22 October 1999

EBVs help you choose the right bull for the job

Planning to buy a bull this

autumn – or at next weeks

Perth Bulls Sales? Then

check out his figures

first to see whether hell

perform in your herd.

Emma Penny reports

CONFUSING although they may initially seem, using estimated breeding values (EBVs) to assess potential performance can help ensure you buy a bull whose progeny will do the job you want.

With more beef producers choosing to breed their own replacements, buying a bull which will result in milky, maternal offspring is important, says Suffolk-based Signet consultant Geoff Fish.

"But when you are running a hill or low maintenance herd, or using the bull on heifers, easy calving will be the key requirement.

"If youre finishing cattle, youll need a bull whose progeny are likely to grow rapidly," he explains.

Choosing a bull with these specific attributes is almost impossible on sight alone, he says. "But EBVs provide all this information; its a matter of choosing and using the information required for the bulls task in your herd."

Although theres now more acceptance of EBVs in the industry, he acknowledges that some breeders are still sceptical about their value, and whether they are accurate enough to be of any real use.

"If you buy a bull without figures, Id say you dont know enough about him and his likely performance. Figures are available rapidly – and free – from Signet, and it seems crazy to buy a bull out of a pen without finding out whether his EBVs are suitable for the task youre buying him for.

"I would always advise looking at a bull first, and backing up your visual assessment with figures. A good stockman can make bulls look terrific, but EBVs are based on known information about the performance of that bulls relatives, and the more information we have, the more accurate the figures."

In some cases, EBVs have a low accuracy figure which may lead producers to disregard them, but Mr Fish believes that they still provide valuable information.

"More information on the performance of the bull and his family increases accuracy, but it doesnt need to be 100% to be useful. A high accuracy figure is obviously better, but I would quite happily accept EBV figures with an accuracy of 40% – they will at least give you an idea of his likely performance."

But rather than just looking at EBV figures across the board and the Beef Value, he reckons bulls should be chosen for specific qualities, and that means looking at individual EBVs.

"This is a key point, as genes for milk and mothering ability tend to be negatively correlated with growth rate, so selecting for growth means selecting away from mothering ability, which could be a concern when you are breeding herd replacements.

"Consider exactly what you want a bull to do in your herd, and buy one which will do that task, whether its breeding replacements, finishing cattle or selecting for easy calving," he advises.

SELECTION

&#8226 Consider bulls task.

&#8226 Choose appropriate EBV.

&#8226 Other factors vital too.

EBVs explained

Calving Value – the overall assessment of an animals effect on calving. This rates bulls in terms of their effect on their progenys calving, and is a combination of EBVs for gestation length and calving ease. A higher positive Calving Value is associated with a shorter gestation length and an easier calving.

200 day growth – a higher positive value – calculated in kg liveweight – indicates faster growth to 200 days.

400 day growth – again, a higher positive value indicates faster growth to 400 days.

Muscling score – an animals muscling judged by eye and measured in points at 400 days. A higher positive value indicates greater muscling. About two points are equal to one EU carcass conformation class.

Muscle depth – an objective measurement of an animals muscling – in mm – measured by ultrasonic scanning. A higher positive value indicates more muscling.

Fat depth – like muscle depth, this is measured by ultrasonic scanning at 400 days, and is reported in mm. A higher negative value indicates a leaner carcass.

Beef Value – an assessment of the economic genetic merit of an animal to produce a carcass demanded by the market in terms of weight, conformation and fat composition. The more positive the Beef Value, the better the carcass meets current market demands.

Accuracy – reflects the amount of information used. The higher the accuracy, the lower the chance of the EBV changing with new data.