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Not Even Fresh Grass Can Deliver The Full Package: Summer Grazing FAQs

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Green pastures packed full of nutritional goodness offer cattle and sheep producers a period to cut back on supplementation. Whilst this may be true for energy and protein, the opposite can be said when minerals and vitamins are concerned. Laura Drury, Rumenco Technical Adviser, answers some of your most frequently asked questions on supplementing grazing livestock throughout the summer.

Why does grass need supplementation?

Grass can be deceptive in its appearance and really gives no clues as to what it contains, or more importantly if there is anything missing that may cause a reduction in performance, fertility or health.

Its nutritional status in terms of dry matter, energy, protein and mineral content can only be accurately assessed by a laboratory analysis and can change throughout the season (figure 1) – sometimes in different ways to you expect such as protein content.

Adequate grass cover in early summer can support required growth rates in cattle youngstock and lambs. During summer, this limitation is most likely to be one or many of the essential minerals and trace elements, easily cancelling out the potential for high performance.

Figure 1: Seasonal metabolisable energy (ME) content of grass (source: AHDB Dairy)

My grazing fields have plenty of cover throughout the season, why should I buy a supplement?

Adequate cover can be defined as 5 to 6cm sward height for sheep and 8 to 9cm for cattle. This will ensure there are no restrictions to intake so that animal appetite is satisfied. If the grazing is well managed, showing good leafy growth and not too many summer seed heads then the digestibility, energy and protein values should be satisfactory to support good growth. However, often grass isn’t very well balanced for minerals and trace elements, particularly if it is a medium or short-term ley (figure 2).


Figure 2: Mineral supply from fresh grass as a percentage of a ewe’s total requirements (shown by green line)

Why are minerals and trace elements essential components of a balanced grass-based diet?

Animal performance, fertility and health can be compromised when nutrients become limiting. Although only a minor component of the diet, this includes minerals, because they are critical for metabolism, oestrus (fertility) and numerous other key bodily functions. Even if mineral supplements are fed through the winter their effects will have been exhausted by summer, meaning supplementation needs to continue year-round.

I use a mineral bolus for my stock in the summer, why do I need another supplement?

Mineral boluses don’t usually supply the full range of the 10 to 12 minerals and trace elements required by grazing ruminants meaning additional supplementation is required in many cases. Laboratory analyses regularly show grazing and conserved forages to contain low levels of many of the essential minerals and trace elements, not just the odd one, so offering a mineral supplement containing a full package of these elements helps cover off all potential and likely risks.

What is the 4 IN 1 bucket and what are the key benefits?

Rumenco’s 4 IN 1 molassed bucket has been formulated using an evidence-based approach based on thousands of UK grass analyses, and therefore targets the essential elements often found deficient in grazing.

The four components in 4 IN 1 comprise:

  • Major minerals
  • Trace elements
  • Vitamins
  • Plant extracts

Natural plant extracts have been specifically chosen for their appetite stimulating effect to support overall animal performance throughout the summer grazing season. In addition, protected zinc and selenised yeast have been included to support good hoof and skin integrity as well as overall health within your herd or flock.

Ensuring cattle and sheep are offered mineral and vitamin supplementation is essential where animal performance and profitability are concerned. Whilst these nutritional elements of the animal’s diet may only be small, ensuring an adequate supply in order to meet requirements is more than fundamental in allowing them to realise their full performance potential whilst utilising one of the most cost-effective and nutritious feeds available.

For further information on 4 IN 1 or to find your local stockist please contact us or visit our stockist page.

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