Lecture 1 Flashcards
List the unique features of a mare ovary
- “inside out”
- Ovulation occurs only from the ovulation fossa
- Follicles can be palpated but no a CL
What cycle does the mare have
Seasonally polyesters
Puberty of mare
14 months
Puberty of stallion
18 months
Average oestrous cycle
21 - 22 days
Average oestrus
7 days
Length of diestrus
14-16 days
Timing of ovulation
1-2 days before the end of oestrus
Ovulatory follicle diameter
35-70mm
How may waves of follicular development per cycle
1-2
When is PGF2a released
13-16 days post ovulation
When is breeding season in the Southern Hemisphere
sep - march
When is breeding season in the northern hemisphere
April - oct
What are the physiological changes associated with seasonality in mares
Increased day length -> Increased GnRH -> increased FSH secretion -> Initiation of follicle development -> follicles secrete little oestrogen -> little LH secretion -> follicles fail to ovulate -> normal follicle develops -> this follicle able to secrete sufficient oestrogen to stimulate an LH surge -> ovulation occurs
What in vernal transition (Autumn or Spring transition)
Transition from anoestrus to undergoing regular oestrous cycles, or transition from undergoing regular cycles to anoestrus
They transition from anoestrus to cycling they often shed in winter
Ventral transition: when do follicles not ovulate
During the transitional period
What are the signs used to stage the oestrous cycle
- Behaviour
- Characteristics of the cervix
- Characteristics of the ovary
- Characteristics of the uterus
What is the teasing score
Should be recorded during the breeding season to assist with breeding management
Number the teasing scores and their meaning
0 - non-receptivity (ears back, kicks at stallion, moves away)
1 - mare is passive (no signs of oestrus but doesn’t kick, common in winter anoestrus
2- mare stands, but may be restless; winks without urinating
3 - mare stands, lifts tail, shows interest in stallion, winks and immediately passes small amount of urine
4 - as for 3, but mare also squats and urinates in continuous stream
What does the cervix feel like in dieostrus
Firm, tubular
What does the cervix feel like in oestrus
Progressively softer
What does the cervix feel like close to ovulation
Soft, wide or barely palpable close to ovulation
Score 1 of the cervix
High, dry, tight (dioestrus)
Score 2 of the cervix
Drooping ( early oestrus)
Score 3 of the cervix
Hanging - dorsal and ventral surfaces soft and extend towards vagina, dorsal surge not fully flat or in contact with vagina
Score 4 of the cervix
Lying - dorsal and ventral surfaces of cervix tent to lie flat on the floor of the vagina
What size are the ovaries
> 35mm
How to detect a soft follicle
by palpation and associated with flattening of wall of follicle with apposition of ultrasound probe
What is the uterus tone in oestrus
More flaccid, oedematous
what is the uterus tone in dioestrus
Increased in tone and feels more tubular
What is the uterus echogenicity in oestrus
Presence of oedema
What is the uterus echogenicity in dioestrus
Uniform echogenicity
What is the oedema score
0 - none
1 - slight. small amount of oedema detectable
2 - moderate oedema throughout the uterus
3 - Heavy. Obvious oedema through the uterus - may indicate heavy uterine infection
