Preventing Important Infectious Diseases: Key to Successful Dairy Farming
Introduction
Livestock sector has always played a significant role in Indian economy. Nearly 20.5 million people depend upon livestock for earning their livelihood. Livestock contributed 16% to the income of small farm households against an average of 14% for rural households. As per 2019 Livestock census, India is being credited as world’s highest livestock holder at about 535.78 million being first in the total buffalo population (109.85 million and second in total cattle population (192.49 million) in the world. This is undoubtedly a matter to take pride.
As per UNDP report of 2008, the global human population is anticipated to increase to approximately 9.2 billion by 2050. The dairy industry in the developed world has undergone immense changes over recent decades. The commendable advances in dairy health in the last 25 years have been the shifts to disease prevention, rather than treatment. It has been rightly phrased that ‘prevention is better than cure’ that applies to many different facets of our lives. This is a way to tell us that it is better to avoid contracting an illness than to have to go around and look for a way to get rid of it.
There has also been improved protection through vaccination against many infectious diseases. Proper health management leads to the promotion of health, improvement of productivity, and prevention of disease in animals. Infectious diseases in dairy cattle pose threats to food security, food safety as well as national economy and rural environment. In this brief communication, we intend to create awareness among the farming community about some important infectious diseases with associated clinical signs so that it will help them to recognize the diseases in animals in early stage in order to prevent and control them in time with further intervention of veterinarians.
Time to remember the iconic person behind white revolution in India
The concerted efforts of people and government translated in the name of ‘Operation Flood’ have truly transformed India from its deficit state in milk production to the world’s largest milk producing country. Presently India has the largest cattle and buffalo population in the world. Cows and buffaloes are the main milch animals, contributing 96% of the total milk production of the country. As of 2020, production of milk in India was 194,800 thousand tonnes that accounts for 40.56% of the world’s production of milk.
All success was due to the pious initiative and active stewardship of Dr Verghese Kurien, for which ‘Operation Flood’ could be launched in 1970 in India with a kick-start of India’s White Revolution. ‘Rome wasn’t built in a day’ is an adage attesting to the need for time to create great things. Very similarly, white revolution was not an overnight operation. It took several phases to make Kurien’s dream come true. Because of such sincere efforts, Dr Kurien was awarded with many awards such as the Ramon Magsaysay Award for Community Leadership (1963), Padma Bhushan (1966), Krishi Ratna Award (1986), World Food prize (1989), Padma Vibhushan (1999), Economic Times award for Corporate Excellence (2001) and several others. This great man never considered himself a great leader, seeing himself as a mere employee of the farmers. His personality and efforts have made him the India’s most iconic milkman, the ‘pioneer or father of white revolution in India’.
Adverse impact of infectious diseases on productivity
Infectious diseases of livestock are a major threat and stumbling blocks to global animal health and their effective control is thus crucial for agronomic health, for safeguarding and securing national and international food supplies as well as for alleviating rural poverty in developing countries. Milk production is profoundly reduced in cows with clinical disease. The duration of acute clinical syndromes can be short, but its effects may persist throughout the entire lactation stage. A single case of clinical mastitis can result in a milk yield loss of 300-400 kg/lactation, with variations ranging up to 1050 kg.
Physical characteristics of healthy and sick cows
The physical state of a cow is a good indicator to its health status. Healthy animals are alert and active with bright eyes, with no discharge, smooth and shiny skin. They breathe and urinate regularly and their tail moves to drive flies away. Signs of stress include loss of appetite, reduced daily milk yield, increased temperature, high respiratory rate, protruding tongue, breathing with an open mouth, inability to lie down.
- Nutritional status: Cows can be fat, normal or thin. Thin cows are not to be regarded as sick, as they could have recently calved or be high-producing.
However, sick cows tend to lose weight due to inappetance, poor feed digestion
or loss of body reserves. - Eyes and ears: Eyes should be expressive with a bright and lively expression with no discharge.Sunken eyes are indicative of dehydration. Ears should be sensitive and able to freely move around with all alertness.
- Skin coat and visible mucous membranes: The skin of healthy cow is elastic and flexible and the coat is smooth and shiny. The visible mucous membranes
around the eye, nose and vagina should be pink and moist. In
sick cows, these membranes become too red or too pale. - Posture and movement: The way an animal moves indicate pain in the body as a
result of any injury or an infected hoof. - Digestion: Healthy cows have a strong appetite. Faeces and
urine are discharged regularly. Faeces should have a normal colour and consistency with no worms. - Rumination: Healthy cows ruminate frequently when healthy.
- Urine: It should be thin, straw-yellow and clear, while thick, mucous or red urine indicates ill health.
- Vagina: It should be closed with no swelling, no discharge and be slightly whitish red in colour, while swollen vagina with whitish discharge says some reproductive problems.
- Respiration: In healthy cows, respiration is quiet and regular, whereas in disease condition respiration rate increases. Coughing, nasal discharge indicates ill health.
- Blood circulation: Pulse rate of 60-70 beats per minute is normal for healthy dairy cows.
- Body temperature: Normal body temperature is 38.5-39.5°C. Higher temperature
indicates fever due to any underlying disease condition. - Milk production: Healthy cow produces normal milk, while during sickmilk production gets reduced with altered composition.
Important infectious diseases to be prevented for better productivity
- Foot-and-Mouth Disease (FMD)
As an enormous quantum of money is lost every year due to FMD, it has been targeted for eradication under National Animal Disease Control Programme (NADCP) launched by Government of India. It is a highly infectious viral infection of cattle and buffalo characterized by fever, vesicles in the mouth, on the muzzle, gums, teat and interdigital space. It is caused by FMD virus (genus Aphthovirus and family Picornaviridae). There are 3 serotypes of FMD prevalent in India e.g. O, A and Asia 1. It is transmitted by aerosol and through contact.
Clinical signs
Clinical signs in cattle include fever of 40°C or more, followed by vesicular lesions on the tongue, dental pad, lips, gums, hard palate, muzzle, interdigital cleft, and teats in lactating cows. Dullness, inappetence, fever, limping and kicking of feet, abortion of pregnant animals are observed. Acutely affected individuals may salivate profusely in thin rope like fashion (drooling) and prefer to lie down. Secondary bacterial mastitis is common due to infected teat vesicles resulting in resistance to milking. After recovery milk yield drastically drops down.
Prevention and control
The owners should follow vaccination of animals twice a year with FMD vaccine. There should not be any compromise of testing and quarantine of newly introduced animal into the herd. The tongue, feet should be washed frequently with 4% Sodium bicarbonate solution with proper dressing of wounds in feet so as to avoid flies.
- Brucellosis
The disease also has got a place in NADCP launched by Government of India. The disease in cattle and buffalo is caused by the bacterium Brucella abortus. Infection spreads rapidly leading to many abortions. Natural transmission occurs by ingestion of bacterium present in aborted fetuses, fetal membranes, and uterine discharges. Cattle may ingest contaminated feed and water. Bacteria may enter the body through mucous membranes, conjunctivae, wounds, or intact skin of animals.
Clinical signs
Abortion during the last trimester of gestation is the most obvious manifestation. Infections may also cause stillborn or weak calves with retention of placenta and reduced milk yield. Testicular abscesses may occur in males. Longstanding infections may result in arthritic joints in some cattle.
Prevention and control
Whole-herd adult cattle vaccination using Strain 19 or RB51 should be followed in high-incidence areas and selected herds. Only female calves of 4-8 months of age are to be vaccinated with the vaccine.
- Anthrax
Anthrax is caused by the spore forming bacterium Bacillus anthracis. Anthrax is a soil borne bacterial disease characterized by exudation of dark tarry unclotted blood from natural orifices. The bacterium can survive for long period of time by undergoing sporulation and be source of infection.
Clinical Signs
The clinical course ranges from peracute to chronic. The peracute form is characterized by sudden onset and a rapidly fatal course. Staggering, dyspnea, trembling, collapse, convulsive movements, and death may occur in cattle. In acute anthrax of cattle, there is an abrupt fever and excitement followed by depression, respiratory or cardiac distress, staggering, convulsions, and death. Body temperature may reach 107°F, rumination ceases, milk production drops, and pregnant animals may abort. There may be bloody discharges from the natural body openings.
The bacteria produce spores on contact with oxygen that are extremely resistant and survive for years in soil. Then if ingested or inhaled by a healthy animal, or entrance through cuts in the skin, they can germinate causing disease. Because the blood of infected animals fails to clot leaking from body orifices, insects sitting on it can also spread the bacteria to other animals.
Prevention and control
Anthrax is prevented through vaccination, rapid detection and reporting, quarantine, treatment of asymptomatic animals. The non-encapsulated Sterne-strain vaccine is used almost universally for immunization. Vaccination should be done at least 2-4 week before the season when outbreaks are expected. As this is a live vaccine, antibiotics should not be administered within 1 week of vaccination. Along with vaccination, proper disposal of dead animals is critical and the carcass should not be opened, since exposure to oxygen will allow the bacteria to form spores. Carcasses are disposed preferably by incineration or by deep burial with more layers of quick lime.
- Blackleg or Black quarter
It is also a soil-born bacterial disease caused by Clostridium chauvoei. It affects animals with good body condition and good nutritional status. Infection occurs through contamination of the environment from infected faeces. The bacterium undergoes sporulation in the soil serving as source of infection.
Clinical signs
Usually, onset of disease is sudden. There is swelling of limbs on heavy muscle. Acute, severe lameness and marked depression are common. Characteristic edematous and crepitating sound is observed on palpation of affected areas in the hip, shoulder, chest, back, neck. Initially, there is fever but when clinical signs are obvious, body temperature may be normal or subnormal.
Prevention and control
Regular vaccination with BQ vaccine is reliable for cattle above 6 months age and to be repeated annually in endemic areas. Treatment of sick animals may be done with appropriate dosage of antibiotics.
- Hemorrhagic Septicemia (HS)
HS is an acute, highly fatal contagious bacterial disease caused by Pasteurella multocida serotypes B:2 and E:2 that affects mainly buffalo and cattle. The chief route of infection is inhalation where cattle are overcrowded and transmission is by direct contact between infected and susceptible animals through infected aerosols.
Clinical signs
Many cases of HS are peracute causing fatality within 8-24 hours. Infected animals often have fever, hypersalivation, nasal discharge with breathing difficulty. Acute disease is characterized by fever of 104°-106°F, restlessness and reluctance to move, hypersalivation, lacrimation, nasal discharge beginning with serous progressing to mucopurulent, subcutaneous swelling in the pharyngeal region that extends to the ventral neck and brisket, extension of head and neck, open mouth breathing with grunting, coughing and sneezing, progressive respiratory difficulty, cyanosis, terminal recumbency.
Prevention and control
Animals above 6 months age should be vaccinated with HS vaccine annually. Animals from unknown sources should not be mixed unless quarantined. Stress conditions should be avoided with proper ventilation in the shed.
- Lumpy Skin Disease (LSD)
LSD is highly infectious viral disease of cattle and buffalo caused by LSD virus (LSDV) (genus Capripoxvirus within the family Poxviridae) and characterized by pox-like intracutaneous firm nodules, edema of the limbs, superficial lymph nodes swelling, and lymphangitis. The disease has recently been reported in many states of India.
Clinical signs
Infected cattle develop fever, lacrimation, nasal discharge, and hypersalivation, painful swelling followed by characteristic eruptions on skin and other parts of the body. The nodules are well circumscribed, slightly raised, firm, and painful involving the entire cutis. Nodules may develop on the muzzle and within the nasal and buccal mucous membranes. The skin nodules contain a firm, creamy-gray or yellow mass. Regional lymph nodes are swollen, and edema develops in the udder, brisket, and legs. Secondary infection leads to suppuration and sloughing leading to ulcers that subsequently heal with scar formation.
Prevention and control
Vaccination of animals and supportive treatment with antibiotics against secondary infection may be followed.
- Tuberculosis
Tuberculosis is an infectious, granulomatous disease of cattle caused by the bacterium Mycobacterium bovis. There is evidence that more intensive dairy farms have a greater risk of infection. The disease is contagious and spread by contact with infected domestic animals. The usual route of infection is by inhalation of infected droplets exhaled from lungs through coughing. Calves become infected when poorly nourished or under stress and by ingesting raw milk from infected cows. An infected animal can spread the disease to many other healthy animals before it begins to manifest clinical signs. M. bovis is spread in a number of ways by infectious animals e.g. in their breath, milk, discharges, saliva, urine. Entry is usually by inhalation or ingestion. Spread from cows to calves may occur via the milk or colostrum.
Clinical signs
The affected animals may become emaciated, weak, anorectic, febrile with chronic cough, difficulty of breath and enlargement of regional lymph nodes.
Prevention and control
The owners should keep herd free by testing animals with tuberculin test to detect infection. Many anti-tubercular drugs are there that may be used with doctor’s supervision. Hygienic management practices may minimize the rate of infection.
Besides these important infectious diseases, a strict biosecurity practice needs to be followed in the farm so as to prevent or avoid infection. Some points on biosecurity measures are mentioned below that may not be overlooked or neglected.
https://www.pashudhanpraharee.com/good-managemental-practices-of-poultry-farms-in-india/
Biosecurity measures
Although disease control and prevention require a multifaceted approach with a thorough knowledge of the prevailing disease situation, biosecurity has always been the key element in the battle against infectious diseases. Movement of cattle between farms and visitors play an important role in transmission of pathogens among farms. For example, in the early stages of the 2001 FMD outbreak in the Netherlands, a veterinary practitioner likely transmitted the infection from one farm to another, resulting in destruction of a substantial proportion of the cattle herds in that practice. In parallel, immunity of the animals can be stimulated by the use of appropriate vaccines. However, vaccines must be used at proper age of the animal. The most common dairy cattle diseases and the preventive steps highlighted in this paper will be hopefully helpful for the farmers to have an awareness so that most of them may be avoided indirectly augmenting the health status and productivity.
Conclusions
Infectious diseases in dairy cattle pose threats to food security, food safety, national economies, biodiversity and the rural environment. Reliance on treatment with antimicrobials is unlikely to be sustainable; therefore, the control and prevention of infectious diseases in dairy cattle seems to be of paramount importance. Vaccination is the most reliable means of boosting immunity to specific infectious agents prompting the animal to produce specific antibodies against infection. Though it is not fool-proof and does not provide absolute protection, still it obviously minimizes the chance of infection in animals in a herd.
Manoranjan Rout* and Jajati Keshari Mohapatra
ICAR-DFMD-International Centre for Foot and Mouth Disease, Aragul, Jatni, Khordha – 752050, Odisha
