Unit6 - Subjective Questions

To distinguish between a healthy and a sick animal, one must observe physical appearance and physiological parameters:

1. General Appearance

• Healthy: Alert, bright eyes, smooth and shiny coat, erect ears, moist muzzle (in cattle/buffalo).
• Sick: Dull, depressed, rough hair coat, drooping ears, dry muzzle, sunken eyes.

2. Appetite and Rumination

• Healthy: Normal appetite, regular chewing of cud (rumination).
• Sick: Partial or complete anorexia (loss of appetite), suspended rumination.

3. Excretions

• Healthy: Normal consistency and color of dung and urine.
• Sick: Constipation or diarrhea, presence of blood/mucus in dung, high or low volume of urine with abnormal color (e.g., Redwater).

4. Physiological Parameters

• Temperature: Deviates from the normal range (e.g., Normal cattle temp: ).
• Pulse & Respiration: Accelerated or labored breathing and increased pulse rate are common signs of illness.

Livestock diseases can be classified based on their etiology (causative agents) as follows:

1. Bacterial Diseases
Caused by pathogenic bacteria.

• Examples: Anthrax, Black Quarter (BQ), Haemorrhagic Septicemia (HS), Mastitis, Brucellosis.

2. Viral Diseases
Caused by viruses; usually highly contagious and often require vaccination for prevention.

• Examples: Foot and Mouth Disease (FMD), Rinderpest, Peste des Petits Ruminants (PPR), Ranikhet Disease (Poultry).

3. Parasitic Diseases

• Endoparasites (Internal): Liver fluke, Tapeworms, Roundworms (Ascariasis).
• Ectoparasites (External): Ticks, Mites (Mange), Lice.
• Protozoan: Coccidiosis, Babesiosis (Tick fever).

4. Fungal Diseases
Caused by fungi or molds.

• Examples: Ringworm, Aspergillosis (Brooder’s pneumonia in poultry).

5. Metabolic/Deficiency Diseases
Caused by nutritional imbalance or metabolic disorders, not by infectious agents.

• Examples: Milk Fever (Calcium deficiency), Ketosis, Bloat.

Biosecurity refers to a set of management and physical measures designed to reduce the risk of introduction, establishment, and spread of animal diseases, infections, or infestations to, from, and within an animal population.

Key Components of a Biosecurity Plan:

1. Isolation (Bio-exclusion):

   • Keeping new animals separate from the herd for a quarantine period (usually 30 days).
   • Isolating sick animals immediately to prevent spread.

2. Traffic Control:

   • Restricting visitor access to the farm.
   • Using footbaths and vehicle dips at entry points.
   • Allowing only authorized personnel into critical areas (e.g., brooder houses).

3. Sanitation and Disinfection:

   • Regular cleaning of sheds, equipment, and water troughs.
   • Proper disposal of manure and dead animals.
   • Regular use of disinfectants (e.g., Phenol, Formalin).

4. Vaccination and Medication:

   • Following a strict vaccination schedule.
   • Prophylactic deworming.

5. Record Keeping:

   • Maintaining records of animal movements, health history, and visitors to trace disease outbreaks.

Foot and Mouth Disease (FMD) is a highly contagious viral disease affecting cloven-hoofed animals.

Etiology

• Cause: Apthovirus (Picornaviridae family). There are 7 serotypes (O, A, C, Asia-1, SAT-1, SAT-2, SAT-3).

Transmission

• Direct contact with infected animals.
• Through contaminated water, feed, saliva, and aerosols.

Symptoms

1. High Fever: .
2. Vesicles/Blisters: Formation on the tongue, gums, lips, dental pad, and inter-digital space of hooves.
3. Salivation: Profuse, ropy, stringy salivation; animal makes a smacking sound.
4. Lameness: Due to foot lesions; animal is reluctant to move.
5. Drop in Production: Drastic reduction in milk yield.

Control and Prevention

1. Vaccination: Biannual vaccination (Polyvalent vaccine covering dominant strains like O, A, Asia-1).
   • First dose: 4 months of age.
   • Booster: 9 months, then every 6 months.
2. Isolation: Segregate sick animals immediately.
3. Treatment: No specific antiviral cure. Symptomatic treatment includes washing lesions with Potassium Permanganate () solution (1:1000) and applying boroglycerine.

A preventive vaccination schedule is crucial for herd health. Below is a standard schedule for Indian conditions:

Note: Combined vaccines (e.g., FMD + HS + BQ) are often used to reduce stress and labor.

Haemorrhagic Septicemia (HS), also known as 'Galghotu', is an acute bacterial disease.

• Etiology: Pasteurella multocida (Serotype B:2 in Asia).
• Susceptibility: Buffaloes are more susceptible than cattle. It is often triggered by stress (transport, monsoon rains).

Clinical Signs

1. Acute Onset: High fever ().
2. Respiratory Distress: Edematous swelling of the throat and neck (hot and painful), leading to difficulty in breathing.
3. Sound: A characteristic gurgling or snoring sound due to respiratory obstruction.
4. Mucous Membranes: Congested and red.
5. Mortality: Very high; death often occurs within 24 hours of symptom onset due to suffocation and toxemia.

Prevention

• Vaccination annually before the rainy season (May-June).

Both concepts are fundamental to biosecurity but apply to different groups of animals.

1. Quarantine

• Definition: The restriction of movement and segregation of newly introduced animals or animals exposed to a disease but not yet showing signs.
• Purpose: To prevent the entry of pathogens into a healthy herd from outside sources.
• Duration: Typically 30 days (covers the incubation period of most diseases).
• Action: Observation, testing, and vaccination before mixing with the main herd.

2. Isolation

• Definition: The separation of sick/infected animals from the healthy herd.
• Purpose: To prevent the spread of an active infection within the herd.
• Duration: Until the animal has fully recovered and is no longer shedding the pathogen.
• Action: Separate housing, separate equipment, and handling sick animals last.

Key Difference: Quarantine applies to potentially infected new arrivals; Isolation applies to confirmed or symptomatic sick animals.

Mastitis is the inflammation of the mammary gland (udder) and udder tissue.

Etiology

Multifactorial: Bacteria (Staphylococcus aureus, Streptococcus agalactiae, E. coli), poor hygiene, and trauma.

Economic Importance

• Reduction in milk yield (up to 70% loss).
• Deterioration of milk quality (unfit for processing).
• Cost of treatment and veterinary care.
• Premature culling of high-yielding animals.

Types of Mastitis

1. Clinical Mastitis: Visible signs are present.
   • Udder: Swollen, hot, painful, hard.
   • Milk: Discolored, watery, presence of flakes/clots/blood.
2. Sub-clinical Mastitis: No visible signs in the udder or milk, but somatic cell count is high and milk yield drops. It is 15-40 times more prevalent than clinical mastitis.

Diagnosis

• Strip Cup Test: checking for clots/flakes in foremilk.
• California Mastitis Test (CMT): A field test using a reagent to detect somatic cell count (gel formation indicates positive).
• pH Test: Mastitic milk is alkaline (pH > 6.7).

Black Quarter (BQ), also known as Blackleg, is an acute infectious disease affecting young cattle (6 months to 2 years).

Etiology

• Causative Agent: Clostridium chauvoei.
• Nature: It is a soil-borne, spore-forming, anaerobic bacteria.

Symptoms

1. Fever: High fever initially.
2. Lameness: Animal goes lame, usually in the hindquarters.
3. Crepitating Swelling: Painful, hot swelling develops on heavy muscles (thigh, shoulder, neck).
4. Crackling Sound: Upon palpation of the swelling, a crackling sound (crepitus) is felt due to gas accumulation under the skin.
5. Lesion Nature: In later stages, the swelling becomes cold and painless. If cut open, the muscle looks dark/black (necrotic) and smells of rancid butter.
6. Outcome: Death usually occurs within 24-48 hours.

Brucellosis (Bang’s disease) is a contagious reproductive disease in livestock.

Etiology

• Brucella abortus (Cattle), Brucella melitensis (Goats/Sheep).

Symptoms in Livestock

• Abortion: typically in the last trimester of pregnancy (6-9 months).
• Retention of placenta.
• Infertility and orchitis (inflammation of testes) in bulls.

Public Health Concern (Zoonosis)

Brucellosis is a significant Zoonotic disease (transmissible from animals to humans).

• Transmission: Humans get infected by consuming unpasteurized milk/dairy products or handling infected fetuses/placenta without protection.
• Human Disease: It causes "Undulant Fever" or "Malta Fever" in humans, characterized by recurring fever, joint pain, sweating, and fatigue. It is an occupational hazard for veterinarians, butchers, and farmers.

Poultry vaccination is critical due to the intensive nature of rearing.

Broiler Schedule (Short lifespan)

Layer Schedule (Long lifespan) - Additions to Broiler schedule

Note: Abbreviations - S/C (Subcutaneous), IM (Intramuscular), RD (Ranikhet Disease), IB (Infectious Bronchitis).

Ranikhet Disease (RD), internationally known as Newcastle Disease (ND), is a highly fatal viral disease of poultry.

Etiology

• Virus: Paramyxovirus type-1.

Clinical Signs

1. Respiratory: Gasping, coughing, sneezing, and rales.
2. Digestive: Greenish, watery diarrhea is a pathognomonic sign.
3. Nervous: Torticollis (twisting of the neck), paralysis of wings/legs, circling movements.
4. Production: Sharp drop in egg production; eggs may be deformed or soft-shelled.
5. Mortality: Can reach up to 100% in unvaccinated flocks.

Control

• No treatment exists.
• Vaccination is the only prevention (F1/Lasota strain at day 5-7, R2B strain at 8-10 weeks).
• Strict biosecurity and destruction of infected birds.

Infectious Bursal Disease (IBD), or Gumboro, is a viral disease affecting young chickens (3-6 weeks old).

Impact

It targets the Bursa of Fabricius (primary lymphoid organ), causing immunosuppression. This makes the bird susceptible to other diseases (vaccine failure).

Symptoms

• Sudden onset of depression.
• Ruffled feathers, trembling.
• Whitish, watery diarrhea leading to soiled vent feathers.
• Severe prostration and death.
• Post-mortem: The Bursa of Fabricius is swollen, edematous, and may show hemorrhages.

Control

• Vaccination: Live attenuated vaccines (Intermediate strain) administered at 12-14 days of age via eye drops or drinking water.
• Good hygiene to reduce viral load in the shed.

Coccidiosis is a protozoan parasitic disease affecting the intestinal tract of poultry.

Etiology

• Caused by Eimeria species (e.g., Eimeria tenella causes cecal coccidiosis).
• Thrives in warm, wet litter conditions.

Symptoms

1. Bloody Diarrhea: The hallmark sign (especially with E. tenella).
2. Weakness, drooping wings, and ruffled feathers.
3. Anemia (pale comb and wattles).
4. Reduced growth rate and feed conversion efficiency.

Prevention and Control

1. Litter Management: Keep litter dry. Wet litter promotes oocyst sporulation.
2. Coccidiostats: Feed additives mixed in poultry ration to prevent growth of the parasite.
3. Treatment: Administration of Amprolium or Sulpha drugs in drinking water.
4. Hygiene: Avoid overcrowding.

Anthrax is a per-acute, fatal bacterial disease.

Etiology

• Bacillus anthracis (Spore-forming bacteria).

Symptoms

• Sudden death without prior signs (apoplectic form).
• Oozing of unclotted, tarry blood from natural orifices (nose, anus, mouth, vulva) after death.
• Bloating of the carcass occurs rapidly.

Carcass Disposal (Critical Protocol)

Since Anthrax spores can survive in soil for decades, proper disposal is vital:

1. Do NOT conduct Post-Mortem: Opening the carcass releases bacteria which sporulate upon contact with air, contaminating the environment.
2. Plugging Orifices: Plug all natural openings with cotton soaked in disinfectant (e.g., formalin).
3. Deep Burial: Bury the carcass at least 6-8 feet deep.
4. Lime Treatment: Cover the carcass with a thick layer of lime (Calcium Oxide) before filling the pit to prevent earthworms from bringing spores to the surface.
5. Burning: Incineration is the best method if feasible.

Diseases spread through various routes. Understanding these helps in control.

1. Direct Contact

• Physical contact between a sick and a healthy animal (rubbing, licking).
• Example: FMD, Ringworm.

2. Indirect Contact (Fomites)

• Through inanimate objects like contaminated water troughs, feed buckets, vehicles, or surgical instruments.

3. Droplet/Airborne

• Pathogens travel via aerosols from coughing or sneezing.
• Example: Pneumonia, FMD (can travel long distances by wind).

4. Vector-Borne

• Biological Vectors: Ticks, mosquitoes, flies (e.g., Ticks transmit Babesiosis; Mosquitoes transmit Japanese Encephalitis).
• Mechanical Vectors: Houseflies carrying bacteria on their legs.

5. Ingestion (Oral Route)

• Consuming contaminated feed or water.
• Example: Internal parasites, Salmonellosis.

6. Vertical Transmission

• From mother to offspring (via placenta or milk).
• Example: Brucellosis, Avian Leukosis.

Fowl Pox is a slow-spreading viral infection of chickens and turkeys.

Etiology

• Avipoxvirus.
• Transmitted by mosquitoes or direct contact with scabs.

Two Forms of the Disease

1. Cutaneous Form (Dry Pox):

   • Most common form.
   • Characterized by wart-like nodules (scabs) on unfeathered parts of the head (comb, wattles, eyes, beak).
   • Low mortality, but causes poor growth and unsightly appearance.

2. Diphtheritic Form (Wet Pox):

   • More severe.
   • Development of yellow, cheesy, necrotic membranes (cankers) in the mouth, throat, and trachea.
   • Can cause suffocation and death.

Prevention

• Vaccination via Wing Web Puncture method at 6-8 weeks of age.

Disinfection is the process of destroying pathogenic microorganisms on inanimate objects (floors, walls, equipment) to render them non-infectious.

Properties of an Ideal Disinfectant

1. Broad Spectrum: Should kill bacteria, viruses, fungi, and spores.
2. Fast Acting: Should kill pathogens rapidly upon contact.
3. Penetrating Power: Should penetrate organic matter (dung/litter) effectively.
4. Non-Corrosive: Should not damage farm equipment or metal cages.
5. Safe: Non-toxic to animals and humans.
6. Economical: Should be cheap and easily available.
7. Stable: Should not lose potency easily when stored or mixed with water.

Examples: Sodium Hydroxide (Caustic soda), Phenol, Formalin, Quaternary Ammonium Compounds.

Immunity is the body's ability to resist infection.

When a disease outbreak is suspected or confirmed, immediate action is required:

1. Notification: Inform the local veterinarian immediately.
2. Isolation: Immediately separate sick animals from the healthy herd.
3. Stop Movement: Halt all movement of animals, feed, vehicles, and people in and out of the farm.
4. Diagnosis: Collect samples (blood, swabs) for laboratory confirmation.
5. Disinfection: Thoroughly clean and disinfect the premises, equipment, and water sources.
6. Disposal: Properly dispose of dead carcasses (burial/burning) and contaminated bedding.
7. Ring Vaccination: Vaccinate healthy animals in the surrounding area (ring vaccination) to create a buffer zone, starting from the outside moving in.
8. Treatment: Provide supportive treatment to sick animals if applicable (viral diseases usually rely on supportive care).