How does “form follow Function” in Nature?

The Aleutian cattle: a closer “look”

In 2009 and 2010, the Aleutian Feral Cattle became known to a number of us. I have wondered over the years how nature selected for the animals we were offered a glimpse of at that time.

On an Island named Umnak, with 686 square miles of surface area, there were approximately 3700 cattle that had had very little human interaction for 80 years.

The cattle, being a bit on the wild side, were hard for humans to have interaction with in the open. And from what I hear, once they were fenced in by a 10’ tall corral … humans found they did not really want “interaction” with those feral cows and bulls.

The climate is similar to the west coast of Scotland. With a limited land base and speculating on the growth and dormancy periods of grass growth, an animal had to be able to “get grass while the getting was good” to have enough backfat to survive the long winter’s nights. In my mind it takes a certain shape, glandular function and butterfat level in an animal to survive and even thrive in that environment.

Tackling the shape element first, an animal has to be deep and wide in the front end to be able to put fat on her back. In a climate this severe (up to 25% died some winters), if you took a cross section of these animals just behind the front legs, it needed to look like an “O” to be able to maintain body heat during the cold and wet winters. If this were a tropical island, that cross section might be more of an oval to help dissipate some of the excess heat.

The cow needs to look like a wedge on three surfaces. The bottom slope from the chest to the back of the ribs needs to be increasing in size. This allows for gut capacity and her ability to “eat enough for three” if her genes are gong to get passed along.

The top slope has to be a wedge in the opposite direction. Kind of getting into the glandular function here, but estrogen stops long bone growth on the front end of the animal first. The heifers and cows producing the most estrogen would look like they are “walking downhill” when on level ground. The reason these cows should have looked this way was that only the most fertile animals were going to conceive. And if they had a body that was easy keeping, they could make it through the winter to have their calf the next spring. Keep in mind, she was probably nursing a calf all the while.

And that third wedge would be looking down from the top. Her rump was always wider than her shoulders. Dr. Michael McDonald (God rest his soul) found that the best linear measurement numbers to compare that most closely predicted fertility was rump length compared to rump width. Another guru of linear measurement, Kenneth Redman (Sydney, Montana) found that old cows had three main things in common: they typically had a larger belly than the herd average, they had a wider rump than herd average, and they had more slope from hooks to pins than the herd average. Two of his findings would give us that wedge look from the side and from the top.

On the male side, testosterone stops long bone growth on the back end first. Among other things, the masculine bulls would look a bit like a male buffalo. Keep in mind that early maturity, which was vitally necessary in this harsh environment, is going to stop ALL long bone growth in both sexes, and tall animals will be selected against. Echoing Dr. Michael McDonald again, the best indicator of fertility in the bull is the comparison of the length of the rump to the width of the shoulders. The wider the shoulders, the more masculine the bull. Horn color patterns tell us something about fertility. Whenever a horned bull goes through a period of lower fertility he will leave a tell-tale white ring in the growth of the horn at this time. With the lack of feed in the winter, the older bulls should have had horns that had a uniform darker/white ring/darker/white ring look to them as the feed was good in the spring and then almost non-existent in the late winter.

It takes 120 days on the best feed you have (epi-genetics) for your bull to produce the highest quality semen he is genetically capable of producing. On the Aleutian Island, that is the time of year that cows would get pregnant if they could “eat enough for three.” Along with this comes the time(s) of year when the Potassium and Manganese are highest in the native forages. Potassium is always highest early in the spring. Potassium in the feed prevents dystocia. Perfect time to calve from the mineral side of the equation. 80-90 days later the Manganese level is highest is the seed heads. Manganese is required for reproduction in both the plant and animal. These two minerals, coupled with the ability to put on back fat and 120 days of green growing feed get that hardy bull to the most fertile time of the year. To recap this, 40-50 days after grass starts growing the cow has put enough fat and energy back to be able to calve and then 80-90 days later she and the bull are eating those manganese laden seed heads.

A lot of us think, “I don’t want that great big bull, he will tear up my cows come calving time!” Mother Nature has a way of handling this. Dr McDonald also found that, at one year of age, each inch the shoulders are wider than the length of the rump resulted in two-and-a-half fewer days of gestation. With that in mind, bull number one, with a plus three-inch shoulder would throw approximately a fifteen-pound lighter calf at birth. Seven and a half days less gestation at a time when the calf is gaining two pounds a day in utero. Bull number two, with even shoulder and rump measurements would play out a bit differently. After he picked himself up out of the dust, where bull number one put him, he might find a heifer that number one had not serviced yet. Come next spring (no winter calving here) the calf goes full term, is too large to come out, and bull number two and that heifer’s genes do not get passed along.

So now we have this ideal shape for a bull and a cow in mind. What else do we need?

Ah yes, glandular function and butterfat. These two are “joined-at-the-hip,” so to speak. You almost can’t have one without the other. First, let’s talk a bit about glandular function. Dr. Jan Bonsma taught us that glandular function controlled everything else in the cow. Without glandular function the cow would not produce the estrogen that gave the wedge shape to the cow. Without glandular function, we would not have those massive shoulders on the bull with all of that testosterone. And to go there for a moment, the bull needed all that testosterone and those massive shoulders for two main reasons; first, he needed to make sure his genes were passed along and being king-of-the-hill made the competition think twice about challenging him, and second, being that fertile he could service a lot of cows, with the added bonus that the quality of his semen helped maintain their pregnancies (Dr. Richard Saacke).

Digestion efficiency and the superior Epi-genetics that come from that both play a part in the animal’s ability to survive in this closed environment. Dr. Don Faulkner of the University of Arizona made the following statement at a conference I attended in the spring of 2014; "We are getting very good at predicting what a group of open cows, pairs, yearlings, bred heifers, etc. will consume depending on whether fed grain, ensilage, alfalfa, grass hay, etcetera. What we can't tell you is what individuals will consume in those groups. Some animals consume half as much as other animals in those groups. “If the group average was 3% of body weight then some animals were eating 2% of body weight while others were consuming 4% of body weight.

Similarly, Anibal Pordomingo of Argentina had found in his research that the average beef cow in America digested 55% of what she ingested. After he heard Gearld Fry lecture, he dug his research back out and found that there were some cows who digested 70% of what she ingested.

With these two pieces of information in mind, I speculate that the Aleutian cattle that survived were the ones eating 2-2.5% of body weight per day and digested 65-70% of what they ingested.

Glandular function also kept the animals free of internal and external parasites. Healthy sebaceous fluid is a natural fly repellant. The bulls bothered by the fewest flies during breeding season could get more females bred, everything else being equal in the bulls. Thinking about this internal parasite thing, bugs are mother nature’s cleaning crew. In our row crop fields, they are trying to do their nature-made job, which is eating what is not fit for man-nor-beast. Then we come along with chemical warfare agents and…oh, I digress.

So that super healthy rumen is not a house for worms. The good biology working in there does not leave a good environment for worms to show up, let alone survive (Pasteur vs. Beauchamp). Once a cow is impregnated, she stops producing estrogen and starts producing progesterone to maintain the corpus luteum and the pregnancy. If the cow is too fat (not a problem in this harsh environment) her own fat gobbles up the progesterone (and a lot of other toxic things) and she sheds the corpus luteum and cycles again.

How does butterfat come into play in this Aleutian Island story? It would be virtually impossible for a calf to stay alive through the winter unless he/she could put some fat on their backs as well. Without a fully developed rumen (the development of the rumen takes approximately ten months at mother’s side) the main way for the calf to get that fat layer is through the butterfat in the milk. Too much milk is a problem because the energy required to produce it pulls the cow’s body condition down too much. A few things indicate that a cow is producing a lot of butterfat. A bald udder is the main indicator of butterfat. Note that there is going to be more hair on the udder of a cow on Umnak Island than on Fiji. The second thing to look for is vertical folds in the hide. The closer they are and the further back over the rib cage they go, the looser the hide is and this is an indicator of more butterfat.

So, with all of this in mind, let’s throw some of natures variability into the equation. As I stated earlier, the data said there were approximately 3700 animals on that island. Some were dying each year as a result of old age, inability to survive the periods of low or no feed, sickness (low glandular function), inability to have the calf and resulting in her death (poor phenotype), some had a calf too early (not enough feed for her to breed back on time). Some had a calf too late (lack of fertility in the cow resulted in a calf too far behind to survive the winter), and other scenarios.

Let’s throw a year in that has 25% more feed than normal. The winter “die-off” is less than normal and now we have 4000 head on the island. Next year is a normal year for forage growth and we have more mouths to feed. Nature is really going to sharpen her selection knife this winter. Remember that at the beginning I said some winters saw 25% of the animals dying? So next spring we wind up with 3000 head, but they are Aleutian Island cattle 2.0. Only the very best shapes, glandular function and butterfat “package” animals survived this winter.

Thinking about my educated guesses above and the portion that might turn out to be correct, and what else might have been happening on that island, I really wish I could go back a decade or more in time and observe these animals in their natural environment. My observations might have been totally different from these speculations, but I don’t think so.

If you have more information on what actually happened there, I would love to hear from you!

Posted on October 18, 2018 .