After a successful disease diagnosis of your livestock animals, obviously the next step is to cure the disease discovered via appropriate treatment regime. The treatment recommended will be according to the type and severity of the disease afflicting the animal.
In most cases, major symptoms seen will be treated alongside the disease agents itself which is a more comprehensive approach to quick recovery.
However, different diseases present with different clinical manifestations which have to be managed using different treatments approaches and medications. In more critical conditions, fluid and/or blood transfusion have to be given before recovery can be attained.
Routes of Drug Administration in Livestock Animals
Several routes are used for the administration of veterinary drugs. The choice of route and the technique of drug administration are based on a number of factors which include the species of animal, the physicochemical properties of the drug, the formulation and the disease in question.
However, the recommendations of the manufacturer should always be followed.
1. Oral route
This is administration of drugs through the oral cavity or mouth and it is a natural route for drug administration. This route is suitable for drugs like antidiarrheals, anthelminthics, supplements etc. When using this route, care must be taken to avoid drugs getting into the trachea.
Drugs administered through this route are however, exposed to the action digestive enzymes and microorganisms that inhabit the digestive tract may affect the drug activity. Also, onset of drug action may be slower when compared with other routes.
Administration of drugs in feed and water is also through the oral route. Drug formulations or preparations administered using the oral route are tablets, boluses, suspensions, syrups and the like.
2. Parenteral route
This route of drug administration involves using a hypodermic needle and syringe to introduce the medication between the skin and the enterical canal.
The drug formulation or preparation is usually a stable aqueous solution or sometimes in oil base when delayed and prolonged absorption of the drug is desired.
The most frequently used parenteral routes are intramuscular (IM), intravenous (IV) and subcutaneous (SC). Other less frequently used parenteral routes are intraperitoneal (IP), intrathoracic, intracardiac, intradermal and epidural.
3. Topical route
Topical route of administration simply describes application of drugs locally to the skin and its adnexa or to any of the mucous membranes. Also included in this route are intrauterine, intravaginal, ocular, rectal, preputial, sublingual and intranasal.
Topical drug preparations include ointments, creams, pastes, dusting powders, lotions and sprays.
4. Pulmonary route (inhalation)
This route is used for drugs in the gaseous state or volatile agents. They absorbed rapidly from the airways and alveoli into pulmonary circulation. They are usually applied using a nebulizer or by standard anesthetic machines.
Drug Administration Techniques in Livestock Animals and their Limitations
There are a number of drug administration techniques including oral, intravenous, intramuscular, subcutaneous etc.
Each of these techniques will depend on the type of drugs and manufacturers specification. However, dosage will depend mostly on Veterinarian’s advice based on symptoms seen and severity of condition.
1. Oral administration
Oral dosing includes administration in feed or water as well as tablets, boluses, pastes and liquids (drenches).
In ruminants, orally administered drugs are often given as a bolus or as a drench.
In-feed administration is a simple method for administration of a drug.
Absorption is relatively slow and a long time (an hour or more) may be required for the drug to have the desired effect.
If medicated feed is refused or only partially eaten then the required dose will not have been administered.
In-feed administration may be the most appropriate method for long-term administration of NSAIDs such as aspirin and phenylbutazone in ruminants.
Such use is not likely to be appropriate for food-producing domestic ruminants; however it may be of use for example in treatment of chronic arthritis in non-domestic ruminants in zoos, or in pet ruminants which will not enter the human food chain.
Palatable drugs should be used if they are to be concealed in food.
Absorption of drugs following oral administration is generally considerably less than 100% and may be very variable between species and even between individuals.
The time to effect following oral administration is delayed by minutes to hours.
In ruminants the rate of absorption may be markedly affected if closure of the oesophageal groove takes drugs directly to the abomasum, bypassing the rumen.
Absorption may also be affected by administration with food although this effect may be less variable in ruminants than in monogastric species such as horses.

Drugs may be destroyed in the digestive tract, or may pass through without being absorbed.
Dose rates for oral administration are generally higher than those for parenteral administration of the same drug, to allow for the reduced absorption and/or the first-pass effect (metabolisation of drugs as they travel through the hepatic portal system).
2. Parenteral administration
2a. Intravenous injections
Intravenous injections introduce drugs directly into the systemic circulation. This provides the fastest distribution of the drug and ensures that 100% of the drug reaches the systemic circulation.
Intravenous administration of drugs in ruminants is usually into the jugular vein.
This route of administration is not suitable in circumstances where restraint of the patient is either not possible or not appropriate, which may occur with non-domestic ruminants.
Injection can be painful and involves a risk of infection.
As well as giving the fastest onset of action, this route also results in the fastest elimination from the system, therefore repeated injections are required if plasma concentrations of a drug are to be maintained.
2b. Intramuscular injection
This is usually the second fastest route for drugs to reach the systemic circulation.
This route also allows the administration of “depo” injections which are absorbed slowly to give a prolonged period of action.
Intramuscular injection can be painful. Injection involves a risk of infection.
Absorption following intramuscular injection may be variable.
Intramuscular injection results in peaks and troughs in the blood concentration of the drug.
Muscle damage may occur following injection of drugs; the amount of damage varies with the drug preparation injected. Repeated injections of some drugs may result in tissue necrosis.
Intramuscular administration in non-domestic ruminants may be carried out by hand injection if circumstances allow but may also be carried out using a pole syringe, in which the operator only has to approach within a couple of metres of the animal, and by remote injection (darting).
2c. Hand injection
This is the usual means of administering an intramuscular injection in domestic ruminants.
Limitations
Requires close approach and that the animal stays reasonably still for the period of time during which the drug is administered.
This may be stressful for non-domesticated individuals including semi-free-range individuals of domesticated species.
There is a risk of injury to animal and administrator during restraint of non-domesticated individuals.
This is often not practical for non-domestic ruminants, except in particularly docile individuals.
3. Pole syringe
A pole syringe is basically a syringe attached to a long pole, designed so that the contents of the syringe can be injected while the operator remains at a distance (the length of the pole, e.g. two metres) from the animal.
This method may be safer and more practical than hand injection when dealing with non-domestic animals or animals which are not used to being handled.
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Limitations
This method is only appropriate if the animal can be reached, e.g. if it is within a confined space (or is held by a trap or by entanglement in a stationary object) and cannot retreat further away than the pole can reach.
It is usually only possible to administer about 10 ml or less of a drug, since animals will generally not stay still for long enough to inject larger volumes.
If the animal jumps away before the total dose has been administered then a second injection is required.
4. Remote injection (darting)
Remote injection is not commonly used for drug administration to fully domesticated ruminants; however this is an important method of drug administration for non-domesticated animals, both captive and free-living.
Smaller species should be injected into the rump or the back of the hind leg. For larger species these sites may be used also, but the neck or shoulder is possible as alternatives.)
The main advantage of remote injection is that it allows injection at a distance.
Handling and restraint are not required, and the stress associated with these is avoided.
Limitations
Limitations of remote injection include all the normal limitations for intramuscular injection, as well as the points listed below.
There is always a risk of injuring the animal.
Small antelope and deer have thin skin which is easily penetrated by a dart; care is required to avoid excessive impact force of the dart hitting the animal.
This method is only suitable for relatively small volumes due to limits in the capacity of individual darts.
When darting small individuals there are also limitations on size of dart and volume related to the trauma associated with impact of darts, which is greater with larger, heavier darts and with higher impact velocity.
This method has limited applicability for injection of viscous drugs, particularly when using gas-pressurized syringes, as there is an increased risk of incomplete injection.
An animal may be stressed by being hit by a dart.
An animal may react badly to being hit by a dart and injure itself e.g. by running into an obstacle, or aggravate an injury such as a foot or leg problem by running.
5. Subcutaneous injection
Subcutaneous injection may be employed for injection of relatively large volumes.
Absorption is generally slower than with intramuscular administration and the time to effect after subcutaneous injection is relatively long.
Absorption from the injection site is variable.
Absorption from subcutaneous sites may be greatly decreased in individuals in shock.
Injection can be painful and involves a risk of infection.
This route is not suitable for the injection of irritating drugs.
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6. Administration by Needleless Injector
Administration of drugs using a needleless injector could provide an effective method for administration of local anesthetics prior to management procedures such as lamb castration and tail docking, without the risks (e.g. of introduction of infection) associated with injection by needle and syringe.
Local anesthetic has been administered using a high-pressure needleless injector in experimental conditions for reduction of pain associated with castration and tail docking of lambs.
It was noted that there were considerable limitations in the volume of drug which could be held in the injector, requiring frequent, time-consuming reloading with relatively expensive drug ampoules, and in the maximum volume which could be injected at one time (0.03 ml with this applicator).
7. Topical Administration
Topical treatment includes direct application to the skin but also to mucous membranes.
Topical administration is commonly used with local anesthetic drugs to provide surface anesthesia of the nose, mouth, ear, bronchial tree (by spray), cornea (by drops), urinary tract or rectal mucosa.
Intramammary infusion is a special case of topical treatment. It is used mainly for administration of antibiotics in the prevention (dry cow therapy) and treatment of mucosa, but is also used for administration of corticosteroids, usually together with antibiotics, in mastitis treatment.
Intramammary infusion of local anesthetic solution can be used for analgesia of the mucosa of the teat cistern.
Intranasal administration has been used experimentally in sheep for the administration of buprenorphine. It gave a high bioavailability and rapid absorption.
8. Local and Regional Administration
Local and regional administration is commonly used for administration of local anesthetic drugs. This may be used in assessment of conditions such as lameness, and while carrying out painful procedures such as toe amputation, teat surgery or caesarean section.
One form of regional anesthesia/analgesia is epidural anesthesia. This involves injection into the epidural space just outside the spinal cord.
This is a technically difficult technique requiring practice for correct use.
Strict asepsis must be employed when this technique is used in order to avoid infection of the epidural space.
Veterinary Preparations
Pharmaceutical preparation intended for use in animals come in different forms depending on the species of animals and the disease for which the preparation is targeted towards.
The various forms in which these preparations come included but not limited to tablets, capsules, creams, emulsions, ointments, injections, powders, gels, sprays, boluses and drops.
For the desired effect to be obtained, the drug must be administered using the appropriate route and in accordance with the manufacturer’s recommendation.
Classes of Selected Veterinary Drugs and Examples
Veterinary drugs can be classed based on the organism on which the drug acts or the organ of the body where the drug action is desired.
For the purpose of this lecture, the drugs are classified based on the disease- causing agent or aetiology. The classes of the drugs and their examples are given below.
Class of drug | Examples of drug preparation |
Antibacterial | Oxytetracycline, Streptomycin and Procaine Penicillin |
Antiprotozoans | Dimanazene aceturate, Amprolium and Homidium bromide |
Antheminthics | Levamisole, Albendazole and Pyrantel pamoate |
Antifungalagents | Ketaconazole, Griseofulvin and Nystatin |
Antidiarrheals | Methoscopolamine, Diphenoxylate and Kaopectate |
Anti inflammatory/analgesics | Dexamethasone, Phenybutazone and acetyl salicylate |
Ethno-Veterinary Medicine/Practices
Pastoralists and other livestock farmers have relied on locally available plants and herbal preparations for treatment of their animals before the advent of western (orthodox) veterinary medicine. This indigenous knowledge system is referred to as ethno-veterinary medicine or practices.
Ethno-veterinary medicine includes indigenous beliefs, knowledge, skills, methods and practices pertaining to the health care of animals. Ethno-veterinary medicine is largely used effectively by local farmers for keeping animals healthy and productive.
Some advantages of ethno-veterinary medicine are that it is cheaper and based on local resources. However, some difficulties associated with ethno- veterinary medicine include, lack of proper documentation and validation, difficulty in standardization and non-availability of plant parts all year round.
The use of several medical plants in the treatment of animals has been documented but the absence of standard dosages and preparations hampers their inclusion in normal animal health care delivery systems.
A Comparison between Ethno-Veterinary Medicine and Orthodox (Western) Veterinary Medicine
Ethno-veterinary Medicine | Orthodox( Western)medicine |
Indigenous, evolved by farmer and farmer oriented | Developed by researchers and science oriented |
Passed on from generation to generation or farmer to farmer | Communicated from researchers to veterinarians |
Compatible with local situation and low dependency on external inputs | May or may not compatible with local situation and more dependent on external inputs |
Not well researched and not well documented | Very well researched and well documented |
Takes longer to show effects | Effects/results are quicker |
Usually specific to local situation since as it is dependent on locally available inputs | Usually general recommendation not tied to any locality |
In summary, the article have analyzed the various techniques and routes of drug administration in animals and the various forms or preparations in which veterinary drugs are supplied.
We have also stated the classes of drugs used in treatment of animal diseases. We have equally looked at ethno-veterinary medicine and compared it with orthodox (western) veterinary medicine.
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