Welcome to March!  It has been a fairly mild winter for the Alberta area.  The BTL team are preparing for our on-site spring farm visits so please contact us if you already haven't already, to book your upcoming on-farm or in-clinic flush or implant appointment.  We are looking forward to seeing you!

This edition we focus on selection of recipients, nutrition, health, synchronization, embryo matching and pregnancy detection.  Embryo Transfer is an excellent way to speed up generation interval and increase genetic uniformity in a herd quickly. With the right recipient management, transplanting embryos can become a valuable tool for your herd. 

Wishing you and your family all the best for the upcoming month.

~Andres, Melissa & Lisa

Selecting Recipients

The first step in managing recipients is selecting the right females to receive embryos. Keep in mind that there are multiple areas to manage for successful pregnancy results.

Tips for success include:

• Ideally select recipients that are 3 to 6 years of age and minimum 60 days postpartum. 
• Recipients should exhibit regular estrous cycles prior to synchronization
• Give pre-breeding vaccinations 30 to 45 days prior to embryo transfer (ET) including calves nursing from those recipient cows.
• Avoid large changes in nutrition 30 days prior to and 45 days post ET
• Minimize transportation before and after ET to decrease stress. Try to avoid first time calvers unless they are under exceptional nutritional management and calved in good condition.  First-time calvers are the most difficult animals to get pregnant in most herds due to their requirments of still growing and raising a calf at the same time so they can lose condition relatively easy. 
• Virgin heifers are a good option for recipients as soon as they are well grown and have at least 3 confirmed heats before getting into the recipient program.

Manage Nutrition for Recipients

Recipient nutrition and health management should be planed ahead of time 2-3 months prior start synchronizing cow to receive embryos. The body condition score (BCS) of the recipient female should be assessed at calving to gauge how she will able to maintain her condition during lactation. Beef cows should calve with a BCS of 5.5 on a 9-point scale (1 = very thin to 9 = obese) Moving one point on the BCS scale is approximately 100 pounds of bodyweight. Recipient rations can be designed to increase body condition to meet the breeding season target of 5. If recipient cows are thin—less than 4.5 BCS—this could be an indication of negative energy balance which will likely have an adverse impact on embryo pregnancy rate. 

Strong link between low BCS and...

• Reproductive performance/open cows
• Failure to cycle 
• Failure to conceive
• Calving Interval
• Calf vigor at birth

Dairy programs utilize heifers for most part as a recipients, these heifers work well particularly when they are 14 months of age or better. Milking cows are more challenging to get in calf and increase of number of culls at the time of the implants due to different factors encounter during examinations prior implanting embryos such as cystic ovaries and uterine infections.  

Work with a nutritionist to develop pre-breeding, gestation and postpartum rations that will support maintenance and lactation requirements of recipients. Starting at least 30 days prior to ET, recipient cows should be on a positive plane of nutrition including complete mineral and trace mineral supplementation. If nutrients, vitamins or minerals are limited, you may see reproductive problems, such as increased interval to first estrus and irregular estrous cycles. By setting cows up on an increasing plane of nutrition prior to ET, response to synchronization will improve. Continue proper nutrition through uterine implantation—40 days post transfer—to aid pregnancy success.

For countries that have access to injectable minerals, it is recommended to use these minerals as it has been shown to favor pregnancy rates, particularly in places with questionable management.

Health

Recipient health management is a key pillar to a successful ET program. Before ET, recipients should be 60 days post-partum to allow complete uterine involution and resumption of normal estrous cycles. Pre-breeding vaccines are regularly given to replacement heifers and cows before breeding season to manage reproductive diseases and the negative effect on pregnancy rates. As the vaccine takes effect in the cow, however, reproductive function is suppressed for a period of time. Therefore, best management practice is administration of vaccines at least 30 to 45 days before ET, ultimately yielding better results.

Work with your herd veterinarian to select a vaccine that will cover the reproductive diseases in your area. Put special attention to modified live virus vaccines for BVD and IBR. Some vaccines can cause the vaccinated calves to shed the viruses while nursing, so be careful with what vaccines are getting used and who is getting vaccinated as well.

Avoid any pour-on, either for fly or parasite control within 20 days prior implanting embryos. 

Synchronization of Recipients

Estrus synchronization is commonly used to set up recipient cows for ET. For recipients to receive an embryo, cows should be in heat 7 to 8 days prior to day of ET. Cows can be set up for ET using synchronization protocols like a 7 day CO-Synch + CIDR or 5 day CO-Synch + CIDR. These protocols take 10 to 17 days to implement, therefore recipient programs need to be scheduled in advance to maximize ET on one date. Best results are seen using heat detection in conjunction with the synchronization protocol. All recipients must be palpated or ultrasound scanned for a corpus luteum (CL) before ET. The ET veterinarian approves or passes recipients based on CL quality. On average, 10-15 percent of recipients are passed during implantation. The embryo should be transferred in the uterine horn on the same side as the CL. Producers should minimize recipient handling, calf separation and excess transportation before, during and after implantation to minimize stress.

Although sometimes unpredictable, avoid implanting embryos under extremely hot weather conditions. Some areas with prolonged hot days during the summer months can be detrimental on pregnancy rates.

Match Embryo to Recipient

Matching embryo genetics with suitable recipients drives a successful calving season. Expected progeny differences (EPDs) are a great tool to predict offspring traits from specific mattings and potential calving performance. This is especially important if young females are used as recipients. Place calving ease embryos in younger females and utilize cows to carry larger or less proven genetics. The ideal recipients to utilize in an ET program are those 3 to 6 years of age with calving experience and higher quality colostrum than younger females. Recipient cows carry high quality genetics, so selecting the best females to raise these embryo calves will drive good results. 

Poor quality (low class) cattle are not suitable for recipients, animals that come open in the fall or after having a fair chance to conceive by the bull are not eligible as recipient cows either.

Pregnancy Detection

Pregnancy detection can take place from 45 to 90 days post implantation. Schedule pregnancy check before 100 days of gestation. After this point, veterinarians have more difficulty accurately predicting fetal age due to size and safe access to the fetus. Once pregnancy is confirmed, create calving lists to plan calving dates based on an average 280-day gestation length.

Pay close attention to recipient due date and lactation development. Have a plan to contact a veterinarian if recipients are not showing signs of parturition, which can cause them to go over the due date.