الفهرس 
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Abstract
SUlDU.RY
The study was carried out to recognize the anatomical
and histological development ofcgastrointestinal
tract compartments in male buffalo calves from birth to
12 months of age.
The anatomical measurements were recOrded on’J7
calves. The histological study was made u~ on 13 calves
from the previous animals which were obtained from the
herd of ”Genetic improvement of bUffaloes”, Faculty of’
Agriculture, Cairo University.
be summarized as followsz-
~(J.$-Iror·7c{~-I,~( 1Y’d4f
- The~(GIT)tissue weight
(LBW)from birth to 12 months of
The important results can
/;”,e b~.4!vt,jllt
develop~d mare fastly than~
age.
- The development rate of GIT tissue weight was
faster through the preweaning stage (0-4 months) than the
postweaning stage (4-12 months of age). The first ~o
months of age were unique with the fastest rate.
-The fOrestomach and the large intestine had the
fastest development rate to adapt with the SWitching of
calf’s nutrition from milk to solid feeds particularly
roughage.
- The percentage of GIT ( tissue weightlLBW) increased
from }.l% at birth to 6.4% at 12 months of age.
- The percentage of intestina.l tissue weight/
GIT was larger than that of stomach through preweaning
stage, while the reverse occurred through postweaning
stage according to the type of feeding.
- Rumen tissue weight Occupied 44.4- 6’1.2% of
stomach throughout 0-12 months of age. RetiCUlum, omasum
and abomasum occupied the rest.
- Small intestine tissue weight occupied 56-79%
of intestines throughout 0-12 months of age.
- Usually the vol~e of stomach equaled }-5 times
of intestin~ through the first 12 months of age. The
nOrmal lumen volume of stomach was 0.7 liters at birth.
It reacned }4.5liters at 12 months of age.
- small intestine surface area, as a percentage of
total intestines developed fastly during the preweaning
stage especially the first ~o months of age, being the
major site of digestion and absorption of milk in this
periOd. Afterwards it decreased, while the percentage
,of colon increased, an adaptation to herbage feeding.
- The wall thickness of reticulum increased rapidly --~~.
to become the greatest within forestomach compartments.
The most development Of forestomach wall OCcurred in
~. ~ .,~ .’._’ •• ”’_L _, __ •. _ ~
preweaning stage.
-Tunica muscularis of forestomach occupied -/11 ,’cJr,.•”~ SoS
80-90% of total wall from birth to 12 months Of age. l(
- The connective tissue of ruminal propria and
submucosa ?eveloped more rapidly than that of reticulum
and omasum to furnish the rumin wall for greater expanding
capacity to offer fOr mare feed intake and to counteract
for gass pressure.
- The :forestomach compartments were ol.e.Sfitu+((. cr
muscularis mUCOsae except the omasum which additionally
contained tunica muscularis extended muscle layer in its
laminae.
- The forestomach compartments histologically developed
to ~,-rw,’-/J, their function. For example, the F1e.x:b,’/i1y
/
of rumen, the strong contraction of reticulum wall, and
strong of omasal leaves.
I’lnll,’IO\
- The wall of cauda-dorsal and ventral sacs were JI.
thinner than the other regions.
- Ruminal papillae play vital role in the digestion
and absorption , thus their epithelial surfacae area increased
the internal rumen Surface by 17 times at birth and
further by 30 times at 12 months of age. The mean number of
papillae decreased from 1999/cm2 at birth to 132/crn2 at 12
months of age, while the meam papillary surface increased
from 0.89 to 23.04mm2 respectively.
- It was clear that the ·pylorus, contrary to that of
the simple stomach, is not equiped with thick musculature.
Thus, the main musculature organ which control the rate of
digesta out put from the ruminant stomach is the omasum.
- Tunica muscularis represented 50-60%, the mucosa
contributed 25-33% of the abomasum wall. Glandular propria
comprised 80-95% of tunica mucosa.
- Parietal cells appeared in fundic region and disappeared
in pyloric region of abomasum.
- Small intestine villi increased in size and decreased
in number 0.034 vs. 0.31 mm2 and 534 vs. 273/mm2 respectively
at birth and at 12 months of age.
- The villi play very important role in increasing the
absorption surface area. It multiplied the epithelium surface
to about 16 times at birth and 38 times at 12 months of age,
- Ileum had the thickest tunica subucosa throughout
the intestines due to the presence of Peyer’s patchs followed
by duodenum which contained Brunner1s gland.
- The rectum had the thickest tunica muscularis
because of the existence of three muscle layers instead
of two layers found in the other compartments of GIT.
- The musculature of the rectum are of good functional
histological structure for feces repulsion and control of
defecation process.
- Goblet cells were enormoulsy found in large intestine.
They increased caudally from cecum to rectum.