Does this beast even exist in North America today? Short answer is certainly yes, but there are far fewer today than there were over the last 30 to 40 years. I remember watching a number of bred female sales out in Western North Dakota in the 80’s. It was very common to see females fit into this 1000 and 1050 mature cow weight. Bigger cows back then moved up to the 1100 or even 1200 pound mark. Those are days that are long gone as our genetics and selection pressures have changed. And with it cows that have increased in size.
Figure 1: Cold Carcass Weight Trend from 1980
I came across a couple of charts that show what direction we are heading in terms of size. The first is a chart Figure 1, produced by CattleFax that looks at carcass weights back to 1980. Although we can feed to different end points, the steady increase has been about 5 pounds per year. It is not too difficult to see that as the size and weight of fed cattle has been increasing, the cow herd producing them has more than likely moved in that direction as well. A review of cull cow size that was done by Bryan McMurry with Cargill that shows a snapshot of what cull cow slaughter weights looked like across the country in 2009, Figure 2. You will notice that cows have gotten bigger and the further north you go, the bigger they get and that’s now been 8 years ago. This is a phenomenon observed in nature and is seen with most mammals with exceptions being birds, and some reptiles like lizards and snakes. Colder climates favor larger bodies that can help reduce heat loss due to their smaller surface area-to-volume. Sorry to digress a bit there.
Figure 2: Cow Slaughter Weights Recorded on February 9. 2009 from Randomly Selected States Across the United States.
Increasing mature beef cow weight, is a topic that comes up often. From a nutritional perspective, we are concerned with how this changing cow herd impacts nutrient requirements in order to still meet production goals needed for financial and sustainable success. I have not really had a big appetite for bringing it up as a blog topic as there are varied opinions as to the direction the cow herd has been headed. First off, I am not taking a side for smaller or larger cows at this point, but rather simply to admit that significant changes have taken place from the “good old days” and along with some of the general rules of thumb that have been used when feeding beef cows. So how do we address this nutritionally? There are nutrient requirement and feed intake estimator charts available based on cow size and production level. The math has been done for us if we truly know the size of our cows within the herd. So no problem right? But do we really know, or are we honest about the size of cows we have running around our pastures?
On top of cow size we also see that there are other traits that have been changing as well, like milk production. Increases in milk translate to greater nutrient requirements to sustain the additional production demands of the cow. David Lalman, from Oklahoma State University has shown considerable interest in beef cow efficiencies over time. He has shown that with the Oklahoma State commercial herds that their average milk yields went from 17.8 pounds per day in 1998 to 31 pounds per day by 2016. This type of increased nutrient demand translates to a sharper focus on the cow nutrition program. You don’t need to be selecting from milk because the genetic base for most breeds has been moving up over the years. Only the Simmental breed has shown a reduction in EPD’s for milk. You need to evaluate where your genetics have taken you over the last decade or two and make sure your feeding program isn’t “just like we’ve always done it”, when your cow herd has been on a much different trajectory.
So we have both cow size that has been shown to be moving higher and nutrient demands from increased milk production on the rise. Are they resulting in additional, saleable product in calf weight for your herd? I can’t answer that here but there is not a lot of clear evidence for observed improvements in production output or cow efficiency. As you can see in Table 1 from a cow herd review at the North Dakota State University Dickinson Research and Extension Center, as cows increase in size, it becomes rather difficult for them to maintain a high percentage of calf weaned in relation to their body weight. If you would target 50% that would mean an 1800 pound cow would need to wean a 900 pound calf. A tall order indeed.
The last thing I would like to leave you with comes back to the self-fed nutrition products that we offer to the marketplace. It is has been our goal to develop and then manufacture products that perform consistently when placed out in the wide variety of production conditions across North America. Much like weaning a 900 pound calf this is no small task when taking into consideration the moving variables with environment and weather events, climate, pasture size, forage quality, forage availability, cattle types and numbers, physiological stage of animals or cattle size to name just a few. One of our challenges with our supplement recommendations has been to meet the same expected intake on a daily basis. As an example, for most of our mineral type CRYSTALYX® Brand Supplement products, .25 pounds per head per day is a common targeted intake and for protein products .75 pounds per head per day has been used as guideline across North America. Do these need to change, should these change based on the last decades of genetic progress that has taken place and currently defines our typical beef cow? These are questions that we contemplate going forward but for today, the historical use and performance of our products have not provided any signals that would call for a change. Stay tuned as we monitor our progress and try to keep pace where the genetics take us. At the end of the day it is our job to provide solutions that work for your cow herd.
