1. Fertility and Infertility

2. There are many factors causing infertility: 1. Anatomical causes.
2. Physiological (Functional) causes.
3. Infectious causes.
4. Managemental causes.

3. Functional cause of infertility:
Anoestrus.
Repeat oestrus cycle.

4. Anoestrus:
It is a period of complete absence of sexual cycles and estrus.

5. Anoestrus: Cattle is normally anoestrus: prepuberty. pregnancy.
Postpartum anoestrus.

6. Anoestrus: There are three types of anoestrus: True anoestrus.
Anoestrus associated with persistent corpus luteum.
Anoestrus associated with cystic ovaries.

7. True anoestrus (inactive ovaries)
in this conditions, there is insufficient pituitary stimulation to cause development of ovarian follicle.
Both ovaries are small and may be some follicle present.

8. The main causes of true anoestrus:
Insufficient energy or bad nutrition.
Production level of milk (postpartum anoestrus in high yielding dairy cows was observed more than in other cows).
Suckling (suckling frequency is the principal inhibitory factor for a return to normal cyclicity).

9. The main causes of true anoestrus:
Any chronic diseases such as internal parasites, John’s disease, chronic peritonitis.
A deficiency of any dietary content such as iron, copper, cobalt manganese, iodine, phosphorus and vit. A.

10. Treatment of true anoestrus:
GnRH.
FSH.

11. Silent heat or suboestrus:
In this condition the genital organs are in normal cyclical functions but the behavioural signs of the estrus are not seen.
This cases are differentiated by rectal palpation, ovary in normal size and presence of developing or mature follicles or corpus luteum.

12. Silent heat or suboestrus:
Repeated examination of the cow increase the possible detection of estrus.
Daily rectal examination of subestrus cows is recommended.
Increase the time of observation is very important to detect these cases or using the bull to detect the cyclic cows.

13. Anoestrus associated with persistent corpus luteum:
In normal estrus cycle, when pregnancy not occur, the corpus luteum regress and begin another cycle.
In some cases the corpus luteum persist and leading to anoestrus.

14. Anoestrus with persistent corpus luteum:
1. Early embryonic death:
In this cases the corpus luteum of pregnancy persist until the embryo is aborted or resorbed.

15. Anoestrus with persistent corpus luteum:
2. Mummification of fetus:
This occurs in cases of fetal death without involution of the corpus luteum and fetal expulsion, followed by autolytic changes, absorption of the fetal fluids. 
In this cases the corpus luteum may persist for many months until natural, therapeutic or surgical evacuation of the uterus.

17. Anoestrus with persistent corpus luteum:
3. Fetal Maceration:
This occurs in cases of fetal death with bacterial infection leading to gradual maceration of the fetus.  
In this cases the corpus luteum persist for many months with chronic mucopurulent vulval discharge.

21. Anoestrus with persistent corpus luteum:
4. Pyometra:
In this cases the cavity of the uterus contain pus and the volume of the pus increased with time.
The corpus luteum persist and causing prolonged the anoestrus.

23. Anoestrus with persistent corpus luteum:
4. Pyometra:
This occurs:
In some cases of embryonic death complicated with uterine infection.
Post partum uterine infection.
Post service uterine infection.

24. Anoestrus associated with cystic ovaries:
Anoestrus in cow sometime associated with a cystic ovary.
By rectal palpation, one ovary is enlarged due to the excessive development of luteal tissue.
Without treatment the cow may be still anoestrus for more than one year.

25. Repeat estrus cycle:
There are two types of repeat estrus cycle:
Regular repeat estrus cycle.
Irregular repeat estrus cycle.

26. Regular repeat estrus cycle
(The repeat breeder cow):
The repeat breeder is one of the most economically important type of infertility in farm animals.

27. Regular repeat estrus cycle
(The repeat breeder cow):
The repeat breeder cow is defined as a normally cyclic cow, with no clinical abnormalities, which has failed to conceive after several (usually three or more) inseminations.

28. Regular repeat estrus cycle
(The repeat breeder cow):
There are two main causes of repeat breeder cows:
Failure of fertilization.
Early embryonic death.

29. (The repeat breeder cow):
1. Failure of fertilization
Infertile bull.
Insemination at the wrong time.
Unefficient inseminator.
Bad or poor semen quality
Delay or an ovulation.
Pathological changes in the bursa or oviduct.

30. (The repeat breeder cow):
2. Early embryonic death
Chromosomal abnormalities or lethal genotypes
Subclinical endometritis.
Insufficient corpus luteum function
Nutritional deficiency.

31. Irregular repeat estrus cycle:
The normal interval between estrus cycle in cows is about 21 days.
In this cases the interval between the cycle become short and irregular.
This case occur due to presence of a follicular cyst on the ovary.