Breeding and Reproduction Flashcards
What starts parturition?
Initiated by the foetus
What are the three stages of parturition?
Initiation of myometrial contractions,
expulsion of the foetus
expulsion of the foetal membranes
Why is there variation in stage 2 of parturition?
Some species cannot separate foetus and membranes- polytocous
Monotocous species can
What are the three Ps of parturition?
Presentation
Posture
Position
What are the different terms and meaning of the terms use to describe presentation of parturition?
Longitudinal- anterior (head first) or posterior (back first)
Transverse- side on
How can you describe posture of parturition?
Dorsal- normal
Ventral- upside down
Lateral- on side
How can posture of parturition be described?
Head, neck, legs either flexed or extended
What is the normal position of parturition in ruminants and horses?
Anterior longitudinal, dorsal, extension of all limbs head and neck
What is the term for a normal birth?
Eutocia
What is the term for a difficult birth?
Dystocia
How is the breech position described with the three Ps?
Posterior longitudinal, dorsal, hindlimb flexed cranially at hips
What are common factors of dystocia?
Age, species, breed, nutrition, BCS, environment, gender, genetics, disease
What are the common causes of foetal dystocia?
Maldisposition
Foeto-maternal disproportion
Foetal monsters
Multiple births- abortion in mares, increased maldisposition in ewes
What are common maternal causes of dystocia?
Skeletal- fracture, dislocation, pelvis size
Soft tissue- excessive fat in vaginal wall
Cervix doesn’t dilate- ringworm in sheep
Uterine torsion- rotation of uterus
Expulsive deficiency- primary uterine inertia (not contracting), secondary uterine inertia (obstructive)
What are the problems with dystocia?
Increased rate of stillbirth and mortality Increased neonatal morbidity Increased dam mortality Reduced productivity of dam Reduced fertility
What should be done after dystocia for dam and neonate?
Stimulus to breathing
Check for another foetus
Check for injuries to repro tract
Pain relief
What is the normal pathway of blood in a foetus?
Placenta through to liver, drains into caudal vena cava into the right atrium of the heart through the foramen ovale into left ventricle, to aorta, to body, drains into umbilical arteries back to placenta
What anatomical changes take place to cardiovascular adaptation to neonate at birth?
Closure or foramen ovale due to LA pressure
Closure or ductus arteriosus botalli
Umbilical vessels- vein collapses, arteries contract
What is the difference between alveoli development in precocial and altricial neonates?
Precocial- most development prepartum
Altricial- most development postpartum
What does surfactant in neonates do?
Prevents alveoli collapse
How is the fluid in foetus lungs removed?
Physical removal- pressure during parturition, absorbed by lymph and blood
What are 4 natural stimuli of respiration?
Hypoxia, Respiratory acidosis, hypercapnia, lower temp, maybe gravity
What are some aids to stimulate respiration in neonateS?
Place into sternal recumbency, resuscitation (extant head and neck pump 4-5x normal breathing rhythm), stimulatory drugs, straw up nose, cold water
How can asphyxia be assed in neonates?
HR- 100 good <50 poor, asses perfusion, asses body tone, colour (anaemic)
What changes occur in the gastrointestinal tract of neonates?
Growth- hormones, neuropeptides, enzymes
Gut flora- takes several weeks
Liver- changes from blood forming to metabolic organ
Meconium- water/amniotic fluid needs to be passed within first 18 hours
Why are immunoglobulins in colostrum so important at birth?
Neonates are gamma-globulinaemic- no immunoglobulins
When does IgA/M first appear in neonates?
Within 4 days
When does IgG1/2 first appear in neonates?
IgG1- week old
IgG2- Month old
When does renal function on a foetus first begin?
2nd half of gestation via urachus
What happens to the renal system in neonates post partum?
Increased GFR
High levels of renin and aldosterone
What neurological changes happen post partum in neonates?
Gain consciousness Spinal reflexes Skin sensation developed Suckling reflex present Papillary light reflex present
What is significant about neonates tendons/ligaments?
Very lax
How do neonates maintain thermoregulation?
Shivering
Ruminants- brown fat
Foal- endogenous glycogen
Why is a foal more tolerant to the cold then other neonates?
Higher metabolic rate
What features indicate prematurity?
Absence of incisors
Tendon laxity
floppy ears
fine and silky coat in precocial species
In cattle what is the definitive sign of oestrus?
Standing to be mounted
What are techniques of detection of oestrus in cattle?
Riding marks- often seen too late Bulling string Tail paint Mount indicator Activity monitor
How can oestrus be monitored in a mare?
Follicle observation- Shape >35mm daily growth (3-5mm) Shape- teardrop <24hours before ovulation, becomes softer <6-12 hours off ovulation Follicle wall thickens 24hr before Oedema
How can oestrus be monitored in a bitch?
Smear from vaginal mucosa-
Anoestrus- paranasal cells (large nucleus)
Pro-oestrus- cornfield cells- shrunk nucleus, triangular shape
Di-oestrus- day after reduces by half
What are reasons for manipulating oestrus?
Poor oestrus detection
Synchronisation
Enable AI and ET
Trigger postpartum resumption
What hormones are commonly used for oestrus manipulation and why?
PGF 2-alpha shortens the luteal phase
Progesterone prolongs the luteal phase
GnRH/Gonadotrophin- recruit and grow follicles/ stimulate ovulation
Progesterone- arrest the oestrus cycle for 9-19 days
What are the common causes of anoestrus?
Lactation- 50 days in beef cow Pregnancy Season Negative energy balance Stress Pathology
How can oestrus synchronisation be achieved for AI dairy cows?
GnRH to synchronise new wave
7 days later PGF 2a for luteolysis
GnRH at day 9 to control ovulation
AI at day 10
How can oestrus synchronisation be achieved in heifers for AI
Give PGF2 2x doses 11 days apart- inseminate 72/96 hours or once at 84 h
Exogenous progesterone remove and give PGF2 causes LH and FSH release to recruit and ovulation (beef cows over 50 days post parturient as well)
How is oestrus synchronisation achieved in sheep?
Progesterone sponge
What is the HPO axis?
Hypothalamus produces GnRH, acts on anterior pituitary FSH/LH acts on ovary, produces inhibin, oestradiol, progesterone, oxytocin, causes PGF release
What is the definition of spermatozoa?
Cells that are capable of fertilisation
What are the three phases of spermatogenesis?
Proliferation, meiosis, differentiation
What are seminiferus tubules?
Tight junctions between Sertoli cells form the sperm testis barrier and divides the basal compartment
Place the following terms in order: spermatids, spermatozoa, spermatogonia, spermatocytes
Spermatogonia
Spermatocytes
Spermatids
Spermatozoa
Where are spermatogonia found and where are the others found?
Spermatogonia- in basal compartments
Others- adlumenal compartment
What does proliferation, meiotic and differentiation start with and finish with?
Proliferation- spermatogonia to spermatocytes
Meiotic- primary spermatocytes to haploid spermatids
Differentiation- spermatids to spherical shaped spermatids
What is the name of the tube which leaves the testes and the name of the duct inside?
Vas deferens
Ductus deferens
What does the sperm-testis barrier separate in the testes?
Basal compartment and adlumenal compartment
What happens during proliferation?
1 spermatogonia divides to become many depending on number of divisions which varies with species
A1- A2- A3- A4- spermatogonia I, spermatogonia B
How is synchronisation of divisions achieved in proliferation?
All cells have intracytoplasmic bridges causing synchronisation
What happens during the meiotic phase?
Starts with spermatocytes
Meiosis causes genetic diversity
Meiosis 1 produces secondary spermatocytes- long time
Meiosis 2 produces spermatids
What is the aim of differentiation phase?
Aims to produce a sophisticated self-propelled package of enzymes and DNA
What is the name for the process of releasing tails into lumen?
Spermiation
How long can the cycle take (range)
4-9 weeks depending on species
How long is a bull, ram and stallions spermatogenesis?
Bull 54 days
Ram 49 days
Stallion 58 days
Describe the structure of the spermatozoa
Head- nucleus and acrosome (contains hydrolytic enzymes)
Tail- self propelled flagellum has middle, principle, terminal piece
Middle has mitochondria
Describe normal endocrine regulation of spermatogenesis?
Hypothalamus produces GnRH
GnRH causes production of LH and FSH
LH acts obnoxious Leydig cells producing testosterone
FSH and testosterone acts on Sertoli cells
Negative feedback from inhibin and testosterone stop production of GnRH/FSH/LH
Where is spermatozoa produced, matures and stored until ejaculation?
Spermatozoa produces in testes
Mature in the head of epididymis
Stored in the tail of the epididymis
How is semen evaluated?
Record volume, colour, appearance
How long does transport of spermatozoa through epididymis take?
1-2 weeks
How is mass motility of semen scored?
1-5, 5 being ‘billowing clouds’ 1 being ‘wave motion
What does the appearance of the sperm show?
Approximate number of sperm
What are spermatozoa sensitive to?
Temperature (cold shock of glassware)
Water
Bright light, blood, cigarette smoke
