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Author: John Summers - P.I.C. (Canada)
Fecal contamination of carcasses continues to be a sporadic problem at processing
plants. The main reason for the problem is rupture of the lower intestinal tract
during processing and thus release of fecal material. However, birds handled in
the proper manner should have a minimum of waste material in their digestive tracts.
Thus the question to be answered is why does the problem continue to occur?
Rate of food passage in the digestive tract has been studied by a number of
people. Under normal feeding conditions it takes around 6 to 8 hours after feeding
for fecal wastes to be excreted. Thus one would anticipate that birds off feed
for the above length of time before processing should not present a problem.
However, there are a number of things which can alter normal feed transit time.
Hot weather is known to slow down transit time while high fibre diets usually
speed up feed transit time. However, the degree of transit time change for the
above conditions is usually relatively small and thus it is questionable whether
they are a significant factor under normal commercial conditions.
Summers and Leeson (1979) reported that stressed birds (birds held in crates)
had a much longer feed transit time than non stressed birds. This work has been
recently confirmed (May and Deaton 1989) and extended to show that water deprivation
has little or no effect on time of gut clearance. Thus it is important for birds
to have an empty gut before being crated.
It is well known that birds settled down and sleeping usually hold digestive
material in their lower intestinal tracts. When they awaken and begin to move
about, this material is then excreted. Thus birds that are held before crating
in darkness then quickly loaded (and thus stressed) could well arrive at the
processing plant with a substantial quantity of waste material in their lower
digestive tract even though they have been off feed for quite some time. Thus
one should look at the lighting program prior to loading, if a fecal contamination
problem is being experienced at the processing plant. It would seem to be an
appropriate practice to have the lights on in a pen for a period of time prior
to crating.
Other factors that may cause fecal contamination problems are the fine grinding
of dark fibrous material (usually seed hulls) which can stick to the carcass
if the intestine is ruptured and not be eliminated during the rinse procedure.
Other problems that have been alluded to are the slower rate of digestion of
pellets where a pellet binder has been used to improve pellet quality. Also
the waste material from some feed ingredients is more prone to fermentation
in the lower intestinal tract, thus producing a swollen or enlarged intestine.
However, the above conditions are probably of limited importance in most of
the fecal contamination problems encountered at the processing plant.
A thorough study should be made of lighting programs, crating procedures, feed
composition, environmental conditions and also processing procedures when carcass
fecal contamination problems occur.
Summers J.D. and S. Leeson, 1979. Comparison of feed withdrawal time and passage
of gut contents in broiler chickens held in crates or litter pens. Can. J. Anim.
Sci., 59: 63-66.
May J.D. and J.W. Deaton, 1989. Digestive tract clearance of broilers cooped
or deprived of water. Poultry Science, 68: 627-630.
Author: John Summers - P.I.C. (Canada)
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