Volume 22 • Issue 02 • 2018
The breeding season for the heifers will stretch
over a period of three months (90 days) but the
goal is to get 85% of the heifers pregnant in the
first 42 days of the breeding season
Ensure that there are enough fertile bulls (1:20)
that are free of sexual diseases. Replacement
heifers are ideal candidates for a synchronization
and AI program that could lead to faster genetic
progress and further shortening of the first
breeding season. If synchronization and AI was
not previously used, a uniform group of well-
grown heifers is the perfect opportunity to start
using this technology. The veterinarian will do
a pregnancy diagnosis at the end of the 90 days
breeding season. Only the heifers that became
pregnant in the first 42 days of the breeding
season will be diagnosed as pregnant. Only the
heifers that became pregnant within the first
two oestrum periods (42 days) are selected as
replacement heifers. That is the most important
selection criteria for a fertile breeding herd. There
must be good supervision when heifers calve for
the first time. This is one of the main reasons
why only the heifers that became pregnant in the
first 42 days are selected as replacement heifers.
Good supervision and nutrient management for
heifers from calving until after the second mating
season is the key to success on a beef cattle farm.
First Calving cows are weighed at the beginning
of the second breeding season and should be a
minimum of 85% of the mature cow weight. If
they are underweight, effective supplementation
should be given. The second breeding season lasts
for 3 oestrus cycles or 63 days. The veterinarian
will do pregnancy diagnosis 8 weeks after the
end of the second breeding season. First calf cows
that are now confirmed pregnant for the second
time can now be managed with the mature cows
in the same group.
Five-year plan for optimal fertility and Herd Health
•
•
•
By mainly focusing on the selection and management of replacement beef heifers, farmers can build
a highly fertile herd within 5 years.
Individual heifer groups are managed according to a plan that starts when the heifers are weaned
and lasts until they are confirmed pregnant for the second time by the veterinarian.
This plan is repeated annually for each new group of replacement heifers, until the entire herd is
replaced with the heifers selected and managed for fertility.
Select heifers
that became
pregnant within
the first 42 days
of the breeding
season
YEAR 01
Grouped 4th
Calf Cows
Grouped 3rd
Calf Cows Grouped 3rd
Calf Cows
Grouped 2nd
Calf Cows Grouped 2nd
Calf Cows Grouped 2nd
Calf Cows
Grouped 1st
Calf Cows Grouped 1st
Calf Cows Grouped 1st
Calf Cows Grouped 1st
Calf Cows
Select heifers
that became
pregnant within
the first 42 days
of the breeding
season Select heifers
that became
pregnant within
the first 42 days
of the breeding
season Select heifers
that became
pregnant within
the first 42 days
of the breeding
season Select heifers
that became
pregnant within
the first 42 days
of the breeding
season
YEAR 02
YEAR 03
YEAR 04
YEAR 05
The end goal is a herd where 85% of the cows become pregnant in a breeding season of 63 days with more
than 60% of the cows that will calve in the first 21 days of the calving season
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