DRY GRASSES – RAIN – GREEN PICK

When grasses reach maturity and dry off, they have evolved a process that allows them to leach nutrients (minerals, trace elements, sulphur and nitrogen) back into the soil around them when they are affected by water (rain, dew, mist, frost, etc.). They have evolved in this way is to provide accessible minerals for the best possible start for new plants to grow when the rains return.

This process, while it sustains the ecosystem as nature intended, creates a number of problems for livestock grazing these pastures.

Firstly, if summer rains fall as pastures are drying off, a large percentage of the pasture’s soluble components (including minerals) will be leached back into the ground where it is unavailable to livestock until new plant material has grown. Until the new growth appears, the mature pasture has lost much of its potential to be digested by microbes in the rumen. This is not to say that pasture low in nutrients is without value. As long as there is plenty of dry matter, deficient minerals can be supplied for microbial growth in the rumen by supplementing a broad range of multi-nutrients and a nitrogen source. If this can be done, livestock will increase feed intake and efficiently use these dry pastures to grow and produce – BUT ONLY IF THE RUMEN IS SUPPLEMENTED AND THE MICROBES SET WITH A CORRECTLY BALANCED NUTRIENT SUPPLY

The second problem occurs when green pick begins to develop. Livestock will select this to the exclusion of dry, mature pasture. A green pick is high in moisture, minerals, carbohydrates and protein. As a result of the high moisture content of this new green pick, the microbial population is diluted and some of the readily fermentable carbohydrate is washed into the lower gut where bugs begin to reproduce. During this process these bacteria (which are often of the Clostridia genus) produce toxins that are absorbed from the lower gut which can result in clinical or subclinical diseases. Scouring is an attempt by the animals to excrete and eventually lose these toxins from the lower gut. When an animal scours it often loses condition, has increased exposure to infestation because of lowered immunity, and increased risk of fly strike due to liquid manure collected on the wool/hide.

The introduction of a bentonite supplement may be beneficial in this case. Because of the large surface area of bentonite and its many active sites on which to bind particularly large toxic molecules, it has the ability to absorb toxins and also to absorb excess moisture in the rumen. Bentonite absorbs ten times its weight in moisture. By doing this, bentonite slows down the movement of feed residues along the gut, allows greater total digestion in the rumen and allows the animal to reduce the water content of the faeces. The net result is that there is more rumen protein (bacteria) available and the animal has the ability to process feed more efficiently.

Professor Ronald A Leng AO B.Sc., Ph.D., D.Rur.Sc., FASAP

How to set-up a rumen correctly: Use the Indicator System.

An example of an Indicator Series is as follows:

A. Group 1: A multi-nutrient protein/urea supplement such as Olsson’s Dry Season 10% & 20% or Sulfos

B. Group 2: A by-pass protein supplement when animals are pregnant, lactating or weaning such as Olsson’s Peak 50

C. Group 3: A sulphur & phosphorus (mineral) supplement to balance the rumen ecosystem and to stimulate fungal breakdown of coarse fibres such as Olsson’s Superphos and Olsson’s 12% High Sulphur

D. Group 4: A bentonite supplement to increase availability of bacterial protein such as Olsson’s Bentobite

If you have any questions regarding the Indicator System, please call Dr. Wayne Backhouse on the Olsson's Nutritional Advisory Service FreeCall:1800 804 096