The Challenges of Blending Dairy Minerals in the Summer
The dairy industry uses a wide array of feed ingredients that can vary substantially in their chemical stability. When slightly reactive ingredients (more acidic or basic) make physical contact with other reactive ingredients, there is always the potential for unwanted chemical reactions that mostly result in heating and activation of free moisture. Although reactive ingredients can cause minor destruction of vitamins and other micronutrients, we generally don’t really worry much about ingredient degradation. What we do worry about is runaway heat production and the possibility of serious compromise of the physical integrity of the blend in terms of flowability and future stability. The presence of water or water vapor, even at low levels, tends to increase the risk of heating during blending, by either increasing the friction of blending or by facilitating chemical interactions. As such, the greater heat and humidity of summer should make every mineral blender more focused on the ingredients they use, how they store them, and their SOPs for blending. There are a number of dairy ingredients that tend to be hygroscopic (water attracting) either because of their innate chemistry and(or) because of their extreme dustiness. The presence of these types of ingredients will naturally make the challenges of making mineral blends in the summer even more difficult. In addition, dairy consultants often submit formulas that are possibly too complex to scrutinize closely and (or) too dense for the conditions of summer blending. What follows is some considerations on specific dairy ingredients and blending procedures that may help limit the risk of the negative ingredient interactions and blend heating that can lead to product heating, clumping, or total compromise of the blend.
Warm and sticky is risky
Obviously, difficult weather in a mineral plant is an interaction between temperature and humidity. In broad terms, an outside temperature of 85o F paired with a humidity of 60% is moving into the higher risk zone for blending, as it may be even more humid in the plant. Observable problems may be blend heating, clumping, or appearing to lack normal uniformity. Top-line things to consider:
- Adjust mixing times to account for riskier ingredients. Humidity can cause feed to adhere to mixers and conveyors and increase frictional heating. Overmixing can generate heat and should be avoided. Even consider smaller batches to reduce exposure time to humid air.
- Be more vigilant if the formula seems to have a lot of dusty ingredients. Fine powders, due to their high surface area, readily absorb moisture, leading to clumping, caking, or reduced flowability. The more uniform the particle size of the blend, across the board, the better. Although it adds cost, a clay-based moisture scavenger (anti-caking agent) can always help.
- Monitor riskier blends for evidence of warming.
- Try to increase inventory turnover of hygroscopic or reactive ingredients (below).
- Increase the carrier level (dilution) in blends when it makes sense.
- Use stabilized versions of highly reactive ingredients (e.g. potassium carbonate).
Some ingredients are just more problematic than others
Ingredients that are more acidic or basic will be more reactive. Some ingredients are just inherently hygroscopic. Hygroscopic minerals readily absorb moisture from the air, often forming hydrates that are even more chemically reactive. Ingredients likely to be at least partially reactive include anything with salt, chloride, sulfate, or carbonate (including limestone) in the name. Any NPN source is likely to be hygroscopic and anything that is made of fatty acids (fat) is likely to be reactive or physically active (tacky). Naturally, concentration in the formula is what matters….compare fat encapsulated micronutrients vs bypass fat or oxide forms of macro-minerals vs trace mineral oxides. Although there are probably several other problematic ingredients that could appear in dairy mineral blends. Here are a few ingredients that will raise their ugly heads a little more often:
- Buffers: Sodium sesquicarbonates (S-carbs), sodium bicarb, and potassium carbonate buffers can be both dusty and are strong alkalizers. Potassium carbonate buffers are both hygroscopic and reactive. Fortunately, there are stabilized forms of potassium carbonate (see K-Carb Plus® below) that are less hydroscopic and reactive. These products absolutely should replace common Pot carb in humid weather.
- Fat sources: All fat sources or fat-coated ingredients should be treated suspiciously in mineral blends. The waxy or powdery texture of these materials can lead to clumping when mixed with other feed ingredients, especially under high humidity. Bypass fats often have some fatty acids that can still react with basic minerals. If the mineral blend does warm during mixing, fats will soften and compound frictional heating. Bypass fat in the form of calcium salts (soaps) are perhaps the most notorious, as some free fatty acids are always present and quicklime (reactive calcium oxide) is used in their manufacture and still present in the material.
- Urea: This commonly-used ingredient is also one of the most problematic. When relative humidity hits about 80% at 80o F, urea can absorb about 2 to 3% of its weight in water in just 24 hours. In humid weather days, the best option may be to cut urea back or remove it from the formula entirely.
- Sugary materials: The polar nature of any sugary compound makes this material a magnet for moisture. Any material with high levels of sucrose, molasses, whey powder (lactose), or confectionery byproducts will tend to become problematic when humidity is high. In addition, these materials are often dusty.
- Amino acids: Although free amino acids like lysine HCl or DL-methionine would be good candidates for reacting with basic minerals, these amino acids are never fed in straight, rumen degradable forms. Although fat-encapsulated, bypass forms of both lysine and methionine are available, these product forms could have some of the slight mixing risks mentioned above. Liquid methionine analogue (e.g. Alimet®) is the most notorious methionine source used in dairy feed from the standpoint of reactivity. It is both highly acidic and used in liquid form. Generally, liquid methionine should be used in more diluted mineral/protein blends and specific SOPs should be referenced relative to the feed matrix and inclusion rates.
K-Carb Plus® is the best option for blend-stable potassium carbonate buffer
In the feed industry, there are two types of stabilized potassium (K) carbonates, K carbonate sesquihydrates (e.g. DCAD PlusTM) and K-Carb Plus. The process of creating K sesquihydrates creates a K carbonate that is less reactive than anhydrous Pot carb but at the disadvantage of having a markedly lower K content (56% reduced to 48.5% K). An alternative chemical strategy to dampen the reactivity of K carbonate is to reduce Pot carb’s accessibility to moisture and other chemical reactants via physical coating. K-Carb Plus is produced by a proprietary process of lightly coating granular 56% Pot carb with 5% hydrogenated vegetable oil. This process not only reduces Pot carb’s reactivity but also increases the product’s flowability (granularity). In addition, K-Carb Plus boasts a much higher K content than the K sesquicarbonates (53% vs 48.5%K). Stabilized K carbonates tend to price in the general range of $2,000 per ton wholesale. What this means in terms of practical formulation is that K-Carb Plus is worth about $300 more per ton than K sesquihydrates, simply due to K level. In understanding the effects of product form, seeing is believing.
Be sure and ask your local Barentz Animal Nutrition representative for a sample and more information.