Quick Review on Veterinary Gynecology

Vetnepal Review Note 2019-03-15

TERMINOLOGY

  • Colostrum: is the first milk produced after birth
  • Dystocia: difficult calving
  • Freemartin: Sterile female born twin with a bull. About 93% of females born twin with a bull are sterile. Registration of such a heifer is withheld until proof of fertility is established.
  • Gestation: Period from conception to birth of offspring; pregnancy. Average length of gestation for dairy cattle is approximately 280 days
  • Impotence: is the inability to mate
  • Impotentia coeundi: is reduced to complete lack of sexual desire
  • Impotentia generandi: is incapacity or reduced capacity to fertilize
  • Infertility: describes the animal that is neither normally fertile nor totally sterile
  • Infertility: is the inability to conceive and have offspring
  • Sterility: describe the animal that cannot produce
  • Estrus synchronization: A procedure using hormones to alter the estrous cycle of cows to bring them into heat at the same time
  • Identical twins: Two individuals develop from one fertilized egg and are genetically alike

The male reproductive organ of system with their function

  1. Penis: Organ that delivers semen to the female reproductive tract
  2. Seminiferous tubules: Where sperm are produced
  3. Vas deferens (sperm duct): The tube that carries sperm from the epididymis to the urethra
  4. Urethra: The tube that carries both sperm and urine down the penis.
  5. Accessory glands: Organs that contribute 90% of the semen.
  6. Epididymis: Tubules where sperm are stored.

The female reproductive organ of system with their function

  1. Uterus: Chamber that houses the developing foetus
  2. Vagina: Canal that receives the penis during copulation
  3. Fallopian tube: Usual site of fertilisation
  4. Fallopian tube: Duct through which the ovum travels to reach the uterus.
  5. Cervix: A sphincter muscle between the uterus and the vagina
  6. Vulva: External genitalia
  7. Ovary: Where the ova are produced

GESTATION Period (Days) of Diffetent Animals

  • Cow: 280,   Dog: 53-71 (63),   Buffalo: 310,   Ass: 366,  Goat: 150, Elephant: 510-730 (624),
  • Sheep: 148, Horse: 329-345 (336), Pig: 114, Chicken: 21, Rabbit: 33,  Cat: 52-69 (63),
  • Guinea Pig: 58-75 (68), Duck: 21-35 (28).

Generally Gestation period is longer in 

  • Young animals than older animals
  • Multiple litter size than single offspring
  • Male calves than female one
  • Winter season than summer season

Prolonged Gestation is due to

  • Iodine deficiency (4-10 days)
  • Vitamin A deficiency (1-4 weeks)
  • Inbreeding ((1-4 weeks)
  • High progesterone

SEMEN COLLECTION: Volume-Concentration-Frequency-Technique

  • Bull: 5-8 ml - (1000-2000)millions/ml - BID 2 days/week - Artificial vagina
  • Buff: 3-6 ml - (800-1500)millions/ml - BID 2 days/week - Artificial vagina
  • Ram/Buck: 0.8-1.2 ml - (2000-3000)millions/ml - Many times/day for several weeks - Artificial vagina
  • Bore: 150-300 ml - (200-300)millions/ml - Every other day - Digital manipulation
  • Stallion: 30-100 ml - (200-400)millions/ml - Every other day - Artificial vagina

Semen collection time

  • In summer                               6-8 AM
  • In winter                                 8-10 AM       

STORAGE OF FROZEN SEMEN

  • -790C: By using solid C02 and alcohol,       
  • -1900C: By using liquid air
  • -1960C: By using liquid nitrogen,               
  • -2960C: By using liquid helium

PLACENTATION: Type, Shape and Animals

  1. Epitheliochorial: Diffuse - Pig, Horse, Donkey
  2. Syndesmochorial: Cotyledonary - Sheep, Goat, Cow
  3. Endotheliochorial: Zonary or Discoid - Cat, Dog, Ferret
  4. Hemochorial: Discoid or Zonary - Primates (Man, Monkey)
  5. Hemoendothelial: Discoid or Spheroidal - Rat, Rabbit

FORMATION TIME: Vesicular follicles - Spermatogenesis - 20 Spermatocytes - Spermatozoa

  • Cattle: 1-12 of age in ovary - 142 days - 181 Days - (224-250) Days
  • Sheep: At Birth - 63 days - 126 Days - 147 Days
  • Pig: 76-83 Days - 84 days - 109 Days - 147 Days
  • Cattle - 21 days - 18 hrs - 18-48 hrs

ESTRUS DETAILS: Species-Cycle-Duration-Ovulation

  • Sheep - 16 days - 30 hrs - 24-36 hrs
  • Mare - 22 days - 4-5 Days - 24-48 hrs prior to end of estrus
  • Swine - 21 days - 48 hrs - 38-42 hrs

Estuus

  • Follicular phase:          Proestrus (Building phase)
  • Estrus (Estrogenic phase)
  • Leuteal phase:             Metestrus (Progestational phase)
  • Diestrus (Resting phase)

Unequal function of ovaries

  • In ewe and goat: 54-60% right ovary
  • In cow: 60-65% in the right ovary
  • In sow: 55-60% in the left ovary
  • In mare: 60% of left ovary

Endocrine Glands and Hormones

  • Hormones are chemicals that are released into the blood by endocrine glands i.e. Glands with no ducts. Hormones act on specific target organs that recognize them.
  • The main endocrine glands in the body are the hypothalamus, pituitary, pineal, thyroid, parathyroid and adrenal glands, the pancreas, ovaries and testes.
  • The pineal gland in the brain produces melatonin that influences sexual development and breeding cycles.

Pituitary gland (Hypophysis): Master gland

a. Anterior Pituitary gland

  • Growth hormone (GH): From acidophilic cell of Anterior Pituitary gland
  • Adenocorticotrophic hormone (ACTH)
  • Thyroid stimulating hormone (TSH)
  • Prolactin/Luteotrophic hormone (LTH) (Acidophilic cells)
  • Follicle stimulating hormone (FSH): Stimulation of ovarian follicles, Release of LH, Spermatogenesis in male testes
  • Luteinizing hormone (LH): Ovulation along with FSH, Development of CL, Stimulates androgen secretion in male

b. Posterior Pituitary gland: Melanocyte stimulating hormone (MSH)
c. Intermediate Pituitary gland:

  • Oxytocin: (Para-ventricular nuclei ) Milk let down, Ovum & sperm transport
  • Vasopression/Antidiuretic hormone (ADH)

Thyroid Gland: Thyroxine, Calcitonin, Thyroxine consists of 60% iodine. Lack of iodine leads to goitre
Parathyroid Gland: Parathyroid hormone or Parathomone (PTH), regulates blood calcium levels and the excretion of phosphates
Adrenal Gland
a. Adrenal cortex:  Glucocorticoids: Corticosterone, Cortisol, Cortisone
Mineralocorticoids: Aldesterone (regulates blood concentration of Na and K)
b. Adrenal Medulla: Epinephrine or Adrenalin (responsible for the flight, fright, fight response) Norepinephrine or noradrenalin
Pancreas

  • Glucagon: α-cell of Islets of Langerhans
  • Insulin: B-cell of Islets of Langerhans (regulates blood glucose levels)
  • Somatostatin: Y-cell of Islets of Langerhans

Gonads
a. Ovaries:

  • Estrogen: in pregnant placental tissues also, lobule-alveolar development
  • Progesterone: in pregnant placental tissues also

b. Testes: Androgen (Testosterone: Produced by leyding cells of testes)

Uterus: a. Prostaglandin   b. Relaxin

GI Hormones

  1. Gastrin: From wall of the stomach
  2. Cholecystokinin (CCK): Wall of the duodenum
  3. Secretin
  4. Gastric inhibitory peptide (GIP): Inhibit gastric acid secretion stimulates

Kidney :    a. Renin    b. Renal erythropoeitic factor or Erythropoietin

Hormone and site of secretion

  1. Estrogen                        Theca interna of ovarian follicles       
  2. Vasopression                Supra-optic nuclei
  3. FSH                                Basophilic cells
  4. LH                                  Basophilic cells
  5. Prolactin                       Acidophilic cells

HORMONES-Origin-Target-Function

  • Gonadotropin Releasing Hormone (GnRH) - Hypothalamus - Anterior pituitary - Release of FH & FSH
  • Luteinizing Hormone (LH) - Anterior pituitary - Ovary & Testis - Ovulation, CL formation, Testosterone
  • Follicle  stimulating hormone FSH - Anterior pituitary gland - Ovary & Testis - Development of follicle, Sperm production
  • Estrogen (several types) - Follicle & Placenta - Uterus, Hypothalamus - Mating behavior, Secondary Sex Characteristic
  • Progesterone - Corpus luteum (CL) - Uterus, Hypothalamus - Maintains pregnancy, Inhibits GnRH release
  • Prostaglandin F2 - Uterus - Corpus luteum - Regression of CL
  • Testosterone - Testis - Skeletal muscle, testis - Sperm production, male libido, sex character

FETUS POSITION IN UTERUS

  • Bilateral deviation of head of fetus: Shoulder presentation
  • Posterior presentation with rear limbs flexion beneath the fetus (Bilateral hip flexion): Breech presentation
  • Anterior  presentation with rear limbs flexion beneath the fetus (Oblique ventro-vertical presentation): Dog sitting position
  • Upward displacement of one or both extended forelimbs in mare: Foot nape posture
  • Vertex posture with bilateral shoulder flexion in bitch: Butt presentation

SOME TIPS ON GYNECOLOGY

  • In mammary gland development estrogen is responsible for duct growth and progesterone is for lobular-alveolar (secretory system) development
  • In female the mullerian ducts develop into a gonaductal system and the wolffian ducts atrophy. The opposite is true in male.
  • Testes are the primary sex organ in which sertolli cells and leyding cells are found.
  • Testosterone is secreted by leyding cells, Progesterone by CL and estrogen by Theca interna of ovarian follicles.
  • Ovulation is the condition when the egg is released and is largely under the control of LH.
  • Fertilization takes place in fallopian tube (Oviduct) and Implantation is in the uterus.
  • Proestrus bleeding is only seen in Dog
  • Pyometra (accumulation of pus in uterus), Hydrosalpingitis (accumulation of watery fluid in oviduct), Hemosalpingitis (accumulation of blood in oviduct)
  • Temperature suitable for normal spermetogenesis in bull is 36.60C
  • Temperature of AV jacket- (45-50)0C  and held in 450C
  • Frozen semen straw are sealed at end with Polyvinyl powder
  • Semen lower than 40% motility is rejected and If
  • Reaction time is inversely proportional to the libido (0-30 second: Excellent and 30-60 seconds good)
  • Yorksire breed of bore > libido than Duroak breed
  • 10-50 billions sperms/ejaculation = dilution with 50 times = Can be inseminated to 300-1000 cows = One straw contains 20 millions spermatozoa
  • Embryo migrates through the oviduct to the uterus in 3-4 days, by which time has developed into the 16- or 32 cell stage.
  • Period of attachment is 20-30 days in cattle and 14-21 days in horses.
  • Embryonic stage is defined as the period when body parts differentiate and essential organs are formed (about 45 days in cattle)
  • Fetal stage is from embryonic to birth, time of growth, called fetus
  • In natural service semen deposited in vagina
  • A female born twin to a bull is called freemartin and 90 to 91% percent of these are sterile
  • Semen are thawed in 93 to 97 degrees or 90 to 95 degrees
  • If heat detection rate is 30% and the conception rate is 30%, then the pregnancy rate is 9%.
  • In the reproductive track, the muscular rings is founding in cervix and as a gateway between the uterus and the vagina
  • The coiled tube that serves as a storehouse of sperm is called as epididymis
  • A combined accessory gland fluid and sperm are called as semen
  • Naval cord or umbilical cord links the embryo to the placenta
  • Abnormal heat cycle length, lack of heat periods, or a cow in constant heat could be caused by cystic ovaries
  • Sperm are the gametes that carry the genetic material (head, mid-piece and tail)
  • In cows period of Ovum is 10-12 days, period of embryo is 12-45 Days and period of foetus is >45 Days
  • Generally 90% of the twins in cattle is bicornualand only 10% in unicornual
  • Extra uterine pregnancy is common in man only
  • Torsion is more common in pleuriparous animals and right torsion is common than left
  • Allantois is the disease condition due to uterus where as amnion is due to fetus
  • Persistence of hymen in female animal is white heifer disease