Palatability and voluntary intake of mineral supplements for grass-fed beef cattle

Ensuring that grazing beef cattle consume the intended amount of mineral supplement consistently, resulting in uniformity of feed supplement intake between animals in a beef herd is one of the most critical success factors in ruminant nutrition. This can be particularly critical for beef cattle under tropical and sub-tropical grazing conditions. A well formulated feed supplement for beef cattle alone does not guarantee performance. Trace mineral supplementation of beef cattle is only efficient when animals voluntarily consume the feed supplement for beef cattle in the right quantity, every day. However, wide variability of consumption is common in pasture systems for beef cattle. This variation compromises productivity, leaving some animals under supplemented and others over supplemented. This will reduce efficiency and economic return in grazing beef cattle. Among the many factors influencing mineral intake of grazing beef cattle such as forage quality, season, feeder placement, water salinity, and genetics, one stands out as both influential and actionable. The chemical source of trace mineral used in feed supplements for grass-fed beef cattle.

Traditional forms of inorganic trace mineral sources for beef cattle such as sulphate salts are highly soluble. They rapidly release free ions not only in the feed or supplement, but also in the upper GI tract of the animal, such as tongue, oesophagus, and finally the rumen. Although sulphates are widely used, their solubility profile can lead to undesirable interactions between free metals (e.g. Cu+2, Zn+2 and Mn+2) and other components in a feed supplement for beef cattle or in a total diet. This can result in a strong undesirable taste that reduces palatability and suppresses voluntary intake of a feed supplement.

Hydroxychloride trace minerals for beef cattle such as Selko® IntelliBond® behave differently. They are practically insoluble when pH is above 4, and therefore relatively stable in the supplement formulation. This controlled release reduces the risk of undesirable taste and undesirable interactions within the supplements. It also means that Selko IntelliBond hydroxychloride trace minerals are stable in mouth, oesophagus and rumen of beef cattle. Metal ions will be released gradually under acidic conditions later in the abomasum. This improves palatability and also minimizes antimicrobial effect and other mineral antagonistic reactions in the rumen, resulting in improved rumen function.

Over the past decade, researchers at the University of Florida have repeatedly demonstrated that trace mineral source influences palatability of feed supplements for beef cattle. This difference in palatability has a big impact on supplement choice and supplement intake of beef cattle^1,2,3,4. Most of these studies were conducted with Bos taurus breeds and with beef calves in creep-feeding and pre-weaning conditions. All studies consistently showed that when sulphate and organic sources of copper, zinc and manganese are replaced by Selko IntelliBond cattle hydroxychloride trace minerals, beef calves have a strong preference for feed formulations including Selko IntelliBond. This preference has been shown across various feed formats for beef cattle, including complete meals, mineral licks and molasses-based tubs (see Figure 1).

While this work provided strong evidence that trace mineral source can have a big impact on palatability and preferential choice, these earlier studies mainly focused on young calves and Bos taurus genetics. Bos indicus breeds represent a major portion of global beef production in the world, particularly in Latin America and other countries in the Southern hemisphere. Data about the impact of trace mineral source on preference and uptake of mineral supplements in Bos indicus breeds of beef cattle are therefore required to optimise performance of beef cattle kept under tropical grazing and management conditions.

Recently, two studies⁵ to evaluate mineral intake behaviour in grazing beef heifers were conducted by researchers from Sao Paulo State University (UNESP-Botucatu) in collaboration with the University of Florida.

Trial in grass-fed beef cattle, material and methods
The studies were conducted with 40 heifers, 20 heifers were Nellore (B. Indicus) breed, and 20 heifers were 50% Angus × 50% Nellore (B. indicus X B. Taurus) crossbreds. The average body weight was 350 kg and the average age was 24 months of age. In both studies, the animals were given simultaneous free-choice access to supplements identical in composition, except for the trace mineral source. One supplement contained sulphates (SUL), the other supplement contained Selko IntelliBond hydroxychloride trace minerals (HYD). In the first study, a mineral-based supplement for beef cattle with a targeted intake of 50-100g of supplement/head/day was included for a trial period of 28days, In the second study, a concentrate-based supplement for beef cattle was used, with a target intake 0.2% of the live body weight, also for a period of 28 days.

Trial in grass-fed beef cattle, results for preferential intake
Both studies revealed a clear influence of trace mineral source on voluntary supplement intake of grazing Bos indicus beef cattle. Throughout the trial period, Nellore heifers consistently demonstrated a strong and sustained preference for beef cattle supplements containing Selko IntelliBond hydroxychloride trace minerals, when compared to sulphate-based formulations (see Figure 2). This behavioural preference reflects not only greater palatability, but also the positive sensory and stability characteristics associated with Selko IntelliBond. Crossbred heifers (50% Angus × 50% Nellore) exhibited a more variable pattern early in the trial, alternating between the two mineral sources for beef cattle initially. However, as the trial progressed, these animals also shifted toward a clear preference for Selko IntelliBond, confirming that palatability advantages extend across beef cattle genotypes relevant to tropical production systems.

Benefits of Selko IntelliBond hydroxychloride trace minerals for grazing beef cattle include:

• Improved palatability, especially in B. indicus cattle breeds
• More animals reach target mineral intake levels for beef cattle
• Lower variation between animals in a beef herd, with fewer under-supplemented animals
• Optimized utilization of the mineral supplement for beef cattle and better value capture
• Greater confidence that mineral programs for beef cattle improve efficiency, which translates into improved beef cattle performance
• Consistent voluntary intake of a beef cattle supplement could improve health, reproduction, growth, and profitability of a beef cattle operation for grass-fed beef cattle