December 11, 2003

Bovine Longevity

The Maximum Leader’s vacation has left a heavy burden on his loyal lieutenants. Since there is nothing in the news that is particularly electrifying, I will blog on the contentious, much-debated issue of bovine longevity. For those of you who care not one whit about cattle, skip this blog. If you are interested in random farming thoughts, read on.

Last weekend a professional photographer came to Sweet Seasons Farm. He is a stock photographer who sells family-type pictures to magazines like “Parenting Today.” In return for allowing him to sell any marketable pics, we will be getting as many professional-quality prints of my daughter as we wish. Cool deal, huh?

We set up one shooting location next the barn my Dad and I have been building. I pushed a few hay bales together in the location chosen by the photographer to maximize light, propped my beautiful daughter atop the hay bale with a Buff Orpington hen, and sat down to pose with the family.

My bovine who thinks she is a canine decided that she needed attention and that the family picture would be incomplete without her presence and joined us. The photographer ended up taking a bunch of shots of just the heifer (What! Are you saying the cow is better looking than my daughter!?).

(In case you were wondering, in the light of the fact that our family portrait includes a chicken and a cow, my “farm dog” Kermit is not in the picture. He has decided that it was too cold for his runty little butt and returned to the warmth of the indoors. The declension model is so, so, true.)

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The photographer was quite taken by Bonnie’s cheerful friendliness. We went through an entire conversation about having a family cow. At one point, he asked about how long a cow lived. I had to pause and collect my thoughts before I answered.

Bovine longevity is a tricky issue.

Very few cows actually live long enough to succumb to old age. Male cattle have an even shorter life expectancy.

Veal calves (usually bull calves of the dairy breeds) have the least amount of time on this globe. They are generally slaughtered at one to three months of age. Of course, considering the conditions that veal calves suffer, the short lifespan may be a blessing.

Baby beef steers are generally walk the last mile at between 8 and 12 months of age.

Most beef steers (or beeves) are sent to slaughter at 14 to 16 months of age after several months of intense grain feeding.

Bulls in beef herds may last to 4 or 5 years – if kept any longer, they will end up breeding their own daughters that have been kept as replacements. Sometimes farmers might trade bulls and that would give the traded bulls a two year extension, but usually bulls are just sent to the slaughterhouse when the threat of inbreeding arises.

Dairy bulls kept for semen – and these represent a tiny, tiny percentage of bulls, may live a couple years longer since inbreeding is not a factor. The limit here is imposed by the constant increase in the genetic merit of each Holstein generation – A bull whose semen carries a premium one year is obsolete two years later. Even a freakishly awesome bull may not live long – his semen can be harvested and shipped for years after he has met the butcher.

Most dairy cows will live for around 5 years – three lactations is the average. With few exceptions, they simply wear out fast. Since Holsteins have now been so genetically modified, their huge udders do not last for years; instead of producing one or two gallons of milk a day, there are now some top-of-the line Holsteins that produce 12-15 gallons of milk a day. Imagine your wife or girlfriend (or yourself) and then increase breast size by a factor of 8. That is where our Holsteins are now. Eventually the udder attachment will start to give out and the cow will lose its ability to produce milk. Genetic advancement lays a role too. If a dairy farmer is following sound genetic practices when purchasing semen, the new heifers will ALWAYS be better than their dams. An older cow producing 24,000 lbs of milk a year will be sent to the butcher to make way for her daughter who produces 24,500. The genetic improvement has come at a price; modern Holsteins have a remarkably small gene pool – good bulls who throw milk production might father tens of thousands of calves. While this has led to unbelievable increases in productivity, it has come at the cost of lower fertility – many cows have difficulty becoming pregnant so they are culled too. Additionally, the conditions in which dairy cows are raised also limits their lifespan. In many operations, the cows never leave their barns and are on hard concrete their entire lives. By the time they reach four or five years of age their knees are so afflicted with arthritis that they have to be culled. Constant exposure to built up manure allows disease to spread. One particularly nasty manure-borne disease is Johnes disease. I visited a 1400 cow dairy two years ago in which the disease was endemic. Johnes disease is the bovine equivalent of Krohn’s disease in humans – the intestinal lining of the stomach is gradually eaten away, causing great pain, and eventually death. The dairy did not even attempt to keep new heifers from catching the disease. Since the progress of the disease is as slow as it is painful, it does not cause a real drop in production until the cow is four or five years old – at which point most cows are going to be culled anyway. A few strong cows that have good udder attachment and are good milk producers might warrant a few more lactations – those cows might be lost to Johnes but the percentage is so small that it isn’t economical to try to isolate them from the pathogen.

Beef cows last much longer. Since the pressure for genetic improvement is much lower, there is not the same incentive to switch out cows for newer models. They also tend to live their lives on sod, which preserves their legs. Most will survive until age takes a toll on their ability to calve or breed back. A tremendously efficient beef producer might replace his cows every seven or eight years – the point at which the pregnancy cycle starts to stretch from twelve to fifteen months. More relaxed cow-calf operations might hold onto a cow to ten or twelve years.

Which brings us to Bonnie. She is an Ayrshire and one of the reasons I chose that breed is because they have not been genetically suped-up to the same extent as the black and whites. A high level of milk production isn’t that important – four gallons a day will raise four calves (and four more after those are weaned). I expect that she will be able to calve and milk for me for twelve years or so. While it doesn’t make much economic sense, at that point I’ll keep one of her daughters and let her retire. She is already a pet – she won’t end her days as hamburger. With grass to eat, a barn to shelter her old bones in the winter and room to roam the other three seasons, she will probably live to twenty or twenty-five, a loyal old 1100 pound pet.

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