Antimicrobial resistance is becoming an increasing problem for both human and animal health and so we must take steps to prevent bacterial infections and thus reduce our antimicrobial usage. In the sheep industry, prophylactic, oral antibiotics were commonly given to lambs at birth to prevent a condition called watery mouth. However, there is no longer a licensed product available in the UK for this condition and it is rarely appropriate to prescribe off license products. Injectable antibiotics are not a solution as the E.coli bacteria that give rise to watery mouth proliferate in the gut and it is the toxins released by dying bacteria entering the bloodstream that cause the demise of the animal. Injecting antibiotics will not reduce the bacterial level within the gut. It is also widely accepted that lambs with watery mouth also have received inadequate colostrum. The ultimate solution to bacterial conditions suffered by new born lambs is to reduce the bacterial challenge faced by the lamb through good hygiene and ensuring adequate, good quality colostrum is received by the lamb.
When a lamb is born, the navel provides an open tract into the abdomen; it contains vessels that lead straight to the liver providing a fast track to the blood stream. Bacterial contamination of an untreated navel scan lead to navel ill, joint ill, peritonitis and septicaemia. All these conditions impede growth and can become fatal. Sealing this direct entry point for bacteria as quickly as possibly after birth is vital to lamb survival. Effective navel preparation is a key aspect to navel management. Several trials have been conducted over the years as to which navel preparation is the most effective and currently no alternative supersedes a 50:50 solution of 10% strong iodine and surgical spirit. This provides efficient drying of the navel to close the tract and also prevents colonisation of bacteria on the navel stump. Dipping the entire stump, rather than spraying is also recommended as there will be complete coverage of the stump with solution. Ensuring the navel is no longer than 3cm will reduce the contact time with underlying bedding. Dipping should be performed immediately after birth and repeated again 6 hours later.
However, it must also be remembered that these infections are not only caused by direct contact and colonisation of the navel , but can also be caused by ingestion of bacteria. Therefore the general hygiene of the lambing environment is also imperative. The dirtier the environment, the higher the bacterial load and risk of challenge. Moisture and organic material such as bedding, faeces and birth products provide an ideal breeding ground for bacteria, but they also reduce the effectiveness of the iodine navel dip solution. It is to be noted that if the navel dipping containers becomes grossly contaminated with bedding, it should be emptied, cleaned and replenished with new solution.
When a lamb hits the ground it has no immunity to environmental bacteria until it has received adequate, good quality colostrum. Therefore if the lamb is born into a dirty environment, it will meet a higher bacterial challenge immediately, before the navel has been dipped and the colostrum has been drank. Furthermore, if the ewe has dirty teats, this will facilitate bacterial ingestion even more so.
Efforts should be made to empty and disinfect lambing pens between each ewe her lambs. Powder disinfectants are recommended as they will also aid drying of the pen. Those handling sheep and lambing should also maintain good personal hygiene by washing hands thoroughly before and after lambings with a chlorhexidine handwash to reduce bacterial transmission between sheep. Hygiene of lambing equipment is also important. All equipment used to perform lambing tasks should be cleansed and disinfected, observing correct concentrations and contact times for the disinfectant used. This includes feeding equipment, lambing aids and elastrators. These pieces of equipment get heavily contaminated and are perfect fomites for bacteria. New, sterile needles should also be used for any injectables administered.
Colostrum provision should never be overlooked. Providing the lambs with adequate amounts of good quality colostrum within the first few hours of life will give the lamb its initial building blocks of an immune system. Good quality colostrum relies on ewes with good quality nutrition, body condition and health. Even with meticulous hygiene and navel preparation, we cannot create a bacterial free, sterile environment so the colostrum will kick start the immunity while the lamb develops its own immunity over time.
These steps will ensure that the lambs immune system is not overwhelmed within the first few hours of birth and allow the lamb to focus on growth. Neonatal infections have a poor response to treatment and so preventative steps are crucial to ensure productive, thriving lambs from the start.
Written by Leanne Ford.