Animal Reproduction/Theriogenology https://www.youtube.com/channel/UCHzZhYqMy10vsVRZdddEkUg

1. THER-608
Prof. Dr. Nasim Ahmad
Chap. 15
Perpuerium and
Lactation
1

2. • Estrogen is a family of hormones
that triggers the production of
other essential hormones in the
body that are critical during
pregnancy in maturing the lungs,
liver and other tissues and vital
organs of the fetus.
• Estriol is made from the placenta.
It’s produced during pregnancy.
2

3. Puerperium
• The period after parturition when
reproductive tract repairs itself and
returns to its non-pregnant condition
(Uterine involution)
• Become prepared for another pregnancy
• Begins immediately after parturition and
recovery period varies among species
• Short and smooth recovery period is
desirable

4. Events of Puerperium
1. Myometrium contraction and
expulsion of lochia
2. Endometrial repair
3. Cyclcity
4. Elimination of bacterial
contamination

6. Stage 1: Myometrium contraction and expulsion of lochia

7. Stage 2 & 3: Endometrial repair
Resumption of ovarian function
– Necrosis of caruncular
tissues
– Sloughing of the
caruncular tissues
– Reorganization of uterine
endometruim
– First postpartum ovulation

8. • Continuation of uterine contraction
• Rise in Estradiol and increase in
leukocytes
• High degree of phagocytosis
Stage 4: Elimination of bacterial contamination

11. 1. Suckling
2. Nerve impulses
3. OT release
4. OT reach
mammary tissue
5. Myoepith. cells
= target cells
Lactation

13. 13

14. The Mammary Gland: Anatomy

15. Secretory Tissues:
• Glandular; secreting tissue =
– Alveoli:
– Duct system; lined by epithelial cells
– Lobules & lobes; clusters of alveolar tissue
supported by connective tissue
The Mammary Gland
Embryo Origin:
• The mammary gland is a
skin gland

16. 16

17. 17

19. The Mammary Gland
• Exocrine gland; common to all
mammals
• Function: nourish the neonate
- Food source: Myoepithelial cells
synthesize and secrete: fat, protein,
sugar (CHO), vitamins, minerals,
water
- Protection: immunoglobulins

20. • Loosely considered part of the reproductive
system:
Serves a “reproductive function”;
nourishment of the neonate = survival of
species.
• Relies on same endocrine (hormonal)
support for development and function.
Example: gonadal steroids, prolactin, etc.
The Mammary Gland

21. Milk Synthesis
• Milk synthesis is dependent on:
– no. secreting cells
– supply of milk precursor
– milking frequency
•No. secreting cells is dependent on:
– genetics
– endocrine support for mammogenesis

22. Example:
What volume of blood would a 1400 lb. Holstein
pump per day?
Blood Flow (cattle)
Blood Components
1400 lb. Cow ~ .9 liters/ heart stroke
Volume/day = .9 x 70 strokes/min = 63 liters/min
63 liters/min x 1440 min/day = 90,720 liters/day
= ~ 22,600 gal/day
• Volume of blood/ volume of milk synthesized =
(this is an approximation; actual ratio is
affected by stage of lactation, efficiency, etc.)

23. Steroid Hormones and Mammogenesis
• Estrogens:
– follicle, placenta,
synergize with progesterone & prolactin to
stimulate protein synthesis and duct growth
• Progesterone:
– corpus luteum, placenta,
stimulates lobulo-alveolar growth– retards
milk synthesis
• Corticoids:
– adrenal cortex
synthesis stimulated by maternal,
fetal ACTH, enhance PRL receptors
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