Infertility & sterility in cows

Question 1

what is good fertiltiy?

Answer 1

e.g. a large numer of fertile inseminated or naturally mated cows could give bith to a live calf with minimum investments and within desired time frame

Question 2

the reality of fertility rates

Answer 2

out of 100% inseminated, 25-50% will result in calving.

influenced by:
fertilisation failure
early embryonic death (largest portion of lost succumb at this point)
late embryonic death
abortion
stillbirth

Question 3

when are cows considered infertile?

Answer 3

if she has not gotten pregnant within 3 months after calving

a heifer is infertile if not pregnant by 18 months old (should be first inseminated around 13-15 months old)

Question 4

infertility is defined as

Answer 4

deviation from normal reproductive cyclicity including economic impact.

Question 5

optimal calving age for heifers

Answer 5

24 months

Question 6

how many times might a cow be inseminated before being deemed hopeless?

Answer 6

typically 4

max 5, depends on the farmer too, somewhat.

Question 7

length of dry period

Answer 7

up to 2 months

(55-60 days)

Question 8

ovarian aplasia

Answer 8

absence of gonads (can be uni or bilateral)

e.g. such as in freemartins but seen otherwise too.

Question 9

ovarian hypoplasia

Answer 9

a condition of incomplete ovarian development, where the affected ovary or part of the ovary completely lacks follicles

Question 10

hermaphroditism in cattle

Answer 10

not common in cows but higher in frequency in goats.

is intersex, repro. organs that could be associated with both male and female sexes.

Question 11

define freemartin

Answer 11

sterile heifer born as a twin to a male calf

essentially a form of intersexuality in the heifer calf due to the influence of testosterone during development.