Livestock production and management

3. Updated:8/23/2023
Uterus
Ovary
Oviduct
Broad
Ligament
Cervix
Bladder
Pelvis
Vagina
Vulva
Rectum

4. Ewe & Doe
Vagina
Cervix
Uterine Body
Uterine Horn
Ovary
Pig Poultry
Ovary
Infundibulum
Isthumus
Magnum
Uterus/Shell gland
Vent
Egg

5.  connective tissue sheet: supports and suspends reproductive tract
• Mesometrium: Supports Uterus
• Mesosalpinx: Supports Oviduct
• Mesovarium: Supports Ovary

6.  Both exocrine and endocrine functions.
 source of the ovum (oogenesis and ovulation)
 Hormones: estrogen, progesterone and relaxin.
 Support:
 Dorso-laterally: broad ligament,
 Medially: Proper ligament.
 The shape, size and location vary:
 the species,
 the stage of the estrous cycle
 gestation.
Sheep and goat
Poultry Sow

7. Corpus Luteum Corpus Luteum
Follicle - Estrogen, Oocyte
Progesterone Progesterone

8.  Means for ova to reach the uterus from ovaries.
 Suspended by mesosalpinx derived from the lateral layer of broad
ligament.
 Three parts
 Constricted Isthmus next to the uterus
 Widened Ampulla (half the length of the oviduct)
 Funnel shaped Infundibulum with its fimbriae.
 Ostium abdominale: Opening into abdominal cavity, cranial extremity of
tube.
 Uterotubal junction: Continuation to uterine horn, caudal end.
 Fertilization at lower part of ampulla

9. Uterine Horn
Utero-Tubal Junction
Ampullary-Isthmic
Junction
Isthmus
Ampulla
Infundibulum
Fimbria
Ostium
Follicle
Ovary
Cumulus Oophorus
and Oocyte

10.  The uterus is a muscular-membranous structure designed for
 the reception of the fertilized ovum,
 Transport, Absorption and phagocytosis and capacitation of sperm
 for the nutrition and protection of the fetus
 for the initial stage of expulsion of the fetus at the time of parturition.
 form sufficient placental attachment to result in normal development of the
embryo and fetus.

11. The uterus consists of
a cervix
two uterine horns
a body

12. Oposum Rabbit, Mouse
2 Cervixes
2 Uterine Horns
2 Vaginas 1 Vagina

13. Ewe
Cow Sow
1 Vagina
1 Cervix
1 Uterine Body
2 Uterine Horns
Smaller
uterine
horns Large
uterine
horns

14. 1 Vagina
1 Cervix
1 Uterine Body
2 Uterine Horns
Large uterine body
Smaller uterine horns
Mare

15. 1 Vagina
1 Cervix
1 Uterine Body
2 Uterine Horns
Bitch
(Canine)
Queen
(Feline)
Small uterine body
Long uterine horns

16. Woman
1 Vagina
1 Cervix
1 Uterine Body
Large uterine body
No uterine horns

17. • sphincter-like segment of the
reproductive tract which
anatomically and physiologically
separates the uterine lumen from
the vagina.
• It may be distinguished externally
by its thick wall, due to the great
thickness of the sphincter muscle,
and internally by its constricted
lumen.
Internal Cervical Os
annular rings
External Cervical Os

19. Cervical
Ring
Cervical
Ring
Fornix
Fornix
Fornix
Anterior Vagina Anterior Vagina
COW
EWE
External Os
Internal Os

21. No
obstacles
Longitudinal
Folds
Interdigitating
pads
Fornix Vagina
No Fornix Vagina
Cow Mare Sow
Cow has 4-5
annular rings

23.  close the uterine lumen against macroscopic and microscopic intruders, and
with few exceptions it remains closed at all times except during estrus and at the
time of parturition.
 At estrus, the cervix serves as a passageway for sperm.
 In pregnancy, the cervical mucus hardens and seals off the canal by forming the
so-called "cervical plug" or "cervical seal" which liquefies shortly before
parturition.
 At parturition the cervix dilates allowing passage of the fetus and fetal
membranes.

24. • The vagina is the most caudal part of the
internal reproductive tract.
• muscular-membranous structure lying in
the pelvic cavity dorsal to the bladder that
acts as a copulatory organ and as a
passageway for the fetus at the time of
parturition.
• capable of great dilation.
• Its caudal extremity is just cranial to the
urethral opening in the region of the
hymen.
Fornix
Vulva-
Vaginal
Sphincter
Anterior Vagina Posterior Vagina (Vestibule)

25.  The length of the vagina varies with the species.
 Cow 26 to 30 cm in length in the non-pregnant animal;
 mare 18 to 28 cm long and 10 to 13 cm in diameter when dilated;
 ewe 7.5 to 10 cm long;
 sow 7.5 to 11.5 cm long.

26.  Copulatory organ
 Glands secrete lubrication
 Birth canal
 Glands secrete pheromones

27.  The vulva is the outer part of the female genitals.
 Around the opening of the vagina, there are 2 sets of skin folds.
 Thevulva includes
 the opening of the vagina (sometimes called the vestibule)
 the labia majora (outer lips)
 the labia minora (inner lips)
 the clitoris.
 Functions:
 Labia: closes entrance to vagina
 Clitoris: female sensory organs
Anus
Labia
Clitoris

28. Mare Cow
Sow
Ewe

30. The gonads are derived from 3 sources:
 The mesothelium (mesodermal epithelium) lining the posterior abdominal wall
 The underlying mesenchyme (embryonic connective tissue)
 The primordial germ cells

31.  The initial stages of gonadal development occur during the fifth week
 A thickened area of mesothelium develops on the medial side of the
mesonephros
 Proliferation of this epithelium and the underlying mesenchyme produces a
bulge on the medial side of the mesonephros called gonadal ridge

32.  Finger like epithelial cords or Gonadal cords soon grow into the underlying
mesenchyme
 The indifferent gonad now consists of an external cortex and an internal medulla
 In embryos with an XX sex chromosome complex, the cortex differentiates into
an ovary and the medulla regresses
 In embryos with an XY sex chromosome complex, the medulla differentiates into
a testis and the cortex regresses

34.  These large, spherical cells are visible early in the fourth week among the
endodermal cells of the yolk sac near the allantois
 During folding of the embryo, the dorsal part of the yolk sac is incorporated into
the embryo
 With this the primordial germ cells migrate along the dorsal mesentery of the
hindgut to the gonadal ridges
 During the sixth week the primordial germ cells enter the underlying
mesenchyme and are incorporated in the gonadal cords

35.  Before the seventh week, the gonads of the two sexes are identical in appearance
called indifferent gonads
 Development of the male phenotype requires a Y chromosome
 The SRY gene for a testes-determining factor (TDF) has been localized in the sex-
determining region of the Y chromosome
 Two X chromosomes are required for the development of the female phenotype

37.  Gonadal development occurs slowly in female embryos
 The X chromosomes bear genes for ovarian development and an autosomal
gene also appears to play a role in ovarian organogenesis
 The ovary is not identifiable histologically until about the 10th week
 Gonadal cords do not become prominent but they extend into the medulla
and form a rudimentary rete ovarii
 This structure and gonadal cords normally degenerate and disappear

38.  Cortical cords extend from the surface epithelium of the developing ovary into
the underlying mesenchyme during the early fetal period
 As the cortical cords increase in size, primordial germ cells are incorporated in
them
 At about 16 weeks these cords begin to break up into isolated cell clusters called
primordial follicles
 Each primordial follicle consists of an oogonium, derived from primordial germ
cell
 Each oogonium is surrounded by a single layer of flattened follicular cells derived
from the surface epithelium

39.  Active mitosis of oogonia occurs during fetal life producing thousands of
primordial follicles
 No oogonia form postnatally
 Many oogonia degenerate before birth and about 2 million remain enlarge
to become primary oocytes before birth
 The surface epithelium becomes separated from the follicles in the cortex
by a thin fibrous capsule called tunica albuginea
 As the ovary separates from the regressing mesonephros, it is suspended by
a mesentery called mesovarium

40.  Both male and female embryos have two
pairs of genital ducts
 The mesonephric ducts (wolffian ducts):
development of the male reproductive system
 The paramesonephric ducts (mullerian ducts):
development of the female reproductive system
 Till the end of sixth week, the genital
system is in an indifferent state, when both
pairs of genital ducts are present

41.  The funnel shaped cranial ends of these ducts open into the peritoneal
cavity
 The paramesonephric ducts pass caudally, parallel to the mesonephric
ducts
 Both the paramesonephric ducts pass caudally and reach the future pelvic
region and cross ventral to the mesonephric ducts
 Fuse to form a Y-shaped uterovaginal primordium in the midline
 This tubular structure projects into the dorsal wall of the urogenital sinus
and produces an elevation called sinus (muller) tubercle

42.  In female embryos, the mesonephric ducts regress because of the absence
of testosterone
 Paramesonephric ducts develop because of the absence of mullerian
inhibiting substance (MIS)
 The paramesonephric ducts form most of the female genital tract
 The uterine tubes develop from the unfused cranial part of the
paramesonephric ducts
 The caudal fused portions of these ducts form the uterovaginal
primordium, it gives rise to uterus and superior part of vagina
 Fusion of the paramesonephric ducts also brings together a peritoneal fold
that forms the broad ligament

43.  The vagina has a dual origin.
 The cranial one third comes from fused paramesonephric ducts.
 The caudal two-thirds comes from the vaginal plate, a solid tubercle that
grows outward from the urogenital sinus at the site of contact between the
urogenital sinus and the fused paramesonephric ducts.
 Degeneration of the center of the solid tubercle creates the vaginal lumen.
 A hymen may persist where the vagina joins urogenital sinus.
 The urogenital sinus forms the vestibule.

45.  Up to the seventh week of development the external genitalia are similar in both
sexes
 Distinguishing sexual characteristics begin to appear during the ninth week
 External genitalia are not fully differentiated until the twelfth week
 Early in the fourth week, proliferating mesenchyme produces a genital tubercle
in both sexes at the cranial end of the cloacal membrane
 Labioscrotal swelling and urogenital folds soon develop on each side of the
cloacal membrane

46.  The anal and urogenital membranes rupture a week later forming the anus
and urogenital orifice, respectively
 Estrogen produced by the placenta and fetal ovaries appear to be involved
in feminization of indifferent external genitalia
 Growth of the primordial phallus gradually ceases and becomes clitoris
 The clitoris is relatively large at 18 weeks
 Most parts of the labioscrotal folds remain unfused and form two large
folds of skin called labia majora
 Labia majora are homologous to the scrotum

49.  Endocrine glands:
 Hypothalamus:
 Occupies only small portion of brain
 Consists of region of third ventricle extending from optic chiasma to the
mammillary bodies

50. Secreted hormone Produced by Effect
Prolactin-releasing
hormone (PRH)
Parvocellular neurosecretory
neurons
Stimulate prolactin release from anterior pituitary
Prolactin-inhibiting
hormone (PIH)
Dopamine neurons of the
arcuate nucleus
Inhibit prolactin release from anterior pituitary
Gonadotropin-releasing
hormone (GNRH)
Neuroendocrine cells of
the Preoptic area
Stimulate follicle-stimulating hormone
(FSH) release fromanterior pituitary
Stimulate luteinizing hormone (LH) release
from anterior pituitary
Oxytocin
Magnocellular neurosecretory
cells
Uterine contraction
Lactation (letdown reflex)
Melatonin
Magnocellular neurosecretory
cells
Controls gonadotrophic activity according to
duration of day length in mare and sheep

51.  Located in the sella-turcica, a bony depression at the base of brain.
Anterior Pitutary (Adenohypophysis):
 Somatotrophs: GH, ACTH
 Mammotrophs: Prolactin
 Thyrotrophs: TSH
 Gonadotrophs: FSH & LH
Posterior piturary:
 No secretion, only acts for storage and release of hormones: Oxytocin and
melatonin

53.  Neural connection with posterior pituitary through Hypothalamo-hypophysial
Portal system
 Vascular connection with anterior pituitary through superior and inferior
hypophysial artery.
 Superficial hypophysial artery forms capillary loop at the medial eminence and pars nervosa.
 From these capillaries, blood flow into Hypothalamo-hypophysial portal system
 Part of venous outflow from anterior pituitary is by way of retrograde back flow
which exposes the hypothalamus to high concentration of anterior pituitary
hormones which provides the feedback mechanism.
 This is known as short loop feedback mechanism

55.  Chemically hormones may be:
 Protein: Poly peptide or glycoprotein: e.g. Oxytocin, FSH, LH
 Steroid: Cholesterol derived: eg. Testosterone, estrogen, progesterone
 Fatty acid: Arachidonic acid derived: e.g. Prostaglandin
 Amines: Tyrosrin or Tryptophan derived: e.g. Melatonin

56. A. Adenohypophysial Hormones
i. FSH:
 In Female:
 Promotes ovarian and follicular growth and development.
 Doesn’t cause secretion of estrogen from ovary itself but need presence of LH
 In Male:
 Acts on germinal cells of seminiferous tubules from ovary itself but need presence of
LH
 Responsible for the anatomical integrity of the seminiferous tubules
 Spermatogenesis upto secondary spermatocyte stage, later androgens support final
stages of spermatogenesis.

57. A. Adenohypophysial Hormones
ii. Leutinizing Hormone (LH):
 In female:
 Tonic/basal level of LH in conjugation with FSH induce estrogen
secretion from follicle
 Preovulatory surge of LH is responsible for ovulation and
leutinizatoin of follicular cells
 Important in the stimulation of the ovary to produce progesterone
 In male:
 Stimulates growth of the interstitial (Leydig) cells.
 Leydig cells produce androgens after LH stimulation.

58. A. Adenohypophysial Hormones
iii. Prolactin:
 Initiaiton and maintainance of lactation
 Leutotrophic properties but less important than LH in
domestic animals
 May mediate seasonal and tactional effects of reproduction in
farm animals
 Delays estrus cycle in lactating animals

59.  B. Neurohypophysial Hormones:
 i. Oxytocin:
 Causes contraction of the smooth muscles of the uterus.
 Varies with species, stage of gestation, and the amount of stress the animal is subjected to.
 Its action is enhanced by estrogen and inhibited by progesterone
 Causes contraction of the myoepithelium of the mammary gland to cause milk
letdown.
 Its action on the smooth muscles in the arterioles is usually vasodilation
 Ovarian oxytocin is involved in leuteal function and act on endometrium to induce
PGF2α release which is leuteolytic in activity.
 ii. Melatonin:
 Increase in darkness causes increase in melatonin which induces ovarian cycle in ewes
and inhibit in mare.

60.  Gonads have dual function in both sex:
 production of germ cells
 endocrine function.
 Ovaries: Estrogen, Progesterone (Steroid) and Relaxin (Protein)
 Testes: Androgens (Steroid)
 The interstitial cells in seminiferous tubule known as Leydig cells secrete
testosterone
 Theca interna cells of Graffian follicle secrete estrogen.

61.  Maturation growth and development of the reproductive organs.
 Stimulation of normal physiological processes of the tubular reproductive
tract.
 growth of the uterine muscle
 development of the endometrial lining of the uterus
 increase the vascularity of the uterus
 Induction of behavioral estrus
 The production of edema in folds of the mucosa at the utero-tubal junction
 Dilation of the cervix

62.  Under the influence of the estrogens the uterus is less susceptible to
infection
 They produce contractions of the uterus combined with oxytocin, they
enhance the effects of oxytocin on uterine motility
 The estrogens inhibit the secretion of FSH and LH via a negative feedback
mechanism
 development of the secondary sex characteristics of the female eg. hair
growth, deposition of body fat, mammary gland development, etc.
 The estrogens are involved in the regression of the corpus luteum.

63.  growth of the glandular system of the endometrium of the uterus, and the
secretions from the endometrial glands (uterine milk) for the nutrition of the
ovum and the attachment of the embryo.
 Plays a role in the maintenance of pregnancy (and pseudopregnancy) by
providing a favorable environment for survival of the embryo.
 progesterone -> etrogen receptors -> effects of estrogen progesterone
block .
 growth of the alveolar system of the mammary gland.

64.  inhibits the smooth muscle activity of the uterus - renders it less sensitive to
oxytocin.
 Target tissues are relatively insensitive to progesterone unless primed by estrogen
- At low levels progesterone acts with estrogen to stimulate ovulation by
promoting LH release.
 At high levels progesterone inhibits the secretion of FSH and LH via a negative
feedback. However enough FSH is released so that follicles may develop during
the luteal phase of the cycle

65.  Maturation, growth and development of the reproductive organs and secondary
sex characteristics of the male.
 Maintenance of the secretory responses of the accessory sex organs-provide the
fluid component of semen.
 Suppressing the secretion of the pituitary gonadotropins through negative
feedback.

66. iv. Relaxin:
 Secreted by the CL during late pregnancy, in some species Placenta and uterus.
 Main biological action is dilatation of cervix and vagina before parturition
 If given in conjugation with estradiol, it inhibits uterine contraction and causes
increased growth of mammary gland
v. Activin:
 Secreted from Follicular fluid and rete testes fluid
 Stimulate FSH secretion

67. vi. Inhibin:
 In male, sertoli cells and in female, granulosa cells are responsible for secretion
 Reduce secretion of FSH to a level which mainatains the species specific number
of ovulation in both single and litter bearing animals
 Inhibit FSH withoutaltering LH, hence partlyresponsible fordifferential release from
pituitary
 In male, it is important to increase thequalityof spermatozoa, regulate Leydig cell
function
vii. Follistatin:
 Inhibit secretion of FSH (as inhibin) and also binds activin and neutralize, thus
modulate secretion of FSH

68. i. Equine Chorionic Gonadotropin (eCG):
 Secreted from endometrial cups in mares from 40-140 days of gestation with
maximum level at 80th day of pregnancy
 Have like both LH and FSH like activity but FSH like activity is more potent
 In mares it results folliculogenesis and ovulation and hence multiple CL
 It is used to treat inactive ovaries as well as used for superovulation in donor
animals in embryo transfer.

69. ii. Human Chorionic Gonadotropin (hCG):
 Secreted from syncytiotrophoblastic cells in primates’ placenta after 8 days of
pregnancy
 Found in blood and urine: pregnancy diagnosis
 Predominantly LH like activity
iii. Placental lactogens:
 Properties near to growth hormone than prolactin activity
 Regulates maternal nutrient to fetus and possibly is important for fetal growth.

70. iv. Prostaglandins:
 PG-F2α is a potent luteolytic agent resulting in a decrease in progesterone levels,
with a concurrent increase in the secretion of FSH by the anterior pituitary and a
return of normal estrus and ovulation within 4 to 6 days.
 Leuteolysis
 Contraction of uterine smooth muscle
 Contraction of smooth muscle of reproductive system and GI tract
 Ovulation, parturition and milk ejection
 Erection, ejaculation and sperm transportation.

71.  1. Endocrine feedback mechanism: Increase or decrease concentration of one
hormone either stimulates or subsides release of another hormone.
 2. Neuroendocrine reflex: The nervous system controls the release of hormone
through neural pathways eg. Oxytocin in milk letdown and LH release following
copulation
 3. Immunoendocrine Control: The endocrine and immune system interact
extensively to regulate each other. Several endocrine organs are involved in some
aspect of this regulatory process e.g. hypothalamus, pituitary, gonads etc.

74. Infantile
stage
Post
pubertal
stage
puberty
Pre pubertal stage
maturity

75. 1. Infantile stage:
 No hormonal change
 No response to hormone
2. Prepubertal stage:
 High initial hormonal change
 Gradual response to hormonal change
3. Pubertal stage:
 Gametogenesis in response to hormonal
change
4. Post pubertal stage:
 Hormonal changes like mature
animal
 Increasing quality and quantity of
Gametogenesis
5. Maturity:
 Mature stage of gametogenesis

76.  Puberty is defined as the achievement of the ability to reproduce.
 Characterized by the expression of estrus in females and by the presence of
sperm (at least 50 millions of which >10% are motile) in ejaculates of males.
 Onset of puberty in different farm animals:
 Horses: 10-24 months
 Cattle: 6-18 months
 Sheep: 6-12 months
 Swine: 5-8 months
 Dog: 6-12 months

77.  Hormones
 Genetic Background: Species specific, breed, crossbred: early puberty
 Nutrition: lack of P, Cu, Co, Fe, Iodine, energy, protein delay puberty
 Environmental Factors: Temperature, photoperiod
 Presence of opposite sex: early puberty
 Sex; Female have early puberty
 Disease: delay puberty

81.  Definite physiologic functional rhythm of reproductive system in female animals.
 It has 2 phases:
• Proestrum
• Estrum
Estrogenic /
follicular phase
• Metestrum
• Diestrum
Progestenal /
Leutal phase

84.  Ill-defined period immediately preceding estrum.
 Graffian follicle is growing under influence of FSH and producing increasing
amount of estrasiol.
 Regression of CL of previous cycle and decreasing level of progesterone.
 CL undergoing rapid degeneration, vacuolization and decreasing in size
 Increase in growth of epithelial tissue, activity of muscle of reproductive tract,
secretion of mucus and vascularity of endometrium and vaginal mucosa known
as building-up period
 Late in this phase the female accepts male

85.  In dog:
 increased endometrial vascularity characterized by bleeding.
 In bitch and Sow:
 vulva becomes definitely edematous and swollen, gradual relaxation of cervix and
increased secretion of viscid, slimy mucus (from goblet cells of cervix)
 In cow and mare:
 milky, viscid mucus, which in late stage becomes clear, transparent, stingy mucus.

86.  Period of acceptance of male
 Starts with first acceptance and ends with last acceptance of male.
 Graffian follicle is mature and grown
 Oviduct is tonic, epithelium mature, contraction of oviducts
 Vaginal and cervical mucus is greatly increased, mucosa pink and congested due
to increased vascularity. Cervix slightly edematous and is relaxed.
 Cow: strings of mucus may hang from vulva, ovulation after 12 hours
 Induced ovulation incat, rabbitand ferret bycoitus (prolonged upto7-10 days incat)

87.  Phase in which CL grow rapidly from granulosa cells under the influence of LH
 Progesterone form CL inhibit secretion of FSH
 Vagina loose most of new growth through desquamation
 In cows, during early part, epithelium over caruncles of uterus is very hyperemic
and some capillary bleeding occur which is different from true mensuration in
primates (loss of superficial layer of endometrium).
 It is associated with estrogen withdrawal (progesterone withdrawal in primates)
 Length about equal to time of ova to reach uterus ( about 3-4 days)
 In dog and cat, Increased length of metestrum result in pseudopregnancy

88.  Longest phase (except dog and cat: absent)
 CL is mature and effect of progesterone is marked
 Endometrium thickened and glands hypertrophy.
 Cervix constricted and vaginal mucus scant and sticky.
 Vaginal mucus membrane is pale, uterine muscle relaxed

89.  Prolonged period of sexual quiescence during which follicular development is
minimal
 CL although identifiable, is regressed and non functional.
 Characterized by quiescent, functionless ovaries and reproductive tract.
 Observed physiological in mares in winter and ewes in summer and late spring
 In bitch and rat, extends to several months or 2/3 times a year.
 Uterus is small and flaccid and vaginal mucus scanty and sticky.
 Vaginal mucosa is pale and tightly closed and pale cervix.

90. Species Length of cycle Length of estrus Time of ovulation
Ewe 16-17 days 24-40 hrs 30-36 hrs from beging of estrus
Goat 21 days 20-36 hrs 30-36 hrs from beging of estrus
Sow 19-20 days 48-72 hrs 36-48 hrs from beging of estrus
Cow 21-22 days 12-18 hrs 10-12 hrs after end of estrus
Buffalo 21-24 days 6-18 hrs 10-12 hrs after end of estrus
mare 20-25 days 4-8 days 10-12 hrs before end of estrus

92. Follicle
 Follicle growth to maturity
 Under influence of FSH
 Most rapid in late proestrus and estrus
 Ruptures--releases ovum
Corpus hemorrhagicum (CH)
 Develops in cavity of ruptured follicle
 Lasts about 2 days

93. Corpus luteum (CL)
 Develops gradually from follicle lining cells
 Mature size--8-10 days after start of estrus
 12 day life
 Progesterone produced in proportion to size of CL
Corpus albicans (CA)
 1. Gradually acquired structure (slow demise of CL)
 2 Gradually changes size as cells dissolve and are reabsorbed into ovary

94.  Stand to be mounted (cows homosexual in activity)
 Attempt to mount other cows
 Mucus smeared on buttocks
 Nervous acting, restlessness (increased footsteps)
 Seek bull; stay nearby
 Rubbed tail-head or mud on hips (has been mounted)
 Chin resting on cow's rump by other cows,
 tail raising,
 licking the vulva,
 excessive urination

95. There are numerous factors which may affect the estrous cycle of the domestic
animals:
 Pregnancy : Estrus cycle is postponed in pregnancy
 Nutrition:
 lack of TDN, energy or any nutritional deficiency especially those impair apetite such
as P,Co, and possibly Fe, Cu, Iodine, Protein and others delays estrus cycle
 Interfare with postpartum cyclicity
 Temperature

96.  Seasonal Influence and Light
 Animals may be seasonal or non seasonal breedres
 Most animals in natural and wild state are seasonal, domestication changed the
pattern
 Heat stress may result in summer (summer strerility)
 Horse and fur bearing animals breed in spring with increasing day light
 Sheep in northern hemisphere breed in winter with decreasing daylight
 Character of Work :
 Horses worked or raced hard and longer don’t develop regular estrus
 Heavy milker cow also delay 3-4 months due to –ve energy balance

97.  Systemic Diseases
 Severe chronic wasting diseases such as John’s disease, TB, Actinomycosis delay
estrus
 Severe parasitism and other diseases causing debility and ematiation causes delayed
estrus
 Pathology of the Uterus or Cervix :
 Pyometra, metal maceration, mummification, persistant CL also delay estrus
 Pathology of the Uterus or Cervix :
 Pyometra, metal maceration, mummification, persistant CL also delay estrus
 Endocrine Disorders :

98.  Transportation:
 Stress during transportation causes hormonal imbalance and hence delay estrus
 Environment/ Management:
 Male effect, group/herd effect, probably mediated by visual, auditory and olfactory
stimuli to CNS and cause increased GnRH secretion
 In summer, sterility may occur due to decreased thyroid activity
 In extreme cold with reduced feed, most energy is used to maintain body heat and
hence negative energy balance
 Age:
 In cattle and swine, young female have relatively short estrum length
 In sheep this depend more upon season than age
 Old age itself seldom causes reproductive failure

99.  Proestrus:
 By massaging the uterus, we get clear mucus from vagina
 Regressing CL of previous cycle and developing follicle of present cycle
 Increasing tone of uterus
 Estrus:
 Cervix is more relaxed and one can pass pipette more easily
 Uterus has excellent tone and is turgid and erect
 Follicle is large

100.  Metestrus:
 Cervix is closed and passage is difficult
 Uterus has lost turgidity
 No palpable follicle and CL but may palpate ovulation depression or early Corpus
Hemorrhagicum
 Diestrus
 Mature CL
 Cervix is closed and uterus flaccid

101.  The term coitus or copulation refers to the insertion of the erect penis of the male
into the vagina of the female with subsequent ejaculation.
 Copulatory patterns of the male domestic animals vary to a great extent
depending on the anatomy of the penis and the contributions of the accessory
glands.
 In general coitus is
 prolonged in pigs, stallions and dogs (camels - 24 hours),
 but rapid in bulls, rams, bucks and tom cats.

102. Copulation and the events leading up to its completion may be divided into the
following phases.
 Sexual Arousal
 Courtship (sexual display)
 Erection
 Mounting
 Intromission
 Ejaculation
 Orgasm-like reaction
 Dismount

103.  Most of injuries occur in young heifers and fillies or even older females and are
associated with the use of large or overweight males.
 These include:
 Fractures of the pelvis, spine or limbs
 Dislocation of the hip
 Muscle, tendon or ligament strain
 Injuries to the mammary gland

104.  These injuries may be avoided by the use of smaller males, by artificial
insemination or by the use of a breeding rack.
 Other injuries which may occur in both the mare and the cow include laceration
and rupture of the vagina.
 False entry occasionally occurs in mares and is associated with a tipped or
horizontal vulva

105.  Early in 1st week of embryonic development, primordial germ cells can be
identified in caudal extraembryonal entoblast (Yolk Sac).
 These migrate by amoeboid movement from yolk sac across dorsal mesentry to
genital ridge
 In a few more days, gonadal sex can be distinguished by formation of oogonia in
primitive ovary
 Oogenesis is transformation of oogonia into oocytes which is completed short
after birth

106.  Bovine oocyte may rest in Pachytene phase fro years if primordial follicle doesn’t
grow
 In late dictyate state as ovulation time approaches follicular growth and
maturation occur.
 The ovum itself will grow triple in size in order to provide nutrition for early
division of fertilized ovum.

109.  In early stage of maturation of follicle the oocyte is mass of epithelial cells known
as discus proligerus, attached to granulosa layer of cells
 In graffian follicle the oocyte has reached to dictyate stage of development by this
time the connective tissue around the growing follicle have organized into the
theca which is outer zone of stroma cells known as theca externa and inner zone
epithelium like cells known as theca interna which later secrets steroid hormones
including estrogen
 As growth continues, the antrum forms and enlarges in the epithelial cells
around the ovum, the epithelial lining of this antrum forms membrane
granulosa.
 The fluid in follicle is known as liquor folliculi

110.  nb

112.  Oocyte growth:
 It completes almost at the time of antrum formation
 Formation of zona pelucida takes place
 Oocyte preparation for fertilization:
 Nuclear and cytoplasm preparation
 From oogenesis onwards, the diplotene nucleus of oocyte remain in resting phase
i.e. dictyate stage
 Meiosis is suppressed due to action of meiotic inhibiting factors secreted by
granulosa cells
 Due to LH surge, modification of granulosa cells causes suppression of MIF, thus
meiosis is resumed and formation of first polar body

113. Preovulatory follicles undergo three major changes:
 Cytoplasmic and nuclear maturation
 Disruption of cumulus cell, cohesiveness among cells of granulosa layer
 Thinning and rupture of external follicle wall

114.  Neuro-endocrine mechanism
 LH surge
 Nero-muscular mechanism:
 Ovary contracts during the time of ovulation
 Neuro-pharmacologic mechanism:
 Prostaglandin
 Stimulates ovarian contraction via smooth muscle contraction
 Increase in theca fibroblast which releases proteolytic enzymes which digests the
follicular wall and rupture of follicle

115. Primary steps leading to
preovulatory LH surge
Ovarian Events Caused by
Preovulatory LH Surge

116. During estrus secretion of
sulfomucins from apical
portion of cervical mucosa
produces sheets of viscous
mucus.
Secretion is towards lumen
and flows in caudal direction.
Less viscous sialomucins are
produced in the basal crypts
of the cervix.
Spermatozoa found in the
basal region are oriented in
the same direction transverse
the cervix towards the uterus
trough these ‘Privileged
Pathways (PP)’ of low viscous
sialomucins.

117.  Capacitation
 Takes pace in uterus and
oviduct (isthmic region)
 Sperm surface components
are modified or removed
by genital tract secretions
causing the phospholipid
bilayer to become
destabilized, permitting
acrosomal activation.

118. Acrosome Reaction
 Fusion of the sperm plasma
membrane with the outer
acrosomal membrane followed by
the extensive vesiculation over the
anterior segment of the acrosome.
 Zona-mediated acrosome reaction
and spontaneous acrosome
reaction.
 Attachment of sperm head to outer
zona pellucida is zona binding

119.  When the spermatozoon completely penetrates the zona
and reaches the perivitelline space, it settles into a bed of
microvilli formed by the oocyte plasma membrane. The
cortical granules have migrated to the periphery of the
oocyte
 The plasma membrane of oocyte fuses with the
equatorial segment and the fertilizing spermatozoon is
engulfed. The cortical granule membrane fuses with the
oocyte plasma membrane and the cortical contents are
released into perivitelline space by exocytosis.
 After fusion between the membrane of the equatorial
segment and the oocyte plasma membrane occurs, the
nucleus of the spermatozoon is within the cytoplasm.
The sperm nuclear membrane disappears and the
nucleus of the sperm decondences.

120.  Immediately following fertilization, the ovum surface changes to prevent fusion
of additional spermatozoa
 Development of Pronuclei and Syngamy, zygot formation
 Meiosis is completed after sperm penetration, 2nd polar body is expelled in to
the perivitelline space.
 Male and female pronuclei are formed, migrate to the ovum center, fuse or merge
(to form one cell zygot), mitotic prophase begins, transcription of maternal and
paternal genes begins.
 After 1st division or cleavage, 2 cell embryo is formed

121.  In the ootid, M and F pro-nuclei along with the 1st and 2nd polar bodies are present.
 Fusion of the M+F pronuclei into a single diploid nucleus constitutes syngamy.
 Shortly thereafter, the zygote undergoes cleavage (Mt. Division) and gives rise to
daughter cells called blastomeres.
 Cleavage division continues. A 4-celled embryo gives rise to an 8-celled embryo.
 After 8-celled stage, a ball of cells is formed and this embryonic stage is called Morula.
 Cells of the morula continue to divide and a blastocyst develops.
 It consists of an inner cell mass (ICM), a cavity called the blastocele, and a single layer of
cells called trophoblast.
 Finally a rapidly growing blastocyst “hatches” from the zona pellucida and forms a
hatched blastocyst that is free floating within the uterus.

122. 2 cell (day 2) 4 cell (day 3)
16 cell (day 4)
8 cell (day 3)
32 cell Morula
(day 5-6)
Tight Morula (day 6-7)
Early Blastocyst
(day 7-8)
Blastocyst
(day 7-9)
Expanded
Blastocyst
(day 8-10)
Hatched
Blastocyst
(day 9-11)
Zygote (day 1)

124.  Cow:
 Cornuate in shape and conical with greatest diameter from the cervix through middle
of the horn containing the fetus
 The distal 3rd of this horn remains relatively small even though fetal membrane
extend to it
 Ewe:
 Similar to cow
 Bicornual twin pregnancy and small abdominal cavity

125.  Mare:
 The apices are directed dorsally and by traction of broad ligament
 The body of horn containing fetus are tubular and about same diameter from cervix
to near apex of horn
 Multiparus animals:
 Gravid horn is tubular and about same diameter in entire length
 Fetuses are usually nearly equally distributed between each horn

126. In heifers
 Lies in pelvic cavity until 3-4 months of pregnancy
In older cows
 Non-pregnant uterus lies on or over the pelvic brim
 Drops into abdomen even before 2 months of pregnancy
In all ages of animals
 Uterus lies on the floor of the abdominal cavity after the 4th month of pregnancy
 By 5th-6th months of pregnancy, uterus is drawn well forward and downward in the
abdominal cavity, so that only the cervix and uterine vessels are palpated per rectum.
 By 6th-7th months, fetus is large enough to be palpated per rectum
 By 8th-9th months, fetal nose and feet are palpated

127.  Unipara/ Monotocus:
 Cow and mare
 Placenta occupies most space of both horn and body
 Cervix is highly developed
 Weight of fetus is approx. 10% of postpartum dam
 Bipara:
 Sheep and goat
 Bicornual pregnancy

128.  Multipara/Polytocus:
 Dog, cat, sow
 Poorly developed cervix
 Weight of each fetus is 1-3% of postpartum dam
 Less chances of dystocia due to wedging
 Average number of fetus:
 Sow-6-10;
 bitch-(large-6-10; medium-4-7; small-2-4);
 queen-3-5
 Primipara: Only one gestation; 1st pregnancy
 Pleuripara: conceived two or more gestation

129.  1st half of gestation: at any position
 After 5 months:
 Length of bovine and equine fetus is greater to diameter of gravid horn
 Umbilicus opposes the lesser curvature with dorsum of fetus against the greater
curvature (in cows and ewes, not in mare, sow, dog and cat)
 In mare, sow, bitch and queen: fetus rest with dorsum or dorsolateral side against
abdominal position wall and ventral portion of uterine horn in dorso-pubic or dorso-
iliac position.
 At birth fetus normally passes through the birth canal with dorsum against the
sacrum of dam. This is brought about by a rotation of the fetus.

130.  Late gestation:
 Cow: 95% anterior presentation
 Mare: 99% anterior presentation
 Ewe: 95% anterior presentation
 Bitch: 70% anterior presentation
 Swine: 54% anterior presentation

131.  Environment:
 Season: dairy cow greater in June and July; beef cattle: August calvings
 Age of dam: low in young, increase with age, and decrease in old age
 Breeding too soon after parturition
 Sires: monozygotic twins
 Hormone injection of FSH
 Hereditary:
 Breed differences: beef cattle have less twinning than dairy cattle
 Differences between dams, sire and families
 Cystic ovaries
 Species specific characters

132.  In most of cases, it is pathological and often distrous to dam as well as fetus
 Twinning represent economic loss and is reflection of genital disease rather than
health
 In mares after twinning, less than 50% foal survive and need care
 Many twin pregnancy terminate prematurely
 Viable twins are smaller in size and less vigour than single birth

133.  Following twin birth or abortion, delayed uterine involution, ROP, septic
metritis, and temporary or permanent sterility
 In dairy cows, decreased milk production due to postpartum metriris
 Free Martin:
 Infertile female with modified/underdeveloped genital tract born co-twin or in
greater multiples with a male with which it has exchanged whole blood

134.  50-80% pregnant bovine uteri have some bacterial load between portion of
maternal and fetal placentas, in the uterine cavity or organs of fetus.
 Common organisms are Streptococcus, Staphylococcus, coliforms, fungi and
viruses
 They remain non-pathogenic until immunity is suppressed
 Immunity decreases with increase of P4 and increase with increase of E2
 They may enter by retrograde infection in systemic infection or enter during
estrus when cervix is open
 Result in abortion, reabsorption, maceration, decreased fertility or sterility

135.  Sex parity/Sex ratio is usually expressed as percentage of male births (previously
complete ratio of male and female birth was given)
 Conception rate of male sperm is greater than female sperm but high EED and
abortion for male fetus makes the ratio to about 50%
 Sperm with Y chromosome has high tendency of early fertilization which may be
due to smaller size and high motility of Y chromosome (this is used for sex-
sorting of semen)

137.  Often associated with abortion and premature birth
 Lesser GP in younger cows
 Male fetus have shorter GP 2-3 days
 Cross breeding have shorter GP
 GP in twin fetus is 3-6 days shorter in cattle
 Adverse disease influencing health of endometrium and placenta
 Malnutrition, deficiency diseases, starvation, stress shorten GP
 Chronic debilitating diseases
 Regression of CL
 Pathology of Uterus, ovary
 Hormonal disturbances

138.  Iodine deficiency in sows or administration of thiouracil to produce
hypothyroidism
 Large continued injections of Progesterone or progestin
 Inbred line of breeding
 Vitamin A deficiency
 Adrenal hypoplacia
 Chromosomal abnormality
 Pituitary pathology
 Brain deformation of fetus
 Increase cold stress causes delayed parturition

139.  After 12-16 days after estrum and fertile coitus, trophobalst grows very rapidly and
its presence causes a persistent CL and cessation of estrus cycle due to
continuous release of LH by neurohormonal mechanism acting on
hypothalamus and anterior pituitary gland due to effect of trophoblast and
prevention of release of uterine leutolysin
 Maternal recognition of pregnancy:
 During maternal recognition of pregnancy CL persistence is most essential, so uterus
should not send any signal to ovary (i.e. no PGF2α secretion)
 Embryo produces INF-Tau which stop production of PGF2α from uterine
endometrium and embryo gets attached to wall of uterus

140.  P4 from CL and placenta is essential for endometrial gland growth and secretion
of uterine milk for endometrial growth and attachment of placenta for later
nourishment of fetus and for inhibiting uterine motility for placental
implantation
 A certain amount of estrogen is necessary to enhance effect of progesterone and
in later pregnancy to produce udder development, relaxation of pelvic ligament
and to sensitize uterus with oxytocin
 Other hormones essential for pregnancy are GnRH and LH

141.  In mare gonadotropins released by endometrial cups (eCG:FSH like activity)
which causes super ovulation and hence multiple CL
 In cow/goat: CL is necessary for continuation of pregnancy
 In sow: ovary is necessary for continuation of pregnancy
 In mares: follicle develop after 17 day of fertile coitus and after 40 days eCG is
released which decreases after 4-5 months with development of accessory CL

142.  Fetus is responsible to produce corticosteroids which dissociates Progesterone
into estrogen and hence initiates parturition.
 Placenta increases secretion of estrogen which sensitizes uterine musculature to
bind with oxytocin (estrogen priming). This causes contraction of Uterine
muscle.
 Also PGF2α is released which causes leuteolysis and hence again decreased level
of progesterone and increased estrogen.
 Also relaxin is secreted which causes opening of cervix and relaxation of pelvic
ligament.

143.  KLC
HORMONAL REGULATION OF PARTURITION IN CATTLE

144.  Neuroendocrine reflex comprising the self-sustaining cycle of uterine
contractions initiated by pressure at the cervix or vaginal walls.
 The Ferguson reflex occurs in mammals.
 Upon application of pressure to the internal end of the cervix, oxytocin is released,
which stimulates uterine contractions, which in turn increases pressure on the
cervix (thereby increasing oxytocin release, etc.), until the baby is delivered.
 Sensory information regarding mechanical stretch of the cervix is carried in a
sensory neuron, which synapses in the dorsal horn before ascending to the brain
 The posterior pituitary releases oxytocin due to increased firing in
the hypothalamo-hypophyseal tract

146. ON BASIS OF PLACENTAL SHAPES AND CONTACT POINT
 Cotyledonary:
 Multiple, discrete areas of attachment called cotyledons are formed by interaction of
patches of allantochorion with endometrium.
 The fetal portions of this type of placenta are called cotyledons, the maternal contact
sites (caruncles), and the cotyledon-caruncle complex a placentome.
 This type of placentation is observed in ruminants.

147.  Diffuse:
 Almost the entire surface of the allantochorion is involved in formation of the
placenta.
 Seen in horses and pigs.
 Zonary:
 The placenta takes the form of a complete or incomplete band of tissue surrounding
the fetus.
 Seen in carnivores like dogs and cats, seals, bears, and elephants.
 Discoid:
 A single placenta is formed and is discoid in shape.
 Seen in primates and rodents.

150. ON BASIS OF TISSUE INVOLVED
 Just prior to formation of the placenta, there are a total of six layers of tissue
separating maternal and fetal blood.
 There are three layers of fetal extraembryonic membranes :
 Endothelium lining allantoic capillaries
 Connective tissue in the form of chorioallantoic mesoderm
 Chorionic epithelium, the outermost layer of fetal membranes derived from
trophoblast
 The three potential maternal layers in a placenta are:
 Endothelium lining endometrial blood vessels
 Connective tissue of the endometrium
 Endometrial epithelial cells

152. Tissues
epithelial-
chorial
syndesmo-
chorial
endothelial-
chorial
hemo-
chorial
hemo-
endothelial
Maternal
endothelium + + + -- --
conn. tissue + + -- -- --
epithelium + -- -- -- --
Fetal
endothelium + + + + --
conn. tissue + + + + --
epithelium + + + + +
Species
pig
horse
ruminant
ruminant
bitch
queen
human
rat
rabbit

153. Type of Placenta Common Examples
Diffuse, epitheliochorial Horses and pigs
Cotyledonary, syndesmochorial Ruminants (cattle, sheep, goats, deer)
Zonary, endotheliochorial Carnivores (dog, cat, ferret)
Discoid, hemochorial Humans, apes, monkeys
Discoid, hemoendothelial Rodents

154.  The primary function of the placenta in all species is to promote selective
transport of nutrients and waste products between mother and fetus.
 facilitated by the close maternal and fetal vascular systems within the placenta.
 It is important to recognize that there normally is no mixing of fetal and maternal
blood within the placenta.
 The placenta is a complex tissue and should not be envisioned as simple
permeable membrane.
 In addition to transporting some molecules unaltered, it also consumes a large
fraction of certain types of cargo - glucose and oxygen being good examples.
 Additionally, a number of molecules are metabolized to during passage.

155.  c

156.  Gases like oxygen and carbon dioxide diffuse through and across tissues in
response to differences in partial pressure.
 In late pregnancy, the mean partial pressure of oxygen (P02) in maternal blood is
considerably higher than in fetal blood.
 Carbon dioxide is produced abundantly in the fetus, and the PCO2 of fetal blood
is higher than maternal blood.
 Despite its low PO2, fetal blood is able to transport essentially the same quantity
of oxygen to tissues as maternal blood.
 This is because the hemoglobin concentration in fetal blood is about 50% higher
than in maternal blood, and fetal hemoglobin has a higher oxygen carrying
capacity than adult hemoglobin.

157.  Glucose is transported by facilitated diffusion via hexose transporters that are not
dependent on insulin (GLUT3 and GLUT1).
 Although the fetus receives large amounts of intact glucose, a large amount is
oxidized within the placenta to lactate, which is used for fetal energy production.
 Amino acid concentrations in fetal blood are higher than in maternal blood.
therefore transported by active transport. (sodium-dependent)
 There is substantial metabolism of some amino acids as they cross the placenta,
e.g., much of the serine taken up by the placenta is converted to glycine.
 There is much more variability among species in placental permiability to fatty
acids than to glucose or amino acids.
 In some animals, there is little transport of fatty acids from mother to fetus, while
in others a significant amount of transport takes place.

158.  There are marked differences among species in whether immunoglobulins are
transported across the placenta.
 In primates and rodents, there is substantial transfer of immunoglobulin G from
maternal to fetal circulations prior to birth.
 This process requires immunoglobulin-binding proteins in the placenta.
 In contrast, there is no transplacental transfer of immunoglobulins in animals
like cattle, sheep, horses and pigs.
 In those species, the neonate is essentially devoid of circulating antibodies until
it absorbs them from colostrum (first milk).

159.  Bilirubin is a waste product derived from the heme in hemoglobin.
 The fetus also produces bilirubin, but conjugates only a small fraction.
 conjugated bilirubin is transported across the placenta very poorly. In contrast,
unconjugated fetal bilirubin is readily transported from the fetal circulation,
across the placenta, for elimination by the mother.
 Many drugs are eliminated in bile through pathways similar to bilirubin.
 The relative inability of the fetal liver to metabolize and conjugate means that it
is impaired for eliminating such molecules compared to adults.

160.  In addition to its role in transporting molecules between mother and fetus, the
placenta is a major endocine organ.
 The syncytiotrophoblast is an important endocrine organ for much of the
pregnancy.
 It produces both protein and steroid hormones. The major placental hormones
are listed below.
 Chorionic gonadotropin
 Estrogens
 Progestins
 Placental lactogen (PL)
 Relaxin

161.  Progesterone itself is often called the hormone of pregnancy because of the
critical role it plays in supporting the endometrium and hence on survival of the
conceptus.
 The placentae of all mammals examined produce progestins, although the
quantity varies significantly.
 In some species (women, horses, sheep, cats), sufficient progestin is secreted by
the placenta that the ovaries or corpora lutea can be removed

162.  In other animals (cattle, pigs, goats, dogs), it does not produce sufficient
amounts.
 Progestins, including progesterone, have two major roles during pregnancy:
 Support of the endometrium to provide an environment conducive to fetal
survival.
 Suppression of contractility in uterine smooth muscle "progesterone block"
 Potently inhibit LH and FSH secretion, hence prevents ovulation during
pregnancy.

163.  The placenta produces several distinct estrogens. In women, the major estrogen
produced by the placenta is estriol, and the equine placenta synthesizes a unique
group of estrogens not seen in other animals.
 Depending on the species, placental estrogens are derived from either fetal
androgens, placental progestins, or other steroid precursors.
 With few exceptions, the concentration of estrogens in maternal blood rises to
maximal toward the end of gestation.

164.  Two of the principle effects of placental estrogens are:
 Stimulate growth of the myometrium and antagonize the myometrial-suppressing
activity of progesterone. In many species, the high levels of estrogen in late gestation
induces myometrial oxytocin receptors, thereby preparing the uterus for parturition.
 Stimulate mammary gland development. both ductal and alveolar growth
 Like progestins, estrogens suppress gonadotropin secretion from the pituitary
gland.
 In species like humans and horses, where placental estrogens are synthesized
from androgens produced by the fetus, maternal estrogen levels are often a useful
indicator of fetal well being.

165.  Chorionic gonadotropins
 Placental lactogens
 Relaxin
 Relaxin is a hormone thought to act synergistically with progesterone to maintain
pregancy.
 It also causes relaxation of pelvic ligaments at the end of gestation and may therefore
aid in parturation.
 In some of the species in which relaxin is known to be produced, it is produced by
the placenta, while in others, the major source is the corpus luteum.
 In some species, relaxin is produced by both the corpus luteum and placenta.

166.  Maternal blood is discharged in a pulsatile fashion into the intervillous space by
80 to 100 spiral arteries in the decidua basalis.
 It spurts toward the chorionic plate and flows slowly around the villi, eventually
returning to the endometrial veins and the maternal circulation.
 The maternal arteries which open into the intervillous spaces are partially
occluded by a plug of cytotrophoblastic cells, presumably to regulate blood flow.
 There are about 150 ml of maternal blood in the intervillous spaces, which is
exchanged 3 or 4 times a minute.
 During the first 12 weeks, the fluid in the intervillous spaces is a filtrate of
maternal plasma without blood cells.

167.  During this period, the fetus has embryonic hemoglobin which binds oxygen
under very low tension.
 After 12 weeks, maternal blood cells appear in the intervillous spaces, and the
fetus produces fetal hemoglobin which requires a higher oxygen tension.

168.  x

171.  Wandering of ovum;
 Fetus and CL of uniparus animal are present in contralateral horn
 Incidence is less than 1%
 Ovum may be transported to opposite horn
 Mechanismnotunderstood butprobablyinvolvemuscularactivityof uterinewall, lubrication
providebyuterinesecretionandattainmentof certainsizeof blastodermicvesicle.
 Causes may be:
 External migration of ovum across peritoneal cavity
 Transuterine migration of embryo
 Regression of CL of pregnant horn and development of another CL in opposite horn
 Bilateral double ovulation with death of one ovum and regression of opposite CL
 Twins and death of one

172.  Superfecundation:
 Produced by female ovulating 2 or more ova during one estrum and copulating with
2 or more male during estrum with ova being fertilized by spermatozoa of each male
 More common in multipara especially dogs and cat
 Superfetation:
 Pregnant female with one or more fetus come to estrum and breeds
 More often in multipara with poorly defined cervix and cervical seal
 It appears unlikely in uniparus animals due to tightly closed cervix

173.  Telegony:
 Superstitious belief prevalent especially among dog breeders that offspring form one
sire may derive characteristics from a sire to which the same dam has previously
born offspring
 It is believed that dam is tainted, No scientific basis
 Pseudopregnancy:
 May occur in bitches where metestrum almost is equal to gestation period
 At this time, bitches develop mammary gland, put on weight and abdominal size
increase.
 Towards the end of pseudopregnancy, bitches may be nervous, aggressive, excitable,
restless or withdrawn and may even exhibit “phantom whelping” by making nest and
mothering and protecting some inanimate object

176.  Characterized, among other things, by a reduced growth of the bones of the
limbs and of the face. It has existed for a long time, at very low frequency, in
many cattle breeds.

177.  Rare and fatal congenital disorder.
 Defining features include spinal inversion, exposure of the abdominal viscera
because of a fissure of the ventral abdominal wall, limb ankylosis, positioning of
the limbs adjacent to the skull and, lung and diaphragm hypoplasia.

178.  Globosus amorphus (shapeless mass) is an incomplete twin with a vascular
connection to the placenta of its twin.
 All three primary germ layers are present (ectoderm, mesoderm and endoderm)
 A fertilised egg doesn’t develop properly in the womb. Instead, it tends to form a
ball of fat wrapped up in skin, and feeds parasitically on the umbilical cord of its
twin

179.  a developmental anomaly characterized by fusion of the orbits into a single cavity
containing one eye.
 The condition isusually combined with various other head and facial defects

180.  x

181.  x

182.  characterized by partial or complete agenesis of the lumbar, sacral, and coccygeal
area
 accompanied by posterior bimelic arthrogryposis characterized by ankylosis of
joints with associated malformations of the musculature.

183.  x
Lion Fetus Multiple limbs
Multiple limbs
Parasitic limb
Ankylosis
Double headed monster