Publish date: 10.18.24
Estrus synchronization is commonly used to manipulate the bovine estrous cycle with exogenous hormones so that females can be bred more closely to one another at the start of the breeding season. We receive many questions regarding estrus synchronization throughout the year. Below you will find the some that are most frequently asked.
How soon after calving can I begin estrus synchronization?
If you’re using an estrus synchronization protocol that requires a CIDR insert, which is recommended when synchronizing females that have calved more recently, you need to wait at least 20 days after calving to insert a CIDR, according to the CIDR label. Nevertheless, the more time you can wait before beginning estrus synchronization, without delaying your breeding season, the better. To be successful, the uterus first needs to undergo involution and return to its original size, and the female needs to begin cycling again.
How do I catch my late-calving cows up to the rest of the herd?
Suppose you are trying to help late-calving cows catch up to the herd. In that case, it is recommended to use an estrus synchronization protocol that utilizes a CIDR insert, as progesterone from a CIDR insert can help kick-start cyclicity in non-cycling females. The likelihood of a cow becoming pregnant to artificial insemination (AI) 30 days after calving is decreased when compared with females that are AI’ed later in their postpartum period.
Nevertheless, late-calving cows that are exposed to an estrus synchronization protocol and fail to conceive to AI are still more likely to become pregnant to the clean-up bull earlier than late-calving cows that are not exposed to estrus synchronization.
Therefore, while pregnancy rates to AI are decreased in late-calving cows, these cows still benefit greatly from being exposed to an estrus synchronization protocol.
What is the best estrus synchronization protocol to use?
The short answer is it depends. A group of bovine reproductive specialists from across the USA, known as the Beef Reproduction Task Force, has published lists of recommended protocols for cows, heifers, and for the use of sexed semen that get updated yearly. Research is required before protocols make it onto those sheets and thus, we recommend using only these established protocols. When considering all estrus synchronization protocols, it is difficult to say that one protocol performs the best, as many factors need to be taken into consideration, and certain aspects affect producers differently.
Here are some questions to ask yourself when deciding which protocol to use.
- Does the number of times through the chute matter most to you?
- Does the cost of the protocol matter?
- Do you tend to plan your protocol last minute so need to use a shorter protocol?
- Are you able to combine heat detection and AI with fixed-time AI?
- Or maybe you don’t mind handling animals a few more times, or how long the protocol takes, if you get the best pregnancy rates possible?
These are all questions that can help determine the ‘best’ synchronization protocol for your herd. Read our blog for more information on estrus synchronization protocols and their individual advantages and disadvantages.
Should I breed my heifers before my cows?
Yes, it is recommended that heifers be bred earlier than the cow herd. By breeding heifers earlier in their first breeding season, they will calve earlier in their first calving season, which is beneficial for many reasons.
As a producer, you can focus your attention on the heifers during calving, and calf losses due to calving difficulties can be minimized. Heifers bred early will also have a greater period between calving and their second breeding season. This will allow heifers more time to properly undergo uterine involution and begin cycling again before the subsequent breeding season, which will increase their chances of conceiving early in their second breeding season.
Are Bos indicus cattle different from Bos taurus cattle in regards to estrus synchronization?
Yes, Bos indicus cattle are different when it comes to estrus synchronization. There are a few physiological differences between cattle subspecies that make synchronization different in Bos indicus females, such as a greater number of follicular waves, a shorter duration of estrus, and greater circulating concentrations of progesterone.
Currently, the recommended protocol for Bos indicus cattle is the Bos indicus PG 5-day + CIDR protocol that requires a CIDR to be inserted for 5 days with an injection of prostaglandin administered at CIDR insertion and CIDR removal. Fixed-time AI is then performed 66 hours later in conjunction with an injection of GnRH.
Are there tools available to help me keep track of my estrus synchronization protocol?
Yes, there are tools available to beef cattle producers that can help keep track of their hormone administration schedule during estrus synchronization. Firstly, estrus synchronization protocol sheets can be found in the back of your ABS Sire Directory or online on the Beef Reproduction Task Force’s website.
Once you have selected your desired estrus synchronization protocol, you can download the Beef Reproduction Task Force’s Estrus Synch Planner. After downloading the Excel file, you can fill in your specific herd information, and a calendar will be generated with specific hormone names and times of administration required. You can also go to estrussynch.com, fill in your herd information, and an estrus synchronization to-do list will be generated. You can also use our Breeding Season Checklist to ensure your herd is set up for success for estrus synchronization.
The most profitable aspect of managing a cowherd for a beef producer is reproduction. Cows who don’t calve every year are just a cost to the business. Furthermore, it has been demonstrated that a shorter calving season improves the longevity of the cowherd and boosts profits since the earlier calving cows produce heavier weaned calves. You can produce a better and more uniform calf crop by using tools and technologies like artificial insemination and synchronization. These are just a few examples of how controlling reproduction impacts the profitability of your business.
As a company that distributes genetic improvement, ABS Global understands that reproductive management and technology are the main means of accomplishing genetic improvement. We hope these frequently asked questions help you with your estrus synchronization protocols. If you have more questions, please contact your ABS Representative or complete the form below.
(608) 846 3721