eChapters

Cleaning and sanitisation are the two processes employed in dairy industry to ensure hygiene and product safety. The safety of milk and milk products is a very important aspect and every attempt should be made, during processing, to minimize contamination through handling and processing equipments. The accumulated dried milk solids (milk stones) consist largely of calcium phosphate, milk proteins (precipitated, coagulated and baked on by heat) and insoluble calcium salts from water and washing detergents. The surface can also contain biofilms, which are formed by the incorporation of bacteria into the accumulated inorganic and organic materials that attach to most surfaces. With time and in the presence of nutrients, a biofilm and the bacteria within the biofilm will grow and become strongly attached to the surface. The removal of dairy soil, milk stones as well biofilms is the prime objective of the cleaning process. International Dairy Federation (IDF) defines a clean surface as one which is free from residual film or soil that will not contaminate the food products coming in contact with it.

While cleaning refers to the removal of soil from the surface of the equipment, sanitisation implies destruction of all pathogenic and almost all non-pathogenic organisms. Cleaning and sanitisation are complimentary processes. Either of the processes alone will not achieve the desired result, which is to leave the surface as free as possible from soil and viable organisms. In actual practice cleaning and sanitisation overlap to some extent, as during cleaning a high proportion of bacteria are destroyed and others get removed in the detergent solution. Inadequate or faulty cleaning and sanitisation can have serious consequences, as milk is a prefect nutrient in which bacteria can multiply. A thorough understanding of the cleaning methods is, therefore, necessary for economic production of high quality food products.

Packaging is a tool that is used to contain the product, protect the product from environmental hazards and help in marketing the product. Examples of ideal natural packaging systems are that of a banana, orange, coconut and egg, where the packaging is provided by nature. The major step forward in the food processing arena has been the ability to protect and preserve products with packaging and hence ensuring the availability of fresh and processed products out of season and over long distances in various forms. Milk is a highly perishable product and is not uniformly available round the year to the whole country due to geographical and genetic variations. If dairy products are to be available all the year round the country, irrespective of the season and area, it must be presented in packages that are convenient to purchase and use.

Packaging has additional responsibilities of providing convenience, safety and facilitating, besides handling, storage and distribution of products. It should prevent spoilage of food by microbial or insect attack. It also preserves the quality and nutritive value of many foods by the exclusion of oxygen and the control of moisture loss or gain. It increases the shelf-life and ensures longer availability and contributes to the product image through structural and graphic design. Product information is also given out through the medium of labeling, which acts as a tool for marketing and advertising.

Milk, as secreted in the udder of a healthy animal is practically sterile, but during its transit to the processing plant, becomes heavily contaminated with a variety of micro-organisms. These may be responsible for spoilage of milk or for causing diseases in animals and human beings. It thus becomes imperative that adequate heat treatment is given to milk to destroy these micro-organisms, thus increasing the shelf-life of milk as well as making it safe. Varied heat treatments offer the potential of producing different kinds of processed milk to satisfy the needs of the consumer. To cater to the ever-increasing demand of consumers, several varieties of processed milk are available in the market, some of which are discussed below.

5.1. Pasteurised Milk

Pasteurisation was named after the renowned French scientist Louis Pasteur, who discovered that spoilage organisms could be inactivated in wine by applying heat at temperatures below its boiling point. The process was later applied to milk and remains the most important operation in the processing of milk.

It is the process by which every particle of milk is heated to such temperature-time combinations (usually to 63°C for not less than 30 minutes or to 72°C for not less than 15 seconds) and promptly cooled to 4°C or below so as to destroy any harmful bacteria that may be present without affecting flavour and food value. Pasteurisation does not involve the use of any additives. Apart from making milk safe to drink, pasteurisation increases the length of time it can be kept before it spoils. The nutrient losses due to pasteurisation are so small, that they are considered insignificant.

Milk, on reception at the dairy factory is subjected to various unit operations on its way to product manufacture. Processing is applied as a means to convert liquid milk into products or to render the milk (and products) safe from harmful organisms. The basic processing operations to which milk is subjected at processing units have been described in this chapter. The common processing operations employed are depicted in Fig. 4.1. Several of these operations are routine compulsory processes common to all dairies, while certain others are undertaken for specialized purposes in some dairies.

4.1. Filtration and Clarification

At the time of milking various foreign materials such as dirt, feed, manure, dandruff, hair, flies, dust particles, worn out cells, cell debris and many other undesirable substances may find their way into milk. The process of removal of this extraneous matter (solid particles of higher density than that of milk) is called filtration or clarification. This can be achieved either by simple filtration through specially woven filter cloth or continuous process of centrifugal clarification that helps

Milk production in India is a subsidiary activity of agriculture in contrast to the organized dairy sector in the western countries. Farmers and landless labour maintain one to five milch animals. As a result, small quantities of milk are produced in a scattered manner. Due to this reason, milk procurement models from western countries, such as bulk cooling and bulk transportation are not applicable under Indian conditions. Collection of small amounts of milk is scattered over long distances and, therefore, poses a formidable challenge in maintaining the quality attributes and keeping costs down.

3.1. Rural Milk Collection

A systematic approach to rural milk collection suitable for the tropical climate and techno-economic conditions prevailing in India has been developed, based on the indigenous experience gained over the past few decades. In the first phase, extensive surveys are undertaken in the milkshed areas, where the milk plant is to be established. The second phase involves ‘route planning’ taking into account, availability of quantities of milk, access to roads for plying vehicles and distance from the site of dairy plant. Then zones are identified, representing equal costs of collection and transportation. In the third phase, planning is done for locating the primary collection centres as well as chilling centres, where, milk can be cooled to 4ºC before transporting to the milk plant. Milk may be collected from individual producers either by the contractor or by forming village level cooperative societies.

Milk is the secretion of the mammary glands of animals. For human consumption, milk is that liquid obtained from the cow or the buffalo during the period following at least 72 hours after calving or until the milk is colostrums-free. It is a complex biological fluid consisting of seven main components: water, fat, protein, sugar (lactose), minerals, vitamins and enzymes. Milk is a white opaque fluid in which fat is present as an emulsion, protein and some mineral matters in colloidal suspension and lactose together with some minerals and soluble proteins in true solution. The opacity of milk is due to its content of suspended particles of fat, proteins and certain minerals. The colour varies from white to yellow depending on the carotene content of the fat. Skimmed milk is more transparent with a slightly bluish tinge. Milk of a good flavour has a pleasant, slightly sweet taste, and no odour. It is an excellent source of calcium, phosphorous and riboflavin. Vitamin A and D are currently added to whole milk, partly skimmed and skimmed milk.

1.1. Introduction

The significance of milk as the most wholesome single food available in nature has never been debated. It is as ancient as mankind itself, as it is the substance created to feed the mammalian infant. All species of mammals, from the lowly rat to the mighty whale, produce milk for this purpose. Several centuries ago, perhaps as early as 6000-8000 BC, ancient man learned to domesticate species of animals for obtaining their milk for consumption. These included cows, buffalos, sheep, goats and camels, all of which are still used in various parts of the world for the production of milk for human use (Fig. 1.1 & 1.2).

Abstract

Drying is a widely used method of food preservation. It leads to some structural changes in the dried material resulting in poor quality and rehydration. Freeze drying, though a costly process, reduces water activity without exposing the food material to high temperatures, eventually retains the original quality to a great deal. Moisture in the foods is frozen to ice which is sublimated under low pressure. Low pressure helps to vaporise the ice without transforming it to liquid, hence leaving the food structure porous in nature. The food is claimed to preserve the nutritional, sensory and re-constitutional qualities.

1.1 INTRODUCTION

Most food materials are composed of a very high percentage of water, which can be as high as 95%, and this makes them susceptible to microbial activity. Microbial activity spoils the products, leaving them useless for human consumption. It not only changes their taste and color but it may also develop toxins, thus making them unsafe. There are various methods for preserving food but in order to make them shelf stable, removing water from foods helps keep them from spoiling for a longer period of time.

Abstract

Multiflash drying (MFD) process is based on the application of multiple cycles of heatingvacuum pulse to a solid food. Heat can be provided by convection (from hot air), conduction (by contact with a hot surface), microwaves, or by a combination of these methods. Due to the moderate temperatures applied to the drying food, and the sudden decompression step (vacuum pulse), MFD processes allow obtaining crispyanddried foods with very good nutritional and sensory properties. Vacuum pulses cause food texturization, which depends on the pressure drop rate during decompression. In fact, the dried products are similar to freezedried foods, but with more open structures, which result in higher crispness. The dehydration can be performed in relatively short processing times, when compared with traditional drying processes (e.g. solar drying, airdrying, vacuum drying and freezedrying). The short process time indicates clearly that this class of drying process presents a huge potential to the production of driedandcrisp foods at industrial scale.

Abstract

Drying is one of the most important industrial operations for preservation of food material. Due to the major limitations posed by convective drying methods, there is always a need for novel drying techniques which are technically, economically and environmentally sustainable. Based on the principle of moisture diffusion due to vapor pressure gradient, atmospheric freeze drying (AFD) offers a promising alternative to conventional drying systems. A cold gas with low water vapor pressure is used as drying medium to sublimate moisture directly from the frozen material at atmospheric pressure conditions. As a result the product gets dried at much lower temperature unlike convective drying. Thus, products dried with AFD retain better nutrition, texture and color and the process is also considerably cost effective. Major limitation of the AFD process is longer drying time, which can however be accelerated by using heat pump drying or new ultrasound technology. This chapter focuses on mechanism, benefits, limitations and comparative study of AFD with other drying methods such as hot air drying and vacuum freeze drying. It provides an insight regarding effect of AFD on properties of food material based on various studies reported in literature.

Introduction

The dairy sector is one of the most important food sectors, which introduced the physical, chemical, microbiological and sensorial criteria duringprocessing steps and in the final dairy products. Several agents/ingredients of non-dairy origin are commonly used to maintain the quality of milk and milk products during processing, transportation and storage. In general, such ingredients are known as food additives and it can be antioxidants, coloring agents, flavoring compounds, preservatives(naturals and synthetic),artificialsweeteners, vitamins, minerals, stabilizers, emulsifiers and curing agents. From the safety point of view, some toxic agents can come into contact of dairy products duringmilking, storage or processing; such as fungal toxins, heavy metals, antibiotics or radionuclide’s, etc., which need to be identified and processed accordingly. Although addition of food additives in food/dairy product is controlled under country specific food laws or Codex Alimentarius Commission (CAC), few dairyproducts such as butter and unflavored fermented milk products are highly restricted for food additives.

Introduction

Spectacular accomplishment in every sector has enabled India to be amongtop achieving nations. However, every section of the society is not benefited by these achievements and problem of malnutrition still remains unresolved. Malnutrition is a common problem faced by underdeveloped and developing countries suchas Philippines, Nepal, Sudan,Tanzaniaand Indiasincelongback. Malnutrition includes undernutrition(wasting,stunting,underweight),inadequate vitamins or minerals as well as overweight, obesity and resulting diet-related non communicable diseases(NCDs). As per the latest report of World Health Organization, 52 million children under 5 years of ageare wasted, 17 million are severely wasted and 155 million are stunted, while 41 million are overweight or obese (WHO, 2018). More than 50% women of marriage age are suffering from anemia. If women are malnourished at the time of pregnancyand delivery, the babybornface theproblems such asphysical retardation,sensitive tocommon infections, reduced cognitive abilities, reducedmental development, etc. As per the World Health Organization (WHO) guidelines, starting from the date of conceiving a child, the first 1000 days are a critical window from nutrition point ofview.Unfortunately, inseveral regions of developingcountries includingIndia, neither the mother nor the babyis provided with the right quantity and qualityof food during this window period. Therefore, it is important for the policymakers to identifymalnutrition at an earlystage for timelyplanningand implementation of various intervention strategies at the community, village, and district level. NitiAyog, Government of India (GoI) (previously known as Planning Commission), in an effort to eliminate malnutrition,regularlyplans several short and longtermnutritionalprogrammesand policies.In thischapter,we willdiscuss some of these policies launched since independence and their impact in combatingmalnutrition.

Introduction

There are manypeople all over the world who have a certain level of sensitivity or intolerance towards milk and milk products. The reactions to milk which involve the immune systemare termed as milkallergy, whereas, difficulty in the digestion of the milk and milk products is known as milk intolerance. Milk intolerance occurs due to malabsorption of milk sugar (lactose) in intestine, a condition in which lactose is not digested into its monomers (galactose and glucose) due to lower activity or insufficiency of lactase enzyme. Inability to digest lactose, which is a disaccharide present only in milk, is specifically known as lactose intolerance. However, hypersensitivity involves the adverse immune reaction(allergic reaction) inthe body causeddue to the ingestion of milk proteins. Milk and milk products are major source of basic as well as essential nutrients and cannot be skipped from the diet of the individual. It is a rich source of calcium,which is essential for the growth and reformationof bones. The decline in calcium may lead to thin, fragile bones that break easily, a condition called osteomalacia or osteoporosis in women. Thus, it is a matter of concern for both children andadults whoare allergic or intolerant towards milk and milk products and not getting enough calcium and other nutrients in diet. This chapter would provide more insight about milk intolerance and milk allergy/hypersensitivity and how to deal with it.

Introduction

Digestion may be defined as the hydrolytic process carried out by various enzymes for breaking down complex food components such as proteins, fats and carbohydrates into simpler molecules like amino acids, fatty acids and monosaccharides, respectively. Whereas, absorption may be defined as the movement ofthese simple soluble digested food componentsalongwithvitamins, minerals and water from gastrointestinal track into the circulatory system.

The process of digestion starts from oral cavity (mouth) and ends at large intestineincluding tongue, teeth, jaws,secretions from salivaryglands (parotids, sub maxillary or submandibular and sublingual glands), pharynx, esophagus, stomach, small intestine and digestive enzymes secreted from pancreas and liver.

Introduction

Nutritive value of any food indicates the calories content as well as quality attributes. Macronutrients such as carbohydrates, fats and proteins provide energy by4-9-4 rule. It meanstheyprovide 4,9 and 4 kcal/genergy, respectively, when oxidized completely. Though micronutrientssuch as vitaminsandminerals do not provide any calories, they are essential for the enzymatic activity and metabolic reactions.

ATP or energy is measured in terms of ‘calories’ or ‘joule’. One calorie is the amount of heat required by 1g of water to increase its temperature from 14.5 to 15.5°C under standard conditions. Nutritive value of any food can be measured on shelf usingcalorimeter, in which food is completelyoxidized under specified conditions and converted into CO₂ and water.

Introduction

Nutrition is the fundamental pillar of life and an essential foundation of human and national development. Rightfrom the earliest stage of human development, the fetal stage, at birth, infancy, childhood, adolescence, adulthood and old age, nutrition forms the basis for survival, performance, mental and physical development & economic and social development.Nutritional deficiencies during pregnancy, fetal and early postnatal life can have a negative impact not only on the subsequent growth and development but can also lead to changes in metabolic regulation and homeostasis.

Introduction

Nutrition, a basic human need, is a critical part of health and development. Nutrition can be defined as the intake of food, deliberated in relation to the body’s dietary needs. On one hand, good nutrition – an adequate, well balanced diet combined with regular physical activity – is a foundation of good health, whereas,poor nutritionleads toreducedproductivity,impairedmental andphysical development, increased susceptibility to disease, and reducedimmunity. According to WHO, under-nutrition, together with vitamin and mineral deficiencies accounts for one-third of all child deaths and impairs healthy development and lifelong productivity. At the same time, sedentary lifestyles, demographic shifts, urbanization and the liberalization of markets have steered the world population to being overweight along with risk of chronic diseases like hypertension, dyslipidemia, type 2 diabetes, coronaryheart disease, stroke, etc.; thus, resulting in a double burden of malnutrition.

To address this dual burden of malnutrition, individuals needaccess to sufficient and good quality food; but focussing solely on food security is unlikely to solve the problem of global malnutrition. The challenges of malnutrition cannot be solvedjustbyincreasingfoodproductioninordertoimprove healthand nutritional status of the population. To resolve such challenges, awareness about food choices for optimal health plays a pivotal role among population.

Human nutrition is the science of understanding food; its component; intake; and how it is related to health, growth, development and diseases. Human nutrition involves the study of ingestion, digestion, absorption and assimilation of the nutrients; their metabolic functions, deficiency or excess disease as well as their regulation through several factors such as choosing particular food components/nutraceuticals or physical activity.

Introduction

The basic physiological structures of mammary glands in all species are almost same and are located externally in order to fulfill the milk requirement of neonates after parturition. The process of secretion of milk from the mammary glands is known as lacto genesis. Milk provides an almost complete nutrition to neonates from birth till weaning period. It is a complex mixture of various constituents like:

Lipids such a striacyl glycerols(TAG),phospholipids,cholesterols and other sterols, free fatty acids and fat-soluble vitamins

Carbohydrates such as lactose, oligosaccharides

Proteins such a scaseins, α-lactalbumin, β-lactoglobulin, immunoglobulin’s, bovine serum albumin, lactoferrin, lysozyme, enzymes, hormones and growth factors

Non-protein nitrogenous compounds like urea, creatine, creatinine, uric acid and amino acids

Major and minor minerals, water-soluble vitamins and cells (leucocytes, macrophages, and epithelial cells).

Introduction

Proteins are the most abundant organic compounds constituting major part of the body. Chemically, proteins are nitrogen containing macromolecules and polymers of L α-amino acids, which serve a wide range of structural and biological functions in animal body. For example, connective tissue made up of collagen, metabolicenzymes, neuro transmitters,signal in gmolecules, structural components of cell membranes and cell organelles, etc. all are chemically proteins.

Before goinginto the details of protein metabolism, first, we need to understand that there are majorly two sources of proteins in our body: dietary protein and body protein. Dietary protein is taken in diet, while body protein indicates the protein and amino acids synthesized in animal body to fulfill the requirements for growth and development. The digestion of proteins will not be discussed here as it has been described in detail in chapter 12. Dietary protein is digested in presence of several enzymes such as trypsin, pepsin, chymotrypsin, aminopeptidases and carboxypeptidases and is converted into mono-, di- and oligopeptides in stomach and small intestine; and finally converted into amino acids. These amino acids are transported to the systemthrough intestinal mucosa via active transport, from where they enter into the cells for further metabolism. Therefore, ‘metabolismof proteins’ is more appropriatelylearnt as ‘metabolism of amino acids’.

Introduction

The diverse cluster of naturally occurring organic compounds including fats, oils, fatty acids, waxes, phospholipids, eicosanoids, terpenes, steroids and fat soluble vitamins that do not prefer to interact with water but soluble in non-polar organic solvents like ether, chloroform, benzene, acetone, are called as lipids. The main functions of lipids in biological system include storage and transport of metabolic fuel, structural component of cell membranes, insulation & protection of vital organs from shock and carrier of fat soluble vitamins. Contradictory to proteins,lipids are not polymers in nature and are hydrophobic due to presence of a long hydrophobic chain. Apart from this, lipids also act as precursor molecules for several pigments, hormones and signaling molecules.

Introduction

Carbohydrates are the most common source of energy for all living cells, which, in presence of light, are formed by the green plants from CO₂ and water during photosynthesis. It canbe said that ‘light’ is theultimatesourceof energyrequired for all livingcells.Glucose,a monosaccharide,plays a centralroleincarbohydrate metabolismin all plants, animals and manymicroorganisms. Glucose is derived from the polysaccharides (starch, glycogen) and non-carbohydrate sources (amino acids, glycerols, etc.) during metabolism and ultimately converted either into carbondioxide and water orotherintermediateproducts.Complete oxidation of glucose to CO₂ and water provides ~2,840 kJ/mol energy. The other monosaccharides such as fructose, galactose, mannose, etc. are also important molecules in carbohydrate metabolism.

Introduction

Hormones may be defined as specific chemical molecules produced in certain specific organs called specialized cells or endocrine glands. They are delivered into the blood stream or some other body fluid in minute amounts by the circulatory system of the body and their they exerts a physiological effect at a site of action remote from its origin, regulating numerous biological activities including growth, development, reproduction, water & electrolyte balance, storage & usage of energy etc.

Introduction

The basic components of diet include carbohydrate, protein, fat, vitamins and minerals. Vitamins are the essential nutrients which are not formed in our body and required in minute amount from the diet. Vitamins are crucial for the optimal functions of several enzymes; thus important for optimal growth and development. Vitamins perform various functions that help in regulation of metabolism, prevent chronic diseases, maintain natural appetite, mental health and immunity.

In 1912, Polish biochemist Kazimierz Funk coined the term ‘vitamine’;a substance that was present in rice polishing and foods that cured polyneuritis in birds and beriberi in humans. The name is from ‘vit’ for vital nutrient and ‘amine’ for its similarity as an amine. Vital signify that these factors are indispensable for life. Earlier they are identified and thought to contain amino groups, thus the word amine was used, which was true for thiamine but later work revealed that most of the vitamins do not have amino groups. Thus the word was shortened to vitamin in English. It should be noted that the term vitamin does not denote to some othern utrients such as essential amino acids, essential fatty acids, dietary minerals or other nutrients that contribute towards good health.

Vitamins may be defined as organic compound needed in minute amount through diet to perform specific biological functions for normal growth and health of the organisms.Vitamins should have following characteristics:

Introduction

The nucleic acids are the molecular depots that are responsible for continuity of life by transfer of hereditary information from one generation to next. The sequence of nitrogenous bases containing programmed instruction determines the structure of every cell constituent and eventually every protein. In 1869, Friedrich Miescher, Swiss chemist, isolated an unknown phosphate-rich substance from pus cells named as nuclein, which was quite different from other organic substances like carbohydrate, protein, and fat. Altmann in 1899 ascertained that the nuclein also had some acidic characteristics and changed its name to ‘nucleic acid’. Later, nucleic acid was also isolated from salmon sperm nuclei as DNA-protaminecomplex. In 1953, James D.Watson and Francis H.C. Crick constructed the model of three-dimensional double helix structure of the DNA molecule which could successfully explain DNA replication.

Introduction

Billions of chemical reactions are happening inside human body and that too with lightning speed. However, the same reactions if carried out in laboratory, they take a very long time. The reasons behind it are the biocatalysts, also known as enzymes, which are synthesized by living cells. Chemically, they are proteins(except ribonucleic acids: RNA), colloidal in nature, thermo-labile in character and very specific in their action. For example, hydrolysis of proteins by a strong acid at 100°C takes a couple of days; but same proteins can be digested within couple of hours inside human body at 37°C. Similarly, carbonic anhydrase is used as a catalyst by living cells to transfer carbon-di-oxide from cells to blood. This process is 107 times quicker than the same process if occurs without the help of enzymes. Therefore, enzymes can be defined as the biomolecules or biocatalysts which can speed up the rate of the chemical reactions. The substance upon which an enzyme acts is called as substrate and the one which is produced as the result of enzyme-substrate reaction is known as product.

    1.    Rice is a
        a)    Edible fruit    b)    Edible Vegetable
        c)    Edible flower    d)    All
    2.    Major components in cereal seeds are 
        a)    Endosperm    b)    Germ or embryo
        c)    a & b    d)    None
    3.    Bran is composed of 
        a)    Pericarp    b)    Testa
        c)    aleuron layer    d)    All
    4.    Oats contains ______________ percent of hull
        a)    50    b)    40
        c)    30    d)    20

The choice of hormones and drugs acting on reproductive system are important as therapeutic agents during reproductive disorders like anoestrus, metritis, pyometra, repeat breeder, retention of fetal membranes, delayed puberty, ovarian disorders etc.  The administration of specific chemotherapeutic agent is of paramount importance in treating reproductive disorders in dairy animals.  The dosage, route, frequency and indications of chemotherapeutic agents acting on reproductive system are mentioned in tabular form as below.

Reproductive process involves many events that have to occur in a well balanced manner if satisfactory fertility rate is to be achieved. Any adverse  effect of  physiological, morphological  or environmental effect on the male  or  female may result  in failure  of  fertility  or reduced fertility  depending  on the severity of the cause. Apart from this, the role of person who stands between the cow and the bull play an important role. The efficiency of the person handling the semen and depositing in the reproductive tract of domestic animal will influence to a great extent on the conception rate in A.I. programme. It is observed that certain bovine population fails to conceive at a single service or series of services.   Some times there is loss of conceptus during gestation or produces a dead calf or weak calf that will die soon after birth.
 
Consequences of these factors affect cows and may have long calving interval, abortion or sterility, all of which tend to decrease the average daily production of milk.

The various steps involved in frozen semen technology are vital as the quality of semen determines the conception rate.  The key factor enabling the successful long term storage of frozen spermatozoa is maintenance at ultra low temperature.  Effective semen storage depends heavily on good identification and stock control.  Frozen semen can be easily damaged in the process of repeated handling to establish identity.

Several cryogenic agents have been used in many countries for freezing and preservation of bovine semen like solid carbon-di-oxide (-79°C), liquid air (-183°C), liquid helium (-268°C) and liquid nitrogen (-196°C).  Liquid nitrogen is 4th coldest substance known and its small amount is converted into a very large amount (near about 700 times) of its volume when exposed to atmosphere.  It is a colourless, odourless, non-irritant, non-toxic, non-caustic, non-corrosive, non-inflammatory and inert gas having boiling point -196°C temperature.  Being a liquid it comes into good contact with the surface of the semen straws and constant storage temperature is maintained throughout the straw and due to these properties LN2 is most widely used refrigerant in the world.

There is no rapid direct test to determine fertility of semen sample. During freezing and thawing of semen 20-80% of the spermatozoa become immotile or die. In addition to this, there may be damage to spermatozoa by disintegration of sperm cell membrane and acrosome leading to loss of intracellular enzymes.   The only reliable method to evaluate the semen is to inseminate a cow and get a calf at the end of gestation period.  Now-a-days new methods have been developed for in-vitro assessment of fertility of spermatozoa.  Some of these methods are exhaustive, time consuming, need for a full fledged analysis and difficult under field conditions.

Production is based on reproduction and health of reproductive system. Economy of livestock industry is directly attached to the maintenance of high fertility in the herd so controlling the reproductive diseases in cattle is a must.  Reproductive health may be disturbed by reproductive infections like Brucellosis, Leptospirosis, Infectious bovine rhinotracheitis and Bovine viral diarrhea.

A typical repeat breeder cow or buffalo is an apparently normal cycling cow / buffalo with normal genitalia which has failed to settle to services or inseminations during three or more consecutive estrus periods. These animals can neither be considered as sterile nor can settle to subsequent services.  Age of the repeat breeder should not have exceeded beyond 12 years.

The causative factors for repeat breeder animals fall in two main categories as failure of fertilization and early embryonic death.

Infertility means reduced fertility or the cow is ultimately capable of becoming pregnant and giving birth to a live calf but the interval may be much longer than 12 months. 

I. Problems leading to infertility

1. No signs of estrus

When the animal is pregnant and for a short time after calving the cows may not show estrus signs. A thorough palpation of the ovaries and tubular genital tract should be performed and a repeat examination may be necessary.

Buffalo plays an important role in Indian livestock economics.  India has more than the half of the world buffalo population, contributing 50% of total milk production of the country.  The buffalo is said more productive than an average cow due to the higher fat percentage (7%) in the milk, better feed conversion ability and disease resistance.  Buffaloes have lower reproductive efficiency in the form of delayed age of maturity, longer calving interval, weak / silent estrus, seasonality of breeding, poor libido and poor semen quality. A large number of buffaloes do not conceive due to some gynaecological problems and are being slaughtered every year.  The most commonly observed reproductive disorders are detailed below.

Non-specific uterine infections reduce the reproductive efficiency of livestock.  They are called nonspecific because the initial colonizing bacterium is not known and the specific bacteria causing the signs of infection are not known.  Even though numerous bacteria, in a variety of combinations, have been isolated from infected uteri, Corynebacterium pyogenes and Escherichia coli are usually associated with uterine infections in cattle and sheep.  Empirical therapeutic approach, prescriptions without scientific validation (extra-label use) or inadequate clinical judgment itself to ascertain the nature of uterine infection, obviously due to lack of diagnostic tools are the prime reasons for therapeutic failure for the unsuccessful treatment of uterine infection by large animal practitioners.

Laparoscopy is an operative procedure performed through a key-hole opening with a rigid endoscope that allows visual inspection of organs.  The laparoscopy helps in arriving diagnosis of various reproductive and digestive disorders quickly.  By laparoscopy clinician can visualize the external surface of the abdominal organs.  Tumours, abscess, cyst, lesions, growth, hemorrhage, adhesions of the organs in the abdominal cavity can be readily diagnosed by this technique.  Aspiration of follicular fluid, biopsy of lesions and sterilization are commonly employed maneuvers by this technique.  It is having both diagnostic and therapeutic value.  The procedure consists of placement of transabdominal rigid endoscope after establishment of pneumoperitoneum in the body cavity.   The images of different organs are displayed on the TV monitor when the laparoscope is moved within the peritoneal cavity with the illumination through halogen light source.

The ultrasonography is a technique which uses sound waves of very high frequency to scan the various organs of the body. The ultrasound waves of 2-10 mHz frequency are used in veterinary practice. A quartz crystal when stimulated by short pulse current ultrasound waves are emitted. The ultrasound waves emitted are directed towards a specific target organ are reflected back as echoes. The echoes are received by the same quartz crystal and are processed in the electronic circuit and finally displayed as image on the monitor.

Buffaloes, though have great production potential, do suffer with many reproductive problems viz.  delayed age of puberty and  sexual maturity, weak / silent estrus, longer inter-calving period,  seasonality in breeding, poor libido  and poor semen quality. Little information is available about the buffaloes as compared to cattle because all the time we try to apply the knowledge available about the cattle to the buffalo.  Some comparative reproductive parameters in cow & she buffalo & cow bull and buffalo bull are depicted in Table 8. 1 and Table 8.2 respectively.

Synchronization of estrus is making a group of cows to come into estrus at the same time.  Effective estrus detection requires much time, labour, skill and expense and it is a major limiting factor in artificial insemination programme in cattle.  It was the principal stimulus that led to research in the development of progestational and prostaglandin compounds. 

Advantages

1.     Improve the efficiency of heat detection

2.     Management tool, better planning of breeding activities and wider use of artificial insemination 

3.     Solve problem of unobserved estrus

4.     Maintain short calving interval

5.     Overall improvement in herd productivity and reproductive efficiency

6.     Controlled lactation

7.     Management of replacement heifers

8.     Useful in embryo transfer programmes

9.     Reduce labour

10.     Possibly reduce involuntary culling for reproductive reasons

After the Second World War, the 1940’s and 1950’s was the wide spread establishment of artificial insemination and the introduction of frozen semen in cattle breeding.  In the late 1960s came revolution in measurement of hormones in the body fluid with the introduction of sensitive radio-immuno-assay (RIA) techniques, which provided a new approach to early pregnancy diagnosis, emerging around the same time were early forms of the ultrasonic which could also employed in the detection of pregnancy. The 1970’s were to see embryo transfer and freezing of embryos in cattle becoming commercial realities and their incorporation into increasingly effective breeding improvement programme with the availability of prostaglandins (PGs) and Gonadotrophin releasing hormones (GnRH) that decade also witnessed new possibilities for estrum control in cattle and horses.  Few years later came the ability to produce the cattle embryos in the laboratories in large numbers and at low cost.

Faulty estrus detection is the most important problem in reproductive management.  There are two requirements for good estrus detection: a skilled observer must spend sufficient time to make observations and cows must show overt signs of estrus during the period of observation.  There are various ways to detect the estrus signs in cows and buffaloes as detailed below.

1.    Palpation of reproductive organs:  Routine rectal examination of all cows between 30-40 days after calving and individual cow that has not been inseminated within two months after calving should be encouraged.   This is to confirm that the reproductive tract is normal and to predict when the next estrus will occur or to identify cows for prostaglandin treatment when estrous cycles are occurring, but estrus has not been detected. 

2.     Teaser bulls:  Teaser bulls are useful in identifying estrus in large number of animals especially buffalo cows.   Teaser bulls can be prepared by vasectomy or by applying apron to a bull. 

3.     Heat detector animals:  Sexually active animals like bulls, cystic cows, hormone treated steer, cows and heifers can be used to identify estrus cows.    They may be fitted with halters containing ink- filled reservoirs and ball paint pen type devices (chin ball markers) that will mark animals that mounted or they can be used without these devices to increase the sexually activity and make visual detection programs more effective.

India has a mega animal bio-diversity, which is manifested in the form of availability of a large number of species, and a variety of breeds even within species. India is bestowed with rich and varied domestic animal biodiversity having a total of 32 breeds of cattle and 10 buffalo breeds. The diversity of livestock is not only accidental, nor purely natural; it is more the outcome of thousands of years of continuous selection. The trends in livestock population over the last three decades have shown that, there is significant increase in the population of buffaloes i.e. from 60.5 crore in 1973 to 96.9 crore in 2003, while cattle population has increased from 180.1 crore to 226.1 crore in the same period. The share of buffaloes, in the bovine population increased from 22 to 32 per cent while that of cattle has shown declining trend. Within the cattle, there has been marked shift from work animals towards milch animals which has resulted in loss of important draught breeds of cattle. Further indiscriminate crossbreeding has resulted in significant decline in number of important milch breeds like Sahiwal.

Livestock diet or ration may be made up of one or several ingredients depending on the species of animal, their physiological state, source of feed and its nutritional composition, nutritional requirements of the animals and voluntary intake of the feed. Chemical and nutrient composition with each ingredient varies tremendously and no single feed ingredient is complete in its nutrient composition with respect to animal’s requirement.  Therefore, animal feed has to be balanced properly to supply required nutrients in appropriate quantity.  Feed formulation is an art of quantitative application of science of nutrition for the optimum supply of all the essential nutrients through actual feeding of animals. This exercise may be as simple as mixing of few ingredients with simple mathematical calculation or preparation of least cost balanced ration by computer programme.  Since the expenditure on feeding is substantial in livestock production, feed formulation needs special attention of nutritionists or feed technologists. The instruments and equipments used for feed formulation and estimation of micro minerals and ingredients like Feed grinder and mixer of capacity 75 kg, Fibertech for fiber estimation, Hammer mill-particle size reduction, Mixer and grinder for feed and fodder (complete feed preparation) of capacity 250 kg, Roughage processing-Chaff cutter, Soxhtech for fat estimation, UV-vis-Spectrophotometer and Voltameter for micro mineral estimation are shown in Fig. 3.1 to 3.8.

In our country livestock are mostly dependent upon cereal by-products or the crop residues such as straws, stovers etc., which are low in nutritive value. According to the National Commission on Agriculture (1989-90), there is a shortage of 40% of concentrates, 20% of dry fodder and 40% of green fodder for meeting the nutritional requirements of livestock. Consequently the livestock is surviving on low weight, low energy and thereby leading to problems in the production and reproduction. Nutritional deficiencies as well as imbalances are implicated as the cause of infertility in animals. The clinical signs observed with the deficiency of a specific nutrient as variable depending on the degree of the deficiency. The information on the important relationship between nutrition and health is necessary for recognizing and correlating the reproductive problems.

Estrous cycle

After puberty the female enters a period of reproductive cyclicity, which continues throughout most of her productive life.  Estrous cycle is the rhythmic sexual behavioral pattern exhibited by the female, which begins at one estrus (heat) and ends at subsequent estrus.   It is the period between two estruses of the regular cycle.  The reproductive activity of the female is maintained by the co- ordinated functioning of different organs of reproduction (Table: 1.1). Estrous cycle provides repeated opportunities for the females to become pregnant. When conception does occur, the female enters a period of anestrous during pregnancy, which ends after parturition (giving birth) and uterine involution (repair and returning to normal size).

I. Dairy Farm Equipments

A. First Aid
1. Abscess
What to Do

    ·    Abscesses should be examined by a veterinarian as soon as possible and within 24 hours.
 
    ·    Fluid may normally drain from the site of an abscess. An abscess does not drain through the tube, but rather around the latex tubing. Therefore, it is important for you to clean the area around the drain twice daily with warm water.

    ·    Apply a hot compress to the affected site at least two times daily for 3 to 5 days after the animal leaves the hospital. Wet a clean washcloth with very warm water and place it directly over the affected site, and then apply gentle pressure ideally for 5 to 10 minutes.

General Signs of Healthy and Ill Animals

Health

It is a state of freedom from disease. It may also be stated as a condition of an animal in which all the body organs are normal and are functioning to their optimum capacity in relation to animal’s age, sex, work, and production with optimum pulse, temperature and respiration rates appropriate to the species, sex and environment.

Disease

Disease may be any deterioration from normal health or normal functioning of any or all the tissues or organs of animal body. Thus, it shuns animal to perform its normal physiological functions though the nutritional and environmental parameters are maintained normal.

Milk

Importance

Milk contains approximately 86% water, 4.7% sugar (lactose), 4.1% fat, 4.2% protein and 1% minerals. It supports the growth of micro-organisms and thus is prone to contamination. The purpose of milking a dairy cow is to obtain milk that is fit for human consumption. Milk from the udder of a healthy cow contains very few bacteria and to ensure that it remains fresh for long it should be handled under conditions of good hygiene. Unclean milk can be a source of disease to the consumer, rejected at the market and so is a loss to the farmer, does not keep for long and is not good for processing.