Ovine and Caprine Reproduction

What species is ovine and caprine reproductive anatomy similar to?

Bovines

When do sheep and goats reach puberty?

6-9 months

Placenta type

Cotyledonary

Type of estrus cycle

• Seasonally polyestrous (some breeds cycle all year)

• “Short daylight breeders” - Cycle summer to fall

Estrus cycle length in ewes

Average 17 days (Range 14-19 days)

Estrus cycle length in does

Average 21 days (Range 18-22 days)

How is estrus stimulated in ewes and does?

Proximity to ram/buck

How can ewes/does be bred out of season?

• Daylight manipulation

• Intervaginal hormone devices

How do intervaginal hormone devices work?

• Vaginal sponge impregnated with progestogen or CIDR with flurogestone acetate

• Left in place for 6-12 days then removed

• Followed by injection of prostaglandins or PMSG to stimulate follicle production

• Will start cycling in approximately 4 days

Signs of heat in ewes

• Restless

• Seek out ram and twitch tail

• Stand to be mounted

• Slight vulvar edema

What are “marker” rams and what are they used for?

• Rams that have been vasectomized or aproned

• Have colored “marker” on chest that transfers on to ewe when mounted

• Shows which ewes are in standing heat

Signs of heat in does

• Seeks buck

• Tail flagging

• Mounting behavior

• Minor vulvar edema

• Bleating

• Decreased appetite

• Decreased milk production

• ± mucoid discharge

Gestation length in ewes/does

150 days

At what age are twins and triplets most common in ewes/does?

From 3-6 years of age

Lactation anestrus in ewes/does

• 5-7 weeks postpartum

• Will cycle 2 weeks after weaning

Reproductive issues

• Hypocalcemia before parturition

• Contagious agalactia

• Dystocia

• Pregnancy toxemia (ewes)

• Pseudopregnancy (does)

Symptoms of hypocalcemia

• Cool extremities

• Weakness

• Failure of cervix to dilate

What causes contagious agalactia?

Mycoplasma infection

What causes dystocia in ewes/does?

• Malpresentation

• Fetopelvic disproportion

Why does pregnancy toxemia occur

Due to inadequate nutrition during gestation

How does pregnancy toxemia occur?

ewe will break down body stores for energy, causing high levels of ketone production that can be fatal

When does pregnancy toxemia most often occur?

• Very cold temperatures

• Pregnancy with multiple fetuses

How does pseudopregnancy present in does?

Hydrometra (uterus fills with fluid)

How is hydrometra treated in does?

Prostaglandins (PGF2 Alpha) to lyse corpus luteum and stop progesterone production