Health & Husbandry
Getting started with front-loaded calving.
August 12, 2024
Some projects, like getting a college degree, require a multi-year commitment with multiple milestones along the way. Moving a cow-calf herd to a front-loaded calving season also requires multiple steps, and it may take years to achieve the overall goal.
Completing college results in a degree that hopefully has benefits for years to come. Creating a front-loaded calving season also offers long-term benefits.
What is a front-loaded calving season? It can be defined as a herd that maintains 65% of calvings in the first 21 days of the season with 85%-90% of all cattle born in the first 42 days of the season. Calving early in the calving season within a short window produces a more uniform calf crop with more growing days, thereby increasing weaning weight.
Early calving creates positive herd reproductive momentum. In other words, herds with front-loaded calving this year are more likely to have front-loaded calving next year and the year after.
Front-loading a herd’s calving season is achievable without a large annual increase in expenses. However, if the herd is not front-loaded, specific steps will need to be pursued to transition to the desired calving pattern.
Several successful methods are useful in creating a front-loaded calving season, including
- modifying the calving season;
- using targeted attrition;
- timing the calving of replacement heifers; and
- maintaining second calvers in the herd.
1. Timing
Moving the breeding season to later in the year is a one-time fix, as moving the breeding season every year is not feasible. A movement of two to four weeks later in the year can make a tremendous difference on the percent of cows calving in the first few weeks of the calving season.
If this can be accomplished, more cows will calve earlier, resulting in older heifers at weaning and, thus, a greater chance of breeding to calve before the cow herd.
Considerations for this approach include the ability to change weaning time and implications on the breeding season. The weaning time should be adjusted to match a similar calf age as previously to maintain the same level of production (pounds) sold at weaning.
Be careful to avoid moving breeding season to a more challenging time of year (further into winter for fall calvers or into the heat of summer for spring calvers), as this could affect overall conception rates.
The overall goal of a front-loaded calving season is to gain positive reproductive momentum that leads to improved outcomes in subsequent breeding seasons.<i> [Photo by Shauna Hermel]</i>
2. Attrition
Voluntary culling, or removing breeding animals from the herd that are pregnant and healthy, can only be implemented when overall reproductive success and herd health are doing well. When the goal is increasing front-loaded calving seasons, voluntary culling of cattle bred after the defined calving season can be valuable to gradually shift the herd to front-loaded (culling late-bred cattle and replacing with heifers calving early in the season to maintain static herd size).
This method may require saving more heifers than truly needed to allow increased flexibility in the culling strategy. The average replacement heifer rate is 10%-15% in herds maintaining static size. This means it takes about seven years for the entire herd to turn over. Each new crop of replacement heifers entering the herd makes a big contribution to the overall herd status.
3. Heifers
Long-term front-loaded calving starts with heifer management and generating the herd of the future. Retention of heifers in the herd relies on calving early with their first calf to allow adequate recovery time prior to rebreeding.
Heifers that calve before the cows with their initial calf have a lengthier recovery period and tend to stay in the herd more years than do heifers calving later in their initial calving season. A major contributing factor is that the postpartum interval after having their first calf is prolonged (80-100 days vs. 50-60 days for multiparous cows).
There is really no way to shorten this period in heifers; however, calving the heifers prior to the cow herd allows increased postcalving recovery time. To achieve this goal, the heifers need to be bred before the cows, which often means selecting some of the older calves born at weaning to be replacements.
In front-loaded herds, in which most calves are born early in the calving season, selecting older heifers at weaning is achievable. However, in herds with a uniform or back-loaded calving season, this can be challenging. Herd momentum is key: Herds that are front-loaded have an easier time staying in sync, while back-loaded herds tend to maintain a higher percent with late calving.
One way to change momentum rapidly is to find heifers from outside the herd that are bred to calve 30-40 days prior to the calving season for mature cows.
Procuring replacement heifers from outside the herd may be necessary to increase front-loaded calving. One way to change momentum rapidly is to find heifers from outside the herd that are bred to calve 30-40 days prior to the calving season for mature cows.
This approach offers value as, with the use of reproductive technologies, it may be possible to find a group of heifers all calving prior to the mature cow herd, giving additional time for recovery before the second breeding season. This enhances their ability to recover and maintain breeding early in the calving season long-term.
Bringing animals from outside the herd involves planning, biosecurity and health considerations. Consult your veterinarian on the best health management plan in this scenario.
4. Second-timers
One of the most frequent times for cattle to not become pregnant is in the breeding season following their first calf. Rebreeding is heavily influenced by calving time allowing an appropriate postpartum interval before breeding.
The postpartum interval cannot be significantly decreased; however, inadequate nutrition prior to the first calving can easily increase the amount of recovery time needed after calving.
To avoid increasing the postpartum interval, it may be necessary to manage replacement heifers as an independent group prior to calving to meet their nutritional needs. Replacement heifers are still growing animals and will be close to 80%-85% of mature body weight at the time of first calving. These growing animals may require supplementation prior to their first calving to provide adequate nutrition to support timely rebreeding.
Conclusions
Creating a front-loaded calving season is achievable, but in most herds requires a multi-year commitment to multiple areas. Once a front-loaded calving season is realized, the bulk of the herd calving early will help make maintaining this calving pattern much easier.
The overall goal is to gain positive momentum in the calving season that leads to improved outcomes in subsequent breeding seasons. Management of replacement heifers and second calvers is key to long-term success.
Editor’s note: Author Brad White is on faculty at Kansas State University College of Veterinary Medicine and serves as director of the Beef Cattle Institute (BCI). To learn more on this and other beef herd health topics, tune in to the weekly BCI Cattle Chat and Bovine Science with BCI podcasts available on iTunes, GooglePlay or directly from www.ksubci.org.
Related Content
Current Angus Beef Bulletin
Articles to help you make the most of your investment in Angus genetics.
