Mineral absorption key to getting more from supplementation

Providing cattle with the right trace minerals is an important part of herd nutrition, but what cattle consume and what they are actually able to absorb can be two different things.

A recent Beef Cattle Research Council (BCRC) article looks at how mineral absorption affects the effectiveness of supplementation programs and how other compounds in feed and water can interfere with the availability of important nutrients.

Trace minerals such as copper, zinc, manganese and selenium support reproduction, immunity, milk production, calf development and overall cattle performance. Deficiencies can occur when cattle do not consume enough of a particular mineral, but they can also develop when other elements in the diet prevent minerals from being properly absorbed.

Understanding mineral antagonists

Mineral antagonists are compounds or minerals that interfere with the absorption or use of essential trace minerals.

According to BCRC, common antagonists include molybdenum, sulfur and iron.

Molybdenum can reduce copper availability, particularly when sulfur levels are also high. In the rumen, molybdenum and sulfur can combine to form compounds that bind with copper and reduce absorption. This means cattle can become copper deficient even when their diet appears to contain adequate copper.

Sulfur, which can be present in both feed and water, can also interfere with copper and selenium nutrition. Iron, while itself an essential mineral, can similarly interfere with the availability of some trace minerals, particularly copper.

These interactions mean producers need to consider more than simply the amount of a mineral included in a ration or supplement.

Bioavailability matters

BCRC also highlights the importance of bioavailability — the portion of a mineral that is actually absorbed and used by the animal.

Different sources of trace minerals behave differently within the digestive system. Inorganic minerals, including sulfates, oxides and carbonates, are commonly used because they provide essential nutrients at an economical cost. However, they can also be more reactive in the rumen and susceptible to interactions that reduce absorption.

Organic trace minerals are bonded to amino acids, proteins or organic acids to increase their availability to the animal, while hydroxy trace minerals have a structure designed to reduce reactions within the rumen and improve bioavailability.

Mineral availability can be particularly important during periods of increased nutritional demand or stress, including breeding, calving and transportation.

Getting more from a mineral program

The BCRC emphasizes that an effective mineral program requires consideration of both mineral intake and the factors that influence absorption.

Understanding mineral levels in feed and water, potential antagonists and the bioavailability of different mineral sources can help producers determine whether cattle are receiving the nutrients they need.

The full BCRC article, From Intake to Absorption: Getting More from Your Mineral Program, provides additional information on mineral deficiencies, antagonists and different sources of trace minerals.

The Beef Cattle Research Council is funded by a portion of the Canadian Beef Cattle Check-Off.