While tail paint is a very effective method of heat detection for cows, it’s less effective for heifers. The number of mounts and the intensity of the heat can often be less with heifers compared to cows.

Also, because heifers are lighter, there is less pressure on the paint making it harder for it to come off during a mount.

For these reasons, alternatives to tail paint are recommended for maiden heifers. There are a number of options including kamars or bubble patches that activate after a mount, or scratch cards that rub off when the heifer is mounted.

While these type of devices are more effective than tail paint, they’re not without their issues. The first one is operator related and is caused by incorrect placement of the device on the heifer.

Heat patch

Kamars should be applied further forward (towards the front of the heifer) than tail paint. Ideally, the top of the Kamar or heat patch should be positioned in line with the heifers pin bones.

Scratch cards should be positioned closer to the back of cow and approximately half way between the pin bones and the hip bones, or roughly where tail paint would normally end.

Importantly, scratch cards should be placed across the back of the heifer with the long part of the card running from left to right. Do not place the card with the long part running from head to tail.

Take time to read all instructions on the device carefully. For scratch cards, many farmers will use spray on glue in addition to any glue that comes on the card. The glue should be tacky before the card or device is applied.

Another issue with devices is that heifers sometimes like to chew and fiddle with them.

Another issue with devices is that heifers sometimes like to chew and fiddle with them. This tends to be more of an issue with Kamars than scratch cards and I often hear of heifers chewing them off.

All of these aids are only an aid to heat detection, you will still need to monitor heifers closely for signs of heat.

And remember, if using sexed semen you should AI 14 to 20 hours after the onset of heat to get good conception rates.

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