Mining an old topic to help improve production

News
Nov 15, 2013
by WLJ

—Minerals are crucial to bovine health

The notion that minerals are a necessity for beef production is not a new topic by any means in this industry. Research, along with years of practice, has shown again and again that the mineral status of a beef animal can affect health, forage utilization, growth and reproductive performance; all factors that can impact profitability. Minerals make up a small part of an animal’s diet, yet it is important to not overlook the fact that the cost of improving an animal’s mineral status is low compared with the potential production returns. Meeting the animal’s requirements for these minerals to achieve desired production levels is not only beneficial for the production ability of the animals, but it provides long-term economic advantages.

Stage of production and forage quality dictates the animal’s requirement for mineral supplement. Therefore, having a working understanding of these values and knowing if your current supplementation program meets the cow’s needs is important. By taking a proactive approach in understanding your cowherd’s mineral requirements during different stages of production, along with knowing the varying mineral content of the forages they consume throughout the year (by taking a forage sample to determine nutritive value), you are able to make better decisions on what minerals to supplement.

The goal of this article is not to give an exhaustive review of minerals, but rather to provide a brief summary of the important macro and trace minerals required by cattle, and how they impact beef cattle productivity.

Hopefully the next time you purchase a bag of minerals you will have a renewed understanding of why we supplement minerals and a stronger appreciation for the specific production benefits associated with mineral supplementation.

Macro-minerals: Major minerals that are required in larger amounts than micro (trace) minerals, usually expressed as a percentage of the diet or grams per day.

Calcium (Ca): Calcium is vital for bone and teeth formation, nerve function, muscle contraction, milk production, and cell permeability.

Calcium deficiencies can cause osteomalacia (weak and brittle bones) and milk fever. On forage-based diets, calcium is usually adequate (especially with legumes). An animal’s calcium requirements must be considered with regard to phosphorus, as these two minerals interact very closely. Therefore, recommendations for calcium are generally expressed in relationship with phosphorus as a ratio: Ca:P, with a range of 1:1 to 4:1, is considered satisfactory.

Phosphorus (P): Like calcium, phosphorus is important for bone and teeth formation, but it is also an essential component in protein and energy synthesis and metabolism, and consequently the animal’s reproductive ability. Phosphorus deficiencies have been shown to decrease growth, reduce dry matter intake, and cause fragile bones. Phosphorus can be deficient in forages, and therefore phosphorus supplementation is especially important during drought conditions or in the fall and winter months when forages are more mature and may have depleted phosphorus concentrations. Phosphorus requirements are presented in terms of the Ca:P ratio described earlier.

Magnesium (Mg): Magnesium is essential for normal skeletal development, reproduction, and is required for more than 300 metabolic reactions within the body. Deficiency symptoms can include nervousness, tremors, hyperirritability and loss of appetite. Low magnesium levels in the blood are also a cause of hypomagnesemia (grass tetany), a condition that may be common among lactating beef cows grazing lush forages.

Potassium (K): Potassium is involved in numerous cellular and enzyme functions. Muscle contraction, fluid transport, hormone release and embryonic development are dependent upon potassium in the body. Potassium deficiencies can result in reduced feed intake, weight loss, poor electrolyte balance and restricted calf growth. Most forage typically supplies adequate amounts of potassium, but low levels can be observed during winter months due to plant dormancy. Potassium retention may be an issue if forage also has low magnesium, which can lead to a potassium deficiency.

Sodium (Na) and Chloride (Cl): Sodium and chloride work in unison to sustain cellular volume, pH, and water balance. Deficiency symptoms include reduced growth and efficiency of feed utilization in growing animals and reduced milk production and weight loss in adults. Additionally, if requirements are not met, infertility in males and delayed sexual maturity in females may occur. Sodium chloride (salt) promotes water intake, which will help maintain or improve milk production. Cattle crave sodium; therefore, salt is fed not only to provide Na and Cl, but also as an incentive for animals to consume other minerals, while also functioning as a limiter of feed consumption.

Sulfur (S): Sulfur is required by the rumen microorganisms to produce sulfur containing amino acids (such as methionine and cysteine). Sulfur is also an important part of lipid and carbohydrate metabolism. Decreased growth is a symptom of sulfur deficiency, which is primarily due to not meeting the sulfur amino acid requirement for protein synthesis.

Micro-minerals: While trace minerals are required in lesser amounts compared with macro-minerals, they still play key roles in maintaining normal body function. Requirements are usually expressed in parts per million (ppm) or milligrams per kilogram of body weight (mg/kg).

Cobalt (Co): Cobalt is a dietary essential element for the production of B-Complex vitamins by rumen microbes. Vitamin B 12 is used by the microbes to produce propionate, which is a volatile fatty acid and an important energy source for the animal. Cobalt tends to be deficient in the southeastern U.S. and in alkali soils. Deficiency of cobalt can lead to loss of appetite and body weight, and reduced milk production.

Copper (Cu): Copper is a major part of a strong immune system. It is essential in many enzyme systems, for hair development and pigmentation, bone development, reproduction and lactation. Deficiency symptoms include fading hair coat, nervous disorders, lameness, joint swelling, reduced conception rates and compromised immune system. The sulfur and molybdenum (Mo) content of a diet affect copper absorption. Therefore, it is important to be aware of their concentrations and how they might impact copper availability. Presence of high dietary molybdenum and sulfur promote formation and absorption of thiomolybdate into blood, which renders copper unavailable to the animal.

Iodine (I): Iodine is critical for maintenance of normal metabolic function through its role in the thyroid gland (which affects nearly every physiological function in the animal). Low levels of iodine can reduce hormone production in the thyroid, which can result in lower milk production, and poorer overall herd health. Enlargement of the thyroid gland can characterize an iodine deficiency.

Iron (Fe): Iron is the most abundant trace mineral in the body, and is an essential component of hemoglobin, which is necessary for transporting oxygen and carbon dioxide to and from the tissues and the lungs. Iron deficiency causes decreased feed intake, reduced weight gain, and lethargic behavior. Iron is antagonistic to the absorption of zinc, copper and phosphorus in cattle, and can contribute to deficiencies in these minerals if supplementation levels are not adjusted to compensate for their losses.

Manganese (Mn): Manganese is essential for normal bone formation, growth and reproduction. Additionally, manganese is involved with amino acid metabolism and fatty acid synthesis. Deficiency symptoms include poor growth, lameness, low birth weights and reduced conception rates.

Selenium (Se): Selenium works with vitamin E to improve immune function and develop antioxidants in the body. Selenium deficiency can lead to white muscle disease (muscle breakdown in calves), weight loss and reduced reproductive efficiency.

Zinc (Zn): Zinc is a major factor in developing and maintaining a strong immune system. Additionally, zinc is an important cofactor in many enzyme systems, and is required for protein synthesis and metabolism. Deficiency symptoms include loss of appetite, retarded growth and a compromised immune system. Foot rot may also be a result of low zinc in the diet.

Summary

Minerals, while a small proportion of a cow’s diet, play an essential role in the productivity and health of the beef animal. Having a firm grasp of the roles that each mineral serves in the body and how it impacts production is a key tool to consider when managing and setting production goals. Investing in a good mineral program and properly managing consumption will pay dividends in the long-term performance of the cowherd, as well as the economic returns to the operation. — Kyle Weldon, Anipro/Xtraformance Feeds

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