eChapters

Family : Mimosaceae

Flowering: January-March

Fruiting: April-June

Botanical Description: The plant is a large, nearly evergreen perennial tree that grows up to 20 m or more in height. It has a broad crown, up to 30 m across, and a short trunk, up to 1 m thick. Leaves are deciduous but foliage is persistent, as the new leaves appear while the old ones are being shed, so that the tree looks like an evergreen. Flowers yellowish-white in colour and are borne in small spherical glomerules of about 1 cm in diameter, forming short axillary panicles of 5-30 cm in length. Pods are greenish-brown to red or pinkish, rather thin with 10-15 cm long with irregular shape and flattened. There are about 10 seeds per pod, shining black in a white pulpy aril.

Family : Myrtaceae

Flowering: April-May

Fruiting: July-August

Botanical description: The plant is an evergreen tropical tree, 50 to 100 ft. tall, with oblong opposite leaves that are smooth, glossy and having a terpentine smell. It has fragrant white flowers in branched clusters at stem tips and purplish-black oval edible berries. The leaves are antibacterial, and are used for strengthning the teeth and gums. The fruit is ellipsoid or oblong, variable in size and shape, usually up to 2.5 cm long, black, shining and juicy when fully ripe. Seeds always one, with thick rounded fleshy cotyledons, closely appressed on their inner faces.

Family : Lythraceae

Flowering: August-September

Fruiting: November-December

Botanical description: The water chestnut is an annual aquatic herb with a rosette of floating leaves and submerged, anchored into the mud by very fine roots. It has two types of leaves, finely divided, feather-like submerged leaves borne along the length of the stem, and undivided floating leaves borne in a rosette at the water’s surface. The floating leaves have saw-tooth edges and are ovoid or triangular in shape, 2-3 cm long, on inflated leaf-stalks 5-9 cm long, which provide added buoyancy for the leafy portion. Flowers are white in colour, with Four petals and are borne for a long period. The fruit is a nut with barbed spines. Seeds can remain viable up to 12 years, although most germinate within the first two years.

Family : Rhamnaceae

Flowering: July-September

Fruiting: October-January

Botanical Description: Jackal Jujube is a very thorny straggling shrub with rusty-velvety young branches with paired thorns. Thorns are, one straight and the other recurved. Alternately arranged simple leaves are ovate to ovatelancelike, often oblique, with three prominent nerves and numerous transverse nervules. Tiny green flowers are borne in nearly stalkless velvety cymes in leaf axils. Fruits are spherical or obovoid drupes, black, shining, seeds woody.

India has a total geographical area of about 329 million hectares which represents about 2.4% of the world’s total landmass but it harbours a total of 47,513 plant species. Out of about 0.4 million species known in the world, it represent as much as 11.4% of world flora. About 28% of plants that occur in India are endemic to the country. The ecological or ecosystem diversity of the country is enormous, ranging from sea level to the highest mountainous ranges in the world, hot and arid conditions in the northwest to cold arid conditions in the trans-Himalayan region, tropical wet evergreen forests in Northeast India and the Western Ghats and mangroves of Sundarbans.

1. Botanical Name : Allophylus serratus (Roxb.)Kurz

2. Family : Sapindaceae

3. Common Name : Tippani

4. Name in Indian languages: Lavate pan (Kodwa), Tippani (Hindi), Sidisale (Kannada), Mukkanamperu (Malayalam), Memdri (Marathi), Amalai (Tamil), Eravalu (telugu), Trputah (Sanskrit).

5. Description

It is an evergreen, low branching small tree or a large shrub about 3-6m tall. Trunk is straight with open canopy. The outer pulp and some time seeds are consumed in fresh state. It is frequently notice in degraded forest areas in Western Ghats. It is known to possess various therapeutic properties.

1. Botanical Name : Aporosa lindleyana (Wt) Baill.

2. Family : Euphorbiaceae

3. Common Name : Lindley’s Aporosa

4. Name in Indian languages: Yechi pan (Kodwa), Salle mara, Sali, Sarali, Sulla (Kannada), Kodali, Kotili, Ponvetti, Vetti, Vittil (Malayalam), Kodali, Vettikan, Vettil, Vittil, Vitti (Tamil),Valaka (Sanskrit).

5. Description

It is tree, belongs to Euphorbiaceae family which grow up to 15 m height. Tree bark is smooth to shallowly fissured, brownish; blaze pink. Leaves are simple, alternate, oblong-lanceolate, acute, 7.5-17 cm long. Flowers unisexual, dioecious; male flowers in axillary catkins; female flowers in condensed cymes.

1. Botanical name : Ardisia solanacea Roxb.

2. Family : Myrsinaceae

3. Common Name : Shoebutton Ardisia, duck’s eye

4. Name in Indian languages

Bisi (Hindi), Kadna, Katapenga, Bugadi, Dikna, nilbedsi (Marathi), Manipudbam, Kozhikkottai, Narikandam (Tamil), Kaka-njara(Malayalam), Bodhina gida, Shuli, Bode, Sore(Kannada), Banjam(Bengali), Damaai Phal (Nepali), Tinkoli (Oriya).

1. Botanical Name : Canthium dicoccum var. umbellatum syn. Pelectronia parviflora Gaertn.) Merr

2. Family : Rubiaceae

3. Common Name : Ceylon Boxwood, Malakafe

4. Name in Indian languages

Amme pannu (Kodwa), Hanage (Kannada), Nanyul (Malayalam), Arsul, Tupa (Marathi), Nanjul, Nallamandharam (Tamil), Nalla balasu, Balasu naikinna (Telugu).

Soil sample collection is the first and most important step for soil quality analysis. A soil sample collected with due care and proper procedure is essential for getting reliable result of the analysis. The sample should represent the field and for practical purposes, an area of about 0.5 hectare is considered as one sampling unit. In case of conspicuous variation observed in the field in terms of texture, colour, slope etc, separate samples should be collected from areas differing in these attributes. In other words, sample should be collected from an area in the field with similar characteristics as seen through normal visual observation. Sampling should thus be avoided from areas like near trees, permanent vegetations, manure pits, manure piles or recently fertilized fields.

Soil Sampling procedure

1. For a particular field unit, one composite soil sample is prepared out of the samples collected from 7-8 spots distributed across the field unit. The entire field is covered by moving in a zig-zag manner from each sampling spot.
2. For each sampling point or spot, scrapping off the surface litter such as grasses or crop residues is done. Then, a “V” shaped pit of 15-20 cm length and of equal width is made. Depth of sampling depends upon the requirement and on the type of crop. For field crops like paddy, wheat etc, samples are collected from 15 cm depth. From the “V” shaped pits, take outslice of ½ inch thickness from both sides of the exposed pit surfaces from top to bottom.
3. The soil samples so collected from the 7-8 points are mixed thoroughly by hand and then is reduced to about 500 g by quartering process. The quartering process consists of a procedure in which the entire soil mass is divided into four quarters; the two opposite ones are discarded and the remaining two are remixed. This process is repeated till about 500g soil is obtained.

Soil pH is the measure of hydronium ion (H₃O⁺) or more commonly hydrogen ion (H⁺) activity in the soil suspension. Soil pH can be measured in soil-water suspension, saturation extract or in 0.01 M CaCl₂ solution. Saturation extract is used to identify specific soil problems such as salinity or sodicity. Measurement of pH using 0.01 M CaCl₂ solution gives more reproducible results than measured through soil-water suspension. It also provides a good approximation of field conditions as the electrolytic composition of 0.01 M CaCl₂ is considered similar to that of soil solution. However, among the three methods, soil-water suspension is most commonly used in research laboratories as well as for fertilizer recommendation as it is simpler and more convenient.

Electrical conductivity (EC) is a useful indicator of soil salinity. Relationships have been developed between EC and salinity classes for a 1:1 soil: water suspension. With increase in salt content in a soil, the EC increases. Thus, for salt affected soils, measurement of EC is vital as accumulation of salts in the root zone is detrimental to plant growth. EC is a measure of the ability of a soil solution to conduct electrical current.

Equipment and Reagents

1. Digital Conductivity meter
2. 0.01 M potassium chloride (KCl) solution: Dissolve 0.7456 g dry KCl in distilled water and make up the volume to 1.0 litre. This solution has an electrical conductivity of 1.413 dS m_-1 at 25ºC.

Ion exchange is a reversible process by which a cation or anion held on the solid phase is exchanged with another cation or anion in the liquid phase. Soil mineral and organic colloidal particles have negative valence charges that hold dissociable cations. The power to retain cations at the surface of soil colloids is referred to as the cation exchange capacity (CEC). Cation exchange is a reversible reaction in soil solution, dependent upon negative charges of soil components arising from permanently charged or pH-dependent sites on organic matter and mineral colloid surfaces. The CEC is the sum of cations held by a kilogram of soil and is expressed in Cmol (p₊)/kg soil. In most agricultural soils, the cation-exchange capacity (CEC) is generally higher than the anion exchange capacity (AEC).

Exchanges sodium (Na+) is animportantparameter forsalt affected soils. This is estimated by extraction with ammonium acetate and then measuring the extract inflamephotometer.

Reagents

1. Neutral normal ammonium acetate solution (1 N CH₃COONH₄ of pH 7): Dissolve 77.09 g of ammonium acetate in distilled water and make up the volume to one litre. Adjust the pH of the solution to 7 with ammonia solution or acetic acid.
2. Standard solution of Na (500 mg/L Na): Dissolve 1.271 g of NaCl in distilled water and make up the volume to one litre.
3. Working standard solution of Na (100 mg/L): Dilute 200 ml of 500 mg/L stock solution to 1000 ml.

Soil bulk density (BD) or apparent density is determined in -situ by core method. Stainless steel or metallic cores of cylindrical shape with known height and diameter are inserted into the soil till the rim of the core. The soil core is then excavated and the soil sample is oven dried to get the dry weight. The ratio of the oven dry weight to the total volume of the core gives the bulk density of the soil.

Aggregation is a direct indicator of soil structure. Ahealthy soil is considered to have well aggregated structure. Though not routinely followed during soil testing and chemical analysis, aggregation is one of the major indicators of soil physical health. Wet sieve method (Yoder, 1936) is usually followed for soil aggregate analysis. This involves gently raising and lowering a nest of sieves in water to assess the stability of aggregates to rapid wetting. However, the Yoder’s wet sieving method has been modified to make it simpler and currently, the method of Kemper and Rosenau, 1986 is being commonly used in research laboratories. One of the pre-requisites in these methods is the availability of wet sieving apparatus and further, these methods are laborious and time consuming. On the other hand, the method described by Cambardella and Elliott (1993) is considered very ideal because of its simplicity and is being widely used for aggregate bound soil carbon fraction study. The soil sample is wet sieved with a series of three sieves (2000, 250 and 53 micron size).

Aggregation is one of the basic physical characteristics of soil. Under natural conditions, primary soil particles, particularly clays, tend to join together to form secondary units called aggregates. Size distribution of soil aggregates is important because the size of the aggregates determines their susceptibility to water and wind erosion. Also, their size is important in determining the pore size distribution and regulating pore space in cultivated soils.

There are a variety of procedures being in use to test the stability of aggregates and aggregate size distribution. However, choice of the method for analysis of aggregate size distribution is determined by the purpose of analysis. The developed measures are relative and purpose specific. This chapter discusses dry aggregate analysis.

Thisprocedure estimates aggregatestabilitytoimpact ofraindropsand water erosion. Wet sieving procedure was originally proposed by Yoder, 1936. Later, the procedure was modified byKemper and Rosenau, 1986.

Equipment

1. Yoder type sieve shaking electrically operated machine (3/4 inch stroke at 30 strokes per minute)
2. Concentric sieves of various sizes of pores to fit properly into the machine.
3. Weighing balance

In dry combustion technique, the combustion of soil sample (about 250 mg and mm sieved) is carried out at high temperature (about 1000 ºC) through feeding in an inert boat in the electric furnace. The CO₂ produced from the oxidation of carbon present in the soil sample at high temperature is carried towards non dispersive infrared detector (NDIR) by a carrier gas where it is quantified and total carbon content is determined.

This is one of the commonly used method to estimate organic carbon content in soil. In this wet digestion method, soil organic matter is oxidised with a mixture of K₂Cr₂O₇ and concentrated H₂SO₄ utilizing the heat of dilution of H₂SO₄. The unused K₂Cr₂O₇ is back titrated with ferrous sulphate or ferrous ammonium sulphate.

Labile fractions of soil carbon (C) refer to the fraction of soil carbon that are easily altered by microbial activities. These fractions serve as sensitive indicators to changes in management induced soil quality and are grouped under active soil C pool. The method described by Weil et al. (2003)estimates changes in biologically active soil C using a dilute KMnO . This is an improvement over the method used by Blair et al (1995), where a very high concentration (0.333 M) of KMnO₄ was used.

Organic carbon present in soil can be very labile, labile or non-labile. This procedure measures the extent of lability of soil organic carbon through relative degree of oxidation by K₂Cr₂O₇.

Particulate soil organic matter (POM) is one of the important soil organic matter (SOM) pools and matches the characteristics of a slow, decomposable or stabilized SOM pool. The POM fraction is considered as one of the indicators to changes in management and thus has been used in soil quality assessment studies.

Soil respiration is a good estimator of overall biological activity and thus is often used for describing soil quality. Soil respiration is estimated as the flux of CO₂ emitted from the soil surface. It represents the sum of CO₂ produced by root respiration and by heterotrophic decomposition. This procedure is a laboratory method where soil is incubated for a given period of days and the released CO is trapped by sodiumhydroxide (NaoH). This is also known as alkali trap method.

This is a distillation method proposed by Subbiah and Asija (1956), where the soil is distilled with alkaline KMnO solution. The ammonia liberated is trapped in boric acid and then determined by titration against a standard acid. This procedure estimates the easily mineralizable nitrogen in soil.

In soil system, potassium (K) exists as water soluble, exchangeable, non- exchangeable and lattice K. The plant available K refers to the sum of water soluble and exchangeable K. Estimation of available K is usually done using neutral normal ammonium acetate as the extractant.

In this method, plant available sulphur (S) is extracted with 0.15% CaCl₂ and the soluble sulphate is estimated on a colorimeter.

The hot water soluble method is the most common method to estimate available B content in soil

Reagents

1. Azomethine-H: Dissolve 0.45 g azomethine-H and 1.0 g L-ascorbic acid in about 100 ml de-ionized or redistilled water. If solution is not clear, it should be heated gently on water bath at about 30ºC till it dissolves. A fresh solution should be prepared every week and kept in a refrigerator.
2. Buffer solution: Dissolve 250 g ammonium acetate in 500 ml de-ionized or redistilled water. Adjust the pH to about 5.5 by slowly adding approximately 100 ml glacial acetic acid, with constant stirring.
3. EDTA reagent (0.025 M): Dissolve 9.3 g EDTA in de-ionized or redistilled water and makes the volume up to 1 litre.
4. Standard Boron solution: Dissolve 0.571 g boric acid (H₃BO₃) AR grade in a small volume of deionized water and make volume to 1000 ml to obtain a stock solution of 100 mg B/L.

Biological activity or index of a soil is the function of number of organisms present in soil and their physiological efficiency. The rate of respiration can be used as an index of the biological activity of soil as it reflects the physiological efficiency of the organisms. Monitoring of dehydrogenase, which are respiratory enzymes and integral part of all soil organisms, will give a measure of biological activity of soil at a given time.

During respiration biological oxidation of reduced compounds occur which is catalyzed by dehydrogenase. In the process TTC gets reduced to a pink coloured compound Triphenyl formazan (TPF) which can be quantitatively extracted by methanol and measured colorimeterically. The soil dehydrogenase activity in the current experiment was measured as per the methods of Cassida, (1977).

Fluorescein diacetate (3’ 6’-diacetyl-fluorescein) is a fluorescein conjugated to two acetate radicals. This colourless compound is hydrolysed by both free (exoenzymes) and membrane bound enzymes, releasing a coloured end product, fluorescein. This end product absorbs strongly in the visible wavelength (490 nm) and can be measured by spectrophotometry. The enzymes responsible for FDA hydrolysis are plentiful in the soil environment. Non-specific esterases, proteases and lipases, have been shown to hydrolyse FDA. The hydrolysis of FDA by soil enzymes can be estimated by methods of Adam and Duncan (2001).

Acid and alkaline phosphatase enzymes are among the extensively studied phosphatases and classified so because of their optimum activities in acid and alkaline pH ranges, respectively. Acid phosphatase is predominant in acid soil while alkaline phosphatase is dominant in alkaline soils. The colorimetric assay of phosphatase is based on release of p-nitrophenol from hydrolysis of p-nitrophenyl phosphate byaction of phosphatase enzyme in buffered soil solution (buffer pH 6.5 for acid and 11 for alkaline phosphatase assay).

Principle

Different ions migrate at different speed dictated by their size and by the amount of charges they carry. As a result, different ions can be separated from each other by electrophoresis. The magnitude of the electric force F exerted on the charged particle when subjected to electrophoresis is product of the charge q of the particle and the electric field E generated between the two electrodes.

Heart

The heart is a cone shaped thick walled and four chambered muscular organ. It lies obliquely craniocaudal in the middle mediastinum in between the left and right lungs and is covered by pericardium inside the thoracic cavity. The major part of heart (about 60 per cent) lies to the left of the middle mediastinum. The broad upper end is the base of the heart. It lies at the junction of the dorsal and middle third of the dorsoventral diameter of thorax at the level of about third to sixth rib and it faces craniodorsally. The narrow lower end is the apex. It lies just dorsal to the sternum at the level of about sixth rib and it faces caudoventrally. The surfaces, right and left are convex. They meet cranially at the right ventricular border and caudally at the left ventricular border. The right (cranial) border is strongly convex. It runs ventrally and caudally. The greater part of this border lies parallel to the sternum. The left (caudal) border is much shorter and nearly vertical. The surfaces of the heart are marked by grooves which indicate the division of the heart into four chambers the two atria dorsally and the two ventricles ventrally. The atria are separated internally by the interatrial septum. The ventricles are separated by interventricular septum. The circular coronary groove indicates the division of the heart in to atria dorsally and ventricles ventrally. It encircles the heart in its upper third part except at the level of the origin of pulmonary artery. The coronary groove is quite deep and wide. It provides passage for the coronary artery and vein. Apart from these, it is deeply filled with fat. The right (subsinuosal) interventricular groove and left (paraconal) interventricular groove indicates the line of separation between the two (right and left) ventricles by the interventricular septum. Both of these grooves run downward from the coronary groove towards the apex parallel to the respective borders and terminate just above the apex. The right and left ventricular grooves are occupied by the respective coronary vessels along with the fat.

The great vessels that leave and enter the chambers of the heart include the Aorta, the Pulmonary Artery and the Pulmonary Veins.

Aorta

The Aorta is the main systemic arterial trunk. It begins as ascending aorta at the base of the left ventricle, passes craniad and dorsad between the pulmonary artery on the left and the right atrium on the right and then turns caudad inclining slightly to the left, thus describing a curve called the aortic arch with its convexity directed upward and forward and the concavity facing downward and backward. From here it proceeds caudad on the ventrolateral surface of the thoracic vertebrae and the longus colli muscle as the descending aorta. At its origin from the base of left ventricle, the caliber of the aorta is greatest forming the bulbus aorta and here it presents three dilatations called the aortic sinuses. As the descending aorta reaches the level of the seventh thoracic vertebra it continues behind as thoracic aorta running through the middle and caudal mediastinum between the left and right lungs. The thoracic aorta first lies to the left of the median plane and then gradually inclines inwards medially and becomes median in position when it reaches to the diaphragm. It then passes through the hiatus aorticus of the diaphragm and enter the abdominal cavity as abdominal aorta. From here it passes caudad below the bodies of the lumbar vertebrae and the psoas major muscle. After reaching at the level of the sixth lumbar vertebra, the abdominal aorta terminates in the iliac quadrification by dividing into two external and two internal iliac arteries.

The lymphatic system is a part of circulatory system and a vital part of the body’s immune system. It is comprised of lymph vessels, lymph ducts, and lymph nodes that move the lymph from tissues to the blood stream and the organs such as the spleen, thymus and bone marrow that produce the lymphocytes and white blood cells. Lymph is very similar to blood plasma. During circulation through the body, the blood reaches to the capillaries at the interstitial spaces. The plasma of the blood is filtered through the capillary wall. The fresh oxygen along with nutrients, hormones and other necessary fluid matters from this plasma are released in to the interstitial fluid and about 85 per cent of the plasma along with the carbon dioxide and metabolic wastes, return into the circulation through the capillary walls. The remaining 15 per cent of the plasma along with the debris of other waste products and the lymphocytes constitutes the lymph which is returned to the circulation through an accessory route of lymphatic vessels and lymph nodes constituting the lymphatic system.

Lymph Vessels: The lymph vessels start as finger-like blind ending thin walled lymph capillaries in the interstitial connective tissue. These capillaries form a network and drain into the thicker walled collecting lymph vessels, lymph ducts and lymphatic trunks. Finally the larger lymph trunks and ducts empty their content the lymph into the cranial vena cava at the thoracic inlet. The lymph vessels contain numerous valves with one or two leaflets preventing the back flow of lymph through the lymph vessels. During its course in a centripetal direction through the lymph vessel, the lymph of each lymph vessel has to pass through at least one lymph node prior to its entry into the blood circulation. As a result there lies a chain of lymph nodes on the pathway of lymph vessels in the body.

Most of the bones of the skull are joined (articulated) with the adjacent bones by sutures. These are immovable joints (synarthroses). The uniting medium is a fibrous tissue and is called the sutural ligament. Most of these joints exist in the early life of the animals and as the age of the animal advances the adjacent bones fuse with each other.

Muscles of the back (spine), muscles of thorax and muscles of thoracic girdle of Horse, Dog, Sheep and Goat, and Pig almost resemble those of ox except for a few miner differences due to variations in the number of bony segments of the vertebrae, ribs and sternebrae.

Fowl

Muscles of back (spine)

Spinalis thoracis is the thoracic part of the spinales complexus. It originates by aponeurosis on the spinous processes of the thoracic vertebrae including the dorsal median ridge of the synsacrum, dorsal surface of the bases of the transverse processes and the cranial border of the ilium. The muscle inserts by multiple tendinous slips on the spinous processes, vertebral arches, transverse processes of several thoracic vertebrae and the vertebral ribs. This muscle helps in straightening of the head and neck of the fowl.

Iliocostalis et longissimus dorsi is the segmented muscle originating on the transverse processes of the thoracic vertebrae and inserting on the vertebral parts of the ribs. This muscle assists in elevating the thorax.

Boundaries

The cavity of thorax (thoracic cavity) is formed like a truncated cone which is compressed laterally in its cranial part and some what wider in its caudal part. The dorsal wall or roof of the thorax is formed by the thoracic vertebrae and the ligaments and muscles connected with them. The lateral walls are formed by the ribs and intercostal muscles and other muscles supporting the walls internally and externally. The floor or the ventral wall is formed by the sternum and costal cartilages along with the ligaments and muscles attached to them. The caudal wall or the base of the thorax is formed by the diaphragm. It slopes craniad and ventrad. It is bound dorsally by the last thoracic vertebra, ventrally by xiphoid cartilage and laterally by the last pair of ribs and the costal arch formed by the union of costal cartilages of asternal ribs. The apex of the cone is narrow, nearly oval or triangular in form and it is directed cranially. The cavity of the apex is bound dorsally by the first thoracic vertebra, laterally by the first pair of ribs and ventrally by the first sternebra along with manubrium sterni. The apex is fully occupied by the longus colli muscle, oesophagus, trachea, vessels, nerves and lymph nodes. The width of the thorax is greatest at the level of ninth ribs. The wall of the thorax is internally lined by the serous membrane which is a part of the pleura.

The venous drainage from the wall of the thorax is performed by the dorsal intercostal veins. These veins are distributed as below.

The dorsal intercostal veins are twelve pairs in number. Of these, the fourth to twelfth intercostal veins from right side and fifth to twelfth intercostal veins from the left side join the vena azygos.

The thoracic spinal nerves of the horse, dog, sheep and goat, pig and fowl almost resemble to those of ox in origin, disposition and distribution. The number of pairs of thoracic spinal nerves, however, vary and it corresponds to the number of thoracic vertebrae present in those particular species of animal.

Surface locations for clinical examination on the wall of thorax

Lymph nodes

Prescapular lymph node is palpable as a cylindrical object just cranial to the point of shoulder. Palpation can be performed by putting the base of the hand on the cranial edge of the scapula and pressing forward with fingers. This enables to roll the skin and feel the lymph node flicking underneath the fingers.

Heart

The clinical examination of heart is performed by percussion and auscultation on the thoracic wall.

For percussion of heart, usually the fifth rib is identified opposite the olecranon of a straight vertical limb. Two fields are identified for percussion of heart. (1) The area of absolute cardiac dullness corresponds to the area of contact of the pericardium with the thoracic wall. It gives a flat sound on light percussion. (2) The area of relative cardiac dullness indicates the outline of heart which is covered by the thin margin of lung. It needs somewhat stronger percussion to define this area which is usually difficult in animals. The absolute dullness is used to test the hypertrophy, displacement and pericardial effusion. In ox, the normal area of absolute dullness is explored in the fourth and fifth intercostal spaces. Traumatic pericarditis may result in absolute dullness in these spaces extending above a horizontal line through the shoulder joint. In horse this area is a triangle bounded by the triceps in front, the sternum below and the lung along the line joining these two. On left side of the normal horse, the dullness extends about 7 cm above the olecranon in the fourth intercostal space and about 3 cm above the olecranon in the fifth space. On the right side, the dullness extends about 3 cm above the olecranon in the fifth space only. In dog, the area of absolute dullness extends about 1 to 2 cm above the sternum in the fourth and fifth intercostal spaces in the line with the corresponding costochondral junction.

Horse

In addition to the common articulations of vertebrae, the lumbar region of horse has two special articulations, the inter-transverse articulations and lumbosacral articulations.

The intertransverse articulations are bilateral joints formed between the transverse processes of the fourth and fifth and between the fifth and sixth lumbar vertebrae. The articular surfaces of these joints are the oval facets on the transverse processes of these vertebrae, the cranial ones being concave while the caudal ones the convex. These are synovial joints (diarthrodial). The capsule of the joint is reinforced ventrally.

The lumbosacral articulations are diarthrodial joints formed between the transverse processes of the sixth lumbar vertebra and the wings of the sacrum. These joints are similar to the intertransverse articulations.

The sacroiliac articulation of the pelvis is similar to that of ox. However, the sacrosciatic ligament is broader. Its lateral surface is related to middle gluteus, biceps femoris and semitendinosus muscles.

The lymph from the fore limb is collected and carried into the circulation through two main lymph nodes, the prescapular and the axillary lymph nodes. There may be two more lymph nodes in fore limb but those are inconsistent and only occasionally found in ox. These include the accessory axillary lymph node and infraspinous lymph nodes and their afferents are mostly from the thoracic wall.

The lymphatics of hind limb is comprised of four lymph nodes namely the deep inguinal, epigastric, coxal and popliteal lymph nodes and the afferents and efferent ducts joining and leaving these lymph nodes.

Deep inguinal lymph node

The deep inguinal lymph node is located in the region of deep femoral artery near the origin of the caudal epigastric and the pudic branches from it. The lymph node receives afferents from the muscles in the prepubic and the thigh regions. The efferent vessel from this lymph node joins and opens in the medial iliac lymph node.

Epigastric lymph node

The epigastric lymph node is inconstant. When present, it is located on the course of the caudal epigastric artery near the pubis on the medial surface of the rectus abdominis muscle. The afferents for this lymph node are received from the abdominal muscles and the peritoneum in the vicinity. The efferent vessel of this lymph node joins the medial iliac lymph node.

In a large random-mating population both gene frequencies and genotype frequencies remain constant from generation to generation in absence of migration, mutation and selection and the genotype frequencies are determined by the gene frequencies. These properties of a random mating population were first explained by G. H. Hardy and W. Weinberg independently in the year 1908 and are generally known as Hardy-Weinberg law. The operational understanding of this law involves three steps as follows:

1. From parents to the gametes they produce.
2. From union of the gametes to the genotypes in zygotes produced.
3. From genotypes of the zygotes to the gene frequencies in the progeny generation.

The gene and genotype frequencies in the original parent generation are assumed as follows:

Alinehomozygousatallloci, ordinarilyobtainedbysuccessive self-fertilization in plant breeding is known as pure-line. W. L. Johannsen (1903), a Danish biologist provided a sound scientific basis for selection in self-pollinated crops when he defined ‘pure-lines’ and described the genetic mechanism by which they are established through a series of experiments for seed weight selection in bean, variety Princess. Pure-lines in principle are supposed to be 100% homozygous but that hardly happens in practical plant breeding programmes and usually the so called pure-lines are ‘near pure-lines. Pure-lines tend to be uniform in the traits of interest. Genetic mutations, admixtures and limited out-crossing are the main causes of variation within pure-lines. This is a rapid and most in-expensive method. Pure-line theory may be summarized as follows:

Mass selection is the simplest, oldest and least expensive method of plant breeding as applicable to cross-pollinated crops. The method involves planting balanced bulk seed of the population to be improved, in isolation, inferior plants rogued out before pollination wherever possible and selecting and bulking superior genotypes that already exist in the population. A balanced bulk of selected ears, for example, in corn is made for planting the next cycle. Selection units are individual plants. Selection is surely on phenotypic performance. This method exploits additive gene effects plus additive x additive interactions. The efficiency of this method depends largely on the heritability of the trait under selection. Selection results using mass selection have been quite effective for less complex traits. Mass selection could be very effective for those traits that can be identified or selected prior to flowering, for example, curd/head shape, size, colour in cauliflower and cabbage, root shape, size, colour and quality traits in radish and carrot and bulb shape, size, colour and weight in onion. A few examples of such traits in maize could be flowering, leaf angle, prolificacy, resistance to thrips, fall armyworm, reduced plant and ear height, reduced anthesis-silking interval and barrenness and tolerance to pre-flowering diseases.

Lack of pollination control is major limitation of this method as both desirable and undesirable pollen will be involved in pollination of the selected plants. Further, if selection intensity is very high (small plant population size advanced), the possibility of inbreeding depression is increased. This selection is not very effective if the heritability of the trait under selection is low (less than 10% on individual plant basis). Mass selection is likely to be more effective for individual or a combination of few traits rather than a whole series of characters. Despite some limitations, mass selection can be very useful and relevant procedure in breeding of cross-pollinated crops in many situations characterized by resource limitations, non-availability of trained scientific manpower and additional test sites, lack of seed storage facilities even for short term and lack of continuity of technical personnel. Lack of control on soil variability also makes this method less effective.

SCARs are DNA fragments amplified by the Polymerase Chain Reaction (PCR) using specific 15-30 bp primers, designed from nucleotide sequences established in cloned RAPD (Random Amplified Polymorphic DNA) fragments linked to a trait of interest. By using longer PCR primers, SCARs do not face the problem of low reproducibility generally encountered with RAPDs. Obtaining a codominant marker may be an additional advantage of converting RAPDs into SCARs. However, SCARs may exhibit dominance when one or both primers partially overlap the site of sequence variation. SCARs are locus specific and have been widely applied in gene mapping studies and marker assisted selection (Paran & Michelmore, 1993).

Synonym : PCR-RFLP (PCR- Restriction Fragment Length Polymorphism)

The Cleaved Amplified Polymorphic Sequence or CAPS method is a technique in molecular biology for the analysis of genetic markers. It is an extension to the Restriction Fragment Length Polymorphism (RFLP) method, using polymerase chain reaction (PCR) to more quickly analyse the results.

Like RFLP, CAPS works on the principle that genetic differences between individuals can create or abolish restriction endonuclease restriction sites, and that these differences can be detected in the resulting DNA fragment length after digestion.

In the CAPS method, PCR amplification is directed across the altered restriction site, and the products digested with the restriction enzyme. When fractionated by agarose or acrylamide gel electrophoresis, the digested PCR products will give readily distinguishable patterns of bands. Alternatively, the amplified segment can by analyzed by Allele specific oligonucleotide (ASO) probes, a process that can often be done by a simple Dot blot.

For the preparation of this book, the authors have drawn heavily from the following sources.

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