According to a National Animal Health Monitoring System survey, 84.85% of operations utilize natural service only and 10.3% utilize AI and exposure to bulls. The implementation of estrous synchronization has the potential to shorten your calving window, concentrate labor, allow for more uniform management of cows and create a more uniform calf crop. AI allows producers to advance the genetic merit of their herd, reduce the number of bulls used during the breeding season, increase weaning weights and when combined with estrous synchronization, shorten the calving season.
There are a few things we need to be thinking about to prepare our cows for the breeding season and to have successful AI rates. These management options would include cows being in a positive plane of nutrition, a good yearlong mineral program to meet any deficiencies, cows in 5 to 6 body condition score and taking inventory of your supplies. Furthermore, have conversations with your veterinarian to ensure you have appropriately timed your pre-breeding vaccination program (at least 30 days prior to breeding for successful conception), and it is also a good time to get any synchronization products you may need.
Other things to consider are making sure your working facilities are in good working condition, and that you have accurate records to identify females and record breeding information. In addition, a successful AI program depends on understanding what protocol you are using and following it exactly as it is recommended.
Keep in mind that moving to pasture or transporting cows should be done shortly after breeding (1 to 4 days post AI) or waiting after 35 days. This will help reduce the incidence of early fetal loss, since maternal recognition of pregnancy is established around day 16. When you are transporting or moving a large group of animals, make sure you keep stress, heat and working stress to a minimum.
For those summer calving and breeding herds, it is important to remember that forage may be declining during this critical time.
The goal of estrous synchronization is to bring cows into heat at the same time. If producers decide to use synchronization, understanding how different protocols can fit their operation, goals and facilities will all be important to consider. Perhaps you are wanting to start with a smaller group of animals; synchronization of heifers before the cow herd can be an option to start implementing these reproductive technologies.
Not every producer may know how to AI, so identifying AI technicians or working directly with bull stud/AI companies to help with that process will be important to secure prior to breeding. What supplies do you need to have for AI? Proper equipment and facilities should be used to ensure the safety of the animals and technicians; this includes good working chute(s) and facilities such as a breeding barn, low-stress animal handling, access to warm water, water bath to thaw semen, paper towels, OB sleeves and a person to keep records of cows being bred.
Perhaps you would like to capitalize on having more calves born earlier in the calving season but want to start simple and do not want to deal with the increase in labor, cost and facilities to implement a multiple-day synchronization and AI protocol. A simple, one shot, one time through the chute may be an option, and then use bulls for natural service during the breeding season.
Data from the University of Nebraska reported that heifers born during the first 20 days of the calving season compared to those born later were heavier at weaning, pre-breeding and calving. This, in turn, produced heifers that were more likely to be cycling by the start of the breeding season and more likely to get pregnant. The benefit of conceiving early results in heifers staying in the herd longer, thus increasing profitability.
For an effective breeding season to be successful with synchronization and AI, nutrition, estrous cycle control, female management, proper facilities, labor, and expertise will need to be considered. — Steve Niemeyer, Nebraska Extension educator; and Kacie McCarthy, University of Nebraska-Lincoln cow-calf specialist
