Signs of Oestrus and Oestrus Detection Flashcards
Why are cows relatively easy to inseminate?
Since oestrus is short and tightly regulated to time of ovulation, problem is detecting oestrus
How does the ewe differ (compared to the cow)?
Longer oestrus, not a problem if correct ram: ewe ratio is used
How does the sow differ (compared to the cow)?
Longer oestrus meaning detection is very important, usually AI day 2 after the onset of standing oestrus
How does the mare differ (compared to the cow)?
Return to oestrus and oestrus length both highly variable, normal practice is to tease daily and breed throughout this period
How does the bitch differ (compared to the cow)?
Very long oestrus and poorly indicate of time of ovulation, better too use vaginal cytology or plasma progesterone measurement
When does the LH surge occur in the cow?
Mid-oestrus, ovulation occurs 24 hours later and therefore 12 hours after end of oestrus
When should you mate a cow?
Mating occurs 1 day prior to ovulation, uterine insemination normally undertaken 6-12 hours prior to ovulation
What are the common signs of oestrus in a cow?
Standing heat, mounting head, mounting, chin resting, mounted but not standing, sniffing vulva, restless, cajoling, ‘bulling’ string
What clinical assessments can be used to confirm oestrus in a cow?
Low plasma/milk progesterone, detecting of a large follicle in absence of a CL, crystallisation patterns in the vaginal mucus, a fall in body temperature prior to oestrus, a reduction in vaginal pH
What factors inhibit oestrus detection in cows?
Concrete floors, high environmental temperature, overcrowding, recent mixing, stress, lameness
What are the signs of oestrus in ewes?
Restless – seek the ram, stand for the ram, vulva slightly swollen with slight mucoid discharge
What are the signs of oestrus in sows?
Vulval swollen and congested 3 days prior to oestrus, desire to seek the boar, stands for a smelly old boar, stands firmly to be mounted (back pressure test is very reliable)
How can ultrasound be used to detect oestrus in mares?
Demonstration of follicle size, follicle wall thickening & follicle softening
What clinical techniques can be used to assess oestrus in the bitch?
Assessment of vaginal epithelial cells, plasma progesterone concentrations, assessment of vulval softening, examination of the appearance of the vaginal wall
How does ovulation occur in induced ovulators?
Copulation results in a neuro-endocrine response resulting in LH release and then ovulation
