An eye for form and function

By Lynda Gray

In Livestock4 Minutes

AS A TEENAGER, Bill Austin used to doubt the claims of two great uncles who said that a mad bull inevitably had upward pointing eyelashes. But it turns out those old uncles were correct when the lash orientation is figured into the overall physical structure of a bull.

Bill, a cattle structural assessor with 14 years’ experience, said that upward lashes indicated the lack of a bone hood that shields a bull’s eyeball from bright light and shadows.

“Always be wary of a bull with an eye not protected by a bone hood. They see shadows and are more likely to spook,” he said at a mini masterclass on structural assessment at the Beef + Lamb NZ across-breed progeny test field day.

Bill knows cattle inside and out. He ultrasound scans cattle throughout the country, measuring eye muscle area (EMA) and intramuscular fat (IMF), and for most of March and April he assesses the structure and phenotype of potential sale bulls using the internationally recognised Beef-Class Structural Assessment system (BCSA). The system classifies an animal for structural soundness and basic type measures according to 11 traits, including docility, feet and leg structure, carcase capacity and muscling. The information is used by breeders to select sale bulls and by buyers to assess whether a bull is suitable for their breeding system.

“Everything that’s measured either adds profit or costs you money,” Bill said. The colour or number of whorls on a bull or heifer’s coat is irrelevant to Bill who says his focus is assessing practical and functional cattle.

“Breeders often talk about structural soundness, but I talk about structural functionality, because it’s about cattle that are functional and productive.”

He pointed out and explained some of the considerations and measurements using a few Kepler cattle. Claw set, foot angle, leg view was explained in the context of mobility and the ability of a bull to fulfill its job description of reliably serving cows.

Aside from temperament, one of the most important measurements was heel depth, or foot/hoof angle.

“If that’s ok, everything else should fall into place,” he said.

The heel depth, measured from the hairline at the top of the hoof to the ground should ideally be 40–60% of the heel-to-toe length.

Mobility – where the animal places its feet when walking naturally – was also a good guide as to whether a bull was fit for purpose. A structurally correct animal placed its hind foot in the imprint left by the front foot. However, a straight-legged bull placed its hind foot short of the front imprint. They were less athletic than a sound bull and were more likely to break a stifle while serving a cow.

Bill’s final word of advice was to select the EBVs relevant to your country and system and go to the breeder who has the most bulls of that type.

“It’s not the individual bull you buy, it’s the driveway of the breeder you choose that will have the biggest financial influence [on your cattle system].”