. It is totally non-invasive. Palpation of a gland can only detect certain levels of abnormality. Ultrasound can give an actual perception of mammary health, a picture of the inside anatomy and pathology. Tumors, scarring, stones, trauma, hematoma formation and level of damage due to mastitis can all be evaluated by this technique. Other diagnostic tools are still primary diagnostic tools, ultrasonogram gives yet another dimension to the hard to diagnose case. It will also allow a better estimate of treatment prognosis to aid in deciding whether to cull or treat a dairy animal.

Congenital anomalies at initial stages of the mammary gland development during gestation may result into presence of supernumerary teats or less number of external teats, in place of usual presence of four teats in buffaloes. Hence, cases with two / three / five or six teats are often encountered in the f ield.

The recent availability and use of ultrasonography in veterinary science has revolutionized the study of bovine reproduction. The information- gathering capabilities of this technology are much higher than those of conventional rectal palpation. Ultrasonic imaging has provided new insights into the complex biology of various reproductive processes such as folliculogenesis and early fetal development. With the pressure on agricultural land, due to ever increasing human population, the grazing grounds for animals are fast squeezing and as a result more and more animals are being stall-fed. This practice has adversely affected the availability of essential nutrients to the animals and their reproductive efficiency. The problem is graverin small states, where pressure on land is more to accommodate the expanding developmental and commercial activities of the national capital situated next door. The routine applications of ultrasonography include evaluation of animals for pregnancy, twinning, cyclic structures on ovaries, uterine and ovarian pathologies etc.

Failure to accurately diagnose ovarian function is said to be one of the reason for poor reproductive efficiency in this species. The information regarding ovarian function can be gathered either by observing the reproductive behavior of the animal, status of reproductive hormones or palpation of ovaries per rectum for the presence of cyclic or pathological structures. However, due to poor expression of estrus signs behavioral observations poorly reflect the accurate information about ovarian function in buffaloes. Similarly, palpation per rectum does not provide reliable diagnosis since the CL is frequently embedded deep in the ovarian stroma of buffalo ovary and findings vary due to its subjective nature. Furthermore, measurement of hormones requires sophisticated laboratory procedures/ instruments for making a correct diagnosis. Therefore, real time ultrasonic examination is a better alternative to ascertain reproductive status of buffaloes and for devising suitable strategies to optimize fertility of this species (Sharma, 2003). However, it is important to mention that information gained from ultrasound must be used in conjunction with reproductive history of the animal, palpation of genital tract, and other diagnostic procedures rather than in isolation.

General Instructions

The monitor of ultrasound machine should be placed at the eye-level. The daylight should not be too bright. The setting of the machine should be done to obtain best picture on the screen. There are various knobs on the machine to set contrast and brightness. There are three other knobs that are used to set near gain, far gain and overall gain. There is also a brightness bar (help-bar) on the screen with different brightness areas. These knobs should be turned clockwise or anti-clockwise, so that all the areas on the help bar (brightness bar) are visible.

Transrectal Procedure

In cattle, trans-rectal ultrasonography is done in a way, similar to rectal examination done for palpation of genital organs. Following steps are suggested for proper procedure

1. Properly restrain the animal.

2. Evacuate the feces from the rectum.

3. Select a transducer of proper frequency (the linear array transducer of 5.0 MHz frequency is useful for general purpose in bovines, however for detailed examination of early conceptus and small follicles, a transducer of 7.5 MHz can also be used. Some transducers have range of these frequencies in single-equipment. Such transducers of switch-able frequency are found more useful.

The affections of abdominal cavity incidence wise are on the top followed by thoracic cavity. Both these affections lead to high morbidity and heavy mortality losses. Most thoracic affections produce almost similar clinical signs but abdominal affections can show different clinical signs. Radiography and ultrasonography play an important role in differentiation and confirmation of various affections.

Radiography is an important diagnostic tool for both thoracic and abdominal diseases in small animals but for large animals it is more useful for thoracic affections as compared to abdominal affections. In large animals, the use of radiography is limited up to the ventral aspect of the abdomen only i.e. for diagnosis of diseases of reticulum, diaphragm and sternebrae. In thoracic cavity, there are numerous diseases that need to be differentiated. Pneumonia, lung cyst, lung abscesses, pleuritis and pleural effusions are some important diseases apart from presence of foreign bodies. In such a situation, radiography can play an important role as an aid in the diagnosis of various affections.

Similarly ultrasonography has also played a major role in the diagnosis of abdominal diseases in small animals such as dogs and newborn calves especially in the field of G I tract and urinary system. The ultrasonography is advantageous over radiography in the sense that internal anatomy of the soft organs can be better known and studied by ultrasonography as compared to radiography. It is also considered to be extremely safe for both the patient and the operator.

In order to evaluate the correct status of the organs their correct disposition within the body becomes very essential. Although one cannot see the organs beyond the skin, but appropriate knowledge of the topography of the organs can act as a glass covered watch wherein one can see from outside the arms and the dial of the watch.

Horse

Heart: The heart is placed in the middle mediastinum of the thoracic cavity with its long axis directed caudo-ventrally. Three fifth of the heart lies on the left of median plane while two fifth is on the right of the median plane. The base is placed dorsally, with its highest point at the junction of the dorsal and middle thirds of dorso-ventral diameter of the thorax. As a whole it lies opposite to second intercostal space/third rib to sixth rib/sixth intercostal space. The apex of the heart lies in the center of the last segment of the sternum about half inch from the sternal part of the diaphragm. Heart is directly related to the lateral thoracic wall at the cardiac notches formed in the lungs. The left surface of the heart extends from third to sixth rib in the lower third of chest while the right surface extends from third to fourth intercostal space.

Most of ultrasound machines are designed for imaging with a particular resolution linear and convex transducers. These machines can be used for general purpose for abdominal, obstetrics, gynecological, small parts, urology and cardiac applications. Most of the machines have standard measurement software viz. distance, area, volume, circumference, and obstetrical gestational age measurement for BPD, HC, AC, FL, GS, CRL, AD and FW.

Assessment of probes: One should examine the probe whether it is linear array or curved (convex) array. The probe should also be checked for its frequency. These days multi-frequency probes are supplied with the ultrasound-machine. These multiple frequencies could be 2.0 to 5.0 MHz with centrally fixed frequency of 3.5 MHz. The frequencies could be 4.0 to 7.0 (5.0 MHz setting), 5.0 to 9.0 MHz (7.5 MHz setting). The area and depth covered by various frequencies should be known.

Before setting the ultrasound machine, one should make sure of all the auxiliary devices for the machines. These are Thermal video printer, Ultrasound gel, Biopsy needle, image saving devices (USB device or internal saving mechanism), wire, Uninterrupted Power Supply etc.

Identifying and knowing the main system: One should note down the name and model of ultrasound machine as these are quoted in all the documents published with the ultrascan images generated on that particular machine. It is written on one side of front panel. On the front panel, there are various knobs for proper setting. One should locate the auxiliary power switch of the machine to begin with. Generally, there is power indicator on the machine that shows light on when power button is pushed to on position. The auxiliary power switch may also have indications of its ON and OFF positions, may be marked with 0 and 1 or other symbols. As shown in the figure below, there are various operating buttons on the operating panel. These might vary from Machine to Machine.

Ultrasonography is the process of obtaining images of an area, organ or tissue with the help of ultrasound beam that can be displayed on a screen. Such images can be recorded on videocassettes or printed on a thermal paper. Ultrasonography in veterinary practice is a revolutionary step for diagnosis of various ailments and to assess normal physiological functions of the body organs of domestic animals. Ultrasonography is considered a wonderful tool particularly for the study of reproductive functions viz. follicular dynamics, pregnancy diagnosis and abnormalities of contents of tubular tract. In 1980, Palmer and Driancourt reported for the first time, real time ultrasonography for diagnosis of pregnancy in the mare. This report generated considerable interest among veterinarians and scientists about ultrasonography and this new discovery contributed significantly towards understanding of functioning of the uterus and ovaries of mare (Chevalier and Palmer, 1982; Ginther, 1983; Ginther and Pierson, 1984a & 1984b), cows (Pierson and Ginther, 1988, Reeves et al., 1984) and other species (Buckrell, 1988; Driancourt, 1991). The ultrasonography is fast replacing the age-old procedure of rectal palpation of genital tract for pregnancy diagnosis (Pieterse et al., 1990). This technique has been used and advocated for the use in the academics and field practice.

Ultrasound is important tool for diagnosis and research that can be compared with other tools like radio-immunoassays. This has become an important tool applicable to farm and pet animals. Ultrasound uses high-frequency sound waves to produce images of soft tissues and internal organs. Electric current is applied to crystals in the transducer, producing vibrations characteristic of the crystals and resulting in sound waves. The sound beams that pass through the tissues are quite thin and a thin “slice” of tissue is sampled. The two dimensional image produced by ultrasound resemble to histological section. The sound waves are propagated or reflected by various tissues in different ways depending on their thickness and composition. The transducer receives those reflections and converts into electric signals and produces an echo on the ultrasound screen. Grey - scale is the term used for monochrome monitors on which a number of grey shades are distinguishable between black and white and constitute the image of reflected portion of tissue. Non-ecogenic (non echoic) tissues like fluids do not reflect sound waves and appear black on the screen. The echogenic tissues, having dense consistency, appear white as they reflect most portion of sound beam. Sometimes the artifacts create problem in the real image of the organ. These artifacts are created by certain tissues that cause bending or back and forth bouncing or blocking of sound beams. For imaging the reproductive tract of the domestic animals, B-mode (brightness modality), real time scanners are used. The amplitude of returning beams is reflected in the brightness of the dots on the screen. B-mode modulates brightness of the dots or pixels on the screen of echo displayer. The echo signals are presented as brightness of pixel corresponding to the amplitude of signal. The picture should be adjusted for clear display. In B-mode display the time-base brightness should be reduced just below the threshold of visibility so that even the smallest echoes could be visible.