Introduction

As with any specie, the Hartley Guinea Pig (GP) NAM chamber design aims to achieve expected sRaw values which affirms the intended objective of eradicating the apparatus from the NAM measurements, leaving the subject’s airway resistance as the only factor in the reported values.  The latest design utilizes the Allay Technology principles of loading and restraining the subject, while deviating from a nose seal to a neck seal design to accommodate the body shape of the Hartley GP.  This deviation requires care when choosing neck seal size, but offers great consistency in return.

Picking the Right Collar

Since GP's are rather docile, choosing the appropriate collar is easy. To do this, hold the animal’s body with access to the neck area.  Pick a collar based on the subject's weight from the table below, place in on the animal’s neck and move it back and forth from the shoulders to skull.  You should be able to move it freely across the neck but feel the skull and shoulders against the collar teeth when reaching them.  Pick the smallest collar that allows free movement to prevent the animal from turning around.

Animal Weight as Related to Collar and Seal:

Animal Loading, Restraining, and Sealing Process

1. Based on subject’s weight, use table above to locate the appropriately sized latex seal and assemble to neck seal assembly. 
   
   
2. The neck seal assembly (shown above in exploded view) can be used in two different methods:
   1. Hold Guinea Pig’s body and limbs tightly (blanket, sleeve or “sock” help) and slide neck seal assembly toward head, noting proper orientation, until the subject “wears” it like a collar.  At that point, slide animal backward into restraint tube until O-ring mates with restrainer groove.  Note seal orientation.  In this method, it’s important to watch that the fur and feet do not get caught against the O-ring.
   2. Place neck seal assembly in restrainer, noting orientation. 
      
      
      
      
      
      

      Guide the subject towards the seal, head first, until its entire head pokes through seal.  In this method, the fur and front paws require less care, but the animal may need some “convincing” to walk towards the seal when pushing it through.

3. Once through the seal using either method, lower the collar picked previously to restrain the animal. 
4. Insert the head rest into the front nose cap.
5. Place the front nose cap over the restraint such that subjects nose protrudes through opening but does not make forced contact against the bottom jaw.  The final position should allow the animal to rest its head against the opening, but not get its top teeth stuck against the plastic: