As an on-farm advisor, the practical aspects of pig behavior fascinate me. In fact, the first press article I wrote — 40 years ago — was on the tail biting problems we had on our own farm.
We've certainly learned a lot since then. We Brits are good at looking after animals (if not so hot in making enough money from them these days). Here is the latest sharp-end advice from Britain. The approach has reduced tail biting by two-thirds on my clients' farms.
The latest research suggests that tail biting is behavioral evidence of three types of stress — climatic, environmental and social.
Nutrition can be a factor, but pig nutritionists these days know what they are doing in formulating diets, so it normally is not a problem. And pig farmers do not underfeed their pigs, but it is important to make sure feeders are operating properly so that pigs have easy access to feed.
Points to check: low salt (<0.5%), digestible fiber (under 3%), accidental overuse of minerals, or some performance enhancers or disease preventers.
Is low animal protein involved? In the post-foot-and-mouth-disease era in Britain, we use far less of it now, if any. Yet, in my experience, tail biting has not increased as a consequence.
Because the three main stressors are usually combined, it is difficult to work out which of these particular causes is most important in your unit.
As a result, there is a tendency to apply all likely treatments at once to minimize further harm. This is known as the “haphazard approach” and will not solve the long-term problem, as it relies too much on chance to reveal the correct solution.
A better option is to apply the “step-by-step approach.” Animal behaviorists sometimes call this the “particulate approach.”
Identifying the Cause
At the outset, it is important to quantify the problems in each pen. Make a list of possible causes, which could include anything that is increasing activity beyond normal levels.
Tail biting is nearly always misplaced exploratory behavior that disturbs the pig's contentment. Therefore, check out what you are doing (or not doing) to interest the pigs.
Are they bored or frustrated? The addition of bedding; old tires; thick, plastic piping; canvas or paper bags; or compost hung from overhead, meshed containers could help. In the United States, I've seen chains in the pens for the pigs to play with. I don't advise this measure because the pigs soon get bored with them. Besides, the chains tend to slap penmates in the face.
Mixing pigs increases antagonistic behavior, but this alone may not be the cause of the tail biting. Prolonged restlessness after mixing, due to poor mixing skills, can create the problem. Overstocking, for example, may cause prolonged restlessness. Competition at the feeder can likewise be a factor. Be sure the pigs can eat comfortably from the feeder.
The main environmental influences include: low ventilation rates in cold weather, elevated ammonia and carbon dioxide levels, excessive dust, proper lighting (keep it down to 60 lux and provide six hours of darkness), incorrect air temperatures against published lower critical temperatures (LCTs) for the weight of pigs, drafts (especially at night), temperature fluctuations over a 24-hour period and wet floors in the resting areas.
Solving the Problem
Here is a step-by-step approach to solving the problem:
Promptly remove the tail-bitten pigs.
Prioritize and select what you think are the most likely causes. Try to eliminate them in the pens with pigs most likely to be affected.
Record what happened.
If the incidence continues, check other items on your priority list. Address two at a time until the problem disappears or becomes much less of a nuisance.
This procedure will give you insight into the possible causes of tail biting on your farm and, hopefully, some solutions.
Not So Simple
At this stage, a client might say: “Not so fast! I see the logic in the step-by-step approach, but I've got an urgent problem here! I've got some pens with blood everywhere. I've got to try anything to get it stopped.”
My answer has always been: “Before an outbreak hits you, go through the list of likely causes and put any perceived or queriable weaknesses right. Then, should an outbreak occur, go through the list again and look hard at the items as they apply to the offending pens.”
Nearly always one, or at the most two, items will appear as suspect in those pens alone. Remedy them and record progress.
Over several years, I've found this strategy has worked on every farm I've been called to. Yes, it can sometimes take time, but a tail biting audit and corrective actions usually stop the nuisance.