Reproduction Flashcards
What is a teratoma?
Tumour formed by ectopic primordial germ cells. They’re usually benign, cystic tumours
What are germ cells?
Progenitors of sperm and egg. Arise outside gonads.
What are gonadal cords? What do they become and what is their significance?
Distal parts of many mesonephroc tubules fuse with invaginated coeliomic epithelial cords. They become infiltrated with primary germ cells and cavitation to form seminiferous ubules where spermatogenesis occurs.
What do the mesonephric tubules become?
Efferent ducts and rete testes which transport sperm to epididymis
What are Sertoli cells? Where are they derived from, what do they secrete and what is their function?
They are the first testis-unique cells to differentiate. They’re derived from coelomic epithelium and are critical for spermatogenesis. Secrete AMH in the embryo. Secrete inhibin and androgen binding protein later also
What is the role of AMH?
Initiates degeneration of progenitors of female reproductive ducts.
What are Leydig cells?
Cells of the testes that synthesise and secrete testosterone
What is the SRY gene? Briefly describe conditions such as XXY and XO.
= transcriptional regulatory gene that is activated within the progenitors of Sertoli cells.
XXY individuals are phenotypically male
XO individuals are phenotypically female
In females, what do the mesonephric tubules become?
Nothing. They degenerate.
What does Wnt4 do?
It has a suppressive effect on the differentiation of steroid-
producing cells. Important in ensuring females aren’t masculinised.
Overexpression in males may lead to cryptorchidism
In males, what does the mesonephric duct become?
The epididymis and the ductus deferens
What do the paramesonephric ducts become?
The uterine horns
How does the vagina form?
Evagination of the urogenital sinus plus the distal part of the paramesonephric duct
In females, the urethral folds and genital swellings form the…?
Labia
Scrotum in males
What does the gubernaculum form?
The scrotal ligament.
What is Klinefelter’s syndrome?
XXY genotype. Results from meiotic x-chromosome nondisjunction during oogenesis. Individuals are phenotypically male. Tortoiseshell cats.
What is a male pseudohermaphrodite? What about a female pseudohermaphrodite?
Male: phenotypically female with testes. Genotypically female (xx) but possess an autosomal gene with Y effect on their chromosomes. (Occurs in goats that are homozygous for polledness)
Female: phenotypically male with ovaries and testicular tissue present. Have an XX genotype with an SRY translocation
What is a freemartin?
Situation on cows with twins where blood crosses from one twin to the other. The XY present in the heifer calf prevents the development of paramesonephric ducts in the female . External genitalia often show some masculinisation
What are some basic differences between an oestrous cycle and menstrual cycle?
Species (non-primates vs primates) Length (28d vs 21d) Shedding of mucosa Sexual receptivity (heat) Length of follicular and lateral phases Time point of ovulation (oestrous cycle starts and ends with ovulation)
What are some things which may cause anouestrus?
Season Lactation Offspring Stress Pathology Pregnancy
What is the cycle length in sheep?
200-260 d (merino)
100-140d in blackface breeds
How is melatonin important in cycling?
Increased light -> decreased melatonin levels -> increased RF-aside related peptide-3 -> increased kisspeptin (in long day breeders) -> increased GnRH release
Pigs and ruminants have 21d oestrus cycles. Duration of oestrus differs how?
🐄 Cattle: 18hrs (ovulation is 10-11 hrs after end of oestrus) 🐑 Sheep: 24-36hrs (24-30 hours after beginning of oestrus) 🐐 Goats: 32-40hrs (30-36 hrs after beginning of oestrus) 🐖 Pigs: 2-3d (35-45hrs after beginning of oestrus) 🐎 Horses: 4-8d (1-2d before the end of oestrus)
Describe the oestrous cycle of the dog.
Oestrus occurs approximately every 7 months.
The beginning is marked by an LH surge which lasts 24-28hrs. Ovulation occurs approximately 2 days after the LH peak
Proestrus (when bleeding occurs) 9d on avg
Oestrus 8-9d
Dioestrus 57d in pregnant bitch
No sharp drop in progesterone
Canine oocytes are ovulated as primary oocytes. True or false?
True. Takes 48-72 hours to mature before fertilisation can occur
Which species are induced ovulates? What does this mean?
Cats and camelids.
The act of penetration stimulates ovulation
Briefly describe the oestrus cycle of cats.
Proestrus- 1.2 days
Oestrus- 7.2 days
Postoestrus- 8-10 days (if ovulation doesn’t occur)
Dioestrus- 40d in pseudopregnant, 60 days in pregnant queen
What are some signs to look out for of oestrus in cattle?
Proestrus/early oestrus: cows mounting, restlessness, vocalisation
Oestrus: standing to be mounted, ruffled tail hair, rubbed off tail paint
When and how often should a mare be teased? Why?
Daily from 3 days post partum until day 60 of pregnancy.
Necessary to detect when a mare is in oestrus
How might you detect oestrus in a dog?
Breeding reflexes
Vaginal exam (using speculum)
Exfoliative cytology
Serum progesterone levels
How might you manipulate the oestrous cycle?
Induce luteolysis (PGF2-alpha) Prolong the luteal phase (progesterone)
What are some reasons for wanting to synchronise oestrus?
- Improved oestrus detection rate
- Allows timed mating and AI
- More efficient use of AI
- Embryo transfer
PGF2-alpha only works on what sort of CLs?
CLs older than 5 days
What is hcG?
Human chorionic gonadotropins
LH-like function. If given to mare at right time (35mm follicle) high likelihood of her ovulating 36-42 hours later
What is the “ram effect”? In which breeds is it most pronounced?
Sudden introduction of rams to ewes that have been isolated from rams will induce ewes to start cycling. Most ewes will come into heat 17 or 25 days after the first ram (or teaser) introduction.
British breeds
What are the three major steps of AI?
- Collection of semen from the male
- Preservation and extension of sperm
- Insemination of the female
What is semen extender? What is it made of? What are it’s uses?
Protector of sperm! Protects sperm against possible damage by toxic seminal plasma. Basic components are:
1. Buffer (tris, citrate)
2. Sugar
3. Antibiotics
Used to enable ejavulate to split into several doses, to increase longevity of sperm outside tract, and allows shipping of semen.
Identify the site of natural semen deposition and AI in the various animals below: Cattle Horse Sheep Pig Dog
Cattle- vagina (uterus)
Horse- uterus (uterus)
Sheep- vagina (cervix if fresh, uterus if frozen)
Pig- uterus (uterus)
Dog- vagina (vagina if fresh, uterus if frozen)
If using frozen semen, when should you try to inseminate a mare for best chances of pregnancy?
Within 12 hours before ovulation or 6 hours after ovulation
What is ICSI?
Eggs are collected and 1 sperm is infected straight into egg
What is the mechanism of erection in a musculocavernous penis?
Increased blood flow + decreased venous return ➡️ engorgement of erectile tissue
(Stimulation leads to relaxation of the wall of coiled and deep arteries of the penis. There is also additional blood pumped in by contraction of the ischiocavernosus and bulbospongiosus)
What causes male and female dogs to be tied together?
Bulbous glandis enlargement (contractions of the muscles at the base of the penis prevents venous outflow). Also sphincter muscle of the vulva constricts and compresses the dorsal vein of the penis
What are some functions of the epididymis?
- Spermatozoal maturation
- acquisition of motility
- structural changes
- physiological changes - Water absorption
- Spermatazoal transport
- Blood-epididymis barrier
When do sperm gain motility?
Distal corpus (cavernosum?)
If the marked uterine inflammatory reaction that occurs with sperm entry does not resolve within 48 hours, what is the female at risk of?
Post-mating induced endometriosis
What are so,e barriers the sperm has to get through to reach the egg?
- Retrograde flow of sulfomucin and sialomucin
2. Phagocytosis (many neutrophils under the mucosa of the vagina and uterus)
What is the privileged pathway for sperm?
Pathway through the crypts of the cervix where sialomucin is produced (less viscous than sulfomucins produced in the apical portions)
What is decapacitation of sperm?
Removal of seminal plasma molecules and part of the plasma membrane on the head of sperm to allow binding to zone pellucida
What is the acrosomal reaction?
Process by which the membrane overlying the acrosomal me,brand fuses with the outer acrosomal membrane leading to vesiculation and pore formation
What is the cortical block?
Release of cortical granules into the perivitelline space which brings about a biochemical change in the zona pellucida that makes it impenetrable to other sperm
What is syngamy?
When the male pronucleus fuses with the female pronucleus
Once the sperm nears the oocyte, what series of steps occurs before embryogenesis can take place? (9)
Hyperactive motility (zigzagging) ➡️ binding to ZP ➡️ penetration of ZP ➡️ sperm-oocyte membrane fusion ➡️ sperm engulfment ➡️ decondensation of sperm nucleus ➡️ cortical block ➡️ formation of male pronucleus ➡️ syngamy
Where do the prostate and bulbourethral glands develop from?
The urogenital sinus
What innervates the gubernaculum?
The genitofemoral nerve
When is GnRH secretion increased in a ram?
Autumn (short day breeders)
Where is the “pulse generator” located in the brain?
Mediobasal hypothalamus
What stimulates the production and release of testosterone from Leydig cells?
LH (testosterone released is proportional to the amount of LH released)
What does FSH do in males?
Important to the developing testes before puberty. Stimulates production of androgen binding protein by Sertoli cells so that the steroid hormone accumulates at its site of action
What is inhibin?
Glycoprotein hormone produced by Sertoli cells in response to FSH. It has a negative feedback action on the hypothalamic-pituitary system to suppress the secretion of FSH
In males, where are oestrogens secreted from?
The Leydig or Sertoli cells
Spermatazoa are present in most rams by the time bodyweight reaches…?
28kg
What does maturation of the sperm in the epididymis involve?
Migration of the cytoplasmic dorplet from the proximal position near the head to the distal position of the end of the midpiece
In the ram and bull it takes approximately ____ days for the production of spermatazoa froma spermatagonium. The sperm appear in the ejaculate _____ days later.
50
10-14
What is unique about the female reproductive tract in birds?
They have a single ovary (usually the left one) that appears like a bunch of grapes
What are the main events characterising oestrus?
Follicles grow to maturity and rupture
Cervix opens
Vagina/vulva prepares fpr copulation
Why are the uterine horns convoluted in ruminants and pigs?
They’ve undergone caudal migration during embyogenesis
What are corpora lutea?
Spherical bodies consisting of endocrine cells which produce progesterone to support pregnancy. They develop from ruptured follicles. Form corpora albicantes if no pregnancy occurs.
What is the opening of the uterine infundibulum called?
Abdominal ostium
How does the cervix remain impenetrable from the external environment?
Cervical canal has interdigitating prominences or folds except at oestrus and parturition
Mucus plug
Briefly describe the 4 events that occur before implantation of the embryo.
- Dvpt within the zona pellucida (ootid to zygote to 2-cell embryo to morula to blastocyst)
- Hatching of the blastocyst
- Formation of extraembryonic membranes
- Maternal recognition of pregnancy
What does totipotent mean?
The ability of a single cell to give rise to a complete fully formed individual. The cells up to an 8-cell embryo are totipotent
How is the blastocoele formed in the blastocyst?
(Inner cells develop gap junctions which facilitate cell-cell communication, and the outer cells develop tight junctions which facilitate cell-cell adhesion)
A sodium pump is responsible for an increase in sodium and consequently water inside the embryo
How does hatching of the blastocyst occur?
Cells continue undergoing mitosis and fluid in blastocoele keeps increasing-> increasing pressure within zona pellucida.
Outer trophoblast cells also produce proteolytic enzymes which weaken the ZP.
Blastocyst contracts and relaxes -> pressure pulses -> rupture of ZP
What gives rise to the chorionic and amnion?
Trophoblast, Primitive endoderm and mesoderm
How does the allantois form?
As an outgrowth of the primitive gut (embryonic hindgut)
At what day is the glycoproteins capsule lost in the equine embryo?
Day 16/17
What is the hymen?
Marks the boundary between structures of different embryological origin. Found near the caudal end of the vagina
The external urethral orifice is raised above the tract floor on a small mound or _______ in the bitch, while in the cow and sow, the opening is in the roof of a small pocket called the ______
Hummock
Suburethral diverticulum
What are the major and minor vestibular glands?
Major: 2 compact glandular masses located in lateral walls of vestibule. Drain by a single duct.
Minor: several rows of simple glands on lateral and/or ventral wall of the vestibule
The vestibule in the female is encircled by which muscle?
Constrictor vulvae
What are the ligaments of the female reproductive tract?
- Mesovarium- most cranial part of broad ligament. Supports ovary.
- Mesosalpinx- supports and encloses the uterine tube
- Mesometrium- suspends the uterine horns
Briefly describe the blood supply of the female reproductive tract.
Arterial arcade (ovarian, uterine and vaginal arteries).
- Ovarian (from aorta) runs within mesovarium
- Uterine (from internal iliac) runs within mesometrium ABSENT IN CARNIVORES
- Vaginal (from internal pudendal in horse and dog)
On which cells in the female does LH act?
Theca interna cells
Membrana granulosa cells at time of ovulation
What are the four steps to maternal recognition of pregnancy?
- Development within the zona pellucida
- Hatching of the blastocyst
- Formation of extraembryonic membranes
- Maternal recognition of pregnancy
What are the number of ducts within the following species:
- Cow, ewe
- Mare, sow
- Bitch, queen
- Cow, ewe= single duct system
- Mare, sow= 2 duct system
- Bitch, queen= multiple duct system
What are the suspensory structures of the udder?
Symphyseal tendon which branches into two lateral suspensory ligament and a median suspensory ligament
What is the blood supply and venous drainage of the udder? What about the lymphatic drainage route?
Arterial supply= external pudendal a., ventral perineal artery.
Venous drainage= superficial epigastric vein (milk vein), external pudendal vein, and ventral perineal v.
Lymphatic drainage= superficial inguinal lymph nodes which then drain to the medial iliac lymph nodes
What is the innervation of the udder?
First and second lumbar nerves (cranial skin) Perineal nerve (caudal skin) Genitofemoral nerve (middle skin and everything else)
What are some defence mechanisms of the udder?
Teat sphincter muscles Keratin plug White blood cells Flushing out of milk held in cisterns Bacteriocidal fatty acids in keratin
To be suitable for human consumption, vats need to have a BMCC of ….?
Less than 400,000 cells per ml
What hormones direct growth and activity of mammary ducts? What about the alveoli?
Ducts- oestrogen, GH, and adrenal steroids
Alveoli- prolactin and progesterone
What are the basic pathways involved in lactogenesis and galactopoiesis?
Lactogenesis:
Stimulation of teat ➡️ increased prolactin and decreased dopamine ➡️ lactogenesis
Galactopoiesis:
Stimulation of udder (or other visual/auditory stimuli) ➡️ oxytocin release. ➡️ myoepithelial cell contraction ➡️ milk let-down
What are some characteristics of colostrum?
▪️ high in vit A (and other vits) ▪️ high in fat ▪️ high in antibodies ▪️ low in carbs ▪️ low lactose ▪️low water content
What are some of the contents of milk?
▪️carbs (lactose and oligos) ▪️proteins (caseins and albumins/globulins) ▪️fats (mostly triglycerides) ▪️salts ▪️epithelial and WBCs
What is the main driver of milk volume?
Lactose (excreted into milk via exocytosis)
How common is dystocia in cows? What about other breeds?
3-25% in cows
1-2% in others
What are some causes of dystocia? How common are each of these (as a percent of total dystocias)?
- Foeto-pelvic disproportion (50-70% in beef, 15-30% in dairy)
- Malpresentation (20-45% in cattle)
- Ineffective labour (10-20% in cattle)
- Other
What are some causes of ineffective labour leading to dystocia?
Hypocalcaemia
Obesity
Debility
Exhaustion
What are some options for the management of dystocias?
- Manipulation
- Extraction
- Foetotomy
- Caesarean section
- Euthanasia
What is an episiotomy?
Cuts in vulva to enlarge vulval opening. Minimises uncontrolled tearing
What are some indications for a C-section?
- Unable to extract foetus per vagina
- Live foetus
- Valuable foetus
- Elective pre-parturient
- Foetal monsters
- Dead, emphysematous foetus
- Uterine torsion
What are some preparturient, parturient and postparturient diseases?
Preparturient:
- uterine displacement
- vaginal prolapse
- uterine torsion (in horses)
Parturient:
- foetal dystocias
- uterine torsion (cattle)
- incomplete cervical dilation
- uterine inertia
Postparturient:
- uterine prolapse
- infections (incl. endometritis, metritis, pyometra, salpingitis/pyosalpinx)
- subinvolution
- RFMs
- cystic ovarian disease
What is uterine displacement? What animals is it seen in most commonly?
Ventral hernia due to stretching or rupture of the prepubic tendon and abdominal muscles.
Late pregnancy in mares, cows and ewes
In which animals is a vaginal prolapse most commonly seen? What factors may contribute to its occurrence?
Older ruminants (especially sheep) and pigs.
Things that may predispose:
-age
-repeated pregnancy
-increased circulating oestrogens (cause swelling and may sensitive perineum to relaxin)
-ingestion of diets high in phytoestrogens
-increased abdominal distension
-short tail docking
-bloating, obesity and hilly terrain
In what animals does uterine torsion occur? How does it occur? When is it a problem?
Most common in cows. Early stages of parturition. Anticlockwise is most common at the level of cranial vagina. Due to lack of support along greater curvature of uterus.
Occasionally in mares. Mid to late gestation.
Problem when torsion is >180 degree rotation. ➡️ uterine and foetal vascular compromise
What is ringwomb? What animals is it commonly seen in? What causes it?
=incomplete cervical dilation in sheep
Ruminants
Pathogenesis is poorly understood. Predisposing factors may include:
- hormonal imbalances
- hypocalcaemia
- hypophosphatemia
- prior vaginal prolapse
What is uterine inertia?
Impaired ability of myometrium to contract and thus expel the foetus. Can be primary (eg. Hypocalcaemia) or secondary
What are some potential causes of primary uterine inertia?
Hypocalcaemia
Over/underdistension
Increased/ persistent progesterone secretion
Decreased oxytocin, prostaglandin or oestrogen
In what animals is uterine prolapse most common? What are some predisposing factors? Does it lead to predisposition to subsequent prolapses?
Older ruminants
Prolonged dystocia, retained placenta, postparturient hypocalcaemia
No
What is endometritis?
In what animals does it occur?
What are some causes?
Inflammation of the endometrium. It is an important cause of infertility and is typically clinically silent.
Cattle and horses
Causes:
▪️venereal disease
▪️ascending infection
What are some examples of venereal and ascending infections that cause endometritis in cows and mares?
VENEREAL
Cows: Camp. fetus, Tritrichomonas fetus, herpes 4, brucella
Mares: Taylorella equigenitalis
ASCENDING
Cows: E.coli, Trueperella pyogenes, Fusobacterium necrophorum
Mares: coliforms, Strep. zooepidemicus, Pseudomonas aeruginosa
What are some consequences of endometritis?
May resolve spontaneously. Otherwise may persist chronically and cause endometrial damage and infertility
What are some signs of metritis? What are some consequences?
Signs: enlarged uterus, vaginal discharge, systemic illness.
Consequences: infertility, uterine rupture/peritonitis, uterine abscessation, peritoneal or retroperitoneal adhesions, sepsis, toxaemia, failure of lactation
What is the pathogenesis of pyometra?
Endometritis/ chronic metritis ➡️ endometrial damage ➡️ impaired uterine prostaglandin secretion ➡️ persistence of CL ➡️ sustained progesterone secretion ➡️ cervix remains closed ➡️ pus trapped within uterus
What is salpingitis/pyosalpinx?
Inflammation of the uterine tube. Usually an extension metritis/endometritis
In which species is subinvolution of placental sites common? What does it involve?
Young bitches (<3 years old) Involves persistent haemorrhagic discharge due to failure of uterine involution. Trophoblasts fail to regress and instead invade uterine wall. Therefore endometrium cannot re-epithelialize
What are the steps involved in placental separation?
- Hormonal signalling (PGF2 alpha and oxytocin)
- Breakdown of connective tissue (placenta secretes collagenases, leukocytes secrete protease)
- Contraction of placental villi (exsanguination of placenta)
- Physical expulsion (uterine contractions)
What are some predisposing factors to RFMs?
▪️Dystocia ▪️Abortion/ premature birth/ induced labour ▪️High progesterone/ low oestrogen ▪️Placentitis ▪️Hypocalcaemia ▪️Vit E/ selenium deficiency
What causes cystic ovarian disease in cattle and pigs? What are the two forms? What are some effects?
Impaired ovulation hormonal signalling (either bc of decreased pituitary sensitivity to oestrogen stimulus, or decreased follicular hormonal receptors)
Two forms= follicular and leutinized
Effects:
▪️anovulatory infertility
▪️persistent hormonal secretion that leads to:
-persistent oestrus, hydrometric, bone marrow suppression (oestrogens); masculinisation (androgens); uterine infections (progesterone)
What may cause oestrus cycling in desexed dogs or cats?
Ectopic ovarian tissue
Ovarian remnant syndrome
How might you differentiate a cystic follicle from a cystic CL?
Cystic CL will have a nodular ovulation tag on one side and a thicker wall on cross section
In which species are paraovarian cysts common? Do they affect reproductive ability? What are they exactly?
Dogs, cats and mares
Usually not
Mesonephric/ paramesonephric duct remnants
In which species are epithelial inclusion cysts most common? How do they occur?
Equine
Ovarian epithelium gets pinched off and trapped within the ovarian stroma following ovulation
What are persistent anovulatory follicles in horses?
=autumn follicles.
Because mares are seasonal breeders, follicle dvpt is often irregular during the autumn and spring transition periods. During these periods, follicles may persist without ovulation and thus suppress subsequent oestrus cycling until they undergo spontaneous regression
What might cause oophoritis?
Systemic bacterial infections (esp. pyogenic bacteria. eg. corynebacterium, streptococcus)
In cattle: bvd, herpes 1
Cat: FIP
Birds: salmonellosis, fowl cholera (p. multocida)
Neoplasia of the ovaries may be classified in three main ways. What are they? What are some types of each of these?
- Germ cell neoplasia
- dysgerminoma (undifferentiated)
- teratoma (differentiated- at least 2 germinal embryonic layers) - Sex-cord stromal neoplasia (***mare)
- granulosa cell tumour
- thecal cell tumour - Ovarian epithelial neoplasia (***bitch)
- ovarian adenomas
- ovarian carcinomas
What may cause hydrosalpinx? Does it lead to infertility?
▪️Congenital: segmental aplasia (rare)
▪️Acquired: fibrosis and stenosis due to infection or trauma
It does if it is bilateral
What is segmental aplasia of the uterus? In what animal is it inherited?
What may it cause?
=congenital defect of paramesonephric duct formation.
White heifers (white shorthorn cattle)
Proximal mucometra/ hydrometra due to retention of secretions. Infertility if bilateral
How long does pseudopregnancy go for in goats? What might it be associated with?
Around 150 days
Hydrometra/mucometra
Once luteolysis occurs, cervix opens and fluid discharges (cloudburst)
What’s the difference between parametritis and perimetritis?
Parametritis= infl. of the suspensory ligament of the uterus Perimetritis= infl. of the uterine serosa
What is endometriosis? What species is it normally seen in?
How does it differ to adenomyosis?
=abnormal localisation of the endometrial glands (ovary, terrine serosa, peritoneum) ➡️ Humans and primates
Adenomyosis=presence of endometrial glands within the myometrium (dogs, cats, cattle and primates)
What is cystic endometrial hyperplasia?
=non specific endometrial response to irritation while under the influence of progesterone after oestrogen priming
In species other than dogs, what might cause cystic endometrial hyperplasia?
Hyperoestrogenism
- granulosa cell tumours (not horses though)
- phytoestrogens/ mycoestrogens
- cystic ovarian disease
Uterine neoplasia is common in which species?
Rabbits (invades uterine wall)
What are some mesenchymal tumours of the uterus?
Leiomyoma
Fibroma
Leiomyofibroma
What are some potential causes of vaginitis/vulvitis?
Bovine herpesvirus 1 ➡️ contagious pustular vulvovaginitis
Equine herpes virus 3 ➡️ equine coital exanthema
What often causes vaginal hyperplasia in bitches? What are Ddx?
Hyper-responsiveness to oestrogen
Ddx= vaginal polyp, prolapse
What neoplasias mar arise in the vagina/ vulva?
Fibropapilloma (in cattle) Leiomyoma/ leiomyosarcoma Squamous cell carcinoma Melanoma (grey mares esp.) Transmissible venereal tumour (bitches)
What are some examples of phytoestrogens? And mycoestrogens?
Phytoestrogens: legume crops, soy, red clover, alfalfa (sheep very affected)
Mycoestrogens: zearalenone (fusarium spp.) 🐖
What are some effects of phyto/mycoestrogens?
- Oedema/hyperplasia of uterus
- Vaginal prolapse (sheep)
- Impaired fertility (impaired ovulation/ decreased sperm migration)
- Mammary hyperplasia and galactorrhea (secondary prolactin secretion)
- Bone marrow suppression
What is puerperium? What does it involve?
The time between birth and full restoration of reproductive function. Involves lactation, uterine involution and return of ovarian cyclicity
What are the four overlapping processes involved in uterine involution?
(Exsanguination of cotyledon)
- Myometrium contractions and expulsion of lochia ➡️ separation of placentomes
- Necrosis and sloughing of tissues
- Repair and growth of surface epithelium (by day 8 for inter-caruncular regions and day 20 for carbuncular regions)
- Removal of bacterial contamination
What is the definition of RFMs in cows? What are the three main steps involved in expulsion of the membranes? What are some risk factors?
Not expelled within 24 hours
- Maturation of the placenta
- Exsanguination of the foetal side of the placenta after blood supply has been cut off
- Uterine contractions
Risk factors: slow calving, dystocia, low calcium, low energy, infection
The whole uterus of a cow should be palpable how many days post partum? How long should it take to return to its original size?
10 days post partum
40-50 days
What are some clinical signs of endometritis?
▪️purulent discharge in uterus / vulva
▪️failure to conceive
▪️ infiltration of neutrophils to uterus
▪️rarely get sick
What are some bacterial causes of endometritis?
▪️Arcanobacter pyogenes, Bacteroides, Fusobacterium= synergistic
▪️pseudomonas, E.coli, strep and staph
How might you diagnose endometritis in a cow?
Observe vaginal discharge Rectal palpation (not very accurate) Vaginoscopy Metricheck (scoop thing) Ultrasound (fluid) Biopsy
What are some risk factors for endometritis?
- Disrupted balance between bacteria and immunity (neutrophil function, progesterone, GC administration, hygiene, bacteria type)
- RFMs, metritis
- Still hurts, twins, dystocia
- Milk fever
- Calving induction
How might endometritis be controlled?
- Reduce dystocia by selective breed8ng
- Ensure clean calving environment
- Adequate feeding, esp post partum
- Reduce RFMs
How might you deal with pyometra in a cow?
Intrauterine antibiotics
Give PG to get her cycling again
What may be some consequences of involution in mares?
Bleeding, colic, laminitis, infection
Oxygen tension in the umbilical vein of a foal is around what?
55mmHg
What are the circulatory changes that occur at birth?
Rupture of umbilicus ➡️ asphyxiation ➡️ reflex gasping, reps movements and increased peripheral vascular resistance due to vasoconstriction of umbilical arteries)
➡️ Reduced pulmonary vascular resistance and increased pulmonary blood flow ➡️ increased venous return to LA and increased LA pressure ➡️ closure of foramen ovale
➡️ reduced blood flow through and closure of the Ductus arteriosus
➡️ ductus venosus closure
The concentration of IgG in colostrum is what compared to maternal serum concentrations?
5-10 times higher
What is the half life for maternal antibodies in the foal?
20-30 days. Most have disappeared by 6 months of age
Failure of passive transfer may be a consequence of…?
- Ingestion of poor quality colostrum
- Failure to ingest a sufficient quantity of colostrum
- Failure to absorb colostrum components beyond 18-24 hours
What techniques can be used in the evaluation of passive transfer?
- Radial immunodeficiency assays (most accurate)
- Enzyme-linked immunosorbent assays
- Zinc-sulphate or sodium sulfite turbidity tests
- Glutaraldehyde coagulation test
- Refractometer (total serum solids) in ruminants (>50g/L is good)
- Gamma-glutamyltransferase activity (<300 U/L on first or second day is bad!)
What is adequate IgG concentrations in foals and calves?
Foals >800mg/dL
Calves >1600 mg/dL
How does nutritional management of the dam impact on neonatal survival?
Poor nutrition in final trimester will lead to poor udder development and poor lactation.
Hungry ewes are more likely to abandon their lamb in search of food
Excessive growth during pregnancy may increase risk of dystocia
In horses, what is dystocia more commonly a result of?
Foetal malpositioning
Flexural deformities
Why are neonates more susceptible to temperature extremes?
- Evaporation of amniotic fluid immediately following birth
- Greater SA:V
- Ltd fat supplies
- Ltd caloric reserves
What is a ‘high risk’ mare? What might lead to this classification?
Mares that have experienced problems in past pregnancies or during the current pregnancy. They’re considered more likely to deliver a compromised foal.
- Repeated breeding or previous premature termination of pregnancy
- Previous dystocia
- Prolonged pregnancy
- Premature placental separation or placentitis in previous pregnancies
- Previous sick neonates
What clinical signs should be a cause for concern prior to parturition? (4)
What abnormal events may occur at the time of delivery that require immediate attention? (5)
- Premature lactation
- Recurrent colic or presence of disease during gestation
- Excessive abdominal enlargement
- Prolonged gestation
- Dystocia
- Meconium staining of the foetus and foetal fluids
- Premature placental separation
- Delivery without adequate udder development
- Abnormalities of the placenta
The firs cycle of a mare after foaling is termed the ___a___ and occurs approximately (b) days after foaling.
Foal heat
10
Mating in horses has what chance of pregnancy?
75-80%
What is “short cycling” in mares and why is it sometimes done?
Administration of PGF2 alpha at about 20 days post foaling. It is done in order to induce an earlier return to oestrus, that will in theory have a better fertility compared to the foal heat
What do the following terms mean? Submission rate Conception rate Pregnancy rate Six week in calf rate Empty rate
Submission rate= % cows submitted in first 21 days
Conception rate= % cows pregnant per 100 seminations
Pregnancy rate= % of the herd pregnant after a given time
Six week in calf rate= % of the herd pregnant in first 6 weeks
Empty rate= % herd that didn’t fall pregnant
What must occur for a cow to get in calf?
- Calve
- Clean up
- Start cycling
- Be detected on heat
- Be inseminated
- Conceive
- Stay pregnant
What is the average conception rate of cows? What is the average heat detection efficiency rate?
30-60%
60-90%
How long after calving does mating occur? What is the recommended calving period for seasonal calving enterprises?
3 months
6-8 weeks
Most farms have a replacement rate of…?
20-30%
What is IGF-1 and what is it’s significance relative to calving?
Produced by liver when energy stores are good. It’s low at calving. Mostly produced in response to GH which is high at calving.
In early post partum cows, the GH-IGF axis is uncoupled due to the negative energy balance
What are the 6 key areas of reproduction that are most important according to InCalf project?
- Calving pattern
- Condition score (nutrition)- 4.5-5.4
- Heat detection
- AI technique
- Growing heifers
- Bulls
What are some risks of early induction of parturition for the neonate?
- mammary development of mother
- lung maturation
- Failure to grow
- asynchrony with colostrum production
What are some downsides to early induction of parturition in cows? What about in mares?
- 5% decrease in milk production
- high incidence of RFMs
- high incidence of toxaemia
Mares: premature placental separation, maladjusted foals, fractured ribs, dystocias
When inducing a mare, what criteria should you try to fulfil?
- > 330 days gestation
- bagged up
- cervix relaxed
- adequate prefoaling Ca levels in colostrum
What are some indications for abortions?
- Misalliance (too young, wrong sire,m out of season)
- Entering feedlot
- Reproductive pathology
- Fractured pelvis
- Ruptured prepubic tendon
- Excessive udder oedema
- Mare with twins
What is the order of passages through which milk flows in the udder?
Alveoli ➡️ intralobular ducts ➡️ interlobulular ducts ➡️ lactiferous ducts ➡️ gland sinus ➡️ teat sinus (cistern) ➡️ teat canal ➡️ exterior
What are the stages of parturition in a bitch or queen?
Stage 1 (6-12 hours- depends on degree of environmental stress).
- puppies orient themselves (craniodorsosacral)
- bitch is restless, displays nesting behaviour, pants, vocalises, shivers and sometimes vomit
- decrease in rectal temp
- concludes with breaking of chorioallantoic membrane
Stage 2 (3-12 hours) [4-42 in queen (avg] 8]
- uterine contractions, abdominal straining, expulsion (within four hours)
- interfoetal interval may vary from five minutes to a few hours
Stage 3
-expulsion of foetal membranes. Greenish colour lochia
Complete uterine involution takes 2-3 months
What are the stages of parturition in a mare?
Stage 1 (1-4 hours)
- restlessness, frequent urination, defecation, sweating, lie down/rolling
- sacroiliac ligaments loosen
- foal positions itself (cranial dorsosacral)
- rupture of chorioallantois at cervical star
Stage 2 (5-20 minutes)
- uterine and abdominal contractions
- expulsion of foal
Stage 3 (within 4 hours)
- rapid breakdown between chorioallantoic membrane and endometrium
- expulsion of foetal membranes (within 30-90 mins)
- retained when not released by 3-6 hours
What are the stages of parturition in a sow?
Stage 1: restless, nesting for about 72 hours, pelvis drops, milk spurts, increased rr
Stage 2: pigs at 12-25 min intervals, farrowing takes 3-5 hours
How long should stage 2 take in a cow?
0.5 to 4 hours
What the rule of thumb for intervening with farrowing?
Manual examination after 45 minutes after pig #7 then give oxytocin
