3. 1.Early Embryonic Death
loss of the conceptus which occurs during the first 42
days of pregnancy, which is the period from conception
to completion of differentiation when organ systems
develop.
Frequency And Economic Consequences
Generally accepted that fertilization rate in cattle is about 90%.
Embryonic loss accounts for a 29-39% loss after fertilization.
Most cases are between days 8 to 16 after fertilization (Roche et
al., 1981; Dunne et al., 2000).
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Timing of Embryonic Mortality
Early Embryonic Mortality
Before day 15 post AI
Does not affect the length of the cycle
No signs of abortion are diagnosed
Late Embryonic Mortality
Between 16 and 42 days post AI
The cow returns to oestrus after corpus Luteum regression -
length of the cycle increased
Late embryonic mortality (after day 35-45) may be diagnosable
as in some cases the embryo and the membranes are aborted.
Remnants are frequently resorbed.
Usually the only obvious sign is return to estrous as late as 35-50
days after insemination.
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Causative Factors:
Poor quality of the oocyte (impaired follicular development,
delayed ovulation)
Disrupted and abnormal fertilization
Embryonic chromosomal abnormalities
Unfavorable changes in uterine environment (endometritis,
increased blood urea levels)
Diseases inducing fever
Heat stress
Inadequate progesterone levels:
impaired luteal function (NEB, infectious causes, heat stress)
increased metabolism of progesterone in highly producing dairy
cows
Precocious luteolysis
Direct effect of some infectious agents (BVDV, IBRV etc.)
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How Can You Prevent These Early Losses?
Two possible approaches in the prevention of
these early losses are:
1- GnRH injection
2-Progesterone supplementation before day 6-7
These two approaches leads to 10.3 % improvement in pregnancy
rate.
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Abortion:
Foetal death and expulsion between day 45 and day 265 of
pregnancy.
Its frequency is normal for 1-2% of pregnant cows.
if the % rises to 5% or more it should be investigated
thoroughly.
Causes Of Abortion
Non-infectious causes
- Genetic
- Environmental: temperature
- Nutritional: phytotoxins including mycotoxins
- Iatrogenic: administration of abortifacient
drugs
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Infectious causes
General Infections With High Fever
Specific Infections Such As Brucellosis (3rd trimester),
BVD (125 days of gestation, BVD may cause abortion)
etc.
Prevention Of Abortions.
Proper hygienic and biosecurity measures in the cow's
environment and feed storage
Isolation of aborting cows and immediate removal of
aborted materials
Systematic evaluation of the feed for mycotoxins and
other phytotoxins
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Adequate immunization against infectious diseases causing
abortion
Maintenance of adequate breeding and treatment records to avoid
insemination of pregnant cows and administration of drugs that
may cause abortion to pregnant cows.
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DROPSY OF THE FETAL MEMBRANES AND
FETUS
Obstetrics:
Branch of medicine and Surgery that deals with
Pregnancy, Parturition and Post partum care of young
baby and mother.
Dropsy: Condition and not a disease indicating
underlying clinical malady.
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Accumulation of large quantity of fluid and abdomen
becomes extended, enlarged and barrel shaped.