Correction to CRI

Wendy Milner (wendy@wendy.cnd.hp.com)
Tue, 25 Nov 1997 9:10:52 MST

I've been corrected:-) I knew that running that distance was
much further. Seems like a mile to me. The correct distance
is 125 feet out and 125 feet back. It was also pointed out that
after the CRI, the heart rate must be back to the starting level
or below. ie. if the starting rate was 16, then the ending rate
must be 16 or lower.

Below is the same article but updated with the correct information.

Several people have now asked "What is a CRI?". So, being the
educator that I am:-) here's the (or at least one) answer.
Perhaps some one could drop this into the FAQ?

CRI - Cardiac Recovery Index

The cardiac recovery index measures how well a horse recovers
after a short stress. While a horse may come into the vet chech with
a high heart rate, the rider can lower the heart rate in a number of
ways. A conditioned horse's heart rate will lower on its own
with little help of the rider. The rider can facilitate the lowering
of the heart rate by cooling the horse, through water on the neck and
legs of the horse, or even by icing the horse down. As the temperature
of the horse declines, the heart rate will also decline. However,
if the horse has been over stressed, even after the heart rate has come
down, if the horse is stressed again, the heart rate will jump up again.

When the rider presents the horse to the vet for the CRI, the vet takes
the pulse. Let's say the horse's rate is at criteria of 64 (or 16 in
15 seconds). Since the horse has been in the check for several minutes,
the vet may be suspcious that the horse is not in very good shape.
The vet check's his/her watch and asks the rider to trot the horse out
to a point 125 feet away and back. While the horse is trotting,
the vet checks for lameness. From the time of the start of the trot,
to the time the vet checks the heart rate again, is exactly one minute -
not more and not less. This time, since the horse was stressed and
barely recovered, the heart rate is up to 80 (or 20 in 15 seconds).
The vet would give a warning, ask for the horse to rest and come back,
or pull the horse - depending on many factors. What would show on
the card was 16/20.

Now let's say there is a horse that is better conditioned that comes
to the vet. The initial heart rate is still at 64 (16 in 15). The horse
trots out and back. The rider calms the horse. The vet takes the heart rate
again, and now the rate is 60 (15 in 15). This horse is ready to go.
The added stress of trotting out 250 feet not only did not stress the
horse, but the horse was in such good shape that the rate continued to drop.
What would show on the card was 16/15.

One more example. A horse comes to the vet with a rate of 40 (10 in 15).
After the trot out, the rate is 36 (9 in 15). You might think this horse
hadn't even started the ride. What would show on the card was 10/9.

When the horse is presented to the vet, the heart rate should be lower
than criteria. If the heart rate is above criteria, the vet will probably
look at the card to see how long it took the horse to come down to
criteria. If the heart rate is still at criteria, and the horse has
been waiting around for several minutes, again the vet might be a bit
concerned. After the CRI, the heart rate must come down to the same rate
or below as at the start of the CRI. If it does not come down, then the vet
can ask for a recheck, or can pull the horse. If the heart rate comes
back to the same level as at the start of the CRI, then the horse is
doing fine. If the heart rate is below the start of the CRI, then the
horse is doing extreamly well.

As always, there are some tricks you can play to lower the heart rate
even while the vet is checking. First, if another horse walks by,
particularly a best buddy, then the horse's rate is sure to go up.
Stand such that you block the horse's view of whatever might excite
him. Do not let the horse eat while the vet is taking the pulse.
Do not let the horse throw his head way up. Perferably, have the
horse hold his head in a "neutral" position. If you have a calming
technique, such as gently rubbing the horse, do so. And for yourself,
take a deep breath and try to relax to show your horse that the excitement
is over, no more trotting right now.

--
Wendy

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