| Grass. | ||||||||||||||||||||||||||||||
| Introduction | ||||||||||||||||||||||||||||||
| Grassland can be divided into two main groups: hill and rough grassland and cultivated grassland (permanent and temporary pastures). Fresh grass remains the main feed for ruminants during the spring, summer and autumn, with conserved grass (silage, hay) being fed during the winter. | ||||||||||||||||||||||||||||||
| Origin | ||||||||||||||||||||||||||||||
| Worldwide. | ||||||||||||||||||||||||||||||
| Nutritional Information | ||||||||||||||||||||||||||||||
| The nutritional value of grass is variable
depending on species in sward, location, weather, time of
year, ley age and fertilizer application rates/timings.
The crude protein can range from 4% - 30% in heavily
fertilized pastures, with crude fibre content ranging
from 20% - 45% in very mature samples. Early in the growing season, it has a high water, organic acid and protein content with low content of carbohydrates and lignin making it highly digestible. As the plant matures, the yield ot forage increases; there is increased structural carbohydrate and lignin, and decreased protein and energy levels. The moisture content can vary dramatically, being highest in the early stages of growth (80-85%) and lowest when the plant seeds. The weather also greatly affects moisture level. Soluble carbohydrates range from 4-30% with the highest levels found in varieties such as Italian ryegrass. The cellulose and hemicellulose content varies between 20-30% of DM and 10-30% of DM respectively. Both cellulose and hemicellulose increase as the plant matures, as does lignin, which influences rumen digestibility. Tne protein content decreases with maturity and the amino acid profile does not alter much with arginine, glutamic acid and lynine present in reasonable levels. The non protein nitrogen (NPN) content and nitrogen level both decrease as the plants mature, with levels tending to be higher during good growing conditions. Oil levels are relatively low in grass and usually below 4% (of DM) made up largely of unsaturated fatty acids. Mineral/vitamin content varies depending on soil type, stage of growth and fertiliser application. Grass is rich in carotene, a precursor of vitamin A, which is present in large amounts. |
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| Colour/Texture | ||||||||||||||||||||||||||||||
| Palatability | ||||||||||||||||||||||||||||||
| Good. | ||||||||||||||||||||||||||||||
| Limits on Usage | ||||||||||||||||||||||||||||||
| Stocking rates, sward height and density, parlour feed substitution rates, trace element imbalances and high molybdenum contents in improved or 'teart' pastures. Later in the season grazing may provide insufficient energy for high performing animals, particularly dairy cows, and careful supplementation is required. | ||||||||||||||||||||||||||||||
| Recommended Maximum Inclusion Rates % | ||||||||||||||||||||||||||||||
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| Handling/Storage | ||||||||||||||||||||||||||||||
| Can be harvested and fed in zero grazed system, maximising output per acre. Grass is usually conserved as silage and/or hay. |