The phantom. The nightmare. Empty cows at your final scan that, when you look back through their records, were early mated, had a good heat and never returned to heat. These are phantom cows: cows that have a good early heat, are put up for AI, don’t return to heat, but are not actually in calf. Of the cows mated early, some farms can have phantom rates of up to 20%. Some of these cows will eventually have a very long return to heat, while others end up on the cull list.
Phantom cows will occur in all herds. The key is to find them early, while there is still time to get them back in calf. Cows that have not returned to heat can be scanned 5+ weeks after AI to confirm whether they are genuinely in calf. If they are empty, we can intervene and get them cycling again. Phantom scanning can be done aggressively in weekly batches, or you can scan larger groups later in December.
The principle is simple: the earlier you find a phantom cow, the more opportunities she has to get back in calf.
“I don’t want to pay to scan my cows that often.”
The good news is that once a cow has been scanned pregnant, she does not need to be scanned again until the dry-off scan. The additional scanning is targeted at cows where we have something to gain – particularly cows that were mated early but have not returned to heat.
There are a few important stipulations: it is only worthwhile if we are confident in the diagnosis. Accidentally calling a pregnant cow empty and treating her as a phantom can lead to cows being aborted.
There are two main options: CIDR or prostaglandin (PG).
A CIDR program allows all identified phantom cows to be synchronised and submitted for another mating. It does not rely on the cow naturally returning to heat or on heat detection.
This is particularly useful when there is only a short window between the phantom scan and the end of mating.
Importantly, a CIDR programme also gives us a second opportunity to check the diagnosis. At CIDR removal, the cow can be scanned again to confirm that she is still empty before proceeding with the program.
This provides an extra safety net for situations where a cow may have been incorrectly recorded, a scanning error occurs or where there has been a mistake in the mating records.
PG is a cheaper way of getting cows cycling again, but it has some limitations.
Not every cow will respond to PG with a fertile heat, and the program still relies on good heat detection to identify when she is ready to mate.
PG is less useful when there is a small window between the phantom scan and the end of mating.
For this reason, PG can be a useful option, but it does not provide the same level of control as a CIDR-based program.
Phantom cows are frustrating because they can quietly reduce your early in-calf rate without anyone knowing they are there. The earlier you find them, the more you can do about them.
Phantom scanning turns an empty cow discovered at the final scan into an empty cow discovered while there is still time to get her back in calf.
Talk to your Vetlife team about the right phantom-scanning schedule for your herd.
