Last month I reviewed how we've slipped on our clean- up routine over the years. Many farms are well above the target of 100,000 viable organisms/sq. cm. (about 1/2 million/sq. in.) that's needed before the disinfectant has a chance to reduce the organism to 1,000/sq. cm. (nearly 600,000/sq. in.) - a level the pig's immune system can handle.
Review Your Strategy What is a more likely scenario on a typical hog farm? Samples of nursery metal and plastic surfaces after hot pressure washing were indicating 2-5 million organisms/sq. cm., 50 times more than the preferred amount.
And this producer thought he was doing a good job. Of course, no stockperson can be 100% thorough on all the jobs he has to do. But a 50-times shortfall is just too much and there are two main reasons why:
1. The biofilm. Most bacteria produce an oily substance called a biofilm to protect themselves. A farm-specific detergent not only loosens the greasy deposit in caked-on fecal matter allowing it to remove more bacteria for the disinfectant to deal with, it also damages the biofilm of those that remain, and many of them will. A detergent gives the disinfectant a head start.
2. Using cheap disinfectants. By a cheap disinfectant I mean the basic chemicals like formaldehyde (formalin), caustic soda, sodium hypochloride and the cresols. These all have drawbacks and you need to be aware of them.
All disinfectants for farm use have approved dilution rates. These are verified and tested under various schemes in different countries. Table 1 lists a few in my own country, Great Britain. The U.S. will have similar dilution rates and you should check them out.
The table shows some are not approved at all and others have to be used at far higher dilution rates (in the case of formalin, 144 times higher) than the appropriate, but expensive, disinfectants we have these days. The product Virkon S, for instance, is not even close to 144 times more expensive than formaldehyde.
So cheapness is relative. Before you can use these basic chemicals responsibly, you should check to see that they are suitable.
Another disadvantage of basic chemical disinfectants is that they are corrosive and caustic, like the cresols and caustic soda. Formalin may be a carcinogen, and in any case is quitedangerous when used to fumigate barns. You must wear an approved fumigation mask.
The coal-tar derivatives like cresol are popular. But in Malaysia, where their industry was almost destroyed by the J.E./Hendra disaster and their stockpeople put at risk, it appears detergent and Lysol advise weren't strong enough. Now they are on specific detergent/disinfectant protocols in rebuilding their industry.
Current Cleaning Advice Check that your cleaning procedure is in line with current advice. Use a farm-specific detergent, not just an industrial/catering product. Agriculture has different problems; rougher, more porous surfaces and a lot of caked-on "polished" body residues.
* Suggest farrowing and nursery manufacturers make at least part of their floors conveniently hingeable or removable to get at the under-slat surface. This is especially true as young pigs are a breath away from 50 million pathogens/sq. in.
* Use a modern disinfectant. While there are a variety of these, the best advice is to follow the protocol of one of the reputable companies.
* Check to ensure the detergent cleaning process and disinfection are being done properly. For example, in the poultry industry the product-volume used has to be accounted for and even the amount of water diluent checked out against a meter.
Part of this checking procedure is to get samples taken after cleaning and disinfection is finished. Your local veterinarian can arrange this.
* Dry out the surfaces. My clients use portable kerosene space heaters to "roast" the inside of the building. Usually 2-3 hours heating is enough. Remember, at least 6,000 organisms/sq. in. will remain, however dedicated you are, and a damp surface allows these escapees to get away some 30 times faster over 24 hours.
* Keep pests out, the Achilles' Heel of most farms. A rat crossing a dried, disinfected surface can at once spread swine dysentery, leptospirosis and ileitis.
* Sanitize the water. Poor quality water leads to reduced performance and increased disease. There are products which can be added both with pigs inside or absent.
* Aerosol disinfection. Spraying a fine mist or fog over pigs can reduce the risk of cross-infection during disease outbreaks. The specific products are safe at the recommended dilution levels and mist droplet size.
The proof is in the pudding. All of my clients are now following the above steps. Some are segregated, 80% are all-in, all-out (AIAO) in whole or in part and 20% still use continuous production grow-finish houses.
Performance is given in Table 2. What is really interesting is that the continuous production systems nearly equal performance of the AIAO/segregated.
Of course, these massive improvements over national average are due to a lot of other factors besides good routine cleaning and disinfection. But that continuous production operators are almost up with the leaders suggests that attention to good hygiene could be as important as segregation and/or AIAO.
Finally, there is the cost of it all. I guess from my studies that good hygiene protocol costs about 4% more - 2.5% on labor and equipment and 1.5% on materials.
But if one discounts two thirds of the 26-33% improvement in output (Table 2) as being due to other factors, this is still nearly a 2.5 REO (Return on Extra Outlay). That's still a good bargain despite all the cost and extra work.