Synchronization Contributes to Higher Pregnancy Rates and Heavier Calves at Weaning

Beef cattle on pasture

“The most significant measurement of success in beef herds is pounds of calf weaned per exposed female,” said Richard Linhart, DVM, DACT, Boehringer Ingelheim. “Pounds weaned per exposed female takes all efficiencies within a cow/calf herd into consideration, including reproductive efficiencies, calf death loss, genetics and nutrition.” 

For example, a 700-pound average weaning weight may appear impressive, but if it’s associated with a 70% calf crop, the pounds weaned per exposed female is only 490 pounds. In contrast, a producer who generates a 90% calf crop that only averages 600 pounds will actually produce more total pounds of calf available for sale at the time of weaning (540 pounds weaned per exposed female).1

So, how can producers work to increase the pounds weaned per exposed female in their herd? Whether you use natural service or artificial insemination on your operation, Dr. Linhart describes three ways in which a simple estrous synchronization program can help improve this important number:

  1. Synchronization boosts pregnancy rates and encourages early calving.  
    “It can take the profit of three to five calves to pay for maintaining a cow that’s not pregnant,” explained Dr. Linhart. Implementing a synchronization program can mitigate the risk of culling open cows, as it boosts both estrus detection and pregnancy rates.2 It can also help increase the likelihood that cows continue to calve early and breed back on time down the road.

    An early calving date is especially important for first-calf heifers, as it influences cow longevity and productivity. “If a heifer calves late, it’s very difficult for her to advance that timing for the next calving season,” said Dr. Linhart. “Late calvers don’t have as much time for their reproductive tracts to recover and are less likely to be pregnant at pregnancy check, putting them at an increased risk of being culled.”
     
  2. Earlier calving in the breeding season results in heavier calves at weaning time. 
    Calving early enables producers to wean older, heavier animals. “The number one thing that determines weaning weight is not breed or genetics,” emphasized Dr. Linhart. “It’s when that calf is born.” In fact, it’s estimated that a calf conceived the first day of breeding season will be worth $108 more than one conceived the last.2 Calves born earlier in the calving season also tend to be healthier, as they’re less likely to be exposed to infectious agents that may accumulate later in the calving season.
     
  3. Narrowing the calving window can create a more uniform calf crop.
    Cattle bring the most money when they all look the same at the time they’re sold. For buyers, that means they can streamline how they feed and manage cattle without having to sort out the big ones from the little ones. Narrowing the calving window with synchronization means calves are more likely to be of similar ages and weights at the time of sale, and therefore be of higher value to buyers.
     

Dr. Linhart wants to remind producers that synchronization protocols do not have to be overly complicated. A simple synchronization program can consist of administering prostaglandin to females five days after the initial bull turnout. With one trip through the chute and a very minimal investment, producers can get the bulk of their calves born within the first 20 days of calving season. Synchronization not only contributes to a more uniform calf crop with heavier weaning weights, but can also help consolidate labor and time needed to get cattle bred.

It’s also important to note that while synchronization can contribute to higher pregnancy rates and heavier calves at time of sale, there are several other herd management practices that lay the foundation for reproductive success, including proper nutrition, effective vaccination and parasite-control programs, and consistent breeding-soundness exams. To increase pounds of calves weaned per exposed females in your herd, Dr. Linhart recommends consulting a local veterinarian and nutritionist.

References:

1 Reiling BA. Standardized calculation and interpretation of basic cow herd performance measures. University of Nebraska-Lincoln Extension, “NebGuide.” 2011. Available at: http://extensionpublications.unl.edu/assets/html/g2094/build/g2094.htm#target6. Accessed February 25, 2020.

2 DeJarnette M. Estrus synchronization. A reproductive management tool. Select Sires Bulletin.

 

© 2021 Boehringer Ingelheim Animal Health USA Inc., Duluth, GA. All Rights Reserved. US-BOV-0176-2020-V2