Mr. David Marrison, Ashtabula County Agriculture & Natural Resources Extension Agent, Ohio State University
In the previous edition of the Buckeye Dairy News, we discussed the need for dairy managers to develop procedures to adequately address heat detection. The failure to detect estrus (heat) in dairy cows can lead to economic loss due to extended calving intervals, additional cost of heat detection aids and semen, and loss of milk production. The first three steps in this approach [ 1) establish a heat detection protocol for your farm. 2) visual heat detection-two eyes are better than none, and 3) develop and maintain cow records] were shared in the previous edition (you can view this article at https://dairy.osu.edu/bdnews/v006iss03.htm). In this month's issue, we will focus on the final three steps.
#4: Minimize herd health problems
Herd health can be a major factor in reproductive failure. Managers should work to maintain a sound nutrition program, an up-to-date vaccination program, and a dry, safe and comfortable environment. Special attention should be given to cows with sore feet as they will not mount or permit other cows to mount. Managers should treat infected or sore feet immediately. Additionally, managers should work with their nutritionist to feed a quality transition ration so feed intake is maximized and postpartum problems are eliminated or minimized during the voluntary waiting period.
#5: Use Heat Detection Aids & Estrus Programs Wisely
A manager's ability to detect heat cycles can be enhanced when visual observations are supplemented with some type of aid. These aids are especially important to help the manager detect standing heats that may have occurred during a time in which no visual observation was conducted. The most important aid is a good record keeping system.
Besides record keeping, the most common heat detection aids being used are the pressure sensitive mount detectors and tail chalking. Additional heat detection aids available include electronic mount detectors, videotape, heat detector animals, pedometers (activity monitors), and vaginal electrical resistance probes.
Heat detection aids should only be used as a supplement to visual observation and management. Research indicates that standing heat identification is incorrect less than 3% of the time, while various other methods are incorrect up to 20% of the time (University of Nebraska). Table 1 shows research conducted by the University of Arkansas with regards to the effectiveness of heat detection aids.
Table 1. Accuracy and efficiency of heat detection aids during continuous observations for cows with more than one mount.
| Items |
Three 30 min Observations per 24 hours
|
Mount Detector
|
Chalk
|
Mount Detectors Plus Chalk
|
| Efficiency of cows in estrus (%) |
60.6
|
93.9
|
93.9
|
93.9
|
| False positives |
0
|
28
|
38
|
3
|
| Accuracy of detection (%) |
100
|
52.5
|
44.9
|
91.7
|
Source: Jodie Pennington, University of Arkansas
Managers may also use progesterone (milk or blood) testing to confirm a suspected heat. Cows with low progesterone levels could be in heat. Milk progesterone should be high 21 days after breeding if the cow is pregnant or at mid-cycle. Dozens of progesterone tests are currently on the market to help farmers confirm early pregnancies or stages of heat cycles.
Managers can also utilize hormonal synchronization programs to induce heat or ovulation. The GnRH, PGF2a, and CIDR® hormonal treatment programs will help increase the probability of detecting estrus or allows for timed inseminations. It is vital that synchronization programs are followed by a good visual heat detection program to catch cows that return to estrus in three weeks.
#6: Develop goals for your breeding program
Just as a producer sets financial and production goals for their operations, they should also establish goals for their breeding programs. Using the worksheet below, managers can obtain reproduction information from their DHIA records or computer records to monitor the herd's reproduction status.
| Goals |
My Farm
|
| Voluntary waiting period (50 to 60 days) | |
| Days in milk at first breeding (60 to 85 days) | |
| Days open (goal of 100 to 115 days) | |
| Calving interval (goal of 12 months) | ___________last ____________next |
| Heat detection (goal of > 65%) | |
| Services per conception (goal of < 2) | |
| Age at first calving (goal of 22-24 months) | |
| Cows bred | ______AI _______natural service _______both |
| Heifers bred | ______AI _______natural service _______both |
Using these data, the manager should develop specific and measurable goals for the upcoming reproductive year. Some of the goals that a manager may consider include:
- Observe 85% of cattle in estrus by 60 days postpartum,
- To breed healthy cows starting at 50 to 60 days postpartum,
- To observe 75% of all heats,
- To maintain a conception rate of more than 40% for all services and greater than 50% for the first service,
- Maintain an average days to first service at 75 to 80 days,
- To maintain 60% of the estrus intervals between 18 and 24 days,
- To maintain an average days open at 100 to 110 days,
- To maintain a services per conception goal of < 2,
- To have an average age at first calving of 22 to 24 months,
- To visually observe cows three times a day for 30 minutes per observation, and
- To take an artificial insemination refresher course.
Final Thoughts
Improving reproduction efficiency on dairy farms takes time and the willingness to examine the current reproduction program. Each dairy farm must design a reproduction program that is suited for their facilities, record keeping management, personnel, and daily schedule. Contact your local County Extension office or your local breed organization for assistance in determining the areas of need for your farm's reproduction program.