The trace minerals (TMs) zinc, copper and manganese are components of a wide variety of enzymes and proteins that support metabolism, growth, production and reproduction. TM supplements are added to dairy cattle rations to prevent mineral deficiencies, and supplementation has traditionally been provided in the form of inorganic salts, e.g. copper sulfate, zinc sulfate and zinc oxide.
The various TMs used as feed additives can be distinguished by their availability to the animal. One problem associated with feeding TMs provided in the form of inorganic salts is that they break apart quite readily in the rumen of the dairy cowâs digestive system.
This allows the trace minerals to form indigestible compounds with other feed components, rendering them unavailable for absorption in the intestinal tract.
In contrast to inorganic TMs, organically bound TMs (chelates) are more stable in the diet, and absorption is improved due to their chemical structure.
TMs have been categorized as either organic or inorganic. A new category of TMs, known as hydroxy trace minerals, has been introduced as an improved source of copper, zinc and manganese in cattle.
Hydroxy TMs are fully defined crystalline structures held together by covalent bonds, similar to the bonds found in top-performing organic TMs.
The combination of stable bonds and the unique crystalline structure provide hydroxy TMs with a high level of product stability in the feed and in the animal compared to alternative trace mineral sources.
All hydroxy TMs provided in the forms of basic copper chloride (54 percent copper), zinc hydroxychloride (55 percent zinc) and manganese hydroxychloride (44 percent) are manufactured from virgin food or feed-grade metal oxides as the starting raw materials.
Thus, they provide a high level of product purity combined with exceptionally high trace metal potency. They are non-hygroscopic (do not absorb water) and free of dust. They are non-oxidative; hence they have no negative effect on essential nutrients like vitamins, fats, etc.
These factors represent a significant improvement over sulfate forms of TMs given the known ability of sulfates to negatively impact vitamin integrity in mineral-containing supplements.
A primary benefit of hydroxy TMs is their ability to efficiently bypass the rumen, avoiding rumen antagonists that can severely degrade TM bioavailability.
This results in more TM being delivered to the bloodstream driving cow productivity and well-being at a price point well below current program alternatives.
A recent transition dairy cow study conducted at Cornell University showed positive effects from feeding hydroxy TM for both FCM production and immune/antioxidant status.
Sixty second-lactation and greater cows were fed one of three mineral programs: inorganic sulfate TMs (zinc, copper and manganese); a blend of 75 percent inorganic and 25 percent organic TMs; or hydroxy TMs (zinc, copper and manganese).
All minerals were fed 21 days before calving and up to 84 days post-calving. Cows fed hydroxy TMs increased milk yield faster than cows fed the other two treatments.
In comparison to the combination inorganic and organic trace mineral treatment group, the hydroxy TM-fed cows also had improved immune status and lower TM feeding costs.
The supplementation of TMs plays an essential role for optimum health and performance of dairy cows. When considering the sourcing of TMs, it is the usable amount of TM successfully delivered to the bloodstream that is crucial.
This requires accurate knowledge of basal ingredientsâ composition and the true bioavailability of different TM sources when determining how to best achieve the targeted level of TM nutrition required by the cow.
Hydroxy trace minerals can provide the ability to cost-effectively replace the use of sulfates and organic trace minerals in rations, resulting in more essential nutrient stability in the feed and increased trace metal absorption, thereby supporting optimized cow productivity and well-being. PD
Higginbotham is the ruminant technical services manager for Micronutrients. He can be reached by email .
Gerald Higginbotham
Ruminant Technical Services Manager
Micronutrients
