Milk produced for consumption should come from animals in good health. It is important to know the health status of milking animals as it can have adverse effects end user products.
Causes of Diseases
This may be broken down into a number of categories. These categories include: infectious organisms, parasites, foreign bodies, nutritional diseases, body imbalances, poisons, allergies, congenital and genetic defects and trauma.
Farmers should ensure that their dairy herd is managed properly to reduce the occurrence of diseases on the farm.
There are a number of factors to consider when addressing herd health. These include:
- Herd size and stocking rates
- The prevention of entry of disease onto the farm.
- Vaccination of animals
- Animals bought should be of known health status. (Identification systems , isolation and quarantine areas in place)
- Monitor any risk which may introduce any disease from adjacent farms/lands
- Enforce Biosecurity measures
- Have Health Management Programs established and implemented.
- Proper use and storage of veterinary medicines.
Dairy Cattle Diseases
Diseases may be defined as any abnormal body condition in which one or more parts of the body do no function properly. Some diseases are relatively easy to identify by their outward symptoms. Others may require clinical/laboratory test to be verified. It is even possible that a disease may affect an animal for its entire life without being noticed by the dairy farmer.
Bovine respiratory disease
Bovine Respiratory Disease (BRD) is the most common cause of illness and death in feedlot, cattle triggered by a complex interaction of stress factors, viral and bacterial infections. Bovine Respiratory Disease affects the lower respiratory tract/lungs (pneumonia) or upper respiratory tract (tracheitis, bronchitis).
Signs and Symptoms
Symptoms are profuse diarrhea, dehydration, elevated temperature during the first day or two of the infection and depressed appetite.
Treatment
Vaccination- Antibiotic therapy is ineffective in treating the disease but may be helpful in controlling secondary infections.
Implications
These outbreaks can result in production losses, reduced growth rates and increase mortality rate as bovine respiratory disease cause abortion in pregnant cattle.
Bovine Tuberculosis
Bovine Tuberculosis is a contagious infection caused by bacteria that mainly affects the lungs but also can affect any other organ in cattle. It is caused by the bacterium Mycobacterium bovis. M. bovis is killed by sunlight, but is resistant to desiccation and can survive in a wide range of acids and alkalis. It is also able to remain viable for long periods in moist and warm soil. In cattle faeces, it will survive 1 – 8 weeks.
Signs and Symptoms
A slight fever and the lymph nodes usually swell or have abscesses. The cow will appear weak, cough and show signs of laboured breathing and have an increased breathing rate are the most common signs and symptoms of this disease.
Treatment
Once animal is tested for Bovine tuberculosis and it is test positive, animals should be slaughter with the present of a veterinarian and follow the guideline of the public health regulation as these animals should not enter the food chain.
Implications
Bovine Tuberculosis can affect production in terms of the animal will become weak and refuse to eat which cause weight lost and milk produce will decrease
Brucellosis (Bang’s disease)
Bovine brucellosis, also known as Bang’s disease, is a bacterial disease caused by the bacterium Brucella abortus. The brucella abortus bacterium causes the contagious abortion of cattle and mainly affects heifers.
Signs and Symptoms
- Retention of the placenta
- Birth of weak or dead calves
- Vaginal discharge
- Decrease in milk production
- Joint injuries.
The most common clinical sign in cattle is late-term abortion, but many infected cattle do not show any clinical signs.
Treatment
Animals testing positive for brucellosis should be slaughtered in the presence of a veterinarian and follow the disposal guidelines of the public health regulations as these animals should not enter the food chain.
Implications
Brucellosis infection of cattle causes abortion or premature calving of recently infected animals, most often between the fifth and eight month of pregnancy, also it causes a decrease in milk production. This affects production as it affects the animal’s ability to conceive and produce milk.
Mastitis
This is the inflammation of udder and teat glands that is not only painful but can also fatal. Mastitis is one of the dairy cow diseases that results in major losses.
Signs and Symptoms
- Hot and firm teats,
- Lesions on teats and udder,
- High body temperatures,
- Low appetite and
- Low milk production
Treatment
Treatment for mastitis in cattle includes the use of antibiotics such as: penicillin, tyrothricin, gramicidin, gentamycin
Implications
Mastitis is difficult eradicate when cows become chronically infected. Farmers suffer huge losses from cows that are unable to produce marketable milk. Both clinical and sub clinical mastitis present challenges for the dairy farmer and can result in affected cows experiencing loss of appetite, weight loss, severe pain and ultimately milk production losses.
Bovine Foot Rot (Hoof Rot)
Foot rot generally occurs between claws of hoof when skin becomes injured. This commonly occurs during wet/ rainy periods but can affect cattle within the herd at any time. Foot rot in cattle often results from injuries caused from hard mud and dirt; stones and any other mud build up. Skin injuries cause bacteria to enter the food and spreads rapidly. Bacteria includes Porphyromonas levii
and Fusobacterium necrophorium
Signs and Symptoms
- Pain and lameness
- Reduced milk production
- Loss of appetite
- Swollen of interdigital space of foot
- Fever
Treatment
Treatment for Hoof rot can include topical dressing of antibiotics or antiseptics, sprays, footbaths with copper sulphate. In chronic cases surgical amputation is carried out.
Implications
Bovine Foot rot should be treated quickly to reduce the spread within the herd. Animals showing signs of lameness should be isolated from the herd until signs disappear. Foot rot disease can have severe economic implication as milk yield will be lower, reduced reproductive performances, higher culling rates and cost associated with treating the animals.
Calf Scours
Calf scours is the most common disease that affects dairy calves.
Signs and Symptom
- High temperature
- Diarrhea
- Lack of appetite
- Sucker eyes
- Depression
- Sudden death
Treatment & Prevention
- Feed good quality feeds
- Provide a healthy environment
- Ensure calves receive enough colostrum to provide antibodies needed to prevent against diseases.