Conversations: July 2010: Pregnancy detection
Early dairy cattle pregnancy detection is critical insight for getting cows bred back timely, keeping them productive and healthy. As producers and their advisors meet in the conference room (or kitchen) to discuss preg-check options, modern technology offers new choices.
By Jeremy Howard
If you know sooner which cows are open, efforts can be made to get them re-serviced earlier in lactation. Modern technologies now offer great pregnancy detection options. Make sure you know the best options, and why they are right for your operation.
1. Why is it important to diagnose pregnancy early?
For most dairy producers, identifying open cows is a critical part of streamlining their herd reproductive program. Once cows have been identified as open, they can be rebred or re-entered into a synchronization program.
Ask your veterinarian to identify the biggest challenges facing your herd’s reproductive program. Ask if earlier pregnancy detection will help address some of those challenges.
2. How will early pregnancy detection help?
A delay in rebreeding will increase the number of days a cow is open, and university experts are beginning to determine the costs associated with higher days open. These expenses include increased breeding costs, a greater risk of culling, higher replacement costs and reduced milk production.
Research from the University of Pennsylvania School of Veterinary Medicine has focused on quantifying a cow’s net present value in a herd, as well as the additional revenue she would be expected to generate if she breeds back and stays in the herd. According to this research, delays in rebreeding are estimated to cost as much as $3 per extra day open.
Dr. Albert De Vries at the University of Florida has taken a similar look at the impact of reproductive efficiency on overall farm profitability. He has determined the cost per extra day open ranges from $3.19-$5.41 per cow, per day over 90 days in milk, with a major factor being the availability of replacement heifers. For herds without replacements available, the costs can be quite high.
Ask your veterinarian to evaluate herd records to determine average days open, benchmarking your average against other herds. Discuss ways that period can be shortened.
3. What options are there for early pregnancy detection?
In the last 10 years, technologies have become available allowing pregnancy detection to be conducted earlier, post breeding. Traditional rectal palpation can be conducted 35-45 days after breeding. Ultrasound and blood-based testing can be used as soon as 28 days after breeding with accurate results. Incorporating either ultrasounding or blood-based testing into an aggressive reproductive program can improve pregnancy rates and percent of herd pregnant by 150 days in milk, of a dairy herd.
Ask your veterinarian to evaluate the average services per conception and the percentage of animals requiring rebreeding. Of those cattle requiring more than one AI service, what is the average service interval?
4. What are the advantages of these options?
Ultrasound is accurate and rapid, and the outcome of the test is known immediately at the time of testing. However, ultrasound equipment is expensive, and requires training and experience to accurately perform pregnancy examinations. If ultrasound equipment is not owned by the producer, it may require more coordination of both personnel and equipment.
Blood-based testing lets breeders check females easily and more accurately, sending samples to a locally certified lab, and receiving results back in as little as 27 hours.
Ask your veterinarian to evaluate current pregnancy detection protocols. Ask your veterinarian to evaluate if staffing, cow handling systems or facilities are better suited for other pregnancy detection options.
5. How does a blood pregnancy test work?
The enzyme-linked immunosorbent assay (ELISA) evaluates the blood (more specifically, the serum or plasma) of a cow for a protein called Pregnancy Specific Protein B (PSPB). PSPB is produced by the placenta, and therefore pregnant animals will have the protein in their blood. The test can be performed as soon as 30 days post-insemination or 25 days after embryo transfer (ET), but cows must be at least 90 days in milk to ensure proteins from the previous pregnancy do not interfere with results.