Disease is referred to as an abnormality of health of an animal. It is a deviation or departure from the normal state of health of an organism. A disease condition normally represents marked symptoms and signs.
Pests and Parasites on the other hand, are organisms that attack farm animals and man. In the course of the attack, they may transmit infection or cause wound that may lead to secondary infection on the animals. Those that attack the animals externally are referred to as ecto-parasites, e.g., tick, lice, tse-tse fly, etc. Those that live internally and cause discomfort are known as endo-parasites, e.g liver fluke, ascaris, tape worms, round worms, etc.
Certain conditions normally referred to as “pre-disposing factors”, expose the animals and help in the initiation and continuation of disease conditions. They include, sanitation level, health status of the animals, stress conditions, nutrition level, etc. Diseases and pests are important economic factors in livestock development because, profitability depends on the extent to which the associated diseases, pests and parasites are managed.
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Diseases Of Farm Animals
The causative agents of farm diseases are bacteria, fungi, viruses, protozoan, worms, nutritional deficiencies, etc.
A. Bacteria Diseases: Bacteria are small microscopic pathogen plant organisms that cause deadly, contagious, and infectious diseases diseases. They exist in the air, water and soil. The following are examples of bacterial diseases:
i. Mastitis : This disease is characterized by the inflammation of the mammary or milk gland of the female farm animals. It is caused by the streptococcus and staphylococcus species of bacteria. It leads to a drop in milk production.
ii. Contagious Abortion: This is caused by bacterium called brucella abortus. It is transmitted through contaminated feed, milk and water. Symptoms include abortion, inflammation of the womb, infertility and low milk yield.
B. Fungal Diseases: Fungi (singular, fungus) are non-chlorophyll processing plants that live on dead or decaying organic materials or on some living tissues. They vary in size. Some species are useful and edible, e.g. the mushrooms; while many are pathogenic (disease-causing) and harmful. Example of a fungus disease is ring worm.
i. Ring Worm: This is a contagious disease of the skin of the animals caused by specie of fungus.
Transmission is through body contact with infected animals.
Symptom include skin irritation, loss of hair on affected part, and round red patches on the skin.
C. Viral Disease: Viruses are ultra-microscopic pathogenic or diseases-causing organisms found only in living cells. Viral diseases are very contagious, infectious and virulent. Viral infections are not treatable but the secondary infections that go with them can be treated. Examples of Viral diseases of farm animals are new castle, rinderpest, foot and mouth diseases, etc.
i. Foot And Mouth Disease: The mode of spread of this virus is by contact and air-borne droplets of saliva. Symptoms include fever, dullness, excessive salivation, sores on feet and tongue.
D. Protozoan Diseases: These diseases are caused by microscopic one-celled animal (protozoa). The protozoa multiply rapidly in the body where they cause rupture of certain body parts. The organism is transmitted by insect vectors like tse-tse fly. In the tropics, the disease caused a lot of harm to farm animals. Examples include coccidiosis and trypanosomiasis.
i. Coccidiosis: This is mainly a disease of poultry and rabbits. Transmission and spread are through faeces, litter, feed, water and soil contaminated with the droppings of infected animals. Symptoms include bloody faeces, emaciation or loss of weight and paleness in poultry and rabbits, ruffled feathers in poultry, etc.
ii. Trypanosomiasis (Nagana): This protozoan disease is caused by trypanonsome organisms, carried and transmitted to cattle by tse-tse flies of the Glossina species, as the chief vectors. Cattle, sheep and goats are mainly affected by the disease. The symptoms include, anaemia, loss of weight, pale mucus membrane, oedema (swelling of the limbs), sleepiness, fever, weakness and eventually death. The central nervous system (brain and spinal cord) is usually invaded.
E. Parasites (Which Include Worms): Parasites are two types viz: endoparasites and ectoparasites; Worms are endo-parasites, as they live inside the body of farm animals and derive their nutrition from the host animals. The different forms of parasitic worms include the round-worms (Ascaris species), tapeworms (Taenia species), liver flukes (Fasciola species) etc. These worms have their various primary and secondary hosts. All farm animals are affected. Eggs of the worms are passed out with the faeces of the primary host. The larvae enter the secondary hosts that consume contaminated foods. Symptoms include, liver rot in the case of liver fluke, loss of appetite, weakness, inhibited bile duct and emaciation.
F. Nutritional Bloat: This is a nutritional disease of ruminant animals (Cattle, Sheep’s and Goats). Animals feeding on dry grasses are not easily susceptible to this disease. The disorder affects the gastro-intestinal tract of the affected animals. The abdomen gets swollen or distended.
Method Of Control And Prevention Of Farm Animal Diseases.
The following control and prevention measures of diseases of farm animals would help check the spread of infection, and the dangerous effects.
i. Adopting Good Sanitation Measures: Sanitary segregation of contaminated equipment is very essential to prevent diseases. Stale feed And water should regularly be discarded. The floors and walls should be scrubbed and disinfected regularly.
ii. Feed and Water Should be kept or placed on a platform that would not allow the animals to defecate or urinate inside them, and thus, avoiding contamination.
iii. The number of visitors into the farm should be restricted.
iv. Foot Dip of Disinfectants, should be placed at the entrance of the pen, so that, people would place their feet in it before and after entering the pen.
v. Inviting a veterinarian for advice and treatment of diseases.
vi. A good immunization Programme would help confer immunity to the animals in order to withstand infection.
vii. Isolating sick or diseased animals to avoid spread to other healthy ones, and to observe the animals for disease signs and symptoms.
viii. Dead animals should be properly disposed, especially when the cause of death is as a result of dangerous infection like, contagious abortion, foot and mouth disease, etc. This reduces the chances of disease spread.
ix. Rotational grazing helps to keep pest and parasites population in the pasture in check.