Richard Turner MA VetMB MRCVS
With Christmas behind us and, what we hope will be the slow return to normality as COVID vaccinations get underway, it is time to do some Spring cleaning and more importantly, think about going back-to-basics. Over the last 12 months, no doubt for many good reasons, we have seen some clients struggling to get good production in even relatively new sheds. Maybe due to staff shortages, and no doubt associated with income levels, there has at the same time been a move to only dry clean sheds with the possible late addition of some disinfectants onto what is basically a very soiled surface. This has slowly but surely led to poor performance, poor peaks, and some increased mortality with E. coli on many farms. Once E. coli is established in the environment and mortality has crept upwards it is very difficult when using the available licensed and zero egg withdrawal products to get it back under control.
In some cases, the use of essential oils and fatty acids to try to adjust the gut microbiome has a positive effect, but often only minor, and the flock goes onto have a clearance mortality over 12%. Peak production of 80% is not uncommon on some second and third crops through new houses and this all leads to pressure on income and more attempts to reduce costs in cleaning, disinfection and medication. The use of E. coli vaccine in rear is also often not enough to rectify the situation and a wholehearted back to basics approach is needed.
Following poor cleaning, the levels of red mite on many sites remains too high and subsequent flocks become infected early on as they are under stress coming into lay, leading to more E. coli leakage from the intestine and more mortality. The problem goes on and everyone is stressed.
The time of turnaround is crucial to fully clean the premises and equipment. Increased mortality on a free-range farm will often lead to increased contamination on the range and this is when the problem really becomes difficult to deal with. One of our clients has seen major issues with Blackhead and has had to resort to washing the stones outside the pop holes with large, noisy and expensive equipment. On top of that, the use of long-term essential oils in the water, lime combined with Halamid disinfectant on the scratch area and a range of other preventative plans have had to be put in place. So far, possibly helped by a lockdown, the site is performing well. A disease incursion like this can come from birds in the house, wild birds, or other carriers such as worms. If a high population of wild birds is an issue this has to be controlled if possible and the methods of control depend on the species. Whilst not all sites have this type of problem it is an example of how, when a disease gets onto the range, it is so difficult and costly to control.
Focusing on the cleanout process, the choice of products to clean the house is so important. Not all products are as effective and easy to use. As a start you need to be sure that the detergent you use on the equipment and building is of a heavy-duty nature and cleans well. Disinfectants in general reduce the bacterial levels but do not make the surface sterile. Therefore, the better the preparation through the cleaner used, the more effective the disinfectant.
Many pathogens build up on a dirty site and the worst companion for any live animal is a dead animal. Often as vets we are unable to isolate or clearly define the change that has occurred to the overall bacterial, viral and protozoal population on a farm that is causing the issue, but without a doubt high quality cleaning makes changes to the microbiome which leads to less disease in subsequent flocks. Dry cleaning of free-range sheds is a waste of time and should only be a last resort where there are issues of waste water control or severe shortages of time. Using a terminal application of formalin has been used successfully for decades and is cheap. Yet, as we all know it has major health issues and so we have move to hot fogging with Halamid as an alternative option to our clients and it has proven very effective.
Once the housing and equipment are clean, keep it clean and avoid letting the contaminated material re-infect. It is not ideal to have washdown liquids washing onto the range, even if it is well drained, as this is only adding even more contamination to an outdoor environment that is difficult and expensive to clean. It is not only the birds that have a microbiome but also the shed, the range and all the equipment associated with the bird’s environment. These various microbiomes all impact one way or other on the microbiomes of the bird and hence on health and performance. Anything you do to alter them will also impact on the animal, so we need to manage this holistically.
The choice of disinfectant is sometimes based on non-scientific reasoning, such as price, ease of collection, ease of removal of empty drums and even, “I like the supplier”. Careful consideration is required for the system you use for the one big opportunity to set the new crop up well. If a challenging microbial population of pathogens is left on the site then all we are doing by not choosing well is increasing the risk to the farm’s future profit. Take impartial advice which is not always easy to find.
If salmonella is a concern or there is maybe a raised risk due to other animals on the range, then using a glutaraldehyde formaldehyde mixture is a good way forward. Other product mixtures will also work but you need to check on dose rates and ensure it is applied correctly, preferably to dry equipment, so the application rate is not diluted. Red Mite control and maybe attempting to reduce worm eggs will also lead to different products. Discuss with your vet the best product to use, considering the challenges the previous flock has seen, and if this is not the cheapest to buy, at least consider the cost of a poor crop when making decisions.
Water quality has sometimes not been taken seriously enough and is another area when thinking about a back-to-basics approach. As a routine you should test water every 3 months on site. It costs so little and then you will know if either you need to treat the water or even whether the treatment you are using is working. Not surprisingly, we see a lot of money spent on products and systems that just do not deliver the suggested advantages.
Finally, in my personal review of my farm I would look at worm control. The modern layer is an athlete who we challenge with a range of parasites, from coccidia to worms to name only two. Wherever worm control, in water or feed, is used correctly and routinely we see better performance. The choice of when to start worming, when to repeat and what to use is dependent on the challenge and structures on the farm. Very few farms do not have some form of worm burden which, for a bird which is sensitive to quite mild stresses, can lead to more pronounced mortality.
Spring is time to review your flock health and the turnaround time is the huge opportunity to reset the health on the farm. We have the tools to do this, we just need to be sure we use them correctly.