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SMALL ANIMAL > 16.8.1: Introduction to repro week and cyclicity in the bitch and queen > Flashcards

16.8.1: Introduction to repro week and cyclicity in the bitch and queen Flashcards

1
Q

The bitch is
* Polyoestrus
* Monoestrus

A

Monoestrus
Oestrus is followed by an anoestrus phase (lasting approx. 7 months)

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2
Q

Which is the main luteotrophic hormone in the bitch?

A

Prolactin
This hormone supports and maintains the function of CL

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3
Q

What happens if you give a prolactin inhibitor to a pregnant bitch?

A
  • Prolactin inhibitor removes support for CL
  • Progesterone falls
  • Abortion occurs
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4
Q

What is it important to establish before giving prolactin inhibitor to a bitch with pseudopregnancy?

A

That the bitch is not pregnant - if she is, prolactin inhibitor will cause abortion.

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5
Q

What is the role of prolactin in the bitch?

A
  • Main luteotrophic hormone
  • From Day 21 progesterone concentrations decline
  • This decline stimulates a rise in prolactin which supports and maintains the CL
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6
Q

Where is progesterone produced during pregnancy in the bitch and why does this matter?

A

Progesterone is only produced in the ovary
* Ovariectomy at any stage of pregnancy will result in pregnancy loss

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7
Q

How can we terminate the luteal phase in the bitch?

A

Repeated administration of a prolactin inhibitor (e.g. cabergoline a.k.a. Galastop) from Day 21 in cycle onwards

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8
Q

Which species are represented with the progesterone graphs here?

A
  • Top - cow - non-seasonal polyoestrus
  • Bottom - dog - monoestrus

Both are non-pregnant

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9
Q

A bitch with mammary gland enlargement is likely to be in which phase of the cycle?

A

Luteal phase

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10
Q

How should you judge if a cell on cytology is big or small?

A

Assess nuclear to cytoplasmic ratio

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11
Q

Key feature of the luteal phase on vaginal cytology

A

Return of neutrophils

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12
Q

1

A

GnRH

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13
Q

2

A

FSH

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14
Q

3

A

LH

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15
Q

Surge in which hormone triggers ovulation?

A

LH

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16
Q

This image shows the oestrus cycle of which species?

A

Dog

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17
Q

What is the inter-oestrus interval in the bitch?
a) 9 months
b) 7 months
c) 6 months
d) 11 months

A

b) 7 months

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18
Q

The bitch is…
a) an induced ovulator
b) an spontaneous ovulator

A

b) an spontaneous ovulator

19
Q

Polyoestrus

A

One oestrus cycle follows the other without a period of anoestrus.
e.g. in the cow
The bitch is monoestrus

20
Q

What does this graph show regarding the progesterone profiles of the pregnant and non-pregnant bitch?

A

The progesterone profiles of the pregnant and non-pregnant bitch are very similar (slightly higher concentration in the pregnant animal)

21
Q

Explain the indicated section of the graph and the change in hormone concentration shown here

A

The spikes in prolactin as associated with lactation

22
Q

What happens if you give a prolactin inhibitor to the pregnant bitch at the time indicated by the star?

A
  • Prolactin is not yet supporting the CL
  • The prolactin inhibitor will not have any effect at this stage
  • If given once prolactin concentrations rise (i.e. later on when prolactin is supporting the CL), the prolactin inhibitor will cause abortion
23
Q

Progesterone is produced by which structures in the bitch and queen?
a) placenta
b) ovary
c) both
d) neither

A

b) ovary only
This means ovariectomy/loss of support for the CL at any stage during pregnancy will result in pregnancy loss.

24
Q

Which hormones would you expect to be elevated in the non-pregnant bitch? What effect would these have?

A
  • Elevated progesterone -> mammary enlargment, potential for milk secretion
  • Elevated prolactin -> milk production, behavioural changes typical of pregnancy
25
Q

This graph shows progesterone concentrations in the non-pregnant animal of which species?

A

Dog

26
Q

Which species?

A

Cow

27
Q

Which species?

A

Ewe

28
Q

Which species?

A

Mare

29
Q

Which species?

A

Bitch

30
Q

Which species?

A

Queen

31
Q

How does season of birth impact the age a female kitten will be when they enter puberty?

A
  • Cats are seasonal long-day breeders
  • A kitten born in spring will come into puberty next spring (12 months old)
  • A kitten born in autumn will come into puberty next spring (6 months old)
32
Q

The queen is…
a) an induced ovulator
b) a spontaneous ovulator

A

a) an induced ovulator
(Occasionally she can also spontaneously ovulate)

33
Q

The queen is an induced ovulator. This means that in the absence of stimulation…

A
  • In the absence of stimulation, ovulation does not occur
  • In the absence of ovulation, there is regression of the follicles
34
Q

What does the blue line on this graph illustrate?

A

LH concentrations from mating must exceed a theshold to induce ovulation in the queen.
* There are individual differences between queens
* There is variation in the magnitude of LH surge on different days of the cycle (greatest response = mid-oestrus)
* Fortunately, there is summation of LH surges when these occur close to each other (frequent matings)

35
Q

What is the typical inter-oestrus interval in the queen?

A
  • 16-21 days
36
Q

True/false: measuring progesterone is a good way to assess whether a queen has ovulated, because if she hasn’t ovulated, the follicle will regress and she will enter the luteal phase.

A

False
If she doesn’t ovulate, the follicle will regress but there is no luteal phase.
Therefore, progesterone will only rise if the queen ovulates.

37
Q

What is the best way to try to ensure ovulation occurs when a queen is mated?

A

Ovulation occurs if:
* There is stimulation of the female (perineal/vaginal)
* Frequent mating occurs within a short period of time (3 matings within 12hrs)
* Matings occur on the second or third day of oestrus

38
Q

Describe the length of the luteal phase in each of these 3 scenarios:
a) the queen is mated by does not ovulate
b) the queen is mated, ovulates, but does not fall pregnant
c) the queen is mated, ovulates, and becomes pregnant

A

a) no ovulation = no luteal phase
b) ovulation but no pregnancy = long luteal phase of approx. 45 days (pseudopregnant)
c) ovulation and pregnancy = luteal phase approx. 68 days

39
Q

In which species are the ovulated occytes immature?

A

Bitch

40
Q

What methods could we use to determine the optimal time to breed a bitch?

A
  • Detecton of ovulation by ultrasound (v hard)
  • Measurement of hormone changes -> look for a rise in progesterone to show approaching ovulation
  • Indirect assessment of hormones: cytology, vaginoscopy, behaviour, vulval swelling
41
Q

When is the optimal day in the cycle to breed a bitch?

A

Very variable = day 5 to day 30
Many breeders say day 10-12

42
Q

In the bitch, the ovulated occyte is less mature than in other species. What relevance does this have for time of mating/fertilisation period?

A

Fertilisation period = 2 days before and 5 days after ovulation

43
Q

Describe how the fertilisation window in dogs affects the apparent pregnancy length

A
  • Late mating = apparent short pregnancy
  • Early mating (at the start of the fertile period) = apparent long pregnancy

SMALL ANIMAL (90 decks)

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