Cows will start to cycle about 6 weeks after calving when they’ll should show the typical heat signs. The main ones are mounting other cows and standing to be mounted themselves, roaring, and walking around a lot.
If you want to control this activity rather then your cows, you can synchronise their oestrus behaviour. This is done by giving the cows a hormone in a plastic intra-vaginal device with wings on that opens out after insertion in the vagina.
The device releases progesterone which tells the cow she’s pregnant so stops all cycling. The vet may also give her some extra hormone to stimulate ovulation. After about 7-11 days these devices are removed and after a few days the cows will start cycling together. The vet must do all this work. This has effectively synchronised the treated animals to be mated in a group and to calve in a group.
This is a great idea but before you tackle it make sure of a few things:
- That you realise the cost of veterinary treatment and visits.
- That if you are using bulls, that you have enough of them to do all the mating.
- If you are going to use AB, you should have warned the technician that you’ll need extra supplies over a few days.
- Make sure you have good facilities for stock handling and clean areas for the technician’s gear.
- That when it comes to calving, that you can cope with the extra work and that you have a bulk of feed saved up for the cows.