Look at any E.U. pig production-related website or magazine and you’ll find something written about pig welfare. The European Union is allocating huge sums of money to projects relating to welfare issues, as consumers are increasingly concerned about how their pork is produced.
We’ve also seen a growing number of animal-welfare organizations which claim they’re in business to ensure that food animals are reared in humane conditions. Some would argue that the groups’ main aim is to put food-animal producers out of business. What these groups would do well to remember is that pig producers are not stupid. The old saying, “you look after your pigs and they’ll look after you” is etched in pig famers’ brains. They know that well-cared-for and nurtured pigs will respond accordingly.
Compassion in World Farming was founded in the United Kingdom 40 years ago and is active in several countries. One of its aims is to abolish farrowing crates, arguing that it’s cruel to keep a sow restrained in a crate for three weeks. There’s no mention of the anguish and pain a piglet can suffer when flattened by its mother. When challenged to suggest a system that provides equal liveability at the same cost, CIWF doesn’t have an answer.
Even though tail biting (and tail docking) has been debated for years, it’s again making headlines in Europe. I remember tail-biting episodes occurring 40 years ago, involving newly weaned indoor-reared pigs. The facilities were naturally ventilated and the problem flared up when day- and night-time temperatures fluctuated dramatically (generally in spring and autumn). We didn’t have hospital pens to isolate affected pigs, and the treatment consisted of smearing Stockholm tar on the wound. It was messy but seemed to work, although infection could lead to abscesses working up the spine. Unfortunately, they were only visible after slaughter and resulted in carcass condemnation.
In Their Nature
It’s well known that pigs are curious and will root and chew wherever possible. If the pig gets stressed and has nothing inanimate to chew on, then another pig’s tail, which is at just the right level, suffices and tail biting starts. Today E.U. producers must provide “enrichment,” such as pieces of wood hung down on a chain, long straw put in a rack at pig level and other options.
The logic behind tail docking was to remove the tip one day after birth, at the same time as clipping needle teeth, because the tip was insensitive. Consequently, with the tip gone, a pig would more quickly know and respond if its tail was being chewed.
It’s difficult to put a financial estimate on the losses associated with tail biting. Plus there is a labor cost associated with the tail-docking process.
The E.U. 2001 Pig Directive, which became law in the United Kingdom in 2003, states that tail docking can only be done when there’s a real risk of tail biting and where other prevention attempts have failed. In 2007, the U.K. government’s Department for Environment, Food and Rural Affairs said that the procedure should only be done as a last resort.
Most studies have focused on tail-biting victims rather than the culprits. Male pigs get bitten more than gilts; barrows and heavier pigs encounter it more than their lighter pen mates. In farms with mixed breeds, Hampshires appear least likely to suffer the condition.
It would be helpful if the characteristics of biters could be identified. However, this is time consuming and little research has been conducted. Two studies found that Landrace pigs were more likely to tail bite than Yorkshires. Another study concluded, “the predisposition to tail bite had a significant positive genetic correlation to lean-tissue growth rate and negatively correlated to backfat thickness. These data suggest
the possibility of a metabolic basis to tail-biting behavior.”
A more practical view is that runt pigs are the culprits, and they tail bite to satisfy a metabolic need for a nutrient (or nutrients) lacking in their blood. In a 2002 experiment, researchers observed that tail biters, when exposed to a blood-soaked artificial tail, chewed it far more than pen mates which were not tail biters. This suggested that the tail biters lacked some component in the blood and had a need for it.
Dietary tryptophan levels might be implicated. When four levels of dietary tryptophan were fed to 21-day-old weaned pigs, less tail and ear biting was seen in pigs receiving the two higher tryptophan levels.
Still another study showed that the heavy pigs in a group were the tail biters. Such inconsistencies might be explained by research in 2010 that suggested “tail biting can arise from several different motivational states.”
It Takes All Kinds
That research (Taylor, et al. 2010) offered three very different types of tail biting.
1) Two-stage biting: It starts with a gentle chewing of tails, often when a pig is lying down. It follows with more forceful biting, causing bleeding. It is thought to originate from frustrated foraging motivation, when the amount and type of environmental enrichment doesn’t satisfy the foraging and exploratory behavior induced by the pigs’ metabolic state.
Northern Ireland researchers studied pigs housed on slats (today classified as a barren environment) with no enrichment. They made rectangular, wood frames covered with wire mesh, liberally covered the frames with spent mushroom compost and suspended them at pig height. The compost, an abundant waste product in Ireland, protruded through the mesh and the pigs could pull it out and chew it. Not surprising, this enrichment resulted in little or no tail biting.
2) Sudden/forceful biting: Here the pig’s tail is bitten with no prior manipulation and occurs when serious competition exists, such as with insufficient feeder space.
3) Obsessive biting: This is when the same pigs go around biting tails over an extended period of time.
Many Motivating Factors
Today, the European Union requires environmental enrichment in swine pens, although many of the “toys” don’t do much to stop tail biting, especially in slatted-floor pens. Dropping straw around (10 grams per pig) twice a day on the slats versus putting it in a rack proved best. Of course, straw and slats are not an ideal combination.
While insufficient feeder space naturally will cause aggression and can lead to a tail-biting outbreak, some other issues include:
• Climatic issues: This can be excessive heat or cold, drafts, dustiness and noxious gases. With drafts, pigs may huddle and end up getting overcrowded and stressed, which can be the trigger. Misting pigs in hot weather has shown to reduce tail biting compared to pigs which were not cooled.
• Health: Increasingly, pig health is being linked to tail biting. Herds with a low health status (enteric or respiratory) have more tail biting. Interestingly, specific health measures such as vaccinating for porcine circovirus have been linked to reduced tail biting.
• Managing outbreaks: Tomorrow is too late. Once tail biting occurs it spreads quickly. (Perhaps it’s primal and involves the taste of blood.) So immediate action is important.
In the end, if we lived in a perfect world, pigs would have nice curly tails and tail biting would never occur. But we don’t and it does.
Tail biting is certainly not in the animal’s best interest and docking tails helps.
With animal-welfare legislation still in its infancy in the United States, you have the benefit of seeing what happens in Europe. The challenge is to find the causes and solutions regardless if tail docking is no longer an option.