2. Estrous Cycle Comparison Between Species

What are THREE animals that have a 21 day estrus cycle?

-cow

-doe

-ewe

describe the 21 day cycle of a cow, doe, ewe. (hint theyre all the same)

1. Proestrus – Follicle develops and estrogen increases.

2. Estrus (heat) – Cow is receptive to the bull. Ovulation occurs ~10–12 hours after the end of standing heat.

3. Metestrus – Ovulation has occurred and the corpus luteum (CL) forms.

4. Diestrus – CL is fully functional and produces progesterone, which maintains pregnancy if conception occurs

- In what stage in ruminants, does the LH surge happen?

- What is the dominant structure on the ovary during this stage?

- What is the dominant hormone?

-follicular

-follicle

- estrogen

- What other part of the cycle are ruminants in when they are in the luteal phase?

-What is the dominant structure on the ovary during this stage?

- What is the dominant hormone?

-diestrus

- CL

- Progesterone

super rapid fire fun time

oh my god so early

How long is the estrous cycle in the cow?

21 days

How long is the estrous cycle in the doe?

21 days

How long is the estrous cycle in the ewe?

17 days

How long is the estrous cycle in the sow?

21 days

How long is the estrous cycle in the mare?

21 days

How long is the estrous cycle in the camelid?

12 days

How long is the estrous cycle in the queen?

17 days

How long is the estrous cycle in the bitch?

6 months

What is the duration of estrus in a cow? (how long they show signs of heat for)

15 hours

What is the duration of estrus in a doe?

36 hours

What is the duration of estrus in a ewe?

30 hours

What is the duration of estrus in a sow?

50 hours

What is the duration of estrus in a mare?

7 days

What is the duration of estrus in a camelid?

5 days

What is the duration of estrus in a queen?

9 days

What is the duration of estrus in a bitch?

9 days

What is the time (in hours) of the onset of estrus to ovulation in a cow?

24-32 hours

What is the time (in hours) of the onset of estrus to ovulation in a doe?

12-36 hours

What is the time (in hours) of the onset of estrus to ovulation in a ewe?

26 hours

What is the time (in hours) of the onset of estrus to ovulation in a sow?

36-44 hours

What is the time (in days) of the onset of estrus to ovulation in a mare?

5 days

What is the time (in hours) of the onset of estrus to ovulation in a camelid?

induced ov. (trick question)

What is the time (in hours) of the onset of estrus to ovulation in a queen?

induced ov (gotcha again)

What is the time (in hours) of the onset of estrus to ovulation in a bitch?

4- 24 days

What makes the mare's estrous cycle different that the other species?

there is a sustained LH rise (meaning that the LH surge isnt really a surge but that's chill)

Describe the mare's estrous cycle simple

1. Estrus (heat): Lasts about 5–7 days. Mare is receptive to the stallion

2. Ovulation occurs 1–2 days before the end of estrus

3. Diestrus: Lasts about 14–16 days. Corpus luteum (CL) produces progesterone

T/F In diestrus, the mare is not receptive to the stallion

True

What hormone comes in if the mare is NOT pregnant that causes luteolysis, and then cycle starts again?

PGF₂α

The sustained LH surge causes what to happen in the mare compared to other species?

longer behaviroal estrus ( 7 days)

What animal has an estrous cycle where the progression is the same whether they are pregnant or not?

bitch

T/F The bitch cycles 12 times a year

False, 1-2 times (every 6 months)

What hormone in the bitch starts to rise PRIOR to ovulation?

progesterone

The bitch ovulates a _____ oocyte. Why is this important?

- primary

- this is important because she ust undergo another meiotic division. (this means that she is not in her fertile window when she ovulates, you have to wait 2-4 days)

You have a Sasha, a 50 lb pitbull mix, that her owner's are trying to breed her. They call you the minute they notice that she is showing signs of being in heat. They want to come in right away. What do you tell Sasha's owners?

you tell them to come in in about a week because this is not her fertile window.

T/F You should make an appointment to be seen the next day if you see signs of bleeding and swelling

False, wait a week

What hormone rises for about 2 months in the bitch if they are pregnant or not?

progesterone

What test is not reliable to detect pregnancy in a dog?

progesterone (bc it is high weather the bitch is pregnant or not)

What disease are bitches more likely to get because of this consistent rise in progesterone?

pyometria

What do all of these following animals have in common?

- cats

- camelids

-ferrrts

induced ovulators

How can you induce ovulation without a male being present?

provide stimulation and give a dose of GnRH or LJ

T/F In inducted ovulators, estrogen only rises after ovulation

False, progesterone

When can mating only occur if the goal is to get an induced ovulator pregnant?

only happens when they are showing estrus behavior

Describe an induced ovulators estrous cycle SIMPLE

1. Estrus (heat) – Female is receptive to the male. (happens in many waves)

2. Mating → stimulates GnRH → LH release.

3. LH surge → causes ovulation.

4. Corpus luteum (CL) forms → produces progesterone

What happens in induced ovulators if they are bred but do not end up pregnant?

they have a shorter diestrus (40 days instead of 60 days)

T/F If a queen is mated and does not end up pregnant, P4 still rises

True

How long is diestrus in a cat when they are pregnant?

60 days

switching gears to anatomical differences okay? okay

okayyyy

Describe how the ovary is in MOST species. How do they ovulate?

- outer cortex, innder medulla

- ovulate to the outsisde-> oocyte is picked up by the infundibulum

Oh no surprise here the horse just has to be different. Describe how the ovary is in MOST species. How do they ovulate?

- ovary is inside out

- oocyte is ovulated into the ovulation fossa and then picked up by infundibulum

What is a major anatomical difference in mares and camelids? Why is this important?

-oviductal papilla

- opening where the oviduct connects to the uterus but only the fertilized embryo can get out. this is why you can flush a mare if there is a uterine infection

What type of placental attachement occurs when there is presence of caruncles? What animals is this seen in?

- cotyledonary

-ruminants

What type of placental attachment occurs when there are NO presence of caruncles? What animals is this seen in?

-diffuse

- mares

What animal has a fibrocartilagenous cervix making it very prominent and easy to feel?

bovine

What makes a mares cervix different?

it is muscular but the tone depends of the hormonal influence

look at the pictures to compare the anatomical difference bc i cannot add more

okay <3