Homestead Veterinary Hospital

November 2007

AHF benefit breaks records, leaves 'em laughing

The 2007 Animal Health Foundation benefit broke previous records in raising money for laminitis research and gave attendees a singing finale unlike any previous party. The event was held Oct. 20, 2007, at the Longview Animal Nutrition Conference Center in Gray Summit.

True to tradition, Dr. Chris Pollitt of the University of Queensland attended and gave an update of his work. Dr. Pollitt, considered the world's leading researcher of laminitis, is a longtime recipient of AHF funding. He presented two recent breakthrough theories.

Dr. Donald M. Walsh gave a slide presentation of his monthlong visit in February 2007 to Dr. Pollitt's facility in Australia. The visual feast
of Australian scenery included images of his ride into the outback to see brumbies, or wild Australian horses.

The live auction featured two posh
vacations; a "neighborhood" promo
produced by Fox 2 at the recipient's
farm to air on Fox 2's station a
minimum of 12 times; the use of a
BobCat 2200 for a year; a custom
acrylic/oil portrait of the recipent's
barn, complete with one's own animals;
a giclee portrait of a pet; and top notch
Blues' and Cardinals tickets.

Dr. Pollitt's ever-popular reciting
of "The Man from Snowy River" was
overshadowed by his finale: a singing
duet of the common man's Australian
national anthem, "Waltzing Matilda,"
by Dr. Pollitt and Dr. Walsh.

Dr. Pollitt's PowerPoint presentation on the inner workings of the hoof included many stunning animated videos. He discussed two major areas of advancement in research that have been produced by his team.

The first was his theory that the hoof wall of a horse who's had severe acute laminitis may grow in an abnormal direction, anteriorly (or forward) rather than downward, due to the descent of the coffin bone below the circumflex vein, as seen on a venogram.

Cells in the hoof wall proliferate in two places, in the coronary corium (coronary band) and the terminal laminar/sole complex (the white line area). When the coffin bone drops, it changes the alignment of these germinal cells. As the proliferative tissue in the two areas pushes forward against the intact hoof horn, the tissue has nowhere to go, so it expands posteriorly (to the rear), causing the venus blood supply in the coronary plexus (venus blood supply at the coronary band) to be shut down, again as seen on a venogram, and causing the tip of the coffin bone, or third phalanx, to be pushed posteriorly, making it appear that the deep flexor tendon is pulling P3 in that direction.

This wedge of tissue pushing up against P3 often will leave a notch in P3 all the way abound the base.

The strongest argument to support this theory is Dr. Pollitt's question to those who argue the pull of the deep flexor tendon causes P3 to rotate posteriorly: Why doesn't the rotation occur at the onset of laminitis when the most damage has been done to the laminae and they are at their weakest? Rather, it occurs weeks after the onset of laminitis, which is when the proliferative response would begin to press against the bone, resulting in the commonly seen ski tip portion of P3 and the loss of bone density just proximal to the tip.

If a venogram shows the coffin bone has dropped below the circumflex vein, this valuable information should tell a practitioner it's time to act to prevent the rotation of the coffin bone by thinning the hoof wall over the distal end of the third phalanx (approximately 1/2 to 3/4 inch from the ground surface) to allow the normal proliferation growth to proceed in the new anterior direction, reducing the pressure on the coffin bone.

Dr. Pollitt's second breakthrough announcement was the work of Kate Asplin and Katherine McGowan at the University of Queensland that showed hyperinsulinaemia produced laminitis in a group of ponies. This new finding raises the possiblity that controlling a horse's insulin with diet and exercise can prevent laminitis.