M. bovis and mating decisions
You’ll need to take into account liveweight, general health and BVD control . . .
Under the current state of heightened biosecurity in New Zealand, DairyNZ has been hearing some farmers are considering extending their use of artificial breeding (AB).
If that’s you, we recommend not adopting an all-AB system and removing all bulls from your mating system unless you meet these standards below.
1. Your repro performance is at national average or higher:
■ A six-week in-calf rate above 65 per cent.
■ A three-week submission rate of 80 per cent or higher.
■ A conception rate of 50 per cent or higher.
■ Less than 20 per cent short returns.
■ Fewer than 15 per cent of cows treated for anoestrous.
2. Your herd is healthy and primed to have a successful mating:
■ Free of bovine viral diarrhoea (BVD).
■ No increase in cow health problems (eg. milk fever and mastitis) through calving.
■ First calvers have reached their target liveweight for calving.
■ No increase in late calvers.
3. You have the skills and staff to carry out prolonged heat detection.
An extended-AB or all-AB system makes accurate heat detection even more critical as the heat detection period increases to 10 to 12 weeks within a very short timeframe. This change will have an impact on feed demand for the following calving season.
If you plan to change the approach with your heifers and use AB instead of bulls, speak to your vet about how to maximise the heifers’ performance. You’ll need to take into account liveweight, general health and BVD control, as well as the practicalities and logistics of synchrony programmes, grazier facilities and technician services.
If you don’t meet all the criteria above, it doesn’t mean you can’t extend your AB period or adopt allAB. However, you’ll need a solid plan in place for how you’re going to mitigate criteria you don’t meet, so you and the herd are set up for a successful mating period.