Weekly genetics review: Watch your feet – assessing bulls ahead of a sale


Spending time evaluating the foundation structure of sires prior to sale can be one of the most effective long-term investments in a herd’s future.

The ability of bulls to roam freely and achieve regular and repeated matings across multiple mating seasons directly impacts a herd, not to mention the return on investment in the first place.

The appearance of feet in cattle is often a direct result of the animal’s overall leg and shoulder structure. Correct shoulder angles result in correctly aligned legs with the front foot at a 45 degree angle to the floor.

With proper alignment, the hoof should be naturally wearable and avoid overgrowth. Uneven hooves are often an indication that pressure is being applied unevenly to the hoof, causing one side to wear down faster than the other.

Aside from the effects of normal wear, foot growth (and shape) is also affected by the environment the animals are in and the type of food they have been exposed to.

The combination of these factors, genetics and environment (including diet) must be carefully considered before making selection decisions.

A Victorian study of the factors behind bull collapse found that 25.2 percent of bulls three years old and older are unsuitable for breeding. A significant proportion of these breakdowns (13.8 percent) were due to problems with getting around. While these may not all have been directly linked to poor hoof and hoof structure, the high proportion of bulls who are unable to walk and kick is a worrying trend.

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While most bull buyers take the time to assess bulls looking at their feet, the mere glimpse of a bull standing in a yard or jostling for space among other bulls often prevents that assessment from being as thorough , as it should be.

Since shoulders, legs and hindquarter structure all affect hooves and hoof growth, it is highly recommended that bulls be walked over a yard or longer distance as part of the evaluation. A few small steps are not enough to show a lot. A Taurus should be made to go beyond a reasonable distance.

Leading a bull in this way allows the producer to judge how well he places his feet and whether the weight is evenly distributed on all four feet and on the claws of each foot. When walking, an adult bull can transfer up to 200 kg per hind barrel and 100 kg per hoof.

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Bulls that roll their feet while walking are transferring that weight incorrectly, and this is a sure sign that foot problems can develop over time. Up to 85 percent of lameness occurs in the hind paws, with weight shifting or loss due to improper paw and pastern structure.

Front feet are often affected by incorrect shoulders, often legs that cause the feet to be misaligned, either rotated inward or slightly outward. These deviations can also cause a bull to roll when walking and affect claw growth over time or contribute to arthritis and mobility impairments in the longer term.

Trim

It is not uncommon for hoof problems to be treated through hoof trimming. While trimming corrects the appearance of the hoof and often helps the animal walk more easily, these are short-term fixes that only affect the individual bull.

As a potential herd sire, the bull’s genetic contribution to the herd is a risk to consider. Although heritability estimates of foot and leg structure suggest the range is between 0.08 and 0.16, this is nonetheless a trait that should be considered in any selection decisions.

It is worth noting that research suggests that the heritability of feet and legs is at the 0.21 level. This has a positive correlation (+0.52) with herd longevity.

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Bulls may be offered for sale that have received some pre-sale attention to hooves that have been trimmed prior to sale. This is often difficult to detect during a pre-sale inspection. However, if you take the time to walk the bull out, assess the bulls’ movement, and observe the placement of the feet and the angle of the feet, you can gain a lot of insight into a bull’s correctness and overall suitability for a herd.

Taking the time for a thorough inspection rather than a hasty inspection where the bull is crammed into a pen with several others prior to sale will pay off in the working life of the bull and the overall longevity of the herd.

Alastair Rayner is the Director of RaynerAg, a NSW based Agricultural Advisory Service. RaynerAg is affiliated with BJA Stock & Station Agents. He regularly lists and sells cattle for customers and attends bull sales to support customer purchases. Alastair provides presale selection and classification for seed producers in NSW, Qld and Victoria. He can be contacted here or via his website www.raynerag.com.au





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