eChapters

A. Define/Explain the followings

1. Mutation: Sudden heritable change in the phenotype of an individual.

2. Macro-mutations: Mutations with distinct morphological changes in the phenotype are called macro-mutations. Such mutations are found in qualitative character and, therefore, are also called oligogenic mutations.

2.1 Introduction in Plant Breeding

A. Define/Explain the followings

1. Plant breeding: Plant breeding is defined as the art, science and technology of improving the genetic make-up of crop plants in relation to their economic use for mankind.

A. Define / Explain the following

1. Mitosis: The multiplication of a body cell into two daughter cells of equal size and containing the same number of chromosomes as in the parent cell is called mitosis or somatic division.

2. Meiosis: Meiosis occurs only in gonads (in germ mother cells) during the formation of gametes like sperm and ovum. Meiosis is a process by means of which double number or 2N or diploid chromosomes is reduced to its half number or n or haploid. It is also called reduction process.

Sonograms of animals suffering from different diseases are presented along with other investigations as case studies to provide a comprehensive picture of the disease.

Utility of ultrasound has extended from diagnostic realm to alternate therapies. Therapeutic ultrasound is also known as ultrasound physiotherapy. It is a commonly used modality for the rehabilitation of the soft tissues of the musculoskeletal system.

Ultrasonography is being routinely practiced in canine and feline medicine for the diagnosis of diseases of the organs and also to confirm pregnancy. Its routine use in ruminant medicine is mainly restricted to pregnancy diagnosis. Recently the potential of ultrasonography is also being explored in zoo and wild animals as well as in exotic pets. Information available in companion and other domestic animals cannot be applied blindly to zoo and wild animals.

During last two decades significant advances have been made in diagnostic ultrasound .These advances have positively impacted on diagnostic imaging across all species of animals and have made ultrasound as an indispensable diagnostic modality in veterinary medicine. Since equines have been more a sport and pack animals, the ultrasound technique has long been utilized in the diagnosis of equine musculo-skeletal disorders. Recent years have witnessed its utility in the management of equine reproduction beside its use in the diagnosis of colic and other diseases.

For the sake of convenience ruminants are broadly divided into two categories as large ruminants and small ruminants. Large ruminants consist of cattle and buffaloes and small ruminants consist of goats and sheep. Sonography is becoming an important part of diagnostic modalities in ruminants also. Its major use in ruminants is in reproduction and lameness.

Architecture of the organ is affected in the primary or secondary diseases of the organs. Ultrasonography plays a significant role in detecting the changes in the organs in various diseases.

Focused assessment with sonography for trauma (abdominal and thoracic) refers to the limited ultrasound examination with the main focus on quick identification of the presence of free fluid within peritoneal, pleural and pericardial spaces in trauma cases in intensive care units. Despite limitations, findings of FAST are helpful in stabilizing the emergency patients.

Abdominal organs in different species of animals have distinctive features with respect to their shape, size, location and echogenicity and echo texture. This is true for dogs and cats also. Therefore, information with respect to sonographic features of dogs cannot be taken for granted for cats in totality

Beside heart, ultrasound of the thorax facilitates the imaging of lungs, pleura, mediastinum, chest wall and diaphragm. Sonographic examination of the heart is discussed in chapter16. Because of nearly total reflection of sound waves at gas interfaces (Fig. 176) thoracic ultrasound has limitations. Pulmonary and mediastinal lesions located deep are difficult to image. Peripheral pulmonary lesions and pleural fluid can be visualized.

Cardiac ultrasound is also known as echocardiography and it has a very important place in the diagnosis of cardiac diseases of the humans as well as animals. Echocardiography is an imaging of the heart using ultrasound. The diagnosis of congenital heart diseases, shunts, complex malformations, valvular heart diseases, different cardiomyopathies, endocarditis, pericardial effusion, cor pulmonale and cardiac tumours has been possible by cardiac ultra ultrasound that was otherwise difficult.

Imaging of muscles, tendons, joints and bones is not common practice in canine and feline medicine. However, scanning of tendons and ligaments is extensively done in race horses to see their fitness. Adhesions, ruptures/ tears and inflammation of tendons and ligaments can be detected by sonographic imaging of these structures. These structures are relatively superficial so a high frequency linear or curvilinear transducer (7.5 to 13.0 MHz) is used to scan these structures. For scanning of joints acoustic window is relatively small so micro convex or sector probes are more appropriate.

Sonography of the nervous system in dogs dates back to 1972 when it was employed in experimental studies. Thick bony cage of the brain limits the sonographic evaluation of the brain. It has an important place in human paediatric medicine. Sonography of the brain and the nervous system is not very common in veterinary medicine.

Ophthalmic or ocular ultrasound can provide important diagnostic information that is readily not available with other diagnostic techniques. Ocular ultrasound is emerging as an important diagnostic modality in veterinary ophthalmology.

Ultrasound has been used to image thyroid and parathyroid glands. It can assist in the diagnosis of hyperthyroidism and hyperparathyroidism in dogs and cats. Recently it has also been used to differentiate cases of primary hypothyroidism or euthyroid syndrome.

Application of ultrasonography has become a routine practice in canine and feline medicine to detect pregnancy, to ascertain foetal wellbeing, to ascertain live/dead status of the foetus, ovarian dynamics, and to diagnose reproductive ailments (uterine, ovarian,) in females. Sonography is also being preferred in males for the diagnosis of diseases of prostate gland, cryptorchid, and testicular diseases.

The urinary tract is the body’s drainage system. It includes kidneys, ureters, urinary bladder and urethra. Ultrasound is a most preferred imaging tool for the diagnosis of diseases of urinary tract not only in humans but also in dogs and cats. Little adipose tissue in urinary system of dogs makes the contrast between different planes and anatomical structures poor.

The pancreas is a thin and elongated ‘V’ shaped organ having two lobes (right and left) and body. It lies in the right cranial quadrant of the abdomen. It is difficult to visualize normal pancreas sonographically because of its echogenicity similar to that of adjacent mesentery and fat.