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Dr. Katie VanValin: Sometimes We Need To Sweat the
SOME IDEAS ON CONVERTING FROM YEAR-ROUND CALVING TO A CONTROLLED CALVING SEASON
DR. LES ANDERSON, PhD
University of Kentucky
Deciding when to calve your cows often impacts profitability. Most people that know me or have heard me “preach the gospel” of a controlled calving season assume that I believe that one or two short calving seasons is best. But reality dictates that the marketing plan should dictate the calving season. A great example is the current trend in freezer beef. I have worked with several freezer-beef producers who need longer calving seasons to ensure a more consistent supply of finished cattle. Most of the industry however remains small herds (25-30 cows) marketing at a stockyard either at weaning or after a short backgrounding period. Maintaining a controlled breeding and calving season can be one of the most important management tools for these cowcalf producers. A uniform, heavier, and more valuable calf crop is one key reason for keeping the breeding season short. Plus, more efficient cow supplementation and cow herd health programs are products of a short breeding season. However, converting from a year-long breeding season to a shortened 2 to 3 month breeding season should not be done haphazardly. A system for converting from year-round to a 75-day controlled calving season over a period of two years would present less loss and fewer problems than to try to convert in one year. The following steps are suggested for getting on a controlled breeding system: 1. Determine the ideal time of year and the length of your new calving season. For example, cows will calve from March 1st to May 10th (71 days). 2. Pull the bull. You cannot gain control of the calving season with the bull in the pasture with the cows. Either sell him or build a strong bull pen or wellfenced bull pasture. An electric fence
in addition to the regular fence may be needed. 3. Determine the reproductive status of each cow in your herd. First, go to your record book to determine the last date each cow calved. If you don’t keep records, try to match the cows and calves up and estimate their age. For example, let’s assume we have 30 cows. Today’s date is January 18, 2019. Calving dates for 2018 are as follows: Jan = 0 calved,
Feb = 3 calved, Mar = 9 calved, Apr = 5 calved, May = 5 calved, June = 2 calved,
July = 1 calved, Aug = 0 calved, Sept = 2 calved, Oct = 2 calved, Nov = 1 calved,
Dec = 0 calved,. The bull has been in the entire time so the cows that calved last spring are most likely getting ready to calve in Spring 2019 and the five cows that calved in the fall could be pregnant.
Next, work with your veterinarian to determine the pregnancy status of the herd. When will the spring cows calve?
Are the fall-calvers open or pregnant?
The cows that calved in October and
November may not have conceived yet so they can roll easily into your springcalving system. 4. Based upon the reproductive status of your herd, determine if you would like one, controlled calving season or two.
In our example, we only have six cows calving in the fall window (July-Nov) so having two seasons doesn’t really make much sense. If, however, half of your herd calved July-December, it is a better economic decision to make these your fall-calving cows and the ones that calve from January-June your springcalving cows. 5. Plan your breeding season. Let’s assume the cow that calved in November was open when the bull was removed
SPRING-CALVING COW HERD
Continue supplying a high magnesium mineral until daytime temperatures are consistently above 60 degrees F. Improve or maintain body condition (BCS 5) of cows before breeding season starts. If necessary, increase energy intake even on pasture. Bulls should have a breeding soundness evaluation (BSE) well before the breeding season (at least 30 days). Contact your local veterinarian to schedule a BSE for your herd sires. They should also receive their annual booster vaccinations and be dewormed. Schedule spring “turn-out “working in lateApril or early-May; i.e. at the end of calving season and before the start of breeding season. Consult with your veterinarian about vaccines and health products for your herd. “Turn-out” working for the cow herd may include: • Prebreeding vaccinations • Deworming • Replacing lost identification tags • Sort cows into breeding groups, if using more than one bull • Insecticide eartags (best to wait until fly population builds up) “Turn-out” working of calves may include: • Vaccinate for IBR-PI3, Clostridial diseases and Pinkeye • Dehorn, if needed (can be done with electric dehorner and fly repellent during fly season) • Castrate and implant male feeder calves (if not done at birth) • Deworm • Insecticide eartags Consider breeding yearling replacement heifers one heat cycle (about 21 days) earlier than cows for “head-start” calving. Mate to known calving-ease bulls. Record identification of all cows and bulls in each breeding group. Begin breeding cows no later than mid-May, especially if they are on high endophyte fescue. Cows should be in good condition so that conception occurs prior to periods of extreme heat. Consider synchronizing estrus in all cows. Exposing late-calving cows and first-calf heifers to a progestin (MGA feed or CIDR device) for 7 days before bull turn out increases pregnancy rates. Choose best pastures for grazing during the breeding season. Select those with the best stand of clover and the lowest level of the fescue endophyte, if known. Keep these pastures vegetative by grazing or clipping. High quality pastures are important for a successful breeding season. If using artificial insemination: • Use an experienced inseminator. • Make positive identification of cows and semen used. This will permit accurate records on date bred, return to heat, calving date and sire. • Good handling facilities and gentle working of the cows are essential. • Choose AI sires that will meet your goals and resist the temptation to get your cows bigger. Observe breeding pastures often to see if bulls are working. Records cows’ heat dates and then check 18-21 days later, for return to heat.
FALL-CALVING HERD
Pregnancy check the cow herd. Remove open cows at weaning time. Plan marketing program for calves. Consider various options, such as maintaining ownership and backgrounding in a grazing program, or precondition and sell in a CPH-45 feeder calf sale. Initiate fly control for the cows when fly population builds up. Calves may be weaned anytime now but you can take advantage of the spring grass by leaving them on the cow a while or weaning and grazing.
STOCKERS
Keep calves on good pasture and rotate pastures rapidly during periods of lush growth. Manage to keep pastures vegetative for best performance. Provide mineral mix with an ionophore. Implant as needed. Control internal and external parasites
GENERAL
Harvest hay. Work around the weather and cut early before plants become too mature. Harvesting forage early is the key to nutritional quality. Replenish your hay supply! Rotate pastures as needed to keep them vegetative. Clip pastures to prevent seedhead formation on fescue and to control weeds. Seed warm season grasses this month.
the pregnancy status of the herd was determined. She will be rolled to the spring with the cows that will calve from January-July. A decision will need to be made for the August-October calving cows. Do we cull them and replace or do we hold them after they calve this year? Remember, they were pregnant when reproductive status was determined in Step 3 so we have to either cull and replace or wait on them to calve and hold them over until the spring of 2020. Typically, it is a little cheaper to simply hold the cow over because the “cost” of this decision is the loss of 4-6 months of potential revenue ($200400). If the cow is older (8+ years) then consider culling her and replacing with a bred heifer that will calve in
February. The cost difference between a bred replacement heifer and a cull cow is about $500 but that is highly variable. Recently, cull cows have been really cheap so the cost to replace is a bit higher. 6. Expose your herd to the bull on May 20th and remove the bull September 1st in 2019. This is later than ideal but the process to move from year-round calving to controlled calving is at least a two-year process. Sixty days after removing the bulls from the herd (or
at a convenient time near this date), pregnancy check all cows and cull open cows. Your fall-calving cows have likely either calved or are very close to calving. 7. If you are developing your own replacements, consider starting the breeding season of replacement heifers 20 to 30 days ahead of the final breeding date for the herd. Most extended calving seasons are the result of failure of young cows to rebreed in a timely fashion. The additional 20-30 days enhances the opportunity for these young cows to rebreed next season. So, the replacement heifer breeding season would start around April 20th and these females would begin calving around
February 1st. Weather in February is not always ideal calf death loss might increase 1-2%. Financially, 1-2% death loss is easier to swallow than a 25% decrease in pregnancy rate the following year. 8. The second year, follow the same system as outlined about except remove the bull on August 1st. If you have fall and spring calvers, then put the bull in for the fall cows around November 20th and remove him around February 1st.
Remove the problem, not the profits.
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