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Calving distribution is the percentage of calves born in each 21-day cycle throughout the calving season. |
As the calving season ends and producers switch gears toward breeding season, there is an opportunity for producers to evaluate their calving distribution and the impact it has on their bottom line. Now is the time for farmers and ranchers to incorporate any changes they want during breeding season, such as when to pull their bulls from pasture, that will affect next year’s calf crop.
Each time a cow is not bred during a 21-day heat cycle, it can cost up to 39 lbs of weaning weight (assuming an average daily gain on calves of 1.85 lbs/day). Having more calves born in the first 21 days of the calving season allows producers to market larger, more uniform groups of calves and increase their profit potential.
The standard industry target is to have at least 60% of females calving within the first cycle, followed by 25% calving between 21-42 days, 10% between 42-63 days and the remaining 5% calving in the fourth and final cycle. An ideal distribution could be 70-20-10 with a condensed breeding season of three cycles (63 days).
How does the industry target compare to actual calving distributions on farms across the country? The 2015/16 Ontario Cow-Calf Production Survey, for example, showed on average 5-10% of all females calved after 63 days or three cycles. The 2013/14 Western Canadian Cow-Calf Survey reported similar numbers with a calving distribution of 55-30-10-5. Recent data on calving distributions in Atlantic Canada is unavailable.
To see what your current calving distribution is, and what the impact on your revenue would be if you move to the industry target of 60-25-10-5, or a condensed breeding season of three cycles (63 days) at 70-20-10, check out the new “Value of Calving Distribution” Tool. As with all decision-making tools, you must consider the balance between any increased revenue with the cost of achieving that outcome.
Heavier weaning weights are the most immediate benefit from more calves born in the first cycle, however having more cows bred early can also affect cow longevity. Research from the Western Beef Development Centre found that over 16 years, from 2001 to 2017, heifers that calved earlier had greater pregnancy rates, remained in the herd longer and produced one more calf in their lifetime than those that calved in the later periods (Daalkhaijav et al 2018). Heifers calving in the first 21-day cycle produced 18.2% and 27.3% more pounds at weaning, generating an additional $773 to $1160 in calf revenues over their lifetime. According to Alberta Agriculture and Forestry it cost $962 per cow wintered in 2016; therefore, a heifer would need to wean five consecutive calves to cover her development costs. In the WBDC study only the heifers the calved in the first 21-day cycle met this threshold (Daalkhaijav et al 2018).
For producers to see an improvement in their calving distribution next year, they need to understand the factors at play in their existing scenario and determine if and how they will adjust their breeding season decisions now.
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References:
Fine-Tune Your Breeding for Extra Money https://www.gov.mb.ca/agriculture/livestock/beef/print,fine-tune-your-breeding-for-extra-money.html
R. A. Cushman, L. K. Kill, R. N. Funston, E. M. Mousel, and G. A. Perry. Heifer calving date positively influences calf weaning weights through six parturitions. J. Anim. Sci. 2013.91:4486–4491. doi:10.2527/jas2013-6465
Daalkhaijav Damiran, Kathy Larson, LeahPearce, Nathan Erickson & H.A.(Bart) Lardner. 2018. Effects of Heifer Calving Date on Longevity and Lifetime Productivity in Western Canada. Sustainable Agriculture Research; Vol. 7, No. 4 https://doi.org/10.5539/sar.v7n4p11
R. N. Funston, J. A. Musgrave, T. L. Meyer, and D. M. Larson. 2012. Effect of calving distribution on beef cattle progeny performance. J. Anim. Sci. 2012.90:5118–5121. doi:10.2527/jas2012-5263
Mousel, E. M., Cushman, R. A., Perry, G. A., & Kill, L. K. (2012). Effect of heifer calving date on longevity and lifetime productivity. Available: http://www.appliedreprostrategies.com/pdfs/2012ARSBC_04MouselProceedings.pdf, accessed May 30, 2019
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Im looing for some national averages in regards to Gestation length. I have 2019 calving dates. What kind of numbers can you offer for me to calculate back for this year. Example being if a Cow calved Feb 20. Whats is the average recovery time until she should start to cycle?
Then what is the average gestation for a Charolais/Limo herd.
Is there any data on Bull calf vs Heifer calf gestation length, We have a smaller heard, and while cows are at home in fenced pasture we are able to record breeding date within the 24 hr window. Looking to maybe make an early calving date and late calving date for some of these cows.
Hi Devin,
Generally speaking gestation length will vary between 279-289 days, so an average of about 283-285 days.
The recovery time after calving before a cow starts cycling again will vary depending on a number of factors. These include body condition (thin cows take longer), if they had any calving difficulty, if they are first calf heifers, or if they lost condition between calving and rebreeding. In an ideal world, it should take between 50-60 days for mature cows to get cycling again. As a rule, first calvers will take at least 15-20 days longer, and sometimes as long as 40 days (we generally expect 80-100 days post-calving before they start cycling again).
Cows carrying bull calves will usually have a slightly longer gestation length, and twins will usually be on the early side.
The Canadian Limousin Association does publish EPDs for gestation length (the Canadian Charolais Association does not). The shortest gestation length in Limo active sires in the database is -8 days, and the longest being +1.1 days, with a breed average of -2.9 days (approximately 283 days).
https://cla.digitalbeef.com/modules/_cattle_evaluation/new_nce_parsing/percentile_ranks_pdf.php
The Canadian Limousin Association also has a calculator that will do the math for you based on an average of 283 days (https://cla.digitalbeef.com, “Calendar Calculator” on the left hand side at the bottom of the page, where you enter the breeding date and it will give you an approximate calving date). From that you can add and subtract a few days on each side to give a calving date range that should be fairly close in most situations.
I think that 1.85 lbs/day is a pretty low ADG to use. I know in our herd even on heifers you could easily figure on 2.20 to 2.50 lb/day
Thanks for your comment. To clarify, the 1.85 lbs/day is assuming the average daily gain of calves from the day of birth until weaning. Daily gains of 2.2 or 2.5 lbs/day would most likely be expected during stages of rapid growth post weaning. However, producers can also adjust the numbers in the calculator to reflect their ADG and see the impact.