The Dairy Cattle Reproduction Council (DCRC) annual meeting was held in Indianapolis, Indiana, on Nov. 7 and 8, 2013. The day-and-a-half event was intense with presentations and a sponsors’ trade show, but the outcome was a variety of topics and good discussion among university and industry people of what is new in research regarding improvements in reproductive performance and in overall dairy management.
Topics varied from calving and transition cow management, nutrition, animal health, genomics and synchronization protocols, as well as new heat-monitoring technologies and their interaction with synchronization programs.
Genomics
Dr. Kent Weigel from the University of Wisconsin – Madison talked about genomics on dairy farms, revealing that as of today, 51 percent of A.I. in the Holstein breed and 52 percent in the Jersey breed are made by selecting genotyped bulls that are less than 4 years old.
He also described that with genomic testing, we still cannot perform predictions in crossbred animals, but research is being done to try to make that possible in the future.
He also touched on a recent hot topic occurring on dairy farms where genomic tests are being used to identify higher-genomic females and then further use the information as a tool to manage breeding and culling decisions.
Weigel said that the accuracy to detect top and bottom quartiles of replacement heifers is very good, and if the management decision will be made based on these results, dairymen can be confident in selecting which heifer calves to keep and identifying the bottom 10 or 20 percent to cull.
Strategies can vary from testing the whole herd, testing potentially elite animals for marketing or testing potentially poor-performing animals for culling.
Reproductive efficiency
Dr. Jose Santos from the University of Florida – Gainesville presented the interaction between animal health and reproduction. Based on data from his lab, 45 to 60 percent of dairy cows across different levels of milk production, breeds and management systems develop metabolic and infectious diseases in the first months of lactation.
The appearance of these disorders are related to a decrease in reproductive efficiency because cows that develop at least one health issue are 50 to 63 percent less likely to resume ovarian cyclicity (anovular cows), and they are 25 to 38 percent less likely to become pregnant on the first A.I. breeding after calving when compared to healthy cows.
Cows that present dystocia and endometritis were 55 percent more likely to lose their pregnancy during the first 60 days of gestation than healthy cows. Another important correlation was made between embryo quality and development and postpartum diseases.
Cows that suffered from at least one case of clinical disease had reduced fertilization rates and compromised embryo quality when conceptions were evaluated at day six or day 15 after insemination.
The correlation between postpartum diseases and impaired fertility is clear, and transition cow management and aggressiveness to detect and treat sick animals can help to avoid some of this deleterious relationship.
Estrous synchronization
Dr. Fabio Lima, now at Cornell University, showed data from his latest trials in estrous cycle synchronization of dairy heifers in Florida, along with an economic analysis comparing reproductive programs using timed A.I. and detection of estrus.
So far, the best results were achieved using a modified five-days CIDR synchronization with two prostaglandin F2 α (PGF) injections. The protocol consists of one gonadotropin-releasing hormone (GnRH) injection on day zero, along with a CIDR insertion.
On day five, upon CIDR removal, one PGF injection is administered, and on day six, another PGF injection is given. On day eight, timed A.I. is performed in conjunction with a GnRH injection. With this protocol, pregnancies per A.I. ranged from 55 to 60 percent.
For the simulated economic analysis, results revealed that incorporation of timed A.I. for first service and estrus detection for re-insemination of non-pregnant heifers reduced the cost for reproductive programs.
Activity monitoring systems
Dr. Jeffrey Stevenson from Kansas State University presented another hot topic occurring today in the dairy industry, showing activity monitoring systems in combination with timed A.I. and heat-detection programs.
It is known that accurate prediction of ovulation is the goal for a good estrous-detection program, as this predicted time will drive the time of insemination after an animal is detected in estrus.
In a recently presented study, they determined the timing of ovulation in lactating dairy cows exposed to an accelerometer (measuring timing of increase in activity) and the HeatWatch system (measuring the actual onset of estrus by detecting the first mount received).
The average interval to ovulation differed by 1.5 hours (27.2 hours for HeatWatch versus 25.7 hours for the accelerometer), and based on a 95 percent confidence interval, the time of ovulation after the start of increased activity or the first standing event were consistently precise and overlapped one another.
The future of reproductive management
Dr. William Thatcher from University of Florida – Gainesville had the honor to wrap up the conference, presenting his views of the future of reproductive management.
He made it clear that the future is now, and it is in our hands to transfer all this technology more widely to the dairies. In the face of factors associated with low fertility in dairy herds, producers need to undertake a holistic approach to optimize reproductive efficiency.
He also mentioned extremely important work that has been developed now to formulate a vaccine to prevent uterine infection and also the advantages of using online technologies to precisely integrate a cow’s biological windows to achieve full potential reproductive success.
As it is important to look to the future, he reminded us that some activities we do now are still critical for achieving success on a daily basis.
Identification of pregnancy status by monitoring progesterone levels or pregnancy associated glycoproteins (PAG) in milk or plasma, using ultrasonography, and incorporating new strategies for estrus detection and its interaction with timed A.I. programs are some of the essential activities that are still relevant for a dairy operation, and understanding that these strategies and technologies actually complement each other is the key to taking your dairy operation to the next level and being ready to face the future. PD
Glaucio Lopes
Reproduction Specialist
Accelerated Genetics
