M. bovis and mating decisions

Trudy and Matthew Holmes.

2 October 2018

Are you thinking about changing your mating management this season? Be sure to consider the risks involved and read our recommendations below.

Under the current state of heightened biosecurity in New Zealand, DairyNZ has been hearing that 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 percent.
    • A three-week submission rate of 80 percent or higher.
    • A conception rate of 50 percent or higher.
    • Less than 20 percent short returns.
    • Fewer than 15 percent 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 (e.g. 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.

Other things to consider

If you’re considering a change to your AB system, DairyNZ recommends you speak with your farm advisor, vet, and a farmer who has experience extending AB or who has gone all-AB. This   will help you work out if the cost benefit fits your plan.

If you decide to extend your  AB  programme,  communicate this to everyone involved in making your plan happen: your vet, semen supplier, AB tech, rural professionals and your on-farm team.

If you increase your use of synchrony of heifers and cows, plan ahead to cater for the increase in the number of cows calving 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.

The InCalf book

To learn more about factors affecting a herd’s reproductive performance and management options, check out DairyNZ’s InCalf Book. Levy-paying farmers can download or order the book for free – visit dairynz.co.nz/incalf.

Media inquiries:

Lee Cowan
Senior Engagement & Communications Manager
Phone 021 930 836

Vanessa Feaver
Senior Communications & Media Specialist
Phone 027 836 6295

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