11/13/2025
Beef Cattle Maturity Pattern and Seasonal Fluctuation in Body Condition Score
Thirty five years ago, I was enamored with Angus sires whose daughters were always fat....regardless of what they had to eat. Younger age to puberty was also correlated. As a reproductive physiology graduate student in Animal Science at Kansas State University, the linear, reductionist thought process was that cows that calve in a higher body condition score had a shorter postpartum interval and, hence, were more apt to breed sooner for their next calf. Based on some of the sires that I used in the early 1990s, I learned that, yes, these daughters would "stay fat" year round, however, they only lasted through 2-3 lactations before coming up open. Plus, their calves did not wean very heavy. Maybe these daughters became too fat prior to their yearling breeding season( extremely early puberty). This is what Larry Leonhardt called the "fat cow syndrome". Cows that would put it on their back instead of into their calf. We have grown to appreciate Angus cattle that will successfully fluctuate in body condition score throughout the year. Build body condition when grazing conditions are really favorable (Spring, Summer and early Fall) and use this body fat through the colder Winter months wherein the cows are expected to function on dry native Winter range with protein. Admittedly, this works quite well if the cows do not calve until late Spring / early Summer because they have until mid July to rebuild body condition until they are expected to rebreed. In contrast, a January/ February calving cow can not lose this body condition and still successfully rebreed early (March/April) on stored, expensive feedstuffs.
I have also grown to appreciate that extremely early puberty usually is correlated with reduced longevity. Conversely, later puberty is usually correlated with greater longevity. So, here's the conundrum.....attempting to create acceptance for later maturity, forage developed bulls that may not come into their own until 2-3 years of age. Let's admit it. Fat sells. Fat covers up a lot of sins. Seedstock producers over-condition bulls because that is what their commercial customers want to buy. Need to think long term instead of short term. Attached two Bolze Ranch Angus herd sires pictured as a yearling / 2 year old compared to their 5-6 year old picture. This speaks for itself. Time between was on 100% forage, and no grain. The really good things in beef cattle require great patience.