Bovine biology series
Part - 45 Life cycle (6/8)
This is our sixth lesson of the life cycle. This month we examine lactation.
Lactation is a word defining our industry, the root of which comes from the Latin word "lactatio" which means to suckle and the word "lactatus" which means to secrete milk. The word milk has English origins, coming from the Old English word "meolc, or milc". The word milk is not always associated with mammary gland secretions, for milkweed is the name of bitter tasting weed in our fields, milk can be found in the juice of a coconut, or in the unripe kernel of wheat, barley or wheat. Even corn.
But for the dairy industry, lactation and milk are central and foundational words defining not only our economic well being, but by our cows’ biological primal function.
One may wonder why cows, of all domestic animals, were selected for the foster mothers of humankind? This was not always the case, for indeed, the ruminant has served many roles as a draft and/or beef animal as well as provider of milk. Actually in ancient times when civilizations desired the milk and honey of bountiful years, the duty of milk production fell upon goats, taking far less feed and easier to maintain when times of food and feed shortages occurred.
Yet ruminants soon became the obvious providers of larger quantities of milk, for in the Northern latitudes of Germany, France, The Netherlands and the Nordic Countries, upon cool pastures there grew bountiful grasses almost year around, so cows could be fed and hence, gallons of milk could be obtained instead of pints or quarts. Cows came to the America’s almost 300 hundred years ago, no doubt riding the sea-faring ships in beds of straw while the crew had fresh milk as long as the cows could be supplied with enough water.
Cows soon populated the East Coast, largely in Pennsylvania, New York and Vermont, until our bold ancestors walked them to the Midwest. Later, of course, cows would leave these fertile states for the West, sometimes walking along the Oregon Trail tended by the children, sometimes riding these cows if the children got tired. Some were even loaded into rail boxcars and thus destined for the West, arriving at a train station, along with horses and large numbers of sheep. The Union Pacific Railroad hauled hundreds of thousands of cows and sheep to the West.
Once cows landed on a farm, the farmer became a dairy farmer, if in part, for he also fed hogs grew cereals and might have even had an apple orchard. The valuable part was the cream, while the skim, a discarded and no value by-product, was consumed eagerly by pigs that became well fed hogs. You see, even back in my Grandfather’s days farmers recognized the value of by-product feeding and recycling!
All that changed in the early two decades of this century when an expanding population desired milk with cream, but the real reason for this volume increase was higher milk quality standards so that milk would not spoil. Farmers had electricity now, and therefore they could refrigerate milk instead of placing the ten-gallon milk can into a cool stream or ice bank.
I have visited our old farms where my ancestors used to store cans in a concrete bin lined with ice kept cold with creek water.
Then, of course, with the advent of artificial insemination and the record keeping system that would become DHIA, along with something called the Land Grant University System (and thus Extension!), cows truly became consumers of grass and hays and cereals while giving several gallons each day of milk that was and is today high in quality so that once on the dairy shelf, its contents will not spoil.
What a wonderful journey! And to think all of this is possible because the cow is a ruminant and she is a grass consumer, making use of feed that we cannot consume, on land (and climate) that is ideally suited for grass, perennial pastures, instead of tillage for cultivation and possible soil erosion loss.
Now when we think about lactation, we may wonder why, in the evolutionary journey of development, a cow developed a secretory system in the first place. In higher animals, of which mammals occupy, the young are born before they are truly capable of existing on their own. That is, the organs and mainly the brain and nervous system are still growing.
The limitations of the in-utero space are many, including limited size because of pelvic bone structure, oxygen supply because the molecules must be transported via blood after maternal absorption, waste products are not easily discharged and most of all, fetal caloric needs outgrow the cows’ ability to supply them (during the finals days of gestation the fetus will increase one pound of body weight daily!).
So in mammals, the fetus is born but the newborn continues to grow. It is the milk, of course, that is rich in high quality amino acids and proteins that supplies the newborn with nutrients for brain and organ growth. Since the newborn can breath on its own, oxygen is readily consumed by lung tissue. And the digestive system is able to discharge undigested food via the large intestine and colon, and unneeded metabolites leave through the efficient kidneys.
We have arrived today with herds of cows possessing tremendous genetic ability, for lactation, for the production of large quantities of milk from feeds of many origins. The mere fact that we may milk a cow for year after year if she is not pregnant and we do not dry her up is quite amazing.
But so is the basis of what makes a cow a cow, and I need to look no further than driving by Sar Ben (St. Paul) the other day and seeing hundreds of fine cows grazing in a field, or two days ago watching a uniformly statuesque pen of two year olds standing at a feed bunk at Slegers Dairy (Dayton), consuming nine or ten ingredients mixed together that morning.
Yet it is in Albertson’s or Safeway’s that I am truly amazed, for with the wide variety of high quality cheeses, yogurts, milk and something called ice cream, therein lies the reason for doing what we do.....feeding the neighborhood and feeding the world, if found on the back of a camel that has a sack of milk powder on it with the initials DF, or a pallet of butter from FCC destined for Europe or Asia.
All this from a cow, a biological wonder, a foster mother for us all, and this is based upon one word: lactation.
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