By Adriane Good, M.Sc., PAG, Livestock and Feed Extension Specialist, Moose Jaw
March 2025
Minerals play a crucial role in livestock nutrition, supporting animal health, productivity and overall well-being. While meeting mineral requirements may seem simple, minerals interact with each other in ways that can either enhance or block absorption. This can lead to deficiencies that are difficult to predict and diagnose, as many deficiencies can present similar signs.
A common antagonist in Saskatchewan is sulfur, which is often found in livestock drinking water sources. Sulfur can interfere with absorption of copper, zinc and manganese, leading to poor performance, reduced fertility and a weakened immune system. Molybdenum also interferes with copper absorption, leading to the same production challenges.
the common mineral interactions in
livestock feed and water.
Antagonism isn’t the only interaction that is important in minerals, some minerals need to be balanced in the diet in specific ratios for optimal performance. The most well-known ratio is calcium to phosphorus (Ca:P). A total diet ratio 2:1 Ca:P is ideal for bone strength, muscle function and growth. Another important ratio is the amount of potassium compared to calcium and magnesium, called the Tetany Ratio. The ratio of potassium to calcium plus magnesium should be lower than 2:2. Excess potassium can lead to grass tetany – a condition where livestock may struggle to stand, arch their back or experience muscle twitching.
In some cases, a deficiency of one mineral can make another deficiency worse. For example, selenium and iodine are both essential for thyroid function. A lack of iodine can cause goiters, poor hair or wool quality and reduced fertility. A deficiency in selenium may exacerbate the iodine deficiency, as selenium is an essential component of several enzymes related to thyroid function. This could result in a minor iodine deficiency having severe results if coupled with selenium deficiency.
Luckily, managing mineral interactions can be relatively simple with proper planning. A great start is to test your feed and water for mineral content. A basic feed and water test package may not analyze all minerals, but additional testing can be added if you have concerns about your animals’ mineral status. Understanding what you are providing to your livestock through the feed and water is the most important step in planning to alleviate concerns associated with mineral interactions. When choosing your mineral, look at both the form and amount of each mineral in your supplement. For example, if your feed and/or water is high in sulfur, avoid minerals that contain a high proportion of copper sulfate. If your forage is high in selenium, choose a mineral that has low or no added selenium to avoid toxicity.
Understanding mineral interactions and the impact they can have on your herd can be complicated, but it can improve your herd’s health and productivity. For more information on selecting the right mineral for your operation, contact your local livestock and feed extension specialist.