Let your animals balance their mineral requirements
By Richard J. Holliday, DVM
Before domestication, cattle lived a lifestyle similar to that of bison in the early American West. Many different plants with different nutrient and mineral profiles were available. Free to roam over wide, naturally fertile areas, the animals could seek out plants that met their nutrient requirements. Mineral needs could be fine-tuned by visiting naturally occurring salt or mineral licks. Specific imbalances of soil in one area would be offset by excesses or adequacy of the same element in other areas. Thus, over a period of time they could seek out and obtain balanced minerals and nutrition.
It’s a lot different today. Several changes have negatively influenced the expression of our animal’s inherent nutritional wisdom:
• Soil depletion has resulted in lower nutritional value of crops and forages.
• Varying degrees of confinement restrict nutritional diversity.
• Contamination of our soils, crops and feeds with toxic GMOs, insecticides and herbicides, such as glyphosate, interferes with mineral adsorption.
• Dairy cattle have been genetically modified to produce at levels never intended by nature, creating a higher nutrient demand for forced production resulting in rations that contain excess protein and minerals.
Feed testing is, of course, a necessary part of our present day computer-generated nutritional science. Unfortunately, nutritionists often rely totally on lab results and overlook the fact that the biological attributes of a feed are more meaningful at predicting the productive response of animals. It is one thing to know what’s in a feed, but quite another to gauge interactions between the chemical composition of the feed with the metabolic capabilities—digestion, utilization and assimilation—of the animal being fed.
The success of the modern dairy industry in achieving high production is offset by its dismal record of animal health and longevity. Most dairy cows do not live long enough to complete two lactations and 50 percent calve with either an infectious disease or a metabolic disorder such as ketosis and clinical or subclinical milk fever.
Many feed analyses do measure mineral content, but as a practical matter most nutritionists add a one-bag-fits-all trace mineral package to the ration without regard for any excesses or imbalances thus created. Either excesses or deficiencies can have serious metabolic side-effects. For example, high iron ties up copper, cobalt, manganese and zinc, which are all essential to immune response. Excess calcium in a ration will increase consumption of phosphorus if available.
There is great variation in mineral concentration in soils in different parts of the country. Given the fact that all soils differ in their mineral content and that no two animals have the same needs, it is a difficult task to correct mineral imbalances.
Today, imbalances—deficiencies or excesses—of major, minor and trace minerals are one of the major factors underlying reduced animal health, production and reproduction.
Dr. Linus Pauling, the only person to ever win two unshared Nobel prizes, has been quoted as saying, “You can trace every disease and every infection to a mineral deficiency from unequally yoked energy fields.”
The solution to many of these problems is to provide a source of individual, self-selected, free-choice, cafeteria-style minerals and again allow the animals to exercise their inherent nutritional wisdom to balance their mineral needs.
Years ago my introduction to this concept occurred when a good client called me because his dairy heifers were calving early and although the calves would live the heifers would often die. He also complained that his cows consumed an inordinate amount of minerals. He decided to try a “cafeteria” mineral program in which each mineral was fed separately. His cows paid little attention as he was putting the separate minerals into the feeder until he carried a bag of zinc trace mineral mix into his cow lot. The cows tore the bag from his arms, chewed the bag open and ate the entire contents. Within a week after the mineral change, mineral consumption returned to normal and his remaining heifers calved normally. Apparently, his forage was deficient in zinc or perhaps high in zinc antagonists. His mineral mix was high in calcium with only small amounts of zinc. Their quest for zinc impelled them to over-eat the mixed mineral. Excess calcium interferes with zinc absorption. Every mouthful they took increased the imbalance and escalated their need for zinc. Inevitably, metabolic problems began in the most vulnerable group—young, growing heifers in the last stages of pregnancy. Finally they just gave up and checked out—all for want of a few grams of zinc.
Anyone who doubts that cattle can make valid nutritional choices needs to watch cows graze in a mixed pasture. They do not just mow grass like a lawn mower, but pick and choose each mouthful. They avoid eating the bright green grass surrounding “cow pies” in the pasture and will search the fence-rows for weeds that concentrate various essential trace minerals. Given proper forage choices, they will balance their nutritional needs during each feeding period.
Eating dirt, chewing on wood, licking or drinking from urine puddles or other abnormal appetites are attempts to secure some vital element or attain some nutritive balance that is not otherwise present in their diet. These behaviors should be considered a warning signal that something is amiss in the ration. Some consider it normal because it is so common. And it may be “normal” in the sense that it is appropriate, compensatory behavior for animals forced to subsist on a mineral-deficient or imbalanced ration.
Milk fever is another good example of the effects of a poorly designed mineral program. Postparturient hypocalcemia is not a disease; it’s the clinical expression of a mineral imbalance at a period of physiological stress. While the final expression of milk fever is caused by low blood calcium, the predisposing cause is high calcium/low phosphorus in the ration or sources of phosphorus that are relatively unavailable. If the calcium-phosphorus ratio is 1:1, or even higher in calcium, during the dry cow period and especially in the last three weeks before calving, there is a relative deficiency of phosphorus. To compensate for this deficit, the body sets up to reject calcium and to absorb phosphorus. After calving, it takes 72 hours for the metabolism to readjust to absorb adequate amounts of calcium. The entire circulatory system of a dairy cow contains only 3.5 to 5 grams of calcium. At calving, the sudden increased demand for calcium—20 to 30 grams—as cows synthesize colostrum and begin milk production depletes blood calcium faster than it can be replenished from other body reserves resulting in varying degrees of hypocalcemia.
Incidence of clinical hypocalcemia in U.S. dairy herds averaged 5.2 percent while the prevalence of subclinical hypocalcemia is about 25 percent in first lactation animals and almost 50 percent in second and higher lactations. In both cases the associated reduction in immune function combined with reduced smooth muscle contraction can lead cows to develop other disorders such as dystocia, uterine prolapse, ketosis, metritis, mastitis, and DAs.”
The major benefit of a cafeteria-style mineral program is that it not only allows the animal to satisfy mineral deficiencies of the present ration, but also allows the animal to consume additional minerals, as necessary, to satisfy tissue deficiencies caused by previously unbalanced rations. This results in the temporary consumption, at times, of some minerals in amounts that are considered by some to be more than the needs of a given ration.
Scientific research has proven time and again that various mineral deficiencies within the physiological system or the animal are the ones that in reality prevent the animal from producing and or reproducing at optimum. Mineral deficiency affects animal performance shortly after mineral deprivation, but it may take several months before clinical signs of the deficiency become apparent. During that lag time productivity suffers.
If you just want to experiment and give your cows a chance to participate in their own mineral formulation, provide separate free-choice sources of these 6 items:
• Plain white salt
• bentonite clay
• Bicarbonate of soda
• A basic mixed mineral with 2:1 Ca/P ratio
• A basic mixed mineral with 1:2 Ca/P ratio
The separate sources of Ca and P allow them to adjust the critical Calcium/Phosphorus ratio, which affects the absorption and utilization of all other mineral elements. (See Mineral Wheel.) Cows with rumen acidosis will prefer bicarb or bentonite. If they lack trace minerals they may eat a lot of kelp. If kelp consumption remains high you may want to provide separate sources of some of the trace minerals such as zinc, copper, iodine and sulfur. There are commercial companies that provide a broad range of separate free-choice minerals and trace minerals.
The bottom line is that we should use our nutritional knowledge to formulate dairy rations, but also rely on the nutritional wisdom of animals to fine-tune their individual mineral needs. It doesn’t hurt to have two opinions: one from your nutritionist’s computer and one from the real experts—your cows. I will leave it to you to decide which one is the most reliable.
Richard Holliday is Senior Veterinary Consultant for the Organic Division of Advanced Biological Concepts®. He has been promoting organic agriculture and holistic veterinary medicine for over 40 years.
From the January | February 2015 Issue