Agriculture Reference
In-Depth Information
Urogenital system
Urinary organs
Two kidneys, two ureters, bladder and urethra.
Sheep and goat
The kidneys are dark brown, bean-shaped and unlobu-
lated and possess a single renal papilla. As in the ox, the
left kidney of the sheep and goat is freely movable. Each
kidney weighs 56-85 g.
Genital organs
Female two ovaries, two uterine (fallopian) tubes, uterus,
vagina, vulva, clitoris and mammary glands.
Male two testes and epididymes, two vasa deferentia,
seminal glands, prostate, bulbourethral (Cowper's)
glands, urethra and penis.
Pig (Fig. 2.15)
The kidneys are smooth, bean-shaped and reddish
brown but thinner and flatter than in the other food ani-
mals; 10-12 renal papillae are present internally. The
weight of each kidney is 85-170 g. In the pig, the bladder
is large with a long neck; the ureters enter posteriorly in
the neck region. This predisposes the animal to bilateral
hydronephrosis, because, when full, the bladder hangs
down into the abdominal cavity and the long neck
presses against the pubis, thus closing the ureter open-
ings and interfering with urination.
Kidney
In addition to their functions in the excretion of urine
and in acid-base balance, the kidneys produce two hor-
mones, renin and erythropoietic factor. Renin acts in the
formation of a blood peptide which increases blood
pressure and stimulates the secretion of aldosterone, a
hormone controlling the reabsorption of sodium. The
erythropoietic factor stimulates the formation of a pro-
tein which increases the red cell production in the bone
mar row.
Horse
The right kidney is triangular- or heart-shaped, and the
left is bean-shaped and longer than broad. The weight of
each kidney is 680 g.
Ox (Fig. 2.14)
The kidneys are reddish brown and composed of 15-25
lobes which are fused at their deeper portions; each lobe
terminates in a blunt process or papilla, visible when the
kidney is split. When the rumen is empty, the left kidney
lies to the left of the vertebral column, but as the rumen
becomes filled, it propels the kidney towards the right
side of the body, though injury due to pressure on the
ureter is usually avoided. This orientation of the left
kidney is rendered possible by its loose attachment to the
lumbar region. The left kidney, by reason of its mobility,
is roughly three-sided and of a somewhat twisted appear-
ance, but the right kidney has a more regular, elliptical
outline. The weight of each kidney is 283-340 g.
Reproductive system
Uterus (Fig. 2.16)
Cow
The uterus consists of a small body, less than 2.5 cm
long, and two cornua or horns, about 38 cm long. The
uterus of the cow and ewe has characteristic cotyledons
on the mucous membrane of the body and uterine
horns; these are oval prominences, about 100 in all, and
in the non-gravid bovine uterus are about 1.5 × 0.5 cm.
During pregnancy, and as the foetus develops, the coty-
ledons hypertrophy, becoming pitted or sponge-like,
and then measure up to 10-12.5 cm in length and 4 cm
in width. Evidence as to whether a slaughtered female is
a heifer or a cow may be established by opening each
uterine horn and cutting transversely through the wall,
including the diameter of a cotyledon. Generally, in the
uterus of a heifer, the cotyledons are surrounded by a
shallow moat which usually disappears in the cow. The
blood vessels in the exposed wall of the uterus of the cow
are contorted and bulge from the surface. In the heifer,
the blood vessels can be seen clearly but do not bulge
and show little contortion. The blood vessels in the coty-
ledon are the most valuable guide; in the heifer, they are
very fine and straight, whereas in the cow, they are very
distinct, contorted and bulge slightly from the cut sur-
face. This method assumes that the cotyledons enlarge
Lateral border
Cranial
extremity
Ureter
Renal vein
Renal artery
Figure 2.14
Right kidney of ox, ventral surface. Organ hardened
in situ. Fat has been removed from fissures between lobes.
