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While most stud producers are reasonably comfortable with how to record the live weights of their animals, there are some important points to mention to maximise the effectiveness of the live weights that are recorded.

• Record weights to the nearest kilogram.
• Breeders should choose weighing dates that fit in with their management and are also reasonably close to when the average age of the group of calves is about 200, 400 or 600 days old (depending on the respective weight being taken). IGS provides suggested weigh dates to help you make this decision.
• Don’t submit weights for heifers that are more than three to four months pregnant at weighing, unless they’re at a similar stage of pregnancy and have been pregnancy tested. This is particularly relevant when submitting 600 day weights for heifers that are being calved down at two years of age.
• IGS can analyse up to two weights in each age range (ie. 2 x 200-day weights, 2 x 400-day weights and 2 x 600-day weights). Generally, it is only necessary to record one weight in each age range, but in some circumstances recording more than one weight in each age range will improve the accuracy of the Growth EBVs.
• A management group should be entered for any calf or group of calves that have either been treated differently or exposed to significant non-genetic influences since the previous weighing. For example, calves given a supplement should be recorded in a different group to those without a supplement. Consideration should also be given to variations in pasture quality, stocking rates, water quality etc. Note that blank is a unique management group.
• To ensure the maximum number of calves are analysed in the same management group, try to weigh all the animals from one management group on the same day. IGS will automatically split your management groups if you weigh on different days.
• Ideally, calves should be weighed when they are in as large a group as possible. Try to weigh calves before any of the calves in the management group are treated differently. For example, weigh before you castrate some of your bull calves or before the show team is separated out from the rest of the group.

Mature Cow Weight EBVs are calculated from the live weight performance of mature cows. IGS will only analyse the weight of a mature cow if the cow has a calf with a weight recorded within two weeks of when the mature weight was taken and the calf was between 80 – 330 days of age when it was weighed.

In short, the mature weight for a cow needs to be recorded at the same time as the 200-day weight is taken for its calf. Breeders looking to optimise the effectiveness of the mature cow weights that are recorded should also consider the following:

• Weights should be recorded to the nearest kilogram.
• As with all weights, mature cow weight should be recorded using appropriate (and accurate) scales. Don’t guess or estimate weight or use measuring tapes to calculate weight. Either weigh the cows using appropriate scales or don’t record weights.
• IGS can analyse up to four mature weights for each cow. So all cows with a calf at 200 days should be weighed each year. It isn’t a good idea to guess whether a cow has had four weights taken previously – the IGS analysis will sort it out for you.
• For temperate breeds, IGS will only analyse a mature cow weight if the cow is older than 2.4 years of age (870 days) at weighing. For tropical breeds, this age is 3.0 years (1090 days).
• IGS will only analyse the mature cow weight performance of a cow if her first valid mature cow weight has been taken before she is 6 years of age (2200 days). If not, then none of her mature weights will be analysed.
• It is essential that correct management group information is recorded with mature cow weight performance. Management groups work slightly differently for mature cow weights.

If no management group information is defined for a set of mature cow weights, the IGS analysis will use the management groups submitted with the 200 day weights of their calves to sub-group the weights of the cows.

This means, if you have correctly recorded the management group information with the 200-day weight performance for your calves, you only need to assign a different management group to a cow that has had an effect on her weight that is different to that of her calf. For example, if the cow was injured/sick or has been supplementary fed.

If both the mature cow weights and the 200 day weights for their calves are submitted without management group information, the IGS analysis will assume all cows and calves have been run under similar management conditions.

Scrotal Size EBVs are calculated from the scrotal circumference information that is recorded for bull calves. When recording scrotal circumference information, it’s important to consider the following points:

• Scrotal circumference measurements should be recorded by pulling the testes firmly down into the lower part of the scrotum and placing a measuring tape around the widest point. Scrotal circumference measurements can be taken by anyone and don’t need to be taken by an accredited technician.
• IGS can analyse scrotal circumference information from bulls that are between 300 – 700 days of age when measured. It is vital that scrotal circumference information is recorded when bulls are within this age range.
• It is recommended that you measure scrotal circumference when the bulls are reaching puberty, which will vary according to seasonal conditions and the maturity pattern of your cattle. In most cases, scrotal circumference should be recorded when bulls are being weighed at 400 days.
• While more than one scrotal circumference measurement can be recorded for an individual animal, IGS is only analysing the first measurement for each bull at this stage so you only need to record one scrotal circumference measurement for each bull.
• Measurements should be recorded in centimetres (to one decimal place).
• While measuring techniques vary slightly, it is important to use a consistent technique for a whole group of cattle. The tension applied to the measuring tape should be just enough to cause a slight indentation in the skin of the scrotum. Avoid placing the thumb of the hand holding the neck of the scrotum between the cords. This will cause separation of the testes and an inaccurate measurement.
• A variety of scrotal circumference measuring devices are commercially available from agricultural supply stores or organisations such as the Australian Cattle Veterinarians. The Australian Limousin Breeders Society also offer a measuring tape for sale. Metal scrotal measuring tapes are more reliable than cloth tapes as they are not prone to stretching.

Docility EBVs are calculated from docility scores recorded on animals when the animals are between 60 and 400 days of age. The recommended time to do this is at weaning or shortly after. The advantage of scoring at weaning is that all calves should have had similar treatment so variation in handling before scoring should be minimised. Animals can be scored for temperament using either a yard or crush test.

• Yard test – Calves are individually put into a small square yard and the handler attempts to hold the animal in one corner for about 30 seconds.
• Crush test – Calves are put up a race and individually held in the crush for about 30 seconds. When using either the crush or yard test, the behaviour of animals should be observed and animals scored using the following criteria.

When recording docility scores, it is important to note:

• There needs to be some variation in the scores for them to be used effectively by the IGS analysis. Scoring all animals in a group with a docility score of [1] won’t identify any genetic differences in docility.
• IGS can accept half scores if animals show behaviour that is intermediate to the above scores.
• Animals should be assigned a different “temperament management group” if they have had a different level of handling before scoring.
• The method of scoring, crush or yard, should be specified when submitting the docility scores.
• When recording docility scores, a consistent scoring method needs to be used and the same person scoring all animals that are being assessed in the herd on that day.

The main points for breeders to consider when collecting live animal ultrasound information are:

• Scan information will only be accepted by IGS if it has been recorded by an accredited scanner.
• IGS can analyse the scanning performance from animals that are between 300 – 800 days of age when measured. Scan your animals when they are within this age range. Most animals are scanned as rising two-year-olds, i.e. around 600 days of age.

Find an accredited technician or contact PBB IGS

Find out more about understanding IGS EBVS.