This power point presentation contains uterine involution in cattle and its probable mechanism.

1. UTERINE INVOLUTION IN CATTLE
Rahul Katiyar
PhD Scholar
Div. Of Animal Reproduction
Roll No.- P-1856

2. Introduction
• Puerperium period is the period after the completion of
parturition, including third stage of labour when the genital
system is returning to its normal non pregnant stage.
• Extension of puerperium may have detrimental effect on
reproductive performance of animal.

3. Normal Postpartum Reproductive
Endocrinology
• The altered ratio of progesterone: estrogen in favor of later, up
regulates the synthesis of uterine prostaglandins (PG) and
labour
(Liggins, 1973; Thorburn, 1991; Challis et al., 2000)
• The PGF2α levels parallel the rate of uterine involution with a
peak at day 4 postpartum and thereafter remain elevated for up
to 20 days.
( Kindhal et al., 1980; Lindel et al., 1982)
• Progesterone levels decline rapidly during the last 48 hours
before parturition and remain at very low levels(< 0.5 ng/ mL)
throughout the early postpartum period.
( Kesler et al., 1977)

4. 4 main areas of
activity
Shrinkage of
tubular genital
tract
Restoration of
endometrium
Resumption of
normal ovarian
function
Elimination of
bacterial
contamination

5. Involution
• Reduction in size of genital tract is called involution.
• Occurs in a decreasing logarithmic scale.
• Reduction is size of myofibrils from 400-750 µm on first day
to less than 200 µm over the next few days.
• Diameter of the previously gravid horn halved by 5th days and
its length halved by 15 days. ( Gier and Marion, 1968)
• Uterus is palpated per rectum by 8 and 10 days postpartum in
primiparae and pluriparae respectively.

6. • Biometry of gravid uterine horn-
( Morrow et al., 1986)
Days Pospartum Diameter of gravid
uterine horn
Between 4-9 days 12-14 cm
By Day 14 7 cm
By day 25 2-4 cm

8. Myometrial contractions are responsible
for reduction in uterine biometry
• Reduction in uterine size and volume is brought about by
myometrial contractions.
Myometrial
contractions
Reduction in
over all size
of uterus
Discharge of
debris
Dischrge of
fluid
Compression
of uterine
vasculature

9. Changes in cervix
• Cervix undergoes atrophy and shrinkage due to elimination of
fluid and reduction in collagen and smooth muscles.
• Involution slower than Uterus
• Complete involution by day 30
Mean external diameter ( cm) Days postpartum
15 2
9-11 10
6-8 30
5-6 60

10. Restoration of endometrium
• During the first 7-10 days after calving there is noticeable loss
of fluid and tissue debris which is referred as ‘secondary
cleansing’ or ‘secundus’.
• Volumes varies greatly from individual to individual.
• Greatest flow of lochia occurs during the first 2-3 days.

12. Endometrial repair
• Necrosis of caruncular tissues
• Sloughing of the caruncular tissues
• Reorganization of uterine endometrium

13. Early necrotic changes in septal mass of caruncle
Constriction of caruncular blood vessels
Sloughing of necrotic material day 5 PP
Small blood vessels protrudes from surface of caruncles
Sloughing is complete by day 15 PP

15. • A systemic response is also observed due to tissue damage and
inflammation.
• Acute phase protein increase rapidly after calving, reaching
peak at 1-3 days before declining to basal levels by 2-4 week. (
Alsemgeest et al., 1993; Sheldon et al., 2001)
• Acute phase proteins limit tissue damage and promote tissue
repair. (Baumann and Gauldie, 1994)

16. Return of ovarian activity (Ovarian
rebound)
• The pitutary is refractory post-partum, immediately post-
calving to GnRH (Lamming et al., 1979).
• Emergence of first follicular wave between days 7-14 post-
partum.
• The first follicular wave can be detected with the first
dominant follicle ≥ 9 mm in diameter being identified at
around 10 days (Savio et. al., 1990).
• One follicle develops increased number of LH receptors and
IGF-1 binding proteases ( Roche, 2006).
• Dominant follicle ovulates in 30-80 % of cows, becomes
atretic in 15-60% of cows; becomes cystic in 1-5% of cows. (
Roche, 2006).

17. • First ovulation occurs at on average at 21 days in dairy cattle. (
Adams, 1999).
• Many of the ovulations of first dominant follicles are not
associated with behavioural signs of estrus. (Moller, 1970;
King et al., 1976; Kyle at al., 1992)

18. Elimination of bacterial contamination
• Very high bacterial contamination rate during first 20-30 days
post-partum, with a subsequent decline, so that, in normal
healthy cows, the uterus should be sterile by 6-8 weeks post-
partum. (Sheldon at al., 2002).
• Main mechanism involved is by phagocytosis by migrating
leucocytes.
• Phagocytes also release TNF-α and interleukins.(Shelson,
2004).

19. Thank You