Ruminant reproductive physiology

PGF2alpha, GnRH, progesterone, eCG/PMSG, FSH

Hormones used in estrous cycle manipulation

PGF2alpha

Which hormone?:

Natural = dinoprost (Lutalyse)

1. Synthetic analogue = cloprostenol (Estrumate)

eCG/PMSG, FSH

Which hormones are used for small ruminants?

FSH

Which hormone?:

1. Superovulation for embryo transfer

2-3 days

How many days after shortening the luteal phase do cows usually come into estrus?

Sheep

Which species has a 18-day cycle with 3-4 follicular waves?

Goats

Which species has a 21-day cycle with 3-4+ follicular waves?

Progesterone

Which hormone is associated with the CIDR?

2 doses, 7 days apart

How many doses of PGF2alpha should be given to a small ruminant, and how many days apart should they be given?

14 days, 2 days

How long is the CIDR put into the small ruminant when manipulating the cycle in season?

How many days after removal of the CIDR should you expect the animal to come into estrus?

Novel ram/buck at start of season, PGF2alpha, CIDR, traditional CIDR + eCG, short CIDR

Ways to manipulate the estrous cycle in season

PGF2alpha

Which method to manipulate the estrous cycle in season?:

2 doses 7 days apart

CIDR

Which method to manipulate the estrous cycle in season?:

14 days, expect estrus two days after removal

Traditional CIDR + eCG

Which method to manipulate the estrous cycle in season?:

1. CIDR in for 12 days

2. eCG 0-2 days before removal

3. +/- PGF2alpha 0-2 days before removal

4. Breed 48 hours (fresh) to 56 hours (frozen) after CIDR removal

Short CIDR

Which method to manipulate the estrous cycle in season?:

1. eCG + PGF2alpha at day 5; remove CIDR at day 7 (one week earlier than CIDR method)

Photoperiod, CIDR + eCG

Methods to manipulate the estrous cycle out of season

CIDR + eCG

Which method can be used to manipulate the estrous cycle both in and out of season?

14-day protocol, higher end of dose range for eCG

What changes should be made to the protocol when administering CIDR + eCG to manipulate the estrous cycle out of season?

Genetic advancement, disease control (STDs), cost

Reasons to use artificial insemination (AI)

Rapid thaw in 95 F water bath (avoid partial thaw), avoid water, keep it warm, max. 15 minutes from thaw to deposition

Protocol when using frozen semen

15 minutes

What is the maximum number of minutes you should take from thawing the semen to depositing it when doing artificial insemination?

Uterine body

Where is sperm delivered in cows during AI?

Uterine horn

Where is sperm delivered in sheep and goats during AI?

Transit from uterus to oviduct, capacitation, hyperactivation, fertilization

Stages after sperm enters uterus through AI

30 hours

In AI, when does ovulation happen after the onset of estrus?

6-12 hours

The ovum is in prime condition for ___ after ovulation.

24 hours

What is the approximate number of hours that sperm survive?

Sperm

Which survives longer: ovum or sperm?

8-12

Breed ruminants ___ hours after the first signs of heat.