By Dr. Roy Burris
Longevity can be defined many different ways by beef producers. However, I’ll just use the definition – how long a beef cow or bull stays in your herd. They may leave your herd for a variety of reasons but every time it happens it represents a significant expense to your operation. This is generally the difference in their salvage value and what it costs to replace them. However, you could possibly be replacing an inferior animal with one that is more profitable. That is what we hope for.
A cow doesn’t have to be highly productive to stay in the herd. Longevity might simply be due to the absence of problems. Everyone probably has different reasons and different levels of tolerance for culling cows and bulls in their herds. My philosophy is probably a little different, too. Most often, cows are culled for reproductive reasons. You don’t have to be a “rocket scientist” to figure out that open cows don’t make any profit. I always cull cows that are open (nonpregnant) at “preg checking” time. We can argue that it might be more economical to keep a barren cow a year than to purchase a replacement heifer but I choose to keep pressure on the cow herd to be productive. Reproduction isn’t a highly heritable trait but selecting cows and heifers that are productive in our particular environment is a good long-term goal.
One of the first things that effects longevity in our herd is disposition. I believe in eliminating problems as soon as they appear. A crazy cow or bull is a liability and needs a dose of “trailermycin”! Calves are evaluated every time they go through the chute and bulls are selected based on their disposition (or docility scores). Docile animals generally perform better and create fewer problems. Thus, docility does affect longevity. There are enough things that can go wrong in your cow herd without selecting rogue animals.
How long should a good cow stay in the herd? I love getting heifer calves out of old commercial cows and both bull and heifer calves out of old purebred cows. If a cow calves every year and is in her “teens”, she is special. I want to keep her as long as I can – but she needs to still have some salvage value and be suitable for marketing. I remember two Brangus cows in our herd here – G5 and G6. G5 was a nice specimen and went directly into the “purebred” group. G6 was not as good looking (to me) and went into the commercial herd. After a few years, G5 was gone but G6 had bred on the first heat every year. She then went into the purebred group and we still have bulls and cows that are her descendants. “Broken” or “smooth-mouthed” animals need to be evaluated but as long as they are pregnant and in good body condition, it is great to generate one more heifer from that “ole cow”.
Udder problems will get cows on our list, too. We select for clean, tight udders with small teats and cull those that are appear to be problematic. Heavy milking cows with pendulous udders and large teats are difficult for a newborn calf to nurse and that initial intake of colostrum milk is critical to their health. These udders also tend to be “dirtier” and can cause more scours. I don’t care to “milk-out” cows when they calve – you are just perpetuating a problem.
Eye problems (like cancer-eye) and any type of lameness will also cause problems and affect longevity. Be on the look-out constantly (especially in bulls) for abnormal hoof growth (like screw-claw). These problems seem to appear frequently now days and should be culled for and selected against. Lack of production, poor production or inferior quality of calves can be reasons for culling cows and bulls.
I am of the opinion that your best source of breeding stock (other than your own herd) is from producers that have been vigilant over many years in culling rigorously and selecting problem free animals. When purchasing a new bull this spring, ask to see his grandmother. If she is still in the herd after several years, his odds are better too. Longevity and “stay ability” are traits of economic importance in our cow herds.
Source:osu.edu