PG . 56
AQHA HORSE HEALTH
( Table 2 .)
In horses , EMS can be a consequence of giving starch / sugar-rich feed ( Table 2 .) or it may be seasonal and linked to the sugar / starch content of the pasture . Fatness is strongly linked to feeds with more than 15 % NSC . Such feeds cause blood glucose to rise too high for too long . Some feed labels list the starch content , but not the sugar ; others list sugar as WSC which = sugar and sugar by another name is just as sweet . The NSC level is the amount of starch PLUS sugar . Label claims of ‘ low glycaemic index ’ and ‘ low starch ’ can be misleading and potentially dangerous unless backed by laboratory analysis !
TABLE 3 . Nonstructural carbohydrate NSC ( NSC = starch + sugar ) levels in common feedstuffs Feeds > 12 % are not recommended for horses and ponies with insulin resistance
Arena-trained horses ( such as working Quarterhorses and dressage horses ) may only cover between 1 and 2.4 km in a hard 30- to 40-min training session - substantially lower than the daily movement of their free-roaming ancestors .
Throughout their 55 million-year evolution , horses have developed ‘ thrifty genes ’ which allowed them to survive times of feed scarcity . Genetically susceptible horses quickly become fat when food is abundant and excessively rich ( with no intervening periods of famine or ice ages !!) and exercise is limited . Exercise in domestic horses compares poorly to wild and free-range horses . Free-range and feral horses exercise for around 16km / day ; horses in a 40 acre paddock about 7km / day and stabled horses for 1km . Many athletic performance horses , such as racehorses , trotters , pacers , elite dressage horses , eventers and even long-distance endurance horses , spend the majority of time inside stables , small yards or paddocks .
In addition , fat is no longer dismissed as a benign deposit of stored energy . Fat cells produce a range of hormones that affect insulin , blood vessels , the immune system , body mass and body composition . The fat cells in horses ’ necks ( and humans ’ bellies ) produce more hormones than fat cells elsewhere in the body and these hormones increase the risk of metabolic syndrome . The other thing that happens to fat cells is that when they are packed too full with fat they swell and squash off their blood vessels , reducing blood and oxygen supply and becoming ‘ sick ’ and toxic . Another source of toxicity in horses with cresty necks , is ‘ glucotoxicity ’ which is caused by high sugar in the blood and inside the cells . High blood sugar damages blood vessels and the hoof . In the hoof , glucotoxicity causes the blood vessels to constrict , reducing blood flow to the foot and laminae .
HOW TO ASSESS THE NECK CREST ?
The cresty neck score ( CNS ) rates the accumulation of fat around along the neck on a scale of 0 to 5 ( Figure 1 ).
Figure 1 . Cresty Neck Scoring ( CNS ) system
AUSTRALIAN QUARTER HORSE ASSOCIATION - WWW . AQHA . COM . AU