eChapters

Introduction

Ideal plant health and productivity of a cropping system depends on an adequate amount of plant nutrients. Fertility of the soil refers to its capacity to support the production of crops. A productive fertile soil can support optimal plant growth, seed germination to plant maturity by providing adequate soil volume for plant root development, essential plant nutrients to meet the nutritional requirements of the plants, and encourage for the consequent plant structure. These attributes of the soil can be distinguished as inherent or dynamic soil quality indicators.Optimum plant health and productivity of a cropping system depends on an adequate supply of plant nutrients. The quantity of nutrients required by plants varies depending on many interacting factors including:

• Agronomic effects

• Soil properties

• Climatic condition

• Management practices

Introduction

Microbial diversity is one of the main factors characterizing natural ecosystems; soil is considered one of the best storehouses of useful microorganisms in the world. Although the role of most of these microorganisms is still unknown, scientific progress is providing a better comprehension of the specific ecological functions of soil microorganisms (Ahmad, I.et al., 2008). Microorganisms in the rhizosphere soil play a key role in maintaining the soil fertility (Yadav et al. 2015), which is key for successful natural crop production to meet the increasing global organic food demand. Soil acts as a reservoir of air, water, and nutrients that is essential for plant growth. Only a few grams of soil contain hundred million to billion microorganisms. Bacteria are the most abundant microbes in soil followed by fungi; however, the actinomycetes are ranges in between bacteria and fungi. Other microbes that are found in smaller numbers are algae, cyanobacteria, protozoa, and nematodes. Soil gives the necessary support for anchorage to plant roots (Yadav et al. 2012; Bhaduri et al. 2015).

Introduction

Rice straw is produced as a by-product of rice production at harvest. Agricultural Waste Burning (AWB) is a major contributor of air pollution in many countries, particularly in South Asia. Exposure to fine particulate matter less than 2.5 μm (micrometer), also known as PM 2.5, released by AWB can cause premature mortality due to respiratory and cardiovascular diseases (Brauer et al.,2012). Combine Harvesters used on the spring rice crop leave behind stubble and straw on the field (Sidhu et al., 2007). Farmers burn the rice residue while preparing the field for wheat sowing season that follows. Further, migrant labour from neighbouring states of Bihar and Uttar Pradesh has decreased (Sirhindi, 2019), and resulted in an increase in the cost of agricultural labour during the rice harvest season (Sharma,2018). Farmers find it both convenient and economical to burn residue to clear and prepare their fields for the next crop. In 2018, over 20 million metric tons of rice residue was generated in Punjab, of which almost 10 million metric tons was subject to open-air burning (MoA, 2019). The time window between rice harvesting and wheat sowing is just 20 to 30 days towards the conclusion of the Kharif season, which is one of the primary reasons of crop waste burning (Balwinder et al., 2016).

Introduction

Soil organic matter is an indispensible component of soil health management. It plays an important role in improving soil physical, chemical and biological environment. Soil health refers to the capacity of the soil in terms of physical, chemical and biological properties for maintaining ecosystem services. With respect to agricultural lands, soil health implies the capability of the soil towards improving crop growth and yield, while also supporting environmental sustainability. Some important determining properties of soil health maintenance are soil reaction, salinity or alkalinity, soil organic matter, soil texture, soil structure/aggregation, water holding capacity, porosity, internal drainage, and nutrient retention capacity. Simultaneously, the key properties maneuvering soil health are soil aeration, internal drainage, nutrient cycling, susceptibility to erosion etc. Except some of the basic properties (soil texture) and processes (soil erosion), most of the determinant properties and processes are maneuvered by the presence of soil organic matter. A healthy soil must have strong resistance to degradation processes and able to recover following a perturbation because of inherent resilience (Magdoff 2001).

Introduction

Productivity has increased as a result of the significant industrialization that has occurred in India during the past 40 years. However, it has also had detrimental effects on the ecology, particularly in India where soil contamination is progressively becoming more severe. In addition to the effects of man and land use, soil is constantly adapting changes in environmental conditions. A characteristic of soil pollution is the decrease in soil productivity brought on by the presence of soil pollutants. Some changes in the soil will be temporary and reversible, while others will be permanent. Pollutants in the soil have a negative impact on the physical, chemical, and biological characteristics of the soil and decrease its production. Soil pollution is a result of a variety of factors, including pesticides, fertilizers, organic manure, chemicals, radioactive waste, abandoned food, clothing, leather goods, plastics, paper, bottles, tins, and corpses. Industrial waste contains chemicals including iron, lead, mercury, copper, zinc, cadmium, aluminum, cyanides, acids, and alkalis, among others, which either directly or indirectly enter the soil.

Introduction

Climate change is threatening food security globally. Countries like India are more vulnerable in view of the tropical monsoon climate and poor coping capacity of the small and marginal farmers. Several agricultural practices like indiscriminate use of agro-chemicals and crop residue burning contribute to emission of greenhouse gasses leading to warming of the atmosphere. Sequestration of carbon both in the vegetation and soil is the most effective means of mitigating GHG emissions. There are several strategies of soil carbon sequestration which can be adopted at farm level. These include: conservation agriculture, biomass recycling, crop rotations and use of organic amendments. One of the recent developments is the conversion of crop residue biomass into biochar and using the char as a soil amendment rather than directly using the crop residues. Several studies show that biochar has a long life in soil and is more effective in sequestering carbon besides improving other soil properties like water holding capacity and nutrient availability. In Indian conditions, there is an immense scope for converting millions of tonnes of crop residues which are not used as fodder into biochar and use the same for enriching soil carbon.

The capacity of soil to function as a vital living system, within ecosystem and land use boundaries, to sustain plant and animal production, maintain or 

enhance water and air quality, and promote plant and animal health (Doran and

Zeiss, 2000). A healthy soil may function is as follows:

• Sustain biological activity, diversity, and productivity

• Regulate, store of nutrients and cycle water and, decompose organic

matter

• Filtering and buffering, degrading, mineralizing, immobilizing, and

detoxifying organic and inorganic materials

• Inactivate toxic compounds, suppress pathogens, protect water quality,

and enhance catchment soil health.

1.1 Perspective

From the very dawn of evolution of human beings, man has been using plants as food, for wellness and as medicine to alleviate diseases and discomfort. People living in different parts of the world, both new and old, in the centres of some of the oldest civilizations, had selected organisms from time immemorial for food and medicine by a process of trial and error or even by experimentation with the biological resources, particularly among the plants growing around them. These have been referred to as ethnic food/traditional food and ethnic medicine/traditional medicine. India is one of the mega centres of biodiversity, and that of the ethnic diversity, that evolved over millennia with settlement of diverse races coming from different regions of the world, besides the indigenous people. Thereby, it inhabits some of the most diverse cultural traditions. This process has led to further evolution of some of the oldest indigenous civilizations originated in the Indian Subcontinent with amalgamation of exotic traditions and the knowledge. Integration of the knowledge associated with the use of plants with medicinal properties has enriched its great heritage of medicinal plant use, the Ayurveda, i.e., the knowledge of life and longevity, dating back to the pre-historic and the early Vedic period.

2.1 Introduction

India is known for its richness in bio-resources including floristic diversity and the associated cultural diversity that evolved over time and holds a vast amount of indigenous traditional knowledge (ITK) assembled over millenniums. The ability to convert this knowledge into wealth of products for social good through the process of innovation based on validation of available information holds great promise. In-depth studies using the modern technologies and further examination of potential sources will determine the future of India in the 21st century, commonly referred to as the century of scientific knowledge and technological expertise/advancements that belongs to Asia/India. In this regard, five technologies namely, biochemistry, biotechnology, herbal technology, information technology, and nanotechnology are going to be the most powerful elements that are crucial for ensuring prosperity, security, and welfare of the people of the nations and the globe at large. Production of an inventory of the medicinal aromatic plants with the associated knowledge evolved and documented over millenniums under different Indian traditional medicinal systems shall be the key in promoting and strengthening their exploitation and use under various herbal medicinal systems and/or under an integrated innovative combination of these with modern medicinal systems.

3.1 Introduction

India is rich in biological diversity as revealed by its floristic diversity comprising 17,926 species of angiosperm, based on which it has been considered one among the 17 mega-biodiverse countries of the world. Also, it is the centre of some of the oldest civilizations of world, starting with Vedic civilization. Using modern day scientific tools and technology backed up with shashtra pramaana, Vedic civilization has been calculated to be as old as 25000 years (Oak, 2018). Because of its rich ecological and biological diversity, Indian Subcontinent has inhabited a large amount of ethnic diversity, consisting of both the indigenous races and those moved from other parts of the world as settlers looking for greener pastures for better living. The major ethnic races are Caucasoid (Aryan), Dravidians, Mongoloid, Negroid, and Australoid. Anthropological Survey of India has identified 461 tribal communities (Xaxa, 1999), belonging to 227 ethnic groups (Pushpangadan et al., 2018) spread over 5000 forest villages. According to the 2001 census of India, the country has 122 major languages and 1599 other languages. Figures from different sources vary, primarily due to differences in definition of the term’s “language” and “dialect”. The largest of the language families represented, in terms of speakers, is the Indo-Aryan language family followed by the Dravidian language family.

4.1 Introduction

The adverse effect of non-vegetarian diet, particularly red meat, on human health and on environment due to destruction/clearing of forest for raising more pasture and to increase the industrial production of grains for animal feed have led to greater greenhouse gas emissions, and environmental pollution due to extensive use of inorganic fertilizers, fungicides, pesticides. Clearing of forest has also caused extinction of plant species. For these reasons, greater interest has been generated in vegetarian diet based on the direct consumption of whole grains, legumes, nuts, fruits, and vegetables that are easily assimilated by the human body, nutritionally more efficient, and have least impact on the environment. In fact, the healthfulness of vegetarian diets has been found to be strongly correlated with sustainability of agriculture because of easy affordability of plant-based foods. Vegetarian people have been often referred to as vegan and pescatarian (including fish and other seafood). Most pescatarians include dairy and eggs as well. Similarly, allopathic medicines, which are synthetic inorganic concentrated drugs, have adverse effect on non-targeted organs, besides being expensive.

5.1 Introduction

Considering the richness of floristic diversity of India represented by 47,513 plant species, of which around are 9,500 reported to be of ethnobotanical botanical significance and around 7,500 - 8900 of ethnomedicinal importance (Anonymous, 1994; Pareek et al., 2005). It has been estimated that of these, around 5,000 plant species have been investigated in some detail in search for potential sources of wellness or health or medicinal drugs to cure various human ailments and diseases. As discussed in the previous sections, the Indian literature on medicinal aromatic plants formally documents information on about 2,500 medicinal and aromatic plants under various traditional systems with sufficient details. In addition, indigenous traditional knowledge exists for another 4,000-4,500 medicinal plant species based on long time experience/observations and their use by various tribes and communities and the individual clan or families in cure of specific ailments. However, this knowledge predominantly exists in oral traditions, which are under danger because of the threat to these traditional orthodox societies and loss of the dialect or languages in which they exist.

6.1 Introduction

The World Health Organization (WHO) compiled a list of 20,000 medicinal plants used in different parts of the world. An estimated 15,000 medicinal plant species, forming about 21% of the total plant species used for medicinal purposes in the world, fall in the endangered category (Schippmann et al., 2006). In India, medicinal plant species used under different traditional systems to a large extent are still gathered and collected from the wild in from of roots, bark, wood, stem and even the whole plant causing severe destruction of their habitat, resulting in loss of species/populations and erosion of genetic diversity. The remaining few are cultivated as crop plants, but marginally because of lack of assured market and can be safely termed as commercially under utilized and are also under threat. Therefore, despite India being rich in plants species with medicinal properties, genetic diversity within the species and the associated traditional knowledge regarding their use, the lack of awareness regarding the loss of species and genetic diversity due to destructive harvesting from the wild and many other factors, such as infrastructure development, iintroduction of exotic species is causing depletion of genetic diversity or loss of indigenous MAPs.

7.1 Introduction

The occurrence of different medicinal and aromatic plant species is often associated with a specific ecology and thereby, to a biogeographical or phytogeographical region of the Indian Subcontinent. The Indian Subcontinent is a confluence of at least two biogeographical realms, i.e., Palearctic or Palaearctic (Himalayas) and Oriental (Sino Indian- mainland India to much of insular the Southeast Asia). The most acknowledged classification of biogeographical zones was proposed by Udvardy (1975), which recognized 12 biogeographical provinces in India falling in these two realms. Based on varied climate, terrain, and faunistic information, Roger and Panwar (1988) tried to distinguish India into 10 distinct bio-geographical regions. Their classification did account for distribution of the plant-communities because they provided information about key components to identify the probable habitat for the presence of animals. An attempt for phytogeographical zonation, based on type of vegetation by Gadgil and Meher Homji (1990), distinguished 16 phytogeographical zones. Rodgers et al. (2002) further revised their biogeographical maps using geographical information system (GIS) techniques. They distinguished 10 biogeographical zones and 26 biotic provinces.

8.1 Introduction

Considering increased awareness and interest in using herbal products because of their safer nature, the world market of traditional medicinal and aromatic plants is growing at a very fast pace. The global herbal industry is projected to be worth 5 trillion US$ by 2050 (the world bank report, 2000). These resources not only provide primary health care, but also nutraceutical support for wellness. Also, it has been experienced that they may help in curing some of the deadly and painful diseases such as cancer, HIV, AIDS, rheumatism, arthritis etc. India, due to its rich heritage in use of medicinal and aromatic plants under various traditional medicinal systems, which are important source of information about plant properties and use, can become a major player in the global context and can increase its market share substantially. To achieve this, an effective, efficient, and vibrant program is required to cover various aspects of management, research, and development.

1 Analysis of Chemical Composition of Milk

 1.1 Determination of Acidity of Milk

 Introduction

The acidity of milk can be determined by titrating the milk against standard sodium hydroxide solution using an indicator like phenolphthalein and is expressed in the terms of lactic acid. Though natural acidity in milk is due to its constituents such as casein, albumin, citrates, phosphates and carbon dioxide but it is customary to express in terms of lactic acid. As one gram equivalent weight of an alkali neutralizes one gram equivalent weight of an acid, the volume of standard alkali required to neutralize lactic acid of fixed volume of milk gives percent acidity of milk according to the reaction.

1 Analysis of Cream

 Sample Preparation

Warm the cream sample to 40 - 50oC if the sample is very viscous. Then pour from one vessel to another 3 to 4 times to mix well. Sample should be tested daily and always within three days after collection since enzymatic deterioration of the cream will cause low tests.

1.1 Determination of Fat Content in Cream

 1.1.1 Gerber Method

 Introduction

Sulphuric acid is added to cream in order to dissolve the protein and other solids and create heat which liquefy and de-emulsify the fat. Iso-amyl alcohol is added to aid the separation of fat. Upon centrifugation, fat being lighter will be separated on top of solution in the cream butyrometer.

Sample Preparation

 Cheese sample is prepared by passing through 8 mesh sieve three times or

grate sample and mix thoroughly or grind to a uniform mass in a glass pestle

and mortar. Keep the sample in an airtight container until the time of analysis.

 1 Determination of Moisture Content in Cheese

 Introduction

The moisture content of cheese is defined as the loss in mass, expressed as a

percentage by mass when the product is heated in a hot air oven at 102 ± 2°C

to constant mass.

Sample Preparation

a) Plain products: Sample should be softened at room temperature. Since the melted fat tends to separate and rise to the surface, it is not advisable to soften the sample by heating on a water bath or oven or flame. Mix thoroughly by stirring with spoon or eggbeater or by pouring back and forth between beakers.

b) Ice-cream containing Fruits and Nuts: Fill one third part of the cup with ice cream sample. Melt the product at room temperature and mix until insoluble particles are finely divided (about 3-5 minutes for fruit pieces and upto 7 minutes for nut pieces). Otherwise, the product may be ground in a porcelain or glass pestle and mortar. Don’t let temperature exceed 25oC at any time during softening and mixing steps. If fat separation occurs, discard sample otherwise immediately pour mixture into wide jar and cap tightly. If allowed to stand, shake vigorously before taking sample for analysis.

Sample Preparation

Sample should be taken at six or more points on the top of the surface by means of a tubular trier of sufficient length to extend to the bottom of the barrel. Remove this cores and transfer to clean, dry, air tight container and seal immediately.

Before opening sample for analysis, make homogenous either by shaking or by alternately rolling and inverting container. If lump are present, sift sample through No 20 sieve, rubbing material through sieve and tapping vigorously, if necessary.

Avoid sampling on rainy day or when humidity is high, so as to reduce moisture absorption from air.

1 Determination of Moisture Content by Moisture Balance Introduction

In this procedure, infra-red radiation is used to accomplish rapid drying. The tester has a sensitive torsion balance which permits rapid determination directly from the balance scale, eliminating the need for computing or calculation to obtain results. This method is useful for the in-process determination of moisture because the results may be obtained in minutes.

1 Detection of Starch Introduction

Starch is widely available in several forms such as wheat flour, corn flour and commercially manufactured starch. It is extensively used by adulterators to raise the SNF content in the milk. When high amounts of starch are added to milk, it can cause diarrhea due to the indigestion of starch in colon. Apart from this, accumulation of starch in the body may prove very fatal for diabetic patients. In this method, starch in milk can be detected by using iodine solution. Iodine from the iodine solution gets absorbed on the starch molecule surface and resultant product of adsorption has deep blue colour.

Reagents

 • Potassium iodide

 • Iodine solution - 1% (Add 1 g of iodine and 5 g of potassium iodide in

distilled water and dilute to 100 ml)

1. Preparation of Standard Sodium Hydroxide Solution

 Introduction

 When oxalic acid reacts sodium hydroxide, sodium oxalate and water are

form. Phenolphthalein indicator detects the end point by its characteristics

colour change.

 Apparatus

 Burettes, pipette, volumetric flask, beaker

 Reagents

 • Oxalic acid crystals

 • Sodium hydroxide – 0.1 N approximate

 • Phenolphthalein solution – 0.1 percent in ethyl alcohol

Procedure Preparation of 0.1 N oxalic acid solution 1. Weight accurately 1.575 g of oxalic acid into a 250 ml beaker using a weighing bottle. 2. Add some distilled water to the beaker and dissolve the oxalic acid with the help of glass rod. 3. Transfer the solution into a 250 ml volumetric flask through a funnel. 4. Wash the beaker 3- 4 times with small quantities of distilled water and transfer the washing into the flask. 5. Make up the volume up to the mark with distilled water and mix thoroughly. 6. Preparation of approximately 0.1 N sodium hydroxide solution 7. Weigh about 4.25 g of sodium hydroxide pellets and dissolve into 200 ml of distilled water.

1. Calibration of Milk Butyrometer

Introduction

Butyrometer is used for determination of fat for milk and milk products by Gerber method. The milk butyrometer is a graduated vessel, which are designed in such a way that the internal volume of each unit is 0.125 ml which is corresponding to 1 percent fat. Sometimes due to manufacturer’s error, the volume of one unit of milk butyrometer is not exactly equal to 0.125 which leads to subsequent error in results in milk fat. So before starting to use a new butyrometer, it is essential to calibrate for its efficiency in the laboratory. Mercury is used to calibrate milk butyrometer.

Apparatus

Milk butyrometer (0 – 10% graduation), analytical balance

Etiology

 Acral lick dermatitis is usually observed on extremities of dogs and the probable etiology is persistent licking. It is also caused due to self-trauma or mutilation.

Etiology

Atopic dermatitis is genetically predisposed to allergic skin disease. It consists of atopy and hereditary cause to produce IgE mediated allergic reaction to environmental allergens.

Immunohistochemistry reveals the presence of Langerhans cell proliferation and strong positive expression of IgE in skin tissue sections.

Gross pathology

Etiology

Superficial pyoderma usually occurs in the epidermis and upper infundibulum of the hair follicle. It usually heals without scar formation and commonly caused by Gram positive cocci Staphylococcus spp., particularly exfoliative toxin of this species.

Etiology

It is caused by Staphylococci spp- characterized by superficial pyoderma in dogs. It is mainly due to exfoliative toxins of S? aureus.

Gross pathology

The lesion reveals cutaneous exfoliation, vesicles, pustules (Figure 6) and crust.

Etiology

The condition is usually caused by implantation of low virulent saprophytic bacteria due to traumatic injury. These organisms stimulate cell mediated immune response by persistence of antigen in the tissue.

Etiology

The condition is characterized by formation of granuloma to pyogranulomatous dermatitis with paniculitis. The causative organism is normally present in the macrophage which may be Mycobacterium tuberculosis, M? bovis and M? microti.

Synonym – Cutaneous ancylostomiasis

Etiology

Hook worm dermatitis is uncommon or rare skin disease due to larval migration of the normal life cycle of Ancylostoma braziliensis and Ancylostoma caninum. It is mainly due to hypersensitive reactions against migrating third stage larvae in the distal extremities.

The condition is one of the most common pruritic skin disease caused by hypersensitivity reaction to the flea salivary antigens. Type I immediate hypersensitivity, type II delayed hypersensitivity and cutaneous basophil hypersensitivity to the flea salivary antigens have been recorded. Late phase IgG mediated reaction also caused in this condition. It occurs in dogs mostly between 1 and 3 years of age.

Etiology

Pemphigus foliaceous is a bullous autoimmune skin disease of canines affect ing epidermis and hair follicles. The recorded targeted auto-antigen in canine pemphigus foliaceous is desmoglein 1 (Dsg 1). This auto-antibody binds to Dsg 1 which is a prominent component of desmosome in the superficial layer of epidermis and hair follicle. It may be due to loss of intercellular cohesion leading to acantholysis followed by formation of superficial vesicles and bul lae. The common sites for the development of pemphigus in dogs are dorsal lateral muzzle, temporal, planum nasale, pinnae, periorbital skin and paw pads.

The disease is characterized by irregular growth and development of hair follicles and associated glands.

Sebaceous gland hyperplasia: It is a rare disease of dogs characterized by high hair coat and underlying skin, greasiness and in mainly due to excessive greasiness followed by clumping of the hair coat.

It is characterized by irregular growth and development of hair follicles and associated glands.

Etiology

Demodecosis is caused by Demodex species follicular mite with increased numbers. But, it is generally caused by Demodex canis. It is divided into two forms – juvenile and adult forms. The juvenile form is more common. This condition may be localized or generalized in nature.

Crust is characterized by the presence of desquamated squamous epithelial cells. The dried exudate consists of necrotic cell debris, leucocytes, RBC’s, plasma proteins and microorganisms. It is classified into serous crust (eosinophilic protein exudates), hemorrhagic crust (RBC’s), cellular crust (degenerative leucocytes mainly neutrophils), serocellular crust (mixture of serum or plasma or leucocytes) and palisadic crust (presence of leucocytic infiltration, pustules and parakeratosis organized in a horizontal manner).

Scales are having imperfectly keratinized superficial layers of the epidermis characterized by cracks or thin flakes.

Ulcerative dermatitis is one of the primary features of the skin disease in which discontinuity of the skin along with marked inflammation and necrosis are seen.

Etiology

Canine dermatophytosis (canine ring worm) is a relatively common dermatological condition caused by Microsporum canis, Trichophyton mentagrophytes and Microsporum gypseum. These fungi are keratinophilic in nature. It can occur mostly in the face and forelegs.

Etiology

It is a pruritic transmissible dermatological condition caused by Cheyletiella yasguri, one of the surface living mite.

A) Hypothyroidism

Etiology

It is one of the common endocrine disorders of skin of dogs mainly due to deficiency of thyroid hormone followed by cutaneous and non cutaneous signs. It is caused by lymphocytic thyroiditis or idiopathic thyroid necrosis and atrophy. Deficiency of thyroid hormone hinders the metabolic processes throughout the body.

Etiology

It is a rare canine dermatological condition. This condition is subdivided into two groups. In the first group, it is seen in Siberian husky and Alaskan malamutes. It is due to inherited impairment in the zinc absorption or metabolism. In the second group, it is due to use of high plant phytates diet (zinc absorption prevention), commercial or home prepared diet which is zinc deficient or diet is over supplemented with calcium and other vitamins and minerals which impair zinc absorption. Group two is mostly seen in large breed dogs and young adults.

Etiology

It is a rare idiopathic primary dermatitis condition seen mainly in Daschund.

Etiology

It is a relatively rare skin disease or dermatologic condition. Hypersensitivity reaction is one of the suggestive cause for this condition characterized by nodules or plaques which are seen in the skin, oral mucosa and external ear canal.

Etiology

It is an uncommon endocrine related skin disorder. It is very rarely encountered in neutered dogs.It is always associated with cryptorchidism and sertoli cell tumor. This condition is closely accompanied with endocrine related testicular tumor followed by skin lesion and feminization.

A very common condition caused by Malassezia pachydermatis in dogs. It is also caused by predisposing allergic skin disease. It occurs in ventral neck, ventral abdomen, axilla, face, pinnae, feet and forelegs. Tape impression smear will reveal numerous yeasts.

This tumour may occur due to specific mutation in the p53 tumor suppressor gene. This is one of the most common epithelial tumor of dog. It is classified into well differentiated, moderately differentiated and poorly differentiated tumour.

Basal cell carcinoma is a locally malignant epithelial tumor of skin which is mainly composed of basal cells. This may occur due to mutation in the tumor suppressor gene p53 and chronic exposure to UV radiation.

Cytologically, neoplastic cylindrical columnar cells, are moderate to high in number. The neoplastic cells are small to medium sized with round to spherical nuclei with basophilic cytoplasm (Figure 42 & 43).

This is a benign/malignant tumor originating from the apocrine and eccrine sweat glands in dogs. It is usually recorded in the head and neck region but it may occur on any site.

Cytology reveals clusters of moderate to severe exfoliated neoplastic cells which contain round nuclei slightly eccentric in position in the light pale granular cytoplasm. In carcinomas, clusters of basophilic epithelial cells had large nuclei and prominent nucleoli. It may also contain one or two large secretory droplets.

It is one of the common epithelial skin tumors. It is more common in head but also recorded in other sites such as back, tail, limb, trunk and eyelids. It is a tumor of sebaceous cells. In sebaceous gland adenoma, it has predominantly sebocytes with less of basaloid reserve cells while in sebaceous epithelioma variant, more of basaloid reserve cells are seen with less of sebocytes.