From Farm Journals Pork, written by Spencer Wayne, DVM, Ph.D., Pipestone:
I am old enough now to have seen a significant arc of attitude regarding antibiotic use. Our attitude. Public attitude. Government attitude. At one time, antibiotic use would have been a very quick decision for me or my clients. Problem… Solution! 
But the landscape is different today, and for several valid reasons. If we are to maintain our trajectory for becoming the farms of tomorrow, our attitudes and actions must be ready to navigate this new terrain.
Antibiotic resistance existed long before the discovery of penicillin in 1928. In the constant and eternal microscopic tug-of-war, genes for antibiotic resistance have been around as long as bacteria have been around. As this balancing act plays out, the more pressure you put on bacteria, the more they deploy defensive measures. So, what is the right way to apply this “pressure” to achieve good results and maintain our tools’ usefulness, as well as satisfying our customers’ concerns?
Differences in Antibiotic Use
From a 1,000-foot viewpoint, it is apparent that some producers use more antibiotics than others. What accounts for this difference? First, some pigs are sicker than others and antibiotic use is vital to improving those animals’ health and well-being. Additionally, habits can be hard to break. There are many times when we reach for an antibiotic solution when none is needed, because that is what we’ve always done. This is just human nature and requires self-awareness to overcome. 
But focusing on the first reason, we should consider why some pigs are sicker than others. Some pigs may have had a rough start or carry disease baggage with them at weaning. If the sow unit is chronically affected by diseases or other pathogens, then your pigs will inherit these issues. 
Others have also spoken more extensively on the importance of having a “clean” pig source. Suffice it to say that along with an older wean age (24 days versus 20 days), it can make all the difference in the world. I consider weaned pig health to be the single most important determinant of performance and antibiotic use. If you have a viral endemic pig source, you need to determine how to clean it up, control it, or get out of that source.
Even a good pig can go bad if the care and environment are not adequate or they encounter new pathogens as they grow. Dangerous neighborhoods, with lots of other pigs and poor biosecurity generally mean a growing pig will stumble through life spending a fair bit of energy recovering from illness. And farmers usually increase their antibiotic use as a result.
In addition, immunity (or lack thereof) can play a significant role in antibiotic use. There is a bit of a trade-off here. Illeitis vaccination should result in less antibiotic to treat diarrhea. Mycoplasma vaccine should reduce the need for antibiotics to treat pneumonia. It’s not a perfect inverse relationship, but it definitely factors into antibiotic use. In those cases, we should be focused on prevention (vaccine) instead of treatment (antibiotics).
Manage Antibiotic Use
These factors explain the “why” of antibiotic use, but tell us nothing about making better decisions in our treatment plans. We recognized the growing importance of managing antibiotic use several years ago and developed PART, the Pipestone Antibiotic Resistance Tracker, that measures antibiotic use. If the idiom is true that “you cannot improve what you cannot measure,” then simply measuring use is foundational to making better decisions going forward. 
Also, are the antibiotics used well-suited to the problems identified? Some bacteria require specific antibiotics as treatment. If a farm is using “gut-oriented” antibiotics when the presumed issues center around respiratory disease, then you have misdiagnosed the problem or there is a more appropriate treatment choice. The cost of a drug shouldn’t factor into its “appropriateness,” but if two antibiotic opinions would both be effective, then knowing the relative costs of treatment should be considered. 
The public is concerned about your antibiotic use. By extension, the packer will be concerned about your antibiotic use. Several packers have begun to ask farmers to share their antibiotic use statistics. At this time, no packer is prescribing or prohibiting antibiotic use regimens, with the exception of antibiotic-free programs. Your packer will likely want to know more about your farm’s antibiotic use going forward. Tracking this data provides the stats that packers are looking for to build higher confidence in the meat they sell. 
Antibiotic Categories
All antibiotics are not the same, and they aren’t classified the same either. The FDA’s published list categorizes antibiotics as Critically Important, Highly Important or Not Important and some antibiotics are not even on their list. These categories are based on the importance of these antibiotics to treating human illnesses. 
The guidance has been, and continues to be, that farmers and their veterinarians should use drugs with a lower classification as first option to protect the effectiveness for humans. Factoring in at the edges is clinical experience. Sometimes, drugs that should work just don’t. In those cases, your veterinarian should be giving you guidance on effective alternative treatment options.
Times have changed. We’re already accustomed to being incentivized for lower backfat. You hear the ask for Duroc-sired pigs and group-housed sows; and soon you will hear the ask for pigs from farms where antibiotic use is planned, reviewed, appropriate and well-documented. A new health paradigm is emerging, where we’re looking for the pig that does more with less (including less antibiotics). To succeed, we will all need to be better students, better planners and better critical thinkers. Even a stubborn old guy like me realizes this journey will make us better.
Read the full article HERE
The Pig That Does More with Less (Antibiotics)