To help with your next beef cattle synchronization project, GENEX has compiled answers to the most frequently asked questions.
There isn't an easy answer to this question. Research does suggest some protocols perform better than others, but just because research says it's the best protocol doesn't necessarily make it the best protocol for your operation.
Instead, ask yourself these three questions before choosing a synchronization protocol:
» How many times am I willing to put the female through the chute?
» How much am I willing to spend on synchronization drugs?
» What are my expectations for results?
Once you know the answers to these questions you can objectively analyze which synchronization program best fits your operation. No matter what the research or experts tell you, the best protocol for your operation is one that aligns with your goals and one you are 100% confident you can perform perfectly from start to finish.
The answer depends if you are synchronizing heifers or cows.
Criteria for synchronizing heifers:
» Should have achieved at least 65% of mature body weight
» Minimum of 50% should have a reproductive tract score of ≥ 4 at six weeks before breeding
If you don't have a veterinarian in your area that offers reproductive tract scoring, don't panic! You can achieve the same thing by visually observing your heifers for heat in the weeks and months leading up to breeding. You want to observe that at least 50% of heifers are cycling six weeks prior to breeding.
Criteria for synchronizing cows:
» Body Condition Score of ≥ 5 at calving
» An average postpartum interval of ≥ 40 days at the beginning of the protocol
» A minimum of 21 days postpartum at the time of Eazi-Breed™ CIDR® insertion
» Low incidence of calving difficulty
Synchronization drugs should be given in the muscle (IM), with the exception of LUTALYSE® Hi-Con which can be administered IM or subcutaneously. When administering synchronization drugs, it is recommended to use a 1-1/2 inch, 18-gauge needle. You should also wear gloves when handling synchronization drugs to avoid contact with skin.
CIDR® inserts are labeled as a one-time use item by the manufacturer, and it is recommended that you follow this guideline. CIDR® inserts can be one of the most expensive parts of a synchronization protocol (retailing at $10 to $12) and it is tempting to cut that cost in half by using it a second time, however if tempted ask yourself what another A.I. calf is worth. It’s likely a lot more than $5 to $6.
Your pre-breeding vaccination program is an important part of an overall successful A.I. program. However, several studies have shown injection of naïve heifers with a modified live vaccine (MLV) around the time of breeding result in ovarian lesions and decreased pregnancy rates. Therefore, it is recommended that you give all pre-breeding vaccinations at least 30 days prior to breeding.
While there isn't any research that suggests administering dewormer at breeding will have a negative impact on fertility, plan to do that at least 30 days prior to breeding as well. The less stress you put on females around breeding time, the better your success. To achieve optimal results, it's best to do as little as possible to the females during the synchronization and breeding process.
The most critical time for embryonic development occurs between day five (when the embryo begins migrating from the oviduct to the uterus) and day 42 (when the embryo has made definitive attachment to the uterus). Research indicates shipping your cows during this critical time can cause a 10% decrease in pregnancy rates. The best time to move cattle is prior to insemination or days one to four post-breeding. If you can't move them within this time period, it's best to wait until after day 45.
Despite what research might say, no single synchronization protocol fits every operation. Know your operation, follow the suggestions above and trust your gut. And, if you have any questions, don’t hesitate to contact your local GENEX representative.
Many issues can impact an animal’s ability to show heat. If you feel you are not finding cows in heat, it might be time to take a closer look at the issue.
First, you need to determine if the problem exists throughout the entire herd or within a specific subgroup. To do this, analyze your dairy's computer record system. Look at records for reproduction and events that have happened by lactation or lactation group. Once the group in which the problem exists is determined, you will be better able to find possible causes and solutions.
Here are some potential causes to consider:
Slippery floors can be a deterrent to cows exhibiting heat and can also cause injury to animals. Generally concrete is the most common flooring surface in dairy facilities. To make concrete flooring more cow-friendly, one could groove or scabble slippery floors. Caution must be used when using grooving or scabbling floor options, as not to make the surfaces too abrasive on hooves. Another option is to use grooved rubber belting or similar rubber products.
Lameness causes stress on an animal. Lameness also tends to cause animals to lie down and eat less. Obviously, if an animal lies down more, it becomes more difficult to observe signs of heat. And, if an animal eats less, lameness can cause a cow to lose body condition.
A one-point loss in body condition can inhibit an animal's ability to exhibit heat. Keeping the ration adequate to prevent body condition loss is critical. Remember a cow is a mother; she needs enough energy to produce milk (feed her calf) before she will want to reproduce again.
The higher the number of pregnant cows in a pen the lower the amount of estrus that is shown; pregnant cows and cows in mid-cycle are much less likely to mount cows in or near heat. A possible solution for this issue is to maintain a higher percentage of open cows within the breeding group.
The more metabolic problems an animal has when freshening, the greater probability of anestrus. According to research, clinical ketosis, dystocia and retained placentas are associated with more days to first service and a lower conception rate at first service. Overcrowding of transition groups may also lead to more metabolic problems at or after calving.
Some estimates place undetected heats on farms in the USA at 50%. One solution for the issue of failure to properly observe estrus may be to adequately train employees in heat detection technique. In regard to specific timeframes for observing animals for heats, the proper time to observe animals is not while they are eating; instead, for best results, it should be every employee's job to make sure they observe animals at all times and properly identify the animals in heat. If herds are housed in stanchion barns, they need to be turned out daily, to conduct proper heat detection.
It is harder to detect heats during times of extreme high temperatures, and if you are able to catch them in heat, many have a hard time staying pregnant. A solution is to engage in heat abatement strategies, which may include sprinklers, fans, tunnel-ventilated barns, or multiple water sources for cows on pasture.
In conclusion, there are many different factors that could cause you to say, "My cows are not showing heat and conceiving the way they should." To overcome the obstacles, drill down through all layers to find the source of the problem - problems that could relate to the cows not showing heat or people not heat detecting correctly. Several products are also available to aid in heat detection such as Reveal™ Livestock Markers, Allflex® Livestock Intelligence cow monitoring systems, heat detection training and more. Work with your local resources (veterinarian, GENEX representative, etc.) to determine your challenges and the right fix for your operation.
Fourichon, C., H. Seegers, and X. Malher. “Effects of Disease on Reproduction in Dairy Cows.”
Theriogenology 53.9 (2002). 1729-59.Stevenson, Jeffrey S. “The question would be are their cows really not showing heat or are we not heat detecting correctly.” 1997.
Varner, M. A. “Stress and Reproduction.” Dairy Integrated Reproductive Management.
Historically, semen fertility has been evaluated by a trained veterinarian or lab technician who checks the semen with a microscope for percent live sperm cells, motility and morphology. In fact, every collection of semen produced by GENEX is evaluated multiple times in the lab before it's approved for use on your operation.
Lab analysis is very effective in ensuring semen has been properly processed, frozen and handled; however, lab analysis only tells part of the story. Semen from two different bulls may look very similar under the microscope yet perform very differently in cows. A better method is to let the cows tell which bull's semen is most fertile, and that's what PregCheck™ sire fertility rankings do.
Beef PregCheck™ fertility rankings use the fertility model the dairy industry has used for many years, except it is set to a beef base. This means beef sires are compared to other beef sires, not dairy sires. Many variables are statistically accounted for in the model, including technician, herd effect, age of cow, number of previous breedings and many others. This sophisticated evaluation model, along with accurate on-farm data, results in beef bull fertility data that is sound and reliable. Note that PregCheck™ rankings are not an EPD but can be read and utilized like an EPD or performance ratio.
PregCheck is set to a 100-base system, meaning a value of 100 is average. Every one point difference is equivalent to a 1% difference in conception rate. For example, if Bull A has a 104 PregCheck™ ranking and Bull B has a 100 PregCheck™ ranking, Bull A is predicted to be 4% higher in conception rate than Sire B.
PregCheck™ rankings are the result of real breedings which have shown differences between bulls.
Each bull’s ranking has an associated reliability level. Consider if Bull A has the 104 PregCheck™ ranking with 93% reliability and Bull B has the 100 PregCheck™ ranking with a 75% reliability. Bull A can be used with confidence; he routinely performs 4% above the average of his contemporaries for conception rate. At only 75% reliability, there is still some uncertainty in how Bull B will perform until he is bred to more females. However, Bull B is trending average for conception rate.
As more pregnancy data becomes available, reliability increases and the amount of change in the ranking will decrease. For a reliable evaluation, which is about 70%, a bull must have approximately 400 breedings in the database.
The true advantage is the ability to eliminate inferior fertility sires from your breeding program. When utilizing bulls with higher PregCheck™ rankings, you can expect increased conception rates resulting in more A.I. pregnancies and pounds of calf per year.
While all GENEX sires are procured with producer profitability in mind, PregCheck™ fertility rankings offer you another option to improve your bottom line.
The rankings are published in the Beef Genetic Management Guide and on individual bull pages on the website. You can also ask your local GENEX representative for a list of bulls with high PregCheck™ fertility rankings.
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