Raptor Repertoire

Sour Crop

Original post by broberg@millcomm.com
Post Date: 24 Jul 97

Can someone explain what sour crop is? I've never heard of this until
recently.
What are the symptoms, what causes it, etc.?

Erica
SE Minnesota


A reply by charliek@golden-eagle.org

At 05:39 PM 7/24/97 -0500, you wrote:
>Can someone explain what sour crop is? I've never heard of this until
>recently.
>What are the symptoms, what causes it, etc.?
>Erica
Sour Crop is basically a failure of the bird to digest what it's eaten.
Signs of sour crop include a dull or lethargic bird, a foul smell from the
mouth, and a crop full of fod that won't move into the digestive tract. The
bird might be thirsty, and probably won't be hungry.
The food may remain undigested in the crop due to a number of different
reasons; spoiled food, parasites, obstructed digestive system, toxic
substances, etc, but basically the food goes bad in the crop. It can not be
digested nor cast out. 
Initial treatment is usually oral fluids to moisten the crop contents and
see if the bird can cast. If this is unsuccesful, manual emptying of the
crop may be necessary. Depending on the situation, antiinflammatories and/or
antibiotics may be necesary. This ailment can be fatal if not treated
promptly. Bacterial infection can set in and it's all downhill from there.
Most good raptor care books will discuss sour crop and its treatments.
******************************************************
Charlie Kaiser
charliek@golden-eagle.org
http://www.golden-eagle.org
Falconer
Live Collections and Wildlife Hospital Volunteer
The Lindsay Wildlife Museum,
Walnut Creek CA, USA
******************************************************



A reply by raptors@efn.org

Although I couldn't find any formal definition or even mention of sour crop in 
Redig's Medical Mgt of Birds of Prey, nor JE Cooper's Veterinary 
Aspects of Captive Birds of Prey - nor Harrison & Harrison's Clinical 
Avian Medicine and Surgery - nor Beebe's A Falconry Manual - nor 
Jemima Parry-Jones Training Birds of Prey- nor the new Care & Mgt of 
Captive Raptors by Lori Arent & Mark Martell (UMinn)... there 
was in Emma Ford's Falconry Art and Practice the following, which 
jives with how I've always used the term:  "If food is not emptying 
from the crop into the stomach after several hours, then this needs 
to be removed as a matter of urgency.  If this is not done then the 
condition known as 'sour crop' ensures rapidly, leading to death.  In 
this condition, the food in the crop goes off and poisons produced 
during this process soon reach the bloodstream, leading to death."  
This is from the chapter by Neil Forbes, MRCVS, B.Vet.Med, titled "In 
Sickness and in Health."

Typically what you see is simply a crop that isn't being turned over;
the food just sits there; what you *smell* when you open the bird's
mouth is close to indescribable.   Toxins produced by bacterial
proliferation from the spoiled meat is the 'sour crop' and what can
kill the bird. 

When I see this, it is typically (but not always) in a raptor that
has been starving, finds food, often gorges, and can't process it -
most often because the bird doesn't have the necessary energy;
sometimes there may be some internal problem.  When I get an
emaciated bird in, I draw blood and look at the PCV (Packed Cell
Volume: red blood cells as a percentage of the total - a measure of
anemia and at times an indicator of dehydration; normal is between
35-55%) and Total Solids (the amount of proteins circulating in the
blood - a rough measure of the ability to catabolize proteins). When
TS are low, it usually means the bird has not eaten in quite some
time and when below 2 g/dL (normal is around 4 or 5) may indicate
that the bird will not be able to digest solid food. However - we
also have seen this in birds with reasonable condition and blood
values that had gorged and simply couldn't process it - who knows
why. This latter includes once in a falconry bird that had been lost
for a day, found by John Q Citizen and way cropped up on hamburger -
there's no reason the bird shouldn't have been able to process food -
though I didn't draw blood - but the falconer brought her to me in a
panic... he had never had the extremely dubious pleasure of removing
the rotten food from her crop. Lean back, close your eyes, picture
this (with your nose): raw meat that has been cooking at 102F for
several hours...just great for bacteria!   Ummm phew!  With diurnal
raptors, we reach into the crop and remove the contents with long
sponge forceps (has rounded ends, like little circles), then flush
with fluids.  With owls, we just flush with lots of fluids and hope
for the best.  But as I said to Jeremy, I have never treated that
condition specifically with antibiotics - as Bill mentioned, it may
also be the result of candida, in which case you need an antifungal
medication, not antibacterial - but often the bird is on antibiotics
for some other reason, either a wound or simply as a prophylactic
against an opportunistic bacterial infection when they are so
starved and debilitated.  

After removing the crop contents, we give plenty of fluids, and then
(depending on blood values) I start the bird on plain amino acids
(the building blocks of proteins that don't take any energy to
digest), then small quantities of food fairly frequently - this can
be a human tube-feeding formula (like IsoCal or UltraCal, products
like Ensure, etc.) or simply meat baby food mixed with Pedialyte. 
Lots of fluids for more than just the first day.  The blood values
will tell me when I can introduce solid food; or with a diurnal
raptor (because I can remove the food from the crop if it doesn't go
anywhere), I may start with small bites of the soft parts of a
day-old chick (seems to be easy to digest) and work up; some folks
simply use small bits of clean meat, etc.  Main thing is to watch
carefully.  Probably more info than you wanted, Erica - but hope it
helps!  Louise

> Can someone explain what sour crop is? I've never heard of this
> until recently. What are the symptoms, what causes it, etc.?
> 
> Erica
> SE Minnesota
> 
> 
******************
Louise Shimmel, Director 
Cascades Raptor Center
PO Box 5386 Eugene OR 97405 USA 
e mail: ; www.efn.org/~raptors
Phone: 541/485-1320; Fax: 541/485-4586
**************************************


A reply by broberg@millcomm.com

Charlie and Louise:

Thanks for the information on sour crop, I'm gonna buy some of those
forceps. I have a lot of books, but not one of them mentions this problem.
Sounds like there is something worse to smell than falcon breath.

Erica
SE Minnesota





A reply by charliek@golden-eagle.org

At 11:29 AM 7/25/97 -0500, you wrote:
>Thanks for the information on sour crop, I'm gonna buy some of those
>forceps. I have a lot of books, but not one of them mentions this problem.
>Sounds like there is something worse to smell than falcon breath.
>Erica
Falcon breath is downright sweet by comparison!
******************************************************
Charlie Kaiser
charliek@golden-eagle.org
http://www.golden-eagle.org
Falconer
Live Collections and Wildlife Hospital Volunteer
The Lindsay Wildlife Museum,
Walnut Creek CA, USA
******************************************************