Beef/Cattle Extension Program
Calving First Calf Heifers
Rick Funston, MSU Extension Beef Specialist, Fort Keogh
Range & Livestock Research Station
a balanced ration the last trimester of pregnancy
will decrease calving difficulty."
What is the optimum pre-partum weight and condition
score for first calf heifers?
Many calving problems can be eliminated if heifers
are of adequate size. Their weight at first calving
should be approximately 85 to 90 percent of their expected
Body condition at calving is the single most important
factor controlling when a beef heifer will cycle after
calving. Prepartum body conditionscore correlates with
several factors, such as postpartum interval, services
per conception, calving interval, milk production, weaning
weight, calving difficulty and calf survival. Heifers
should have a body condition of 5-6 at calving through
breeding to assure optimal reproductive performance.
Animals with excess body condition (>7) have lower
reproductive performance and more calving difficulty
than animals in moderate body condition (5-6). Body
condition score is generally a reflection of nutritional
management. However, disease and parasitism can contribute
to lower body condition scores even if apparent nutrient
requirements are met. A sound herd health program
is an essential part of any reproductive management
What special management strategies should I
use for first calf heifers?
Properly developed and managed beef heifers generally
have a 20- to 30-day longer postpartum interval than
older cows. If you breed virgin heifers 20 to 30 days
earlier than the cow herd, the heifers will have additional
time to return to estrus and rebreed with the older
cows the next year.
It is important to manage these heifers separately
for two reasons: Earlier calving will likely mean that
pastures are not available as soon, and you'll need
to supply additional nutrients. Also, nutrient requirements
(% of ration) are higher for first calf heifers than
for mature cows. Breeding heifers early will be of no
benefit if they are not properly managed after calving.
What feed and management plan will assure acceptable
post-partum intervals and lifetime productivity of first
Nutritional demands increase greatly in late gestation
and even more in early lactation. Reproduction has low
priority among partitioning of nutrients and consequently,
heifers in thin body condition often don't rebreed.
The plane of nutrition during the last 50 to 60 days
before calving has a profound effect on postpartum interval.
Positive energy balance postpartum is essential for
prompt rebreeding of heifers that calve in thin condition.
Feeding a balanced ration the last trimester of pregnancy
will decrease calving difficulty. Heifers fed diets
deficient in energy or protein the last trimester not
only experience more calving difficulty, but breed back
later in the breeding season, have increased calf sickness,
death and lower calf weaning weights. Use caution
when feeding excessive amounts of nutrients before or
after calving. Overfeeding protein during the breeding
season and early gestation, particularly if the rumen
receives an inadequate supply of energy, may lead to
decreased fertility. The combination of high levels
of degradable protein and low energy concentrations
in early-season grasses may contribute to lower fertility
rates in females placed on such pastures near the time
What unique management procedures are used
with calves of heifers vs. older cows?
Heifers obviously experience more calving difficulty
than do mature cows, and calves born from a difficult
birth require special attention. Calves born from a
difficult birth have lower heat production, take longer
to stand and nurse, and may have a compromised immune
system, so it is essential that these calves receive
colostrum in a timely manner.
Also, heifers that experience calving difficulty will
take longer to cycle, so it is important to minimize
calving difficulty in your breeding herd. When obstetrical
assistance is needed, the time of intervention also
affects cyclicity. Dams given early assistance have
a reduction in postpartum interval, a higher percentage
in estrus at the beginning of the breeding season, require
fewer services per conception, an increased fall pregnancy
rate and heavier calves at weaning. Therefore, early
assistance, when needed, is important to assure heifers
return to estrus as soon as possible.
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