Reading a BREEDPLAN Catalogue

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Introduction

When buying bulls, first ensure that they are sound and fertile, with an acceptable temperament. BREEDPLAN figures can then assist you to check that their genetics will suit your cows, the type of country, and the market.

Areas in which BREEDPLAN can assist include growth rate, milk, fertility, calving ease, carcase predictions and, in some cases, feed efficiency and docility. Other attributes such as structure, eye pigment etc, still need to be assessed visually.

Estimated Breeding Values

The basic descriptive units of BREEDPLAN are estimated breeding values (EBVs). These are calculated from:

  • the animal’s own performance (weights, scrotal size and other factors);
  • the performance of relatives (parents, relations and progeny) in all linked herds;
  • other related measurements (for example, yearling weight and weaning weight are genetically linked, so each of these weights contributes to an estimate of the other weight).

Therefore, EBVs are a much better predictor of the performance of a bull’s progeny than single measurements on the bull near sale time (e.g. weight, scrotal size, raw scan measurements).

EBVs are expressed in everyday units, for example:

  • kilograms (kg) for weight.
  • centimetres (cm) for scrotal size.
  • millimetres (mm) for fat.

The values can be positive (+) or negative (–), depending on whether the value for an animal is under or over the ‘base'. The current breed average is often a more important benchmark than the base (see Using the catalogue).

Using the catalogue

Catalogues vary, but most entries should look something like this:

BREEDPLAN table

* Accuracy figures (expressed as a percentage) are an indication of how much information has been provided, and hence the ‘reliability’ of each EBV. EBVs of lower accuracy are more likely to change as more information is collected. There is an equal chance of this change being up or down.

It is more important to compare EBVs with the breed averages for the year of birth. In this case, 2-year-old bulls for sale in 2003 were born in 2001. In the above example, bull A is above average for all the weights, and average for milk and scrotal size, compared with calves of this breed born in 2001.

Looking at the Progeny of Bull in Catalogue

We can now examine in more detail how the progeny of the bull above will look.

  • Birth Weight. The birthweight EBV is the best predictor of the birthweight of a bull’s progeny. This bull is below the breed average and will birth progeny 0.1kg lighter than the breed average (progeny only inherit half of the bull's traits, as the other half comes from the dam. Birthweight is by far the most important genetic influence on calving ease. Gestation length, calf shape, and the uterine environment and pelvic area of the cow also influence calving ease, as do many non-genetic factors.
  • Milk. BREEDPLAN partitions weaning weight into the ‘milk’ and ‘growth’ components. The ‘milk’ EBV predicts the milking ability of a bull’s daughters, expressed as the kilograms of extra weaning weight that their calves would have. This Bull is above breed average and would produce better milking daughters. In some situations, ‘high milk’ is a disadvantage.
  • 400 Day and 600 Day Weights. These EBVs are used to predict weight at various ages, so they are most useful, in turn, for yearling or heavy steer producers. The bull above is well above the breed average for both of these weights.
  • Scrotal size (SS). This bull is above average for the breed and will breed daughters with earlier puberty and shorter calving intervals, and sons with earlier puberty and bigger scrotal size. (Some breeds also give the Female Fertility EBV, ‘Days to Calving’ (DC).
  • Carcase Traits. Carcase traits include rump fat, eye muscle area (EMA), and intramuscular fat (IMF). Compared with the breed average, this bull will produce average progeny in terms of rib fat, and rump fat with a larger eye muscle area than average. The progeny will be slightly more marbled than average (0.1%).

Further Information

See other Agnotes in this series for further information on BREEDPLAN and EBVs.

About the Author

Brian Sundstrom is Cattle Breeding Coordinator with NSW Agriculture. Part of this role involves technical specialist and advisory work with BREEDPLAN from an office at the Agricultural Business Research Institute (ABRI) at Armidale. His other role is with the Beef CRC group.