Reproductive Management Practices Used on Large Dairy Herds

Achieving and maintaining a profitable 21-day pregnancy rate is a major challenge on any size dairy operation. There are numerous management practices and strategies available to manage reproduction. By analyzing reproductive management practices used in larger herds information may be obtained to help dairies of all sizes handle the challenge of reproductive management.

In a recent article in the Journal of Dairy Science, Caraviello and coworkers from the University of Wisconsin summarized management practices, especially those related to reproduction, from 103 large dairy herds from across the country (six herds were in Pennsylvania). This information was gathered during 2004.

The average herd size was 613 cows with 76 ± 7 lbs of milk sold /cow/day. The average annual cull rate and calving interval were 34 ± 7 percent and 13.8 ± 0.6 months, respectively. The following tables summarize responses to some of the questions from this comprehensive survey. Much more information was summarized in this survey, however, only the major concepts are presented in this article. Depending on the question, the data are presented as the mean ± SE or the actual number of herds in each category.

 

What are some general conclusions from this information? Most of these herds assigned responsibility for heat detection to employees but for a majority of the herds other tasks were performed during the time periods allotted for heat detection. Marking tailheads with chalk was the primary heat detection aid used. Since the accuracy and efficiency of detection of estrus is a major challenge, a high proportion of the herds utilized estrous synchronization and /or timed AI to improve the submission rate for first insemination and resynchronization of open cows for subsequent inseminations. Approximately 30 percent of the herds used ultrasound as the method for determining pregnancy status. Since this survey was conducted in 2004, it would be interesting to know the current distribution of herds using ultrasound or the blood test for pregnancy (pregnancy specific protein B) for assessing pregnancy status. Eighty-five percent of the herds had their pregnant cows reexamined for pregnancy at 118 ± 6 days following insemination.

Although not listed in the tables above approximately 25 percent of the herd managers noted that the voluntary waiting period (VWP) depended on milk yield, body condition score or other factors. So it is surprising that there was no difference in the VWP between primiparous and multiparous cows. One must be cautious when interpreting survey data. The VWP is not the same as average interval to first service. Most recent research information indicates that when using an estrous synchronization or timed AI program for the initial insemination the days to service should be targeted at 75 days in high producing herds. The problem in many herds struggling with poor reproductive performance is the tremendous variation in days to first service among cows within the herd. The average days to first service may be acceptable but the distribution among cows is problematic. This is a major reason why many herds have implemented synchronization / timed AI programs.

Fifty-six percent of these herds used AI solely and 43 percent used natural service following numerous attempts with AI. It is noteworthy that on average, cows were not moved into the “clean-up” pen until after 6.6 unsuccessful AI services or 232 days postpartum. Approximately 40 percent and 15 percent of the respondents used male or female fertility data when selecting AI sires, respectively. With increased promotion and education regarding reproductive traits now available in sire summaries these percentages will likely increase.

Hoof care, vaccination for BVD, IBR and Leptospirosis and strategies for heat abatement appeared to be high priorities in these herds. Also the authors of this research summary listed the health issues of major concern as mastitis, hairy heel warts and lameness followed by abortions, death loss, Johne's disease and ketosis. Furthermore, they noted these herds were in a constant state of expansion and the practices used to minimize health problems when purchasing animals varied considerably. Visual inspection of animals before purchase (66 herds), vaccination of new cattle before (41 herds) or after purchase (51 herds), increased vaccination of existing herd (24 herds), and quarantine of purchased animals (23 herds) were used most frequently.

It must be noted that this study was not designed to correlate the adoption of management practices to actual herd reproductive performance or profitability. The information from this detailed survey simply summarizes the practices, technology and strategies managers of large commercial herds used in 2004 to address the challenges of managing reproduction. Hopefully some concepts may confirm strategies currently used by some producers or offer new ideas for others.

Michael O'Connor
Dairy and Animal Science Extension