Calving First Calf Heifers
From "Beef: Questions & Answers" newsletter*
Rick Funston, MSU Extension Beef Specialist, Fort Keogh Range & Livestock
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 mature weight.
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 system.
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 calf
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
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 of breeding.
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
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.
* Beef: Questions &
Answers is a joint project between MSU Extension and the Montana Beef Council.
This column informs producers about current consumer education, promotion and
research projects funded through the $1 per head checkoff. For more information,
contact the Montana Beef Council at (406) 442-5111 or at email@example.com
Feeding a balanced ration the last
trimester of pregnancy will decrease calving difficulty.
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