After a heifer calf hits the ground, what are the chances she will survive calfhood, reach the breeding pen, become pregnant and deliver a healthy calf herself? Many variables affect a heifer’s journey from birth to the milking herd.
In the past, dairies often had a surplus of heifers. But as more dairies move to dairy x beef crossbreeding, they often have fewer replacement heifers available. That leaves less room for error when it comes to reproduction. On the flip side, continuous improvements in semen cell sorting technology creates opportunities to generate more and higher-value replacements at maturity with the use of sexed semen.
A deep dive into your herd records may hold insights to help improve heifer reproduction efficiency, ensure adequate replacement numbers and add value to your operation.
Maximize pregnancies to shorten days to conception
Days to conception is a key measurement of reproductive success. With the high cost of feed, an additional five to 10 days can significantly impact a dairy’s bottom line. The following factors influence days to conception and the number of pregnant heifers in your herd:
Conception rate. This is a big driver of reproductive efficiency. Maintaining a high conception rate is a must. Although operations vary, a reasonable goal is at least 50% conception at first service.
Days to first service. To maintain optimal days to conception, strive for 90% or more heifers bred in the first 21 days after entering the breeding pen. If you use DairyComp 305, be sure to accurately assign the date when heifers are moved to the breeding pen. If that information is missing or wrong, your metrics will be misleading. In DairyComp, you can track days to first service by subtracting date of first service from AIDAT.
Reinsemination interval. Because not all heifers will become pregnant in the first service, it is important to strive to reduce reinsemination interval by having an accurate and efficient heat detection program.
Overall, seek to maximize the percentage of heifers pregnant within 100 to 150 days after entering the breeding pen. With good management, at least 90% of heifers should become pregnant in this timeframe.
Role of monitoring technology
Technology continues to develop to improve reproductive efficiency. Whether through ear tags or collars, activity monitoring can improve accuracy of heat detection and improve response to prostaglandin treatments.
In a University of Florida study1, 1,019 Holstein heifers were fitted with activity monitoring collars from SenseHub Dairy®, the monitoring technology from Merck Animal Health. Researchers evaluated the results of administering either ESTRUMATE® (cloprostenol injection) or Lutalyse® (dinoprost tromethamine injection) to induce estrus. Also, the researchers evaluated the response to both active ingredients according to the stage of the estrous cycle, which was determined by occurrence of previous heats detected by the SenseHub Dairy activity monitoring system.
Administering a prostaglandin injection to heifers in late diestrus and proestrus resulted in a higher average conception rate (62.8%) than injections given at early and mid-diestrus (<45%). In addition, among heifers that were in heat seven to 12 days prior to the prostaglandin injection, ESTRUMATE resulted in a greater proportion of heifers in heat than Lutalyse. Previously, researchers have shown that stage of the estrous cycle at prostaglandin treatment will influence the response of the injection. Poor response is expected in heifers that were in heat three to five days prior to a prostaglandin injection. Altogether, findings from this study suggest that targeted administration of prostaglandin may maximize fertility in herds utilizing monitoring technology.
Monitoring technology also can help determine the optimal number of heat events before heifers are eligible for insemination. Conception rates may increase by waiting for the heifer to have a couple of heats before moving her to the breeding pen. Making breeding pen moves based on heifers’ cyclicity status besides age or weight can help overcome space limitations in the pen, too.
When considering monitoring technology as a tool to fine-tune reproductive efficiency, ask for research to back up manufacturer’s claims. Ensure the system is compatible with your existing software and recordkeeping systems. Just like different types of cell phones, different monitoring technologies function differently. Each system has its own algorithms. Make sure the monitoring system generates actionable information – not just data.
Conclusion
Data insights from records and monitoring technology can help identify breeding bottlenecks, uncover areas of opportunity and assist in making decisions to increase efficiency. With the M-Power dairy portfolio from Merck Animal Health, you have every solution available to optimize heifer reproduction and help ensure adequate replacements to keep your herd at peak efficiency.
Important Safety Information
ESTRUMATE: Do not administer ESTRUMATE to a pregnant cow unless abortion is desired. Severe localized post-injection clostridial infections have been reported; in rare instances infection has led to death. Women of childbearing age, asthmatics, and persons with respiratory problems should exercise extreme caution when handling ESTRUMATE. ESTRUMATE is readily absorbed through the skin and can cause abortion and/or bronchospasms; direct contact with the skin should be avoided, and accidental spillage on the skin should be washed off immediately with soap and water. For complete safety information, refer to the product label.
1 Veronese A, Marques O, Moriera R, Belli AL, Bilby TR, Chebel RC. Estrous characteristics and reproductive outcomes of Holstein heifers treated with 2 prostaglandin formulations and detected in estrus by an automated estrous detection or mounting device. J. Dairy Sci. 2019:102(7):6649-6659.
