Know your weights, mate

03 June 2016

Critical Mating Weight (CMW) of heifers – what is it and why is this information critical to running an efficient beef breeding business?

According to veterinarian and speaker at next week’s Deniliquin ReproActive event, Dr Nigel McMahon, every breeder should know their herd's CMW and its power to improve fertility and efficiency.

“By recognising at weaning, or shortly after, which heifers are likely to reach their CMW, producers can prioritise feed for heifers that may need supplementary feeding," he said.

"If the season is poor, producers can choose to sell off those younger, lighter heifers unlikely to make CMW, conserving pasture and fodder reserves.”

What you need to know about CMW, according to Nigel:

  • It is the target weight for the start of the six week joining period if you want to guarantee 85% of heifers fall pregnant.
  • CMW occurs when heifers reach approximately 66% of their mature body weight, but this varies from herd to herd and between breeds.
  • Establish CMW by taking the average body weight of a mature cow (for example 500kg) and work out 66% of that weight (330kg).
  • However, the most accurate way to establish CMW is to 'overmate' maiden heifers, weigh them just prior to joining and do the maths after receiving the foetal aging results.
  • Remember CMW is a minimum weight, it shouldn’t be the average of your heifer mob.

For a guide to the weight targets of various frame scores for weaning, joining, pregnancy and calving visit the More Beef from Pastures manual.

The ReproActive one-day workshop, on Thursday 9 June, will also provide information on body condition scoring, weaner management, bull management and joining periods, and reproductive disease awareness and management, presented by speakers including:

  • Rob Inglis, Senior Livestock Production Advisor, Elders
  • Nigel McMahon and Andrew Johnstone, Deniliquin Veterinary Clinic Andrew Hancock, Veterinary Operations Manager – Livestock, Zoetis Australia.

Where: Moroco West Cattleyards/Bullatale Fire Shed, Cnr Lower River Road and Tocumwal-Mathoura Road, Bullatale, NSW.

When: Thursday, June 9, 8.30am - 3pm.

Cost: $40 (ReproActive materials, refreshment and lunch provided).

RSVP: by June 8.

More information: Nigel McMahon E: 

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