Collecting 400 Day Weights

Collecting 400 Day WeightsBanner

Live weights taken on animals when the average age of the contemporary group is between 301 and 500 days of age are used to calculate 400 Day Weight EBVs within the TransTasman Angus Cattle Evaluation (TACE).

Recording 400 day weights

All weights should be recorded using appropriate (and accurate) scales. Do not guess/estimate weight or use measuring tapes to calculate weight. Either weigh the animals using appropriate scales or don’t record weights. Weights should be recorded to the nearest kilogram.

When should 400 day weights be collected?

The  400  day  weight  for  an  animal  needs  to  be

recorded when the average age of their contemporary group is between 301 and 500 days of age.

Within this age range, a date should be chosen that fits in with normal, routine management practices and is reasonably close to when the average age of the group of animals is 400 days of age. TACE provides suggested weigh dates to assist you when making this decision.

Animals do not need to be weighed when they are all individually 400 days of age on the day of weighing, but rather the whole contemporary group weighed when the average age of the group is approximately 400 days (i.e. 13 – 14 months).

  • 400 day weights should be collected for all animals in a contemporary group. Only recording 400 day weights for a subset of animals is of no value and can lead to biased 400 Day Weight EBVs.
  • All animals in a contemporary group should be weighed on the same day. TACE will not directly compare the 400 day weights of animals that have been weighed on different days. Similarly, any subsequent performance for animals weighed on different days at 400 days will also be analysed in separate groups (e.g. 600 day weights, ultrasound scanning measurements).
  • 400 day weights should be collected when animals are in as large a group as possible. Consequently, try to collect 400 day weights before any of the animals in a management group are treated differently. For example, before some bulls are joined, or females separated into different groups for joining.
  • There is no requirement to curfew or “empty out” animals prior to weighing for TACE. Care however should be taken to ensure that the weights of some animals are not unduly affected by significant differences in the length of time off feed and water prior to weighing.
  • A management group should be recorded for any animals that have been treated differently or exposed to significant non-genetic influences since weighing at 200 days that may affect their 400 day weight. For example, the 400 day weights of animals given a supplement should be recorded in a different management group to those without a supplement. Consideration should also be given to variations in pasture quality, stocking rates, water quality, animal health, injury etc.
  • TACE can analyse two 400 day weights on each animal. Generally speaking, it is only necessary to record one weight, however in some circumstances, recording more than one weight will improve the accuracy of the 400 Day Weight EBVs. ◊Consideration should be given to also collecting live animal ultrasound scanning and scrotal circumference measurements in association with the collection of 400 day weight information.

  • Angus Australia acknowledges the funds provided by the Australian Government through the Meat & Livestock Australia Donor Company (MDC).  

    This resource was created as a result of a collaboration between Angus Australia and Meat & Livestock Australia Donor Company (MDC) (Project P.PSH.1063).