Uterine involution

Question 1

What is uterine involution?

Answer 1

• Reduction in uterine size
• Repair of endometrium
• Expulsion of lochia

Question 2

Describe uterine involution in the cow

Answer 2

• Day 1pp= Cervix closes within 12-12 hours than involutes

- Day 4pp= lochia forming

Question 3

What is the mechanism for uterine involution?

Answer 3

• Myometrial contractions produce peristaltic waves towards the cervix= these cause discharge of fluid/ tissue debris and act to compress vasculature. Stimulated by oxytocin and PGF2a
• Coordinated atrophy of myometrial cell size.

Question 4

What stimulates the myometrial contractions during uterine involution?

Answer 4

-Oxytocin and PGF2a

Question 5

What is lochia?

Answer 5

• Blood tinged discharge containing debris of fetal placenta and endometrium
• Caruncles slough between days 5-10

Question 6

Discuss the repair of the endometrial tissue

Answer 6

• 2 days PP= septal mass with early necrosis
• Days 5-10 PP= sloughing of the necrotic septal mass
• Days 10-15 PP= Mass has sloughed off and vascular stubs formed
• Day 20 PP= smooth surface of endothelium returned
• Whilst this is occurring the myometrial layer is thinning

Question 7

How long does uterine repair take in a cow?

Answer 7

Beef=30 days

Dairy=35-45 days

Question 8

Discuss uterine involution in the mare

Answer 8

• Very raid as is hastened by foal heat
• Small amount of lochia= should stop after 1-2 days
• Endometrium should be normal after 14 days
• Post partum infection with coliforms is very common-> should be eliminated by foal heat.

Question 9

Discuss uterine involution in the bitch

Answer 9

-Has 2 lochia:
1st= immediately after birth, is green in colour, then 2-3 days PP is red/ watery then mucoid
2nd= 4-6 weeks PP
-Endometrium repair is slow= takes approx. 3 months

Question 10

Name 2 opportunistic pathogens that can cause whites

Answer 10

-Trueperella pyogenes and fusobacterium

Question 11

Discuss ovarian rebound in the cow

Answer 11

-Days 5-10PP= Pituitary gland refractoriness to GnRH decreases, FSH wave leads to follicular wave development
-Days 10-20 PP= increased sensitivity to GnRH -> LH secretion as follicles get bigger
Ovulation (silent oestrus)
-Ovarian cyclicity re-initiated with short 1st cycle.