Raul Carreiro / 07 Dec 2010 20:58

DROPPINGS INTERPRETATION

By Dr Colin Walker BSc, BVSc, MRCVS, MACVSc (Avian health)

One good way of monitoring the birds' health is by observing their
droppings. As most fanciers clean their racing loft each day, simply
observing the droppings during the cleaning process is a good way of
monitoring the birds' health over the previous 24 hours. Many problems that
affect race performance are subclinical. This means that race form is
affected before the birds actually start to look sick to the fancier. As
changes in the dropping usually occur 1 - 2 days before an unwell bird
starts to look sick to us, observing and effectively managing the abnormal
changes in droppings does much to head off a downward turn in form.

Essentially, the bowel is a hollow tube into which several organs, in
particular the liver, empty via ducts. The bowel terminates in the cloaca (a
bag just inside the bird's external opening). Ducts leading from the kidney
also terminate here and deposit the bird's urinary waste. Birds,
interestingly, produce two sorts of urine, a liquid urine, which looks like
clear water, and also a solid urine made up of a white paste of uric acid
crystals. Therefore, in the cloaca accumulate the undigested remnants of
food from the bowel, liquid and solid urine from the kidney and a number of
normal discharges, notably bile from the liver and also mucus from the bowel
wall. Once in the cloaca, some fluid is resorbed until, in health, a firm
dropping, normally of a brownish colour, is produced. When the cloaca is
uncomfortably full, the bird relaxes the cloacal opening and passes a
dropping.

Green droppings
The main factor affecting the colour of a pigeon's dropping is what it has
eaten. Pigeons digest many of the pigments found in their food rather poorly
and so these pass relatively unaltered through the system and colour the
dropping. In this way, birds eating, for example, a lot of pink minerals,
can be expected to have brownish droppings. Also birds eating greenish grain
(eg dun peas) or supplemented with green vegetables (such as silver beet) or
free-ranging and pecking at grass will have more green droppings. Green can,
however, alert the fancier to the possibility of a problem. This is because
green droppings can occur with bowel disease. The green colour comes from
bile, which in birds is a brilliant fluorescent green. Bile is a digestive
enzyme produced by the liver. After a number of metabolic steps, it passes
from the liver down a duct (called the bile duct) into the bowel where it
aids the digestive process. After digestion in the bowel, components of the
bile are reabsorbed through the bowel wall for reuse. If the bowel is
diseased, this process cannot occur normally, with the result that more
green bile stays in the bowel and is passed in the dropping, resulting in a
green dropping. Green droppings, therefore, can alert the fancier to the
possibility of bowel disease. Usually, microscopic examination of a faecal
smear will show the cause. There is always some bile left, which when mixed
with the rest of the dropping, gives it a greenish hue. Although in the
early stages of bowel disease birds can produce a firm dropping that is
green, as a general rule such droppings are associated with the ingestion of
non-digestible green pigments. It is always safest, however, to have a vet
or technician microscopically examine a few green droppings to check that
everything is okay. Because inflamed bowels not only absorb bile but also
water poorly, green droppings that are also watery do, however, almost
invariably point to a problem. The only notable exception here would be the
droppings of recently returned race birds. Because these birds have not
eaten during the race, their droppings are made up of urine, bile and bowel
mucus and appear as a clear fluid ring with a small central amount of green
mucousy material and white paste (the solid urine). In healthy birds, once
in the loft and having eaten, their droppings should start to become normal
within a few hours and unless the race was particularly taxing, should be
completely normal by the next morning.

Watery droppings
Watery droppings occur commonly in only one of two situations, either where
there is bowel disease interfering with absorption of fluid or alternatively
where the urine component of the dropping is visible. A watery dropping
associated with bowel disease occurs because any inflammatory condition of
the bowel interferes with its function and compromises its ability to absorb
fluid. The result is a watery dropping. Possibilities include infectious
problems such as worms, coccidia, 'thrush' or a bacterial infection, while
the most likely non-infectious causes are ingestion of either irritant or
toxic substances either while free-lofting or associated with a change of
diet. Usually an infectious cause can be detected quickly by microscopic
examination of a faecal smear.

A watery dropping due to visible urine may or may not be a problem. As
discussed above, the bowel and urinary waste accumulate in the cloaca . Here
urine is absorbed by the bowel component of the dropping and some fluid is
resorbed back into the body until a moist, well-formed dropping is ready to
be passed. If the bird is disturbed, the cloaca will be evacuated
prematurely before this process is completed. The result is a healthy
dropping from a healthy bird that, because it is watery, can concern the
fancier. The most common time that this is observed is after the morning
exercise. Here the birds have not been fed so there is virtually no digested
food in the dropping. Provided the birds are not dehydrated, urine
production is constant. The birds often empty their cloaca on landing. The
result is a small amount of green-brown material (mainly bile and bowel
mucus), surrounded by a ring of clear water. And so a watery dropping in the
morning prior to feeding, and particularly after exercise, is usually quite
normal. A better time to assess the dropping is after feeding and a period
of rest. As digested food starts to appear in the cloaca several hours after
feeding, this acts like a sponge, mopping up the urine and cloacal emptying
by the birds only occurs when the cloaca is full.

If droppings with urine rings persist through the day, it is probable that
the birds are producing excessive urine. This occurs if the birds are
drinking excessively. In a race team, this is almost invariably due to one
of only two problems, namely wet canker or airsac inflammation. The wet
canker organisms produce a toxin, which amongst other things makes the birds
thirsty, resulting in an increased water intake, while inflamed airsacs lose
their moisture-conserving ability, resulting in excess fluid loss in the
expired air. To prevent dehydration, the birds need to counteract this and
often overcompensate and drink to excess. A fancier can determine if wet
canker is involved by organising for his local bird vet or technician to do
a crop flush. If this is not possible, the condition may on occasion be
diagnosed by response to treatment, eg giving a 2-day course of Turbosole
(ronidazole) and monitoring the response. If there is inflammation in the
deeper respiratory structures like the airsacs, there is usually also
inflammation in the upper respiratory structures, such as the trachea and
sinuses. This almost invariably leads to an increased level of sneezing in
the loft. If there is no sneezing in a race loft, it is unlikely that a
respiratory infection is active. If uncertain, a sample of mucus from the
back of the throat can be examined microscopically (often done at the same
time as a crop flush) which will, if a respiratory infection is present,
reveal signs of inflammation and secondary infection. If infection is
confirmed, usually a 3 - 5-day course of Doxy-T (doxycycline / Tylan) is
given. Because approximately 80% of birds with respiratory infection during
the race season also have a concurrent wet canker, often the Doxy-T and
Turbosole are blended together. One teaspoon (3 g) per 2 litre of each is
given in the drinking water. This blend turns the water a pale yellow colour
and the birds drink it readily. By simultaneously treating any wet canker
present, the response to antibiotics is always much better.

Submitted by Raul Carreiro on 12/7/2010 8:45:58 PM