Depth, Capacity, and the Calf Underline: An Early Selection Cue in Dexter Cattle

From the start of our herd, one of the traits we have insisted upon in our cattle is depth of body and overall body capacity. We raise small-framed cattle, but a small frame does not excuse narrow, shallow, light-bodied cattle. A Dexter should still look like a bovine.

Depth and capacity matter because they are tied to function. A deep-bodied cow with adequate heart girth, spring of rib, and depth through the flank has the physical capacity to consume forage, maintain condition, carry a calf, milk, and remain useful over time. In a dual-purpose breed, that is not decorative language. It is part of the working animal.

So how do we improve depth in a herd?

The first answer is the obvious one: select cattle with depth and capacity. Look at the sire. Look at the dam. Look at siblings. Look at mature relatives. Study the animal itself. Does it have heart girth? Does it have rib? Does it carry depth from the fore-rib through the flank?

There is also an early visual cue we have learned to take seriously in our own herd: the underline of young calves, including navel-flap development.

Yes, you hear it often enough. You go to a cattle show to “learn” about selection, and you hear a judge downgrade this animal or that one for being “loose in the navel” or “trashy underneath.”

For us, when we show calves under 12 months of age and hear those comments, we evaluate them in context of the whole animal. A loose or more developed underline in a young calf is not automatically a defect. It may be a defect, depending on the animal. But it may also be an early indication of future depth, capacity, and body volume.

Bottom line, in our herd, we pay close attention when a young calf is tight, shallow, and lacking underline development. That calf may still have value, but it is much less likely to mature into the kind of deep, capacious animal we retain.

Kind of like a kid wearing a shoe two sizes too big, some young calves carry underline development they have not yet grown into. In our herd, that has often been a useful early clue. The question is not whether the calf looks finished at three or four months of age. The question is whether the calf has the physical promise to mature into a deeper, more capacious, more useful animal.

To be clear, we are not talking about umbilical hernias, navel infection, injury, or unsound sheath structure. Those are health and soundness concerns. We are talking about calf underline development as one early visual cue, read alongside the whole animal, its relatives, rib shape, flank depth, heart girth, maturity pattern, and overall function.

Here's a prime example in one of our bulls from a few years back that grew into his navel. This is SMD Paycheck Ballan #033108 at a few months, at 6 months, 2 years, and at full maturity. There's nothing wrong with the navel flap or sheath on the mature bull.

So, focus on depth and capacity. It is critically important even in short cattle. There is a tendency in our breed, because we want smaller-framed cattle, to select and cull in ways that significantly decrease both depth and capacity. This is not a good thing, resulting in animals that are inefficient and ineffective forage processors and resemble more an antelope than a bovine.

Select and cull for depth and capacity. Do not select or cull a young animal based solely upon too much navel flap. But do not ignore the lack of underline development either. In our herd, that absence has proven to be a useful warning sign.

JMC