INTERPRETATION IN RACE SEASON
By Dr Colin Walker BSc, BVSc, MRCVS, MACVSc
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.
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 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
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.
A more full explanation of changes observed
in droppings can be found in my book The Flying Vet’s Pigeon Health & Management.