45 Questions
During oestrus, the female becomes sexually receptive to the male. This is typically preceded by a period of pro-oestrus and/or other clinical signs. What is the classic sign of oestrus in cows?
The female shows interest in the male
When does oestrus occur in most animals?
During the follicular phase
Which hormone drives oestrus by increasing oestradiol concentrations?
Luteinizing hormone
In which species does oestrus occur without being preceded by the luteal phase?
Dogs
In cows and sows, how long does oestrus typically last?
1-2 days
In which species is the length of oestrus increased and often not linked to when she first showed signs of oestrus?
Bitches
When does ovulation typically occur in cows and sows?
At the end or just after the end of oestrus
What is the main goal when timing mating in relation to oestrus?
To ensure successful mating
When does oestrus occur in relation to the oestrous cycle?
At the beginning of the follicular phase
What is the role of oestradiol in driving oestrus?
To promote follicle development
Which hormone is most commonly used for monitoring oestrus and ovulation in animals?
Progesterone
What hormone triggers the LH surge and subsequently ovulation?
Oestradiol
Which hormone is the ideal hormone to measure for predicting optimal chances of pregnancy in humans?
LH
What is the optimal time to mate the female animal?
Shortly before ovulation
What is the period when oocytes are available to be fertilized by sperm in most species?
Immediately after ovulation
What is the period when mating could result in pregnancy?
During oestrus
What is the main clinical tool for monitoring oestrus and ovulation in large animals?
Monitoring ovarian structures by ultrasonography
What is the expected size of an antral follicle in a cow when monitoring oestrus and ovulation?
Between 10-20 mm
What is the expected size of a follicle in a mare when monitoring oestrus and ovulation?
Between 40-50 mm
What does the rise in progesterone in a dog indicate?
Ovulation is imminent
Which of the following is a key indicator that ovulation is imminent in mares?
The follicular wall will thicken
What is the characteristic change in cervix and uterus under progesterone dominance in the mare?
Cervix is hard and narrow, uterus is smaller with increased tone
What is the characteristic change in cervix and uterus under oestrogen dominance in the cow?
Cervix is narrow and tense, uterus is oedematous with increased tone
What is the characteristic change in cervix and uterus under progesterone dominance in the cow?
Cervix is flaccid and soft, uterus is flaccid with reduction in tone
What is the characteristic change in vaginal cytology during late oestrus in dogs?
Majority of cells are large intermediate cells that are anuclear and cornified
What is the purpose of pharmacologically controlling the time of ovulation in cows?
To time mating/artificial insemination accordingly
What is the hormone that directly induces ovulation in cows?
HCG (LH activity)
What is the commonly used method for controlling ovulation in cattle?
OvSynch
What type of cells are largely seen in vaginal cytology during prooestrus in dogs?
Parabasal or small intermediate cells
What is the characteristic change in follicular morphology as ovulation approaches?
It loses its turgidity and becomes more irregular in shape
What are the key indicators that ovulation is imminent in mares?
Follicular shape changes, follicular wall thickens (luteinizes), and uterine tonicity changes throughout the cycle.
What are the characteristic changes in cervix and uterus under oestrogen dominance in the mare?
Cervix is broad and soft, uterus is larger and oedematous.
What are the characteristic changes in cervix and uterus under progesterone dominance in the mare?
Cervix is hard and narrow, uterus is smaller with increased tone.
What are the characteristic changes in cervix and uterus under oestrogen dominance in the cow?
Cervix is narrow and tense, uterus is oedematous with increased tone.
What are the characteristic changes in cervix and uterus under progesterone dominance in the cow?
Cervix is flaccid and soft, uterus is flaccid with reduction in tone.
What are some considerations for the optimal time to mate male animals?
Introduction of a specific (high value) male, controlled mating through artificial insemination, monitoring for oestrus signs, synchronizing ovulation, and optimizing genetics for the offspring.
What is the importance of the pre-ovulatory follicle growth maturation period in female animals?
It maximizes the production of oestradiol and ensures that the egg is fully mature, increasing the chances of fertilization.
When can oocytes be fertilized in most species?
Oocytes can be fertilized immediately after ovulation, typically for a few hours, but in dogs it can be days due to the need for myosis.
What are some clinical tools available for monitoring oestrus and ovulation?
Monitoring hormones like progesterone, oestradiol, GnRH, and LH can provide insights into the timing of oestrus and ovulation.
What are some key indicators of ovulation in large animals?
Monitoring the ovaries through ultrasonography, checking for the presence of an active corpus luteum (CL), and assessing the size of follicles can help determine the timing of ovulation.
Fertility and Breeding time: Oestrus is when the female becomes sexual receptive to the male. Can be preceded by a period of pro-oestrus and/or other clinical signs. What is the classic sign of oestrus in cows?
The classic sign of oestrus in cows is when the female 'stands to be mate by the male'.
When does oestrus occur in dogs?
In dogs, oestrus is not preceded by the luteal phase and occurs after lactational anoestrus.
What is the difference in oestrus and time of ovulation across species?
The timing of oestrus and ovulation varies across species.
Which species have a relatively similar pattern of oestrus and ovulation?
Cows and sows have a relatively similar pattern of oestrus and ovulation.
In which species is the timing of oestrus and ovulation difficult to predict?
In mares and bitches, the timing of oestrus and ovulation is difficult to predict.
Test your knowledge on fertility and breeding time in animals with this quiz! Learn about the concept of oestrus and how it relates to the female becoming sexually receptive to the male. Explore the different clinical signs and behaviors associated with oestrus, and discover how ovulation timing can vary across species. Challenge yourself and become an expert on reproductive cycles in animals!
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