My good friend and client Carl lived down the highway about 3 miles from our home. He was a good farmer and dairyman who milked about 30 cows. My vet calls to his place were mostly for routine jobs like dehorning or vaccinating with an occasional milk fever or dystocia. His cows were well cared for and healthy. For many years he supplied our family with fresh milk right from the bulk tank. One year inclement weather made planting and harvesting hay and grain crops a great gamble with the result that feedstuffs that fall and winter looked good but had low nutritional value. By late winter Carl consulted me with two seemingly unrelated problems. One, his cattle were eating almost 2 pounds of a mixed mineral per head per day! Two, about 10 days before they were due to calve, his heifers would abort a live calf. The calf, with some care, would live, but in spite of all we could do the heifer would die within two or three days. After the third one in a row had died, I did what every smart vet would do ... I passed the buck and sent a dying heifer to the University Vet School for autopsy. Their diagnosis came back as starvation! Carl took good care of his animals and was feeding them almost all they could eat. This diagnosis was like an insult to Carl and difficult for either of us to accept. We could have accepted a diagnosis of malnutrition because of the poor crops that year but starvation seemed a little too harsh.
We then turned our attention to the mineral consumption problem. Available in that area at that time was a “cafeteria” mineral program in which each mineral was fed separately on the theory that each animal could then eat only what it needed to balance its own needs. Carl decided to try this program. His mineral feeder was in the middle of his cow lot and he had to carry each bag of mineral through the lot to empty into the feeder. Things went well for the first few trips, and then suddenly several of the normally docile cows suddenly surrounded him, tore a bag of mineral from his arms. chewed open the bag and greedily consumed every bit of the mineral, the bag and even some mud and muck where the mineral had spilled out ... astounding behavior for a bunch of tame dairy cows!
What was in the bag, you ask? … a source of the trace mineral, zinc. During the next several days they ate several bags of this zinc source while completely ignoring all other minerals. Gradually they began eating normal amounts of the regular mineral. From that day on his heifers calved normally and things gradually returned to normal.
Apparently, the difficult growing season has resulted in crops that were deficient in zinc or perhaps high in zinc antagonists. The basic mineral mix had a small amount of zinc in it but to get the zinc they needed, they had to consume large amounts. This gave them too much calcium. Calcium interferes with zinc absorption, which in turn increased their need for zinc. Even though their quest for zinc impelled them to eat the mixed mineral, every mouthful they took increased the imbalance.
Inevitably, symptoms began to show up in the most vulnerable group ... young heifers, still growing and in the last stages of pregnancy. Finally they just gave up and checked out ... all for want of a few grams of zinc. The decrease in feed conversion associated with zinc deficiencies coupled with the poor quality feed would result in malnutrition even when feed intake appeared to be adequate. I realize that other secondary factors may have been involved here, but the main factor was a zinc deficiency as evidenced by the remission of symptoms when zinc was supplied. (See “Zinc” side bar).
Carl had done as good a job as he could with the knowledge that was available at the time. When the essential ingredients were finally provided so that the animals could make their own choice, they picked out what they needed to regain their health. For me this incident epitomizes the concept that, given the chance, animals can balance rations better than computers or nutritionists can.
Many nutritionists tend to discount the ability of animals to balance their ration, asserting that by the time they feel the need to eat a certain item they are already in a deficient state. From their point of view, I suppose they have a point. The fallacy in their reasoning may be that they expect the animal to choose for the level of production that man desires while the animal chooses only what it needs to be healthy.
Healthy production is the most profitable...in the long-term,
if not in the short-term!
Many years ago I was associated with a feed company that formulated and sold premixes for dairy cattle. It was a good feed, based on “natural” ingredients and principles. Many of the users commented on the superb health experienced by the animals on this program ... better reproduction, less mastitis, low cull rate. healthy calves, low vet bills, etc.
The down side was that production, although profitable, did not reach the high levels they had come to expect when feeding a more “conventional” ration designed mainly to increase production. Many dairymen who switched to such a feeding program often saw their production increase dramatically.
Unfortunately, in most of these cases, it wasn’t very long, and problems began creeping back into the herd ... cows didn’t come in heat like they should, conception rate when down. There were more cases of mastitis, calves didn’t do as well, vet expense increased, more cows began leaving the herd for health reasons. Eventually even production began to slide. The short-term higher production had been gained only at the long-term expense of lowered herd health, proving that old saying “there is no free lunch.”
There does seem to be a level at which animals can maintain health and have profitable production. The animals on the “natural” feeding program had achieved this happy state and the overall financial benefit associated with good health more than overcame the lower production and slightly higher feed costs.
When a herd like this is switched to a “conventional” program concerned mostly with high production the increased production and slightly lower feed costs usually do not make up for the increased costs of poor health.
See everything you look at!
The above experiences, along with many others, confirmed for me what Dr. Albrecht, Sir Albert and Mr. Poirot had discovered years before. Building on the foundation they had provided, I subsequently learned a lot about nutrition and animal health just by paying attention to what animals ate and the effects on their health. You, too, can prove these things to yourself, by doing the same thing. I remember Dr. Albrecht saying, “Study books and observe nature, if nature and the books do not agree, throw away the books.” I agree.
1. Albrecht, Dr. William. Soil Fertility and Animal Health. Fred Hahne Printing Company. Webster City, Iowa. 1958, Has been reprinted as Volume 2 of a 4 volume set, “The Albrecht Papers”, available from ACRES U.S.A., P.O. Box 8800, Metairie, LA. USA (505) 889 2100.
2. Howard, Sir Albert, An Agricultural Testament. Oxford University Press 1940
3. Poirot, Eugene M. Our Margin of Life. Acres, U.S.A. Raytown, MO 1978
Stress (including parturition) appears to increase the zinc requirement of animals.
Zinc is required for the incorporation of cystine into keratin and thus plays an important role in maintaining hoof, horn and skin integrity.
Zinc plays an important role in wound healing, immune function and disease resistance. Some studies indicate that the first symptoms of a zinc deficiency is a decrease in immune function and a decrease in feed conversion.
Zinc plays a role in vitamin A transport and utilization and appears to play a role in vitamin E absorption. Reproductive performance after parturition improves with both zinc and vitamin E supplementation in late pregnancy.
High calcium and iron intake (including Ca and Fe in water). will increase the zinc requirement.
Deficiency symptoms may include general listlessness, poor growth, stiff joints and unthrifty appearance, hair loss, general dermatitis of head and neck and failure of wounds to heal properly.