Bedding: Pine Shavings
The pros of using pine shavings as a bedding are: the pine shavings are often cheap, it is easy to spot clean the cage by removing soiled bedding without having to change the entire cage and that pine shavings are widely available.
The cons of using pine shavings as a bedding or litter tray product are: the pine bedding will often stick or catch on your pigs fur or your clothes and that pine bedding is dangerous to all small animals.
The Dangers of Pine Bedding...
...is one shared among many rodent and rabbit organisations; the oils present in the pine shavings giving the shavings the pleasant fresh pine smell may cause potentially fatal problems to pets. In guinea pigs, these problems consist of both respiratory problems and liver problems, the latter of which may result in an unexpected death of the animal and both can lead to a variety of health complications and vet trips in the long term and may shorten your guinea pigs life (Guinea Lynx: http://www.guinealynx.info/bedding_wood.html#pine),
The House Rabbit Society in an independent investigation as to the cause of random (and numerous) deaths among their foster rabbits during routine spey and neuter surgery discovered that the loss of rabbits during the surgery was due to an already existent present of liver damage, a condition which was strangely present in both old and young rabbits. After further investigtion, a link was discovered between rabbits showing an excess of liver enzymes in the blood and pine bedding. It was also realised that when the pine bedding was removed, the liver enzymes in the blood returned to normal (House Rabbit Society: http://www.rabbit.org/journal/1/liver-disease.html) Although the House Rabbit Society does not clain this survey to be wholey scientific, there is enough evidence to suggest caution should be taken when deciding to use pine as a bedding, it's also recommended that regular blood pannels are performed on animals housed on pine to monitor the liver's ability to process toxins.
From the House Rabbit Society's article:
"What is it in the wood that�s doing damage? Apparently it�s not a result of ingesting but rather inhaling the fumes, which contain phenols, or toxins which pass in the fumes from the lungs to the blood and are finally filtered through the liver."
Other sources state that while it is well known that cedar shavings should never be used for small animals due to the fatal problems the phenols in cedar will cause, what many people don't recognise is that the toxins present in pine is very similar to that of cedar. (TaSelle: http://www.afrma.org/rminfo2a.htm#pine)
TaSelle goes on to explain "Phenols are caustic, poisonous, acidic compounds present in softwoods [such as pine or cedar], which are routinely diluted for use in disinfectants (for instance, Pine-Sol and Lysol both use phenols and can cause liver and kidney damage in rodents, rabbits, cats, dogs, and humans). They are what make disinfectants cover smells and cedar and pine shavings cover the smell of animal urine... Since phenols are caustic, their direct connection to respiratory problems and pneumonia in rats, mice, and guinea pigs is clear"
For more articles on the use of pine, please consult the following link on GuineaPigCages, a particular point of interest of this link is featured at the bottom of the page where a Pet Store Chain Store changes their policy on bedding which removes pine shavings from the shelves:
http://www.guineapigcages.com/pine.htm
While according to Guinea Lynx, airing the pine shavings for a few days (a small amount placed in the open to air to allow the oils to dissapate) until the smell has completely gone should make the pine shavings safe to use. (Guinea Lynx: http://www.guinealynx.info/bedding_wood.html#pine) some rescues and pet owners refuse to use pine believing the risks of using the bedding are too great, especially when there are many alternatives available to pet owners without the same life threatening con.
One such alternative to using pine shavings which is deemed safe to use is kiln-dried pine, however, is is also recommended by distributers that even kiln-dried pine should be used in a well-ventilated cage:
"*Recommended for open, well ventilated cages and aquariums. *Not recommended for closed environments, such as habitrails or in aquariums with limited ventilation. *Contains aromatic oils * For more information on Natural Pine Bedding, contact customerservice@kaytee.com." (Kaytee: http://stage.kaytee.com.clients.pint.com/products/pine-bedding-litter.php)