The threat posed by mycotoxins to beef and dairy cattle performance is increasingly understood by the modern producer. There is however a common misconception surrounding potential sources of mycotoxins that livestock are exposed to. Many producers believe that these sources are mainly contaminated grains and the threat posed by contaminated straw and straw bedding is often overlooked.
Mycotoxin concentrations in straw vary considerably and can often be higher than the associated cereal grains from the same crop. Optivite believe straw consumption should be accounted for within the total feed intake when considering the overall threat posed by mycotoxins. Straw is commonly used in dairy/beef rations for a number of reasons:
- Reducing the nutrient density of diets to prevent over-conditioning. This strategy is also used with dry and transition cows
- A small inclusion of straw is often incorporated into lactating dairy cow diets, ensuring adequate fibre levels to stimulate rumination thus preventing acidosis
- To soak up moisture when wet ingredients such as distillers grains are used
- Due to straw's low potassium content, it is also used in the formulation of low potassium diets formulated to prevent milk fever in transition dairy cows
Silage quality is likely to heavily influence the levels of straw used in the diet. The nutrient quality of silage can vary greatly between seasons and indeed clamps. Analysis of silage in the UK has highlighted the nutritional variance between 2012 and 2013 crops. Significant increases in starch of 6.9% were detected with levels rising from 27.6% to 34.5% while neutral detergent fibre (NDF) levels showed a decrease of 5.6% from 50.7% to 45.1% (Farmers Weekly, 1st November 2013). As a result of this analysis it is clear that fibre will need to be included in the TMR, with straw likely to be the primary choice of producers.
Straw is commonly used for bedding beef cattle and whilst use amongst dairy herds is decreasing, it remains a common sight. Cattle that are fed below appetitie or lack stimulation will often consume significant quantaties of bedding as a matter of course.
Clearly straw plays an important role in the overall production process, we therefore believe that feeding contaminated straw and straw bedding could pose a significant mycotoxin challenge and should therefore be considered as a high risk factor.
The effect of mycotoxins on animal performance varies according to the level and type of toxins present. We know that they are seldom present in isolation and the synergistic effects of mycotoxins and their impact on animal health and performance are only begining to be understood. General symptoms associated with mycotoxins include; reduced food consumption, reduced nutrient utilisation and reduced milk yield as well as increased somatic cell counts, cellular death and altered reproduction.
To date there has been very limited data available which shows the levels of mycotoxins in straw, Optivite therefore wanted to confirm the risks by screening straw samples for mycotoxins. The samples tested were clean/bright straw taken from the 2013 harvest with no visible signs of moulds. Our findings below proved surprising, highlighting the real danger present.
Mycotoxins found in wheat straw, October 2013:
| Sample 1 | Sample 2 | Sample 3 | Average | EU Guidance levels; complete feeding stuffs for Dairy | EU Guidance levels; complete feeding stuffs for Cattle | |
| T2 (ppb) | 25 | 33 | 47 | 35 | No Max | No Max |
| Aflatoxin (ppb) | 4.9 | 3 | 4.4 | 4.1 | 0.02 MPL* | No Max |
| DON (ppb) | 6,200 | 5,800 | 3,900 | 5,300 | 0.5 | 5 |
| Ochratoxin A (ppb) | 10 | 20 | 27 | 19 | 0.25 | No Max |
| Zearelenone (ppb) | <50 | <50 | 134 | 44.67 | 0.5 | No Max |
*MPL: Maximum Permitted Level
From the table above, it is important to note the significant range in mycotoxin levels detected, all of which exceed EU guidance levels above which symptoms of mycotoxicosis would be expected to occur. Adding such material to the total ration or, if bedding is being consumed by the cow, will add to the overall loading of mycotoxins present in the diet.
Not all mycotoxin binders are the same!
The use of a mycotoxin binder is the most effective method to control the mycotoxin threat. It is important to understand that not all binders are the same. Certain binders are successful at binding only a limited range of mycotoxins and we know that mycotoxins are seldom present in isolation. It is therefore imperative to select a broad spectrum binder with proven success.
Ultrabond provides the broadest binding capacity of any product currently available on the market. Backed by years of research and proven success it is the natural choice for effective mycotoxin
Reference / Further Reading
Ultrabond - The hidden risk in home grown forage from Mycotoxins...