Using benchmarking data from similarly managed dairy herds can be helpful when developing herd goals for reproductive performance.
By: Kathy Lee, Richard Pursley, Michigan State University Extension
Profitability of dairy herds is dependent on cows beginning a new lactation on a regular interval. When reviewing a herd’s reproductive performance, dairy herd managers and their consultants may wonder how the herd compares to other dairy herds in their state and elsewhere. A comparison to herds that are managed similarly can be referenced when developing performance goals.
The DairyMetrics program, available from Dairy Records Management Services (DRMS), was used to summarize performance data for Michigan dairy herds in the Dairy Herd Information (DHI) system. For Table 1, herds were divided into 3 groups based on rolling herd average for milk (< 23,000 lb, 23,000 - 26,999 lb, and > 27,000 lb). The herds are grouped in Table 2 by herd size (< 200 cows, 200 – 499 cows, and > 500 cows). The items in each table are from the DHI-202 Herd Summary report and include key indicators of overall herd management. Data presented in each table are the averages for each key performance indicator.
Table 1. Averages of Michigan DHI Herds by Rolling Herd Average Milk Levels
Table 2. Averages of Michigan DHI Herds by Herd Size Levels
Pregnancy rate (PR) is an overall indicator for reproductive performance in dairy herds. It is defined as the percentage of eligible cows that become pregnant in a given time period, typically 21-day intervals. Eligible cows are non-pregnant cows in which their days in milk are beyond the voluntary waiting period (VWP). VWPs reported through DHI should be reviewed periodically and updated as needed. When the herd’s actual VWP is longer than the reported VWP, pregnancy rate will be underestimated. The reverse is true when VWP is actually shorter than the reported value. Average days to first service is an indicator of the compliance level to the herd’s voluntary waiting period. A previous article (Monitoring reproductive performance in dairy herds) in Michigan State University Extension News contains more information about the calculation of PR.
Conception rate (%) is a key indicator of level of fertility of the herd. Fertility can be affected by diseases such as bovine viral diarrhea virus (BVDV) and mastitis, in addition to nutritional deficiencies.
Conception rate (%) can be altered in herds with normal fertility by improper heat detection, timing of artificial insemination, and inadequate compliance when using synchronization programs. Fertility programs G6G, Double Ovsynch and Presynch-10 or 11 can be used to enhance fertility in dairy herds that are free from diseases and nutritional problems. Go to the Reproductive Management of Dairy Cattle website to learn more about these fertility programs.
Projected days open is based on current confirmed and projected pregnancies in the herd. To achieve a desired calving interval of 13-13.5 months, the corresponding days open would be 115-130 days.
Dairy herd reproductive performance should be monitored routinely to identify strengths and determine opportunities for improvement. Dairy herd owners and managers should work with their management teams to evaluate reproductive status and set appropriate goals for their herds.