THE collection of weights is critical for the calculation of BreedPlan weight EBVs.

As scale accuracy can deteriorate over time, weigh scales should be regularly calibrated. Additionally, there can be variation between different sets of scales; this can be removed through the calibration process.

This is particularly important in situations where beef producers have multiple sets of scales, such as in different yards on their properties.

It is also common for different scales to be used for birth weight compared to post-birth weights, due to portability and weight range requirements. Regular calibration is required to ensure that all sets of scales give the same reading.

The scale calibration process typically involves the test weighing of multiple known or ‘standard’ weights. The scales are then adjusted until they report the known weights of the standards. Some important points to consider when calibrating scales include:

The use of multiple standard weights. This is required as it is possible for scales to be accurate at a single weight point but inaccurate across a range. The use of multiple standard weights allows for scales to be tested with a single weight (light) or various combinations of multiple weights (heavier). Additionally, multiple smaller weights are easier to move on and off the scales compared to a single large weight.

The use of inert standard weights. Our own body weight changes over time, as does the weight of containers filled with liquid (eg through leaks, evaporation). For this reason, using inert standards such as tractor weights or buckets full of concrete is advised. To obtain a known weight for these inert standards, they should be weighed at a certified weigh scale like those found at your rural supply store for weighing seed and other produce.

The use of the same standard weight across all scales. This ensures that the calibration of all scales used on a property, or from property-to-property, is equal. However, when collecting a particular weight (e.g. 200 day weight), the whole management group/mob should be weighed using the one set of scales.

The re-calibration of scales when moved. The process of transporting scales can affect their accuracy, therefore, scales should be re-calibrated if they have been transported between yards/properties. Birth weight scales are an exception to this; as they are designed to be portable, they do not need to be re-calibrated every time they are moved.

Regularly clean under scales. Scales located in cattle yards are prone to the build-up of mud, hair and other detritus underneath. This can prevent the load bars from compressing and accurately measuring the animal’s weight.

The frequency at which a set of scales should be calibrated will vary depending on how often they are used, and the conditions they are operated under.

More information on recording weights for BreedPlan can be found here.