7.4 Classification of diseases

• Diseases are classified to be either:

  • Non-infectious, or
  • Infectious

  Non-infectious diseases          

  Non-infectious diseases are cause by:

  • Injuries
  • Trauma
  • Poisons/chemicals
  • Poor nutrition (metabolic and nutritional factors)
  • Birth defects
  • Hormonal imbalances
  • Other things not caused by an organism living within the animal

  Infectious diseases

  Infectious disease is caused by:

  • Other living microorganisms (called pathogens) that invade the animal’s body
  • Usually contagious diseases that the animal can pass to another animal

  There are 3 types of infectious pathogens:

  • Bacteria
  • Viruses
  • Protozoa

   

   

   

   

  7.4.1 Bacterial Diseases       

  The definition: Bacteria is microorganisms that are the basis of fermentation and infectious diseases.

  Bacteria: 

  • Live in a wide range of conditions
  • Live on and in the bodies of all animals
  • Many can be harmful
  • Invade the cells of an animal’s body

  Bacterial diseases in cattle

  Refer to the summary of bacterial diseases, description of the symptoms and prescribed control measures as summarised below.

   

   

   

   

   

   

   

   

   

  7.4.2 Clostridial disease 

  Clostridial diseases are caused by bacteria that occur widely in soil, sewage, water and in the intestines of animals.

   

   

   

   

  Clostridial organisms are rod shaped, and because they don’t like oxygen they are classified as anaerobic bacteria.  

  A very important fact is that they form spores and as spores they survive for very long periods in soil or grass. The Clostridia bacteria is very resistant to heat and cold, drying and disinfectants and therefore are almost impossible to get rid of. The bacteria are picked up by grazing animals, or can enter the body through wounds, as well as from contaminated carcasses and infected faeces.

   

   

   

   

  The Clostridia group of bacteria is best grouped according to the organs it can affect:

  • muscles
  • intestines
  • liver and
  • the nervous system

  Clostridia produce various toxins as soon as they start replicating in the animal, and it is these toxins that will kill the animal.  

  So how do Clostridia cause disease?  

  It will invade tissue through wounds or will start multiplying in the intestine of the animal where there is very little oxygen. The spores will then germinate and proliferate and at the same time start producing toxins. This can cause haemorrhaging or bleeding in the tissue – and the tissue then starts dying off. This eventually leads to a total collapse of all systems in the animal and death follows.  

  So, what are some of the factors causing Clostridial growth?  

  An animal can contract this disease from injuries;

  • sustained during transportation
  • when they are restrained
  • locked up for long periods of time
  • if they are cut – this can happen during surgical procedures such as castration or dehorning
  • even sometimes after a difficult calving

  Liver damage by liver flukes or other causes may also open the animal to Clostridial diseases.

  Intestinal Clostridia is usually associated with animals when they ingest too much milk, as in the case of calves or grain, in older animals.  

  Let’s take a more in depth look at the Clostridial diseases associated with different organs.   

  Let’s begin with muscles.

  There are three muscle associated Clostridia namely; 

  • Clostridium chauvoei,
  • Clostridium septicum, and
  • Clostridium sordelli.   

   

   

   

  • The first muscle associated Clostridia is Clostridium chauvoei.
  • Clostridium      chauvoei     causes
  • Blackleg or Quarter evil, which is also known as “Sponssiekte” in Afrikaans.            With      Blackleg            the organisms are usually taken in by mouth or through wounds.   

  Young stock is primarily affected, and it is usually seen in the best fed animals or animals which are on a high plane of nutrition.  One usually sees a seasonal pattern with Blackleg, associated with rainfall and management practices, as an example shearing in sheep.

   

   

   

   

   

  • How does Blackleg develop?
  • When the muscle is injured spores start to germinate and the bacteria multiply. Toxins and gas are produced.
  • It is this gas that will give us the typical crackling under the skin seen so frequently in animals dying from blackleg. And it is the toxins that will cause the dying off of the muscles, eventually leading to the death of the animal.   
  • As with all the Clostridial diseases it is a very fast and rapid disease. The animal will usually die within 12 to 36 hours after becoming sick.    
  •  
  • Some may show 
  • lameness or limping in one or more legs
  • sometimes we can observe a swelling in the hip, shoulder, neck or upper leg  

   

   

   

   

  • In dead animals, there is very rapid decay. An animal that may be dead for just a few hours will look as though it has been in the sun for a day or more.  
  • The next muscle associated Clostridia is Clostridium septicum.
  • This organism  is usually associated with infected wounds such as after a caesarean section operation but can affect animals of all ages.  
  • The organism will enter the tissue via injured areas in the mouth or in  the skin and  will  start multiplying in an area low in oxygen and in this process, start producing the fatal toxins.
  •  
  • Signs to look out for       
  • animal is depressed
  • lose their appetite
  • will have a wet “doughy” smell around a painful wound
  • The temperature is usually very high, and animals are very weak and will die within 12 – 48 hours after the first clinical signs.  
  • On post mortem, we will see wet foul-smelling lesions under the skin going into the muscles which will have a pale reddish to brownish appearance.  
  • The last Clostridium in the muscle group is Clostridium sordelli.  
  • Although it is found more in feedlot animals it is frequently also seen outside feedlots.  
  • It is usually associated with:
  • a massive area of bleeding in the brisket and throat area
  • a very foul odour

  The next organ system affected is the intestine.

   

   

   

  • We have 4 Clostridia playing a role here called Clostridium perfringens type A, B, C and D.
  • Let’s start with Clostridium perfringens type A – perhaps the most common and also the most over diagnosed of all 4 types.   
  • It is known as malignant edema or yellow lamb disease.   
  •  
  • The organism is found everywhere in the environment and will be found in almost all healthy animals in their intestines.
  •  We basically get two syndromes with

  Clostridium perfringens type A. 

   

   

   

  • The first one is known as the Abdominal syndrome leading to;
  • severe diarrhoea
  • animals are depressed and
  • become dehydrated with usually a distended abdomen
  • The second syndrome is known as the Gas gangrene syndrome with;
  • swelling and pain
  • a very high temperature and
  • death within 12 hours after the first clinical signs
  •  
  • Clostridium perfringens type B is a very quick disease, usually affecting lambs and kids or small goats less than 14 days old  especially  when  these animals are born in very small camps.
  • The organism is ingested very soon after birth and then starts growing in the small intestine and in this process, starts producing toxins.

  This disease is almost exclusively seen in lambs and goat kids but may be seen in calves younger than 10 days.

   

   

   

  • Animals will be:
  • weak
  • listless, and
  • refuse to suckle
  • signs of abdominal pain and

  blood in the stool

   

   

   

   

  • We get a local dying off in the intestine in the area where the toxins are produced having an effect on the normal function of the intestine. Eventually the animal dies from shock, the toxins and dehydration.
  • Clostridium perfringens type C is transmitted by mouth causing an inflammation of the abdomen.
  • Clinical signs are again similar to some of the other Clostridia, but lambs younger than a few days are usually affected.   
  •  
  • The lambs will have:

  greyish/black faeces and die very quickly

   

   

   

   

  • Older sheep may also be affected, and
  • will become weak
  • lie down
  • go into a coma and die
  • This brings us to Clostridium perfringens type D or Pulpy kidney – perhaps the most important Clostridial disease in sheep and goats and from time to time in cattle. 
  • Animals affected will usually be well nourished, grazing in lush pastures – usually the first ones to die will be the biggest and fattest animals. We sometimes see it also in animals after de-worming.

  Sheep of all ages may be affected but it is more common in lambs from 3 weeks to 3 months of age and lambs from 6 to 12 months of age.  Sudden changes in a diet, especially to a diet high in carbohydrates like maize may influence the onset of Pulpy kidney. 

   

   

   

  • The organism is present as a normal “inhabitant” of the intestine and starts multiplying as soon as conditions become more suitable.   
  • Large amounts of non-lethal toxin are produced which are then activated causing damage to the blood vessels in the brain and kidneys.  
  • There are very few clinical signs – usually we only see dead animals, especially after a change in ration or after deworming.   
  •                                                            
  • If we do find sick animals, they will be:
  • Dull
  • very depressed
  • completely lose their appetite
  • sometimes we will see animals staggering
  • having convulsions
  • Death is usually within 12 hours after the disease has started.  
  • This brings us to the Clostridia associated mainly with the liver namely; Clostridium novyi.
  •  
  • We get 4 types of Clostridia novyi based on the toxin they produce – namely A, B, C and D.  
  • Clostridium novyi is seen in sheep and occasionally in feedlot cattle and rarely in beef cattle.  
  • Clinical symptoms are:                         
  • depression
  • loss of appetite and again

  sudden death 16 to 48 hours after the animals became sick

   

   

   

   

  • The last group of Clostridia is those affecting the nervous system.

  Clostridium tetani and Clostridium botulinum.  

   

   

   

  • Clostridium tetani are responsible for tetanus, and Clostridium botulinum responsible for Botulism, or “Lamsiekte” as it is known in Afrikaans.  
  • Clostridium tetani will enter the body through deep puncture wounds and is frequently associated with castration, ear tagging or tail docking wounds.  Animals of all ages can be affected but it is seen more frequently in younger animals.
  • Animals with tetanus will usually be:
  • uncoordinated
  • lying down when we see them for the first time
  • their ears will be erect
  • their tails stiff
  • They won’t die as quickly as with the other Clostridia and it can take up to 14 days before they die. Treatment at the stage when we see the aforementioned symptoms is usually not effective and 60% or more of affected cases will die.  
  • Clostridium botulinum is associated with contaminated feed and decomposing animals.  
  • Animals in the veld will sometimes eat bones from other dead animals and by doing so will pick up the Botulism bacteria.  
  • Over time we will see:
  • progressive paralysis
  • disturbed vision – animals may appear blind
  • They will then lie down and will be dead within 6 to 72 hours after the first symptoms.  
  • The question now is how do we prevent Clostridial infections?  
  • To list a few: 
  • prevent injury
  • avoid overcrowding
  • avoid digestive upsets
  • feed balanced feed rations
  • a progressive transition from one feed source to another
  • ensure enough water always
  • sanitation
  • clean equipment
  • rotate processing area
  • treat to prevent parasites
  • ensure intake of colostrum in young animals
  • We can also improve the immunity of the animals against Clostridial infections by immunising them with a bacterin-toxoid vaccine.  
  • A bacterin is made up of killed organisms and the toxoid is made up of the toxins of the various Clostridia.   
  • Because it is so difficult to distinguish between all the Clostridia we suggest that you use a vaccine containing more than one Clostridia. Animals are usually vaccinated at 3 months of age with a booster vaccination 4 to 6 weeks later.    

  If you, however, experience Clostridial diseases much earlier you can start vaccinating as early as 2 weeks of age with a second vaccination 4 to 6 weeks after the initial vaccination and a third vaccination after 3 months of age.

   

   

  • Animals should then be vaccinated on a yearly basis.  
  • The Clostridia are a very interesting group of bacteria causing a number of diseases in livestock. 
  • Fortunately, we do have vaccines available to assist us in our battle against the Clostridia.   
  •  

  In all cases of acute mortalities, a full post mortem, which will include bacteriological and other laboratory tests to confirm our diagnosis need to be conducted by a veterinarian and then to vaccinate yearly or as recommended by the veterinarian

   

   

   

  • In any livestock enterprise, the question is not whether your animals will get Clostridia but rather when especially if they are not immunized.
  • Speak to your veterinarian!
  •  
  • 7.4.3 Virus Diseases

  Viruses may be defined as acellular organisms whose genomes consist of nucleic acid, and which obligately replicate inside host cells using host metabolic machinery and ribosomes to form a pool of components which assemble into particles called VIRIONS, which serve to protect the genome and to transfer it to other cells.

   

   

   

   

  • A virus is a small infectious agent that replicates
  • only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to bacteria and archaea. 
  • A virus is made up of some of the material found in cells but are not cells because they do not have a nucleus or other cell parts.
  • Do not grow and cannot reproduce outside a living cell
  • Once inside a living cell, virus reproduces using energy and materials in the invaded cell
  • Harm cells by causing them to burst during reproduction
  • And by using material that the cell needs to function properly
  • Viral diseases cause the animal to be sick by preventing certain cells in the body from functioning properly
  • More difficult to treat than bacterial diseases
  • Antibiotics are not effective against viral infections
  • Best means of dealing with them is prevention
  • Virus diseases in cattle
  • Refer to the summary of viral diseases, description of the symptoms and prescribed control measures as summarised below.

   

   

   

   

   

   

 

 

 

Immunization program for cattle

The veterinary Research Institute at Onderstepoort recommends the following vaccination programme. 

 

 

7.4.4 Protozoa Diseases

• Protozoa (meaning “first animals”) are heterotrophic, single-celled or colonial eukaryotes. Individuals are microscopic and range in size from a few to hundreds of micrometres, depending on the species. Most protozoa  are animal-like

(heterotrophic) because their carbon and energy must be obtained by eating or absorbing organic compounds originating from other living organisms. As eukaryotes, they have several organelles, including at least one nucleus that contains most of the cell’s deoxyribonucleic acid (DNA)

 

 

• Microscopic illustration of a Protozoa.      
• Microorganism that cause disease
• Single-celled organisms that are often parasitic
• Trichomoniasis: a common cause of vaginitis. It is a sexually transmitted infection and is caused by the single-celled protozoan parasite.
• Coccidiosis: Coccidiosis is a parasitic disease of the intestinal tract of animals caused by coccidian protozoa. The disease spreads from one animal to another by contact with infected faeces or ingestion of infected tissue. Diarrhoea, which may become bloody in severe cases, is the primary symptom. Most animals infected with coccidia are asymptomatic, but young or immunocompromised animals may suffer severe symptoms and death.
• Protozoa diseases in cattle
• Refer to the summary of Protozoa diseases, description of the symptoms and prescribed control measures as summarised below.

 

 

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7.4.5 Genital diseases 

• Reproductive performance plays a fundamental role in the profitability of cattle herds, the main cause of economic loss as a result of infertility or subfertility being prolongation of the interval between calving.  Genital disease is not restricted to the environment or the production system.
• The following genital diseases are important in particular.

 

•  

 

7.4.6 Health risk areas

• The occurrence of pathogens and viruses causing diseases is directly related and dependable to the climatic conditions of rainfall, humidity, temperature and sunlight. 
• These climatic conditions sustain or refrain the survival of pathogens and viruses responsible for disease outbreaks in livestock. The dry and arid areas of the Central Free State and Northern Cape for example, contributes to a healthier area for livestock production, and the higher rainfall and sub-tropic to tropical climates of KwaZulu Natal, Mpumalanga and the Eastern Cape coastal areas, contributes to a higher occurrence of diseases.  
• The map below shows the area where serological evidence of SAT1 (Mouth and Foot Disease) infection in cattle was detected in 2011. 

•  

 

7.4.7 DRUGS OR MEDICATION

• In pharmacology, a drug is a chemical substance used in the treatment, cure, prevention, or diagnosis of disease or used to otherwise enhance physical or mental well-being.

Classification of drugs

• The therapeutic claims, indications or purposes of a drug, refer to the treatment of a disease, disorder or abnormal physical state; or treatment, mitigation of its symptoms; or the modification of an organic function (such as digestion). 
• Drug therapeutic claims can only be made for products which have a therapeutic purpose or intent of use (drugs) and are therefore not suitable for feeds. 

Examples of therapeutic (or drug) claims are:

Treatment claims (treatment of a disease, a condition (intoxication) or abnormal state (wounds, oedema) or its symptoms, e.g. diarrhoea. – Antibiotics, ointments, disinfectants.

Control claims (control intestinal parasites, control breeding), – worm dose remedies.

Prevention claims (prevent mastitis, prevent acetonemia, prevent bloat, prevent Coccidiosis), excluding prevention of nutritional deficiency claims – vaccines

Mitigation claims (reduce severity of pneumonia, relief pain associated with colic, relief of inflammation, decrease incidence of laminitis, reduction of early mortality – anti-inflammatories

Animal Performance claims (production claims) not supported by a nutritional purpose or mode of action (stimulate egg production, increase litter size) – Hormone growth stimulators

Antibiotics

• Antibiotics are a group of medicines that are used to treat infections caused by bacteria and certain parasites. They do not work against infections that are caused by viruses – for example, the common cold or flu. Antibiotics are normally only prescribed for more serious bacterial infections – for example, pneumonia.

Penicillin

• Penicillin’s are a certain collection of antibiotics that eliminate infection causing bacteria. Also known in short as pen or PCN, they originate from a type of fungi called Penicillium fungi. They are used in the treatment or prevention of many different bacterial infections, usually caused by Gram-positive organisms

Tetracycline

• Tetracycline’s were discovered in the 1940s and exhibited activity against a wide range of microorganisms including gram-positive and gram-negative bacteria, chlamydia, mycoplasmas, rickettsia, and protozoan parasites. They are inexpensive antibiotics, which have been used extensively in the prophylaxis and therapy of human and animal infections and also at Subtherapeutic levels in animal feed as growth.

7.4.8 PARASITES

7.4.8.1 Internal parasites

• Internal parasites can be divided into three groups, namely:
• Round worms
• Tape worms
• Flukes
• They are divided according to their various life cycles.
• Roundworms
• They have a direct life cycle. This means that they do not need an intermediate host to complete the cycle.

•  

 

• Adult female worms occur in the gastro-intestinal tract of the host animal where she lays eggs that are passed out in the faeces of the animal onto the pasture.
• Temperature, light and moisture are important factors influencing the hatching of eggs.
• Three larval stages occur before the infectious stage is reached.
• The infective larvae are taken in by the host animal together with grazing.
• A further two larval stages occur before the worm is sexually mature. Even these stages have a negative effect on the host animal, which makes diagnosis of the infection difficult.
• Diagnosis of roundworm is done by means of faecal egg counts.
• The two most important roundworm species are wireworm, a blood sucker, and brown stomach worm, which causes the animal to waste away and severe diarrhoea.
• In cases of severe infection, an animal can die before any symptoms are observed
• Tapeworms

 

•  

 

• Tapeworms require an intermediate host to complete their life cycle.
• The adult tapeworms are found in the small intestine of the host animal.
• Ripe segments are released from the worm and excreted together with the faeces of the host. These segments are filled with thousands of eggs.
• Different tapeworms require different intermediate hosts. All the important species affecting sheep, goats and cattle require grass mites. The mites ingest the eggs while feeding and the larval stages of the worm develop inside the mites. The mites are taken in by the host together with grazing and the tapeworm attaches itself to the wall of the small intestines to complete its life cycle.
• Tapeworms do not cause much physical damage to the host animal but absorb the nutrients that the animal needs for growth.
• Diagnosis in live animals are often difficult and sometimes a postmortem is necessary.
• Symptoms of severe infection may include extended belly (or potbelly) and retarded growth.
• Total obstruction of the small intestines by heavy worm infestations may result in rapid death.

 

•  

 

• Flukes
• Flukes require an intermediate host to complete their life cycle. In this case, it takes the form of a freshwater hardshelled snail.

 

 

 

• Flukes are usually associated with freshwater sources such as pans or marshes and occur mostly in autumn and winter when animals are forced to graze the greener edges of the marshes because of a lack of pastures.
• The most important species are Liverfluke and conical fluke.
• Liverfluke occurs in the bile ducts of the liver. The eggs are passed into the bile and are then excreted with the faeces of the host animal. Immature stages infect the snails where further development takes place. The parasites escape from the snails and encyst on the herbage to form the infective stage which is taken in by the host.
• Conical flukes inhabit the rumen of sheep, goats and cattle and have a similar life cycle to that of Liverfluke. The adult parasites do not cause any pathology to the host, but the immature stages destroy the mucous membranes of the small intestines, causing severe diarrhoea. Diagnosis depends on time of year and grazing history of the area involved.

 

 

 

 

• Control and prevention
• All parasites mentioned can be limited by effective management and the use of worm remedies or anthelmintics.
• Worm resistance
• This occurs when a worm population or a worm strain becomes immune to the effect of a remedy. Such a remedy then no longer achieves the control for which it was registered, because certain resist ant worm strains render them less effective.
• No worm remedy can, however, be rejected as resistance varies in different region or farms.

How does resistance develop?

• It is often the result of the frequent use of remedies in small stock, most often at times when they are not really necessary.
• Under-dosing (to save cost) of animals can also result in the development of resistance.
•  
• Resistance initially develops very slowly but then rapidly increases to a high stage.
• Once resistance to a specific anthelmintic group has developed, it is permanent and cannot be reversed.
• How to determine the level of anthelmintic resistance
• Consult your nearest veterinarian or animal health technician and have a faecal egg count reduction test done.
• Helpful hints
• Dose per the mass of the heaviest animal.
• Never estimate the mass, always use a scale.
• Do not under- dose to save money.
• Read and follow the instructions on the label.
• Check apparatus frequently for accuracy.
• Dose all animals and make sure not to skip any.

 

7.4.8.2 External parasites

• External parasites live on the skin of cattle and feed as a bloodsucking parasite. External parasites are divided into the following groups:
• Flies
• Ticks
• Lice
• Mites
• Most of these parasites can be seen with the eye alone, although for mites you need to look through a microscope.

Why are external parasites important?

• Some are just a nuisance to the animals.
• Some cause skin and eye irritation and damage, which can lead to bacterial infection and fly maggot attack.
• Some create large wounds.
• Others suck blood, causing the animals to become weak.
• Some can spread diseases between animals.
• Some can cause disease through poisonous bites (toxins).
• All of this can result in decreased production and even death.
• Flies
• Flies are most active in the rainy season and warm months.
• There are many types of flies.
• Some are biting flies, others are important because they lay eggs on animals, while others irritate the animals.

 

•  

 

• Control of flies
• Practice good stable and kraal hygiene (clean regularly)
• Remove manure to large bins to restrict fly breeding and to make compost
• Drain damp areas to stop breeding of mosquitoes and biting midges
• Use dips, sprays and treat wounds to prevent fly and strike problems
• Immediately treat skin wounds so that strikes do not occur
• Ticks

 

•  

 

• There are many different types of ticks.                               

• Ticks are usually most active during the warmer and wetter parts of the year.
• Ticks suck blood from animals, and large tick numbers can lead to blood loss and weakness.
• Some ticks have long mouthparts and can cause severe skin damage, which can lead to fly strike and bacterial infection.
• Ticks can also spread diseases such as Heartwater (bont ticks), Redwater (blue ticks), Gallsickness (blue ticks) and corridor disease (brown ticks) among animals.
• Some ticks (Karoo paralysis tick, glossy brown tick) can cause paralysis because of the toxins they produce.
• Other ticks (small smooth bontlegged tick) can also cause sweating sickness because of the toxins they produce.
• Treatment of tick damage
• Clean the wound; treat with an insecticide-disinfectant combination to heal the wound and to keep flies away. Antibiotics may be needed.
• Control of ticks
• Control is by acaricides which are chemicals that kill ticks or prevent their attachment. They can be used as sprays (handsprays or race-sprays), dips, pourons, spot treatment or injectable drugs
• Some breeds of cattle are more resistant to ticks and tick-borne diseases
• It is best to get advice from your state veterinarian or animal health technician on control methods for ticks in your area.

 

• Mites

 

•  

 

• Mites are very small and can usually not be seen with the naked eye.
• Mites live on the animal for the entire lifecycle and are spread among animals by close contact.
•  
• They cause skin irritation, which leads to rubbing, scratching and hair loss; this is called mange.
• Irritation from mites is usually seen on the head, neck and legs. It is associated with crowded conditions and poor husbandry.
• There are different types of mange, depending on the type of mite involved: Sarcoptic mange, demodectic mange, chorioptic mange and psoroptic mange.
• Skin disease with irritation, scratching, rubbing and biting should always make one suspect mange or lice.
• Because it is impossible or very difficult to see the mites with the naked eye, diagnosis is by skin scrapings and looking for mites under the microscope.
• Control and treatment of mites
• Control and treatment are by acaricides, which may be applied as injectable drugs such as ivermectin, handsprays or dips.
• Sarcoptic mange may require repeat treatments.

 

• Lice (Pediculosis)

 

•  

 

• Lice are wingless. They live exclusively on the skin and cannot survive for long periods off the animals.
• Lice can be seen by parting the hair; you can see them moving and their eggs may be attached to the hair.
• Lice are very specific to the type of animal and will not spread to other animal species. They are spread by contact among animals of the same species.
• There are sucking and biting (chewing) lice.
• Heavy lice infestations can cause irritation and distress. Animals rub and lick themselves and damage their hides.
• Sucking lice can also cause weakness from blood loss.
• Lice are usually associated with unhealthy livestock in crowded conditions.
• Often heavy lice infestations are secondary to some other disease problem, largely because sick animals do not groom themselves.
• Clinical presentation
• Heavy infestations cause irritation leading to rubbing against feed barriers etc. resulting in hair loss most often over the neck and shoulders and disrupted feeding patterns.
• Heavy lice infestations cause irritation leading to rubbing against feed barriers and hair loss most often over neck and shoulders. 

 

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•  

 

• Heavy lice infestation present at pasture in the spring – this calf should have been treated at turnout.
• Severe lice infestation in a Limousine bull.
•                                       
• Careful inspection of the skin will identify adult lice populations and eggs adherent to hairs.
• Control of lice
• Control by insecticides (dusts, pour-ons, spot treatment, handsprays, dips).
• Treatment of the lice infestation using a pour-on synthetic preparation.

 

 

 

 7.4.9 BASIC PROCEDURES TOWARDS CLINICAL EVALUATION OF A BOVINE  

• It happens from time to time that a veterinarian is not immediately available and that the stock owner is then required to examine the cow.   
• It is important to remember that the farmer cannot take the place of the veterinarian.

 

•  

 

• First and foremost a complete history of the animal is needed, such as:
  The following measures will only give the farmer an indication of how urgently the service of the veterinary surgeon is needed. The farmer could give his observations by telephone and the vet can then suggest preliminary steps to be taken in the time before he arrives to examine the animal.
• age
• gender
• breed
• stage of lactation
• level of production
• This information will be readily available if the farmer has kept the relevant records up to date.
• Other important matters that should be noted:
• clinical symptoms
• number of animals affected
• recent vaccinations or other procedures
• introduction of recently bought animals 
• The area where the animals are kept       must     be        inspected          for poisons, poisonous plants, etc.   
• Check the water source as well. Have the cows been watering somewhere else than at the usual water source?  

 

 

 

• As the animals are moved to the crush, note the way they move – a sore hoof may become obvious when the animal walks. Check for a swollen abdomen, sunken eyes, and whether the animal is alert.  
• With the animal in an appropriate crush-pen, check the body using the fivestation approach to ensure that nothing is omitted.
• Examine the:                                                                                            
• hind side
• left side
• right side
• head and neck, and
• the hind side again
• Always in the same order, to ensure that the entire animal has been covered.  
• First of all, go to the hind side of the animal. 
• This might seem like a strange area to start, but it is, firstly and most importantly, necessary to measure the cow’s temperature.  In this way, contagious diseases may be differentiated from other diseases.  
• The normal temperature for a cow is about 38,5 ˚C. While taking the temperature, check the colour of the mucous membranes and any discharges from the external genitalia in cows and heifers.  Usually at this stage of the examination a cow will urinate – note the colour of the urine. The colour of the skin and the condition of the hair as well as the general condition of the animals must also be noted.  

 

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Now we move to the left-hand side of the animal.

• A veterinarian will examine this area with a stethoscope. Without a stethoscope to listen to the heart and lungs there is little that the farmer can do. However, count the number of breaths per minute – normal breathing tempo is between 25 – 30 breaths per minute.
• You  may also examine the area between   the posterior side of the ribs and the anterior side of the hind leg, known as the hind flank hollow,  to determine  the movement of the rumen. About one contraction  per minute is normal.   

 

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• A bloated animal will have a large bulge in this area and a drum-like sound due to excess gas in the intestines (rumen) may be detected. Before you move to the front of the animal also have a look at the penis in bulls and observe any abnormal swellings or perhaps umbilical or navel hernias.

 

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3. From the left side, we move to the third station, which is the front of the animal

• The breastbone and neck areas must be examined for any swellings. 

 

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• Also, note the pulse tempo of the jugular vein. Your veterinarian could also show you where to locate the pre-scapular lymph node. Some viral infections are associated with enlarged lymph nodes, but there could be many other causes as well.   
• Check the head for symmetry and if there are any abnormal swellings. Also, examine the nostrils, mouth and inside of the mouth. NEVER put your hand into the mouth of an animal if there is any possibility of rabies.
• Carefully examine the eyes in detail, and especially note the degree of dehydration and the colour of the mucous membranes. Blood samples may be taken from the tips of the ears for the veterinarian to examine at a later stage. Ask your vet to show you how to make a blood smear.

 

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The fourth station is on the right-hand side.

• Here we need to repeat the procedure as for the left side.

After the four stations have been completed, return to the hind side, the fifth station.

• In females, the udder and teats may now be inspected in detail for any signs of swelling, pain and discomfort, which might indicate possible mastitis.  Milk samples may also be taken at this stage for later examination in a laboratory. 

 

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• The testes of a bull can also now be examined.  
• An internal examination is also part of a clinical examination, but this has to be performed by the vet. This is the usual stage for pregnancy in females to be confirmed and any abnormalities of the pelvis must be noted. Also, check the dung for mucus or blood.  
• As is apparent, a specific method is followed to prevent the omission of any organ or system. All abnormalities need to be noted. The best option remains to contact the veterinarian, who is a trained scientist and is able to administer the correct treatment after a thorough examination of the bovine.  
• By practicing this approach, we will learn how to observe the abnormal. It is fundamental that we must be able to observe the normal before we can observe the abnormal.
• Many incorrect diagnoses are made, not because we don’t know, but because we are not looking!

 

7.4.10 BIOSECURITY 

• When farming with a herd of cattle, you are exposed to risk on a daily basis. Your herd comes in contact with other cattle, in extensive areas even in contact with wild antelopes and your animals are at risk to become sick and even to die.   
• How do I reduce my risk? The answer is to  introduce  a biosecurity programme on my farm.  

 

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What is biosecurity?

• The definition of biosecurity is the sum of the management practices, which protect the health of the herd and the quality of the end product produced for the consumer.  
  If we look at the word biosecurity, bio stands for biological and security is to keep your herd secure.

Why do we need biosecurity?  

• Productivity and whether we are making a profit on a beef farm is measured in various ways, usually it is the;
• percentage of calves born per year
• the number of calves weaned, as well as
• the weaning mass
• other beef farmers will calculate the kilograms of meat produced per hectare
• These goals can only be reached if we reduce the risk of disease.  
• Let’s take an example:
• A farmer wanted to expand his herd and went to an auction to buy ten of the most expensive cattle.  
• Together with the expensive animals, the farmer unfortunately brought a new disease to his farm. One of the animals was infected by Bovine Viral Diarrhoea or BVD – a viral disease. His herd was not vaccinated, and he did not follow some of the very basic principles when introducing new animals to a herd.   
• About two weeks after the introduction of the new animals he started observing clinical symptoms in his existing cows such as upper respiratory infection, diarrhoea in calves as well as abortions at various stages of gestation.
• Several other diseases such as Contagious abortion, Tuberculosis, Leptospirosis, IBR, Bovine leucosis and Johnes disease can be introduced in this way into your herd. 

 

 

 

• When you go to auctions it is crucial that you at least know the farm where the animals are coming from and to follow these important guidelines.   
• If you must buy female animals rather go for cows that are certified pregnant by a veterinarian – they must be at least 3 months pregnant. If you buy older cows, they could have been exposed to some disease that could be detrimental to your herd’s health.
• Make sure that heifers are the correct mass and height for their age.
• All animals should be at a condition score of at least 3 to 3,25.
• Make sure they are vaccinated against BVD, IBR and Clostridial diseases as well as Contagious abortion or also known as Brucellosis.

 

• Ensure that a bull has been tested for TB and ear notched for BVD. A breeding soundness certificate should also be available. This test should have been performed by a veterinarian.   
• Also, try to establish the housing conditions and general management on the sellers’ farm.
• This brings us to biosecurity strategies – it is quite easy to understand but harder to implement.  
• The biosecurity triad consists of 3 aspects namely:
• animals
• people
• programmes

 

1. Let’s consider animals.

• All newcomer animals should be isolated for at least 30 days and about 50 meters away from the existing herd before they are introduced into your herd.  
• In this period a large number of tests can be done to ensure that you are not bringing any disease into your herd. Your veterinarian would be able to tell you which tests are essential, and which are optional.
• The new animals can also in this period be vaccinated against diseases – your veterinarian is again the person to make these recommendations.

 

 

 

2. Now peoplle 

 

• All people entering your farm should be controlled – it is very easy to transmit viral diseases from one farm to another by representatives of (for example) feed or pharmaceutical companies.
• You need these people on your farm to come and tell you about the latest developments but if possible restrict their movement perhaps only to your office or vehicle if you need to drive amongst the cattle.
• If you work with animals, first work with the animals more vulnerable to disease namely the calves and then with the older animals to prevent the transmission of disease from older cows to the calves.

 

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• Only identified people should be allowed to work with these animals and these people should not come into contact with your existing herd.
• Also, make sure to properly disinfect your instruments.
• Ideally when you are vaccinating animals a new needle should be used for every animal – this is not very practical but at least use a new or sterilised needle for every crush you are treating or vaccinating.
• When you are vaccinating, rather use heat sterilisation than chemical sterilisation of needles as the chemical may inactivate the vaccine, especially modified live viral vaccines.
• A very practical method is to take an old jam tin and to make a few holes. This tin is then left in boiling water while you are vaccinating the animals. After you have used the first needle you replace it in the first hole. After every crush or number of animals you replace the needle and then use the next needle – when you get to the last needle the first needle is then sterilised and you can use that again. By doing this you will prevent the transmission of a large number of diseases

 

 

 

Programmes

• This brings us to last of the three biosecurity aspects namely programmes and more specifically structured immunisation programmes.  
• We use the word “immunisation programmes” instead of “vaccination” as vaccination is only the act of injecting a biological product into an animal.  
• If you do this at the wrong time of the year, or if you use a wrong vaccine, your animals will be vaccinated but not immunised.
• The immune system will therefore not be capable to fight off a specific disease.
• It is therefore very important to have a structured immunisation programme, specifically designed for your farm. This can be discussed with your vet.
• Always remember: a secure herd is a healthy herd!