Author: ballyabio Just like humans, dairy cows are also prone to a number of infectious diseases and health conditions. Timely diagnosis of diseases and effective treatment strategy is very much important for the well-being animals and significant growth of dairy business. Overall profitability of the dairy business highly depends upon how you keep cows healthy and free from diseases.
ANTIBIOTICS ARE PRODUCED BY MICROBES AND USED AGAINST MICROBES Antibiotics are low molecular compounds/medicines which are produced by living organisms and are used to treat and prevent the diseases caused by microorganisms (exclusively bacteria). Antibiotics either kill or stop the growth of bacteria. Here we will discuss how antibiotics should be rationally used in dairy cows along with a lot of risks associated with the misuse of antibiotics under the light of scientific literature.
WHY WE USE ANTIBIOTICS IN DAIRY COWS? Antibiotics have been used in humans and animals since long ago. Their use has significantly improved the overall growth, performance, productivity and reduced the chances of diseases and health related events in food animals. In return, their use in animals has bestowed us with good quality, safe, and low cost nutritious animal products such as milk and meat. Dairy cows experience a number of infectious diseases where antibiotics literally play an important role to prevent the dairy cows from developing further complications. For instance, mastitis (inflammation of udder) and other reproductive and system infectious diseases require antibiotic therapy. But dairy farmers must take veterinary consultancy as a veterinarian can do the proper diagnosis and recognize the exact root cause of infection. Furthermore, he can suggest the exact dose and help you in selecting the better antibiotic to deal with that particular medical condition. NOTE: Dairy cows at any stage can become infected with any bacterial infection such as conjunctivitis, any kind of wound, skin infections and many more. So, they require antibiotic treatment to get back to their normal life.
WHAT ARE IMPORTANT CLASSES OF ANTIBIOTICS WHICH ARE USED IN DAIRY COWS? Antibiotics can be divided into many classes based upon their target of action and spectrum of activity. On the basis of spectrum of activity, antibiotics are of two types: BROAD SPECTRUM These can act against a few types of bacteria (Limited activity). NARROW SPECTRUM These show activity against wide range of bacteria (Wide activity) On the basis of their mechanism of action (target), antibiotics are of following types: BETA-LACTAM ANTIBIOTICS Because of the beta-lactam ring present in their structure, these antibiotics are called Beta lactam antibiotics. Important antibiotics of this family are: 1) Penicillin & Penicillin derivatives Examples : Penicillin G, V, Amoxicillin, Ampicillin, Oxacillin etc 2) Carbapenems Examples: Doribax,doripenem,ertapenem,imipenem/cilastatin 3) Cephalosporins. Examples: Ancef, cefazolin Ceclor, Cefaclor, Cefdinir. MECHANISM OF ACTION: These all antibiotics target the cell wall of bacteria. They interference with the synthesis of peptidoglycan (a major strengthening molecule of bacterial cell wall) USES: These antibiotics are used to treat a wide range of infections in dairy cows including mastitis, septicemias, Urinary tract infections (upper and lower both), respiratory tract infections. NOTE: This is the widely used antibiotic class in dairy cows to treat a variety of infections. Almost all antibiotics present in these class are broad spectrum (active against both gram +ve and –ve bacteria)
AMINOGLYCOSIDES This is another widely used class of antibiotics. Examples: Important members of this class are gentamicin (cheapest drug to cure mastitis in cows), amikacin, streptomycin, tobramycin, neomycin etc. MECHANISM OF ACTION: These antibiotics basically interfere with the 30S ribosomal unit and inhibit the bacterial cell protein synthesis. Remember, ribosomes are major entities which are involved in protein synthesis. USES: These antibiotics are commonly used in cows to treat urinary/gastrointestinal and skin infections. Majorly for the treatment of mastitis in dairy cows. NOTE: Aminoglycosides show synergistic effects with beta-lactam antibiotics. They both are usually given in combination to get a desirable response.
TETRACYCLINE This is another highly important class of antibiotics. They show activity against a number of gram +ve and gram –ve bacteria (broad spectrum). MECHANISM OF ACTION: These antibiotics also disturb the normal translational process(protein synthesis) and bind with the 30S or 50S (to a certain extent) ribosomal subunits and interfere with the protein synthesis. USES: Tetracyclines are also widely used antibiotics which for various purposes in dairy cows. The oxytetracycline is one of the important members of this family that is also Food and Drug Administration approved. It is used to treat bacterial scours, metritis (inflammation of uterus), shipping fever, and a number of other respiratory and reproductive bacterial infections.
MACROLIDES These are important bacteriostatic (stop growth of bacteria) groups of antibiotics which have broad spectrum of activity (mostly effective against gram +ve bacteria). Important members are azithromycin, Erythromycin, Clarithromycin etc. MECHANISM OF ACTION: They also interfere with the bacterial protein synthesis. USES: Macrolides are mostly used to treat respiratory infections in the dairy cows.
QUINOLONES This is a group of bactericidal (kill the bacteria) and bacteriostatic group of antibiotics which have a wide range of applications in the world of dairy cows. Important modified subclass of this group is Fluoroquinolones. MODE OF ACTION: These drugs interfere with the DNA coiling. Actually, these antibiotics inhibit the activity of an enzyme called DNA gyrase that helps in DNA coiling. This results in inhibition or death of bacteria cells. USES: They are used to treating urinary tract infections, gastrointestinal infections and respiratory tract infections in dairy cows.
HOW ANTIBIOTICS ARE MISUSED IN DAIRY COWS? ENCOURAGE THE RATIONAL USE OF ANTIBIOTICS Antibiotics are given by different ways to dairy cows including injection, oral, mixing in feed/water, etc. Importance of antibiotics to treat a lot of deadly infections in dairy cows can’t be ignored. But their over or under use also creates a number of issues for the humans and animals both. Antibiotics are being lavishly used to treat dairy diseases. Due to their improper usage, bacteria have created resistance (they don’t respond to the antibiotics). This antibiotic resistance is becoming a concern for humans and animals both and increasing day by day. Sinus-infection-antibiotics Due to antibiotics resistance, it is becoming a challenge for veterinarians and farmers to cure the bacterial infections. IMPORTANT NOTE: Antibiotics should only be used under veterinary supervision. A vet will make a diagnosis and suggest you the preferable antibiotic In an appropriate dose. Complete the recommended antibiotic course. This is also important to read all the instructions written on the label with proper attention. Special care must be given to WITHDRAWL PERIOD (minimum time from the administration of the last antibiotic dose to the production of milk/meat). During this period antibiotic residues are present in milk and meat. So, farmers should wait for the withdrawal period (mention on the label/discuss with the vet). Remember, antibiotic residue milk also causes antibiotic resistance in humans when they consume that. This is why; it is highly advisable to give proper care to this sensitive thing.
WHY PROBIOTICS ARE USED IN DAIRY COWS? Probiotics are (good bacteria) which have a lot of health benefits. Due to the increase in antibiotic resistance, probiotics are gaining more attention in the dairy sector. They are administered in animal food or by other ways. Antibiotics for tonsillitis Basically, these good bacteria boost up the immunity, increase milk quality and quantity overall performance, feed efficiency/intake, and improve the gut microflora. In short, they help dairy animals to live well and fight infections effectively. Mostly commonly used probiotics in dairy cows are yeast and lactobacillus species. Moreover, probiotics are available in different commercial preparations/feeds and must be administered in animals after consulting with the vet in proper dose. Rational use of both probiotics and approved antibiotics guarantees better health and performance in dairy cows.
REFERENCES: Frost AJ and O’Boyle D (1981). The resistance to antimicrobial agents of Staphylococcus aureus isolated from the bovine udder. Australian Veterinary Journal, 57:262–267 WHO (World Health Organization) (1997). The Medical Impact of the Use of Antimicrobials in Food Animals. Report of a meeting organised by the WHO in Berlin, Germany, 13–17 October 1997. (Volumes 1 and 2: Report and background papers). Woodward KN (1998). The use of microbiological endpoints in the safety evaluation and elaboration of maximum residue limits for veterinary drugs intended for use in food producing animals. Journal of Veterinary Pharmacology and Therapy, 21:47–53. Ingkaninum P (1994). Probiotics: guidelines for evaluating efficacy and objectives. In: Tournut J and Poomvises P (eds), Proceedings of the 13th International Pig Veterinary Society Congress, Bangkok, Thailand, June 26–30, 292. https://www.farmantibiotics.org/progress-updates/progress-by-sector/dairy-cattle/