We often talk about forage quality factors such as percent protein and amount of total digestible nutrients when we look at how good a forage is for a particular group of livestock and if it meets their nutritional needs.
Seldom however, are vitamins and minerals in a forage for beef cows even mentioned in the conversation. I think this happens, often, because problems from minor mineral shortages are not easily detected and seldom attributed to a mineral shortage unless a prolonged period of a deficiency occurs.
Since forages vary so much in their ability to provide adequate minerals, it’s generally recommended to provide supplemental minerals and vitamins to a beef animal’s diet. Minerals are essential for normal animal functions to take place and problems can arise when forages fed do not supply enough minerals.
The problem may be because the feed is low in minerals, the availability of the minerals within the feed is low, or another nutrient is interfering with the ability of the animal to absorb the mineral. Do your livestock need supplemental minerals? How would you know if they did need something additional? Are there deficiency signals? What are they? Are you losing production (pounds of calf to sell) because your feed does not contain enough minerals?
Mineral supplementation in beef cattle is usually divided into two major categories: macro-minerals, or those generally required in amounts greater than 1 gram per head per day; and micro-minerals, ones required in amounts less than 1 gram per head per day.
The macro and micro terms have no relationship to the importance of a mineral in the diet. A micro-mineral can be as essential to the health and performance of an animal as a macro-mineral.
The macro-minerals include calcium, phosphorus, magnesium, potassium, sodium, chlorine and sulfur. Among some of those needed in trace amounts are iron, zinc, manganese, copper, iodine, cobalt and selenium.
No mineral is absorbed and utilized 100 percent as fed. The rates vary depending on the source of the mineral and several other factors. Adequate intake and balance are required for proper functioning of metabolic processes such as reproduction and the animal’s immune response, among others.
The old saying “A little is good, so more must be better” does not apply in mineral supplementation. Certain minerals can actually be toxic if supplemented in excessive amounts.
Balance is the key because one mineral can affect the absorption of another mineral. All forages have different amounts of minerals in them and the amounts may vary depending on stage of maturity when the crop was harvested.
Also, different stages in the livestock production cycle require different amounts of minerals. For example, a lactating beef cow consuming lush, quick-growing grass pasture in the spring is more likely to experience grass tetany than at other times of the year. Prevention measures could include adding additional magnesium to the diet.
So, how do you provide the proper minerals for your livestock? Each producer must look at their forage’s nutrient levels along with their production and management practices to determine their need. One mix or supplement is not applicable to all situations or locations in the state and producers should not buy minerals on price point alone.
Some minerals in the oxide form are only 10-20 percent as absorbable by the animal as other forms. Soil characteristics and concentrations of minerals in the soil, amount of fertilization applied, timing of forage harvests and other factors must be taken into account to determine your needs.
For this reason there are many commercial mineral supplements available in a variety of formulations. Choose one that most closely fits your need (laboratory forage analysis of your hay lots will be a big help here). Custom mixes may also be tailored to fit specific situations where a known lack of a mineral in an area is prevalent.
For most grass-based grazing operations free-choice feeding of minerals is a satisfactory method of mineral supplementation. However, some animals may over consume a self-fed supplement while others will eat less than they need. In this system, salt or highly palatable concentrates are used to encourage supplement intake.
Salt is really the only mineral livestock crave, so by adding a complete mineral mix with salt producers can be more confident livestock will not over consume, yet still obtain enough minerals to meet minimum requirements. A target intake of 2-4 ounces per animal per day is a common recommendation (see the label).
At this point some might even say, “I’ve never supplemented minerals and still have calves to sell each year.” If you do an extremely good job harvesting forages properly you may not see much of a problem, but would the calves have weighed more when weaned if minerals were supplemented? Did momma cow breed back the first cycle after turning the bull in or were there two or three cycles before she settled?
Did the calf gain as much as it possibly could? Did the cow produce her maximum amount of milk or, would she have produced more with mineral supplementation? Were there any animals that looked a little unhealthy at some point?
Determining pounds of gain lost in feeder calf production, due to minor lack of minerals or nutrients, is very hard to do. This is because there are so many variables that can not effectively be measured by the producer and they are strung over a 16-18 month period, from when momma should have been bred until the feeder calf is sold.
Feeder calf weaning weights are going to be highly correlated to your pasture and water’s quality and availability during the calf’s growth period, but adequate minerals play a role too. Don’t get caught short!
(The author is an OSU Extension Agriculture and Natural Resources Extension Educator in Monroe County, Ohio. Questions or comments can be sent in care of Farm and Dairy, P.O. Box 38, Salem OH 44460.)