Grass
Characteristics
Typically based on ryegrass, but often mixed swards with cocksfoot, fescues, timothy, and legumes (e.g. clover). It is present in rough/hill grazing (often with heather, rushes, mosses), permanent pasture and rotational leys, the latter often high yielding italian or perennial ryegrass monocultures.
| DM (%) | ME (MJ/kg DM) | CP (g/kg DM) | |
|---|---|---|---|
| Grass (young) | 15 - 20 | 11.5 - 12.5 | 150 - 250 |
| Grass (mature) | 25 - 50 | 9.5 - 10.5 | 50 - 130 |
Associated Problems
Scours, hypomagnesaemic tetany (especially in winter, or in rapidly growing grass (e.g. spring,/early summer, late summer/autumn), bloat (especially as mixed legume swards), pasture-induced laminitis.
Silage and Haylage
Characteristics
Silage is a fermented crop with a low dry matter content. It is cut at a relatively early stage of development and stored under anaerobic conditions (clamp or big bale). Haylage is similar to silage but is often cut at a more mature stage and is typically baled. Haylage has a higher pH and DM than silage and can often be of more variable quality. With horses haylage is typically preferred (by owners) to silage.
| DM (%) | ME (MJ/kg DM) | CP (g/kg DM) | pH | |
|---|---|---|---|---|
| Silage | 15 - 20 (20-30 clamp)(40-50 bale) | 9.5 - 12 | 120 - 190 | 3.8 - 4.8 |
| Haylage | 50-60 | 9 - 11.5 | 75 - 110 | 4.5 - 5.5 |
Associated Problems
Clostridia. Listeriosis. Acidosis. Moulds/mycotoxins. Poor fermentation (pH > 4.8) or too acidic (pH < 3.8).
Hay
Characteristics
Hay is dried grass, either naturally or artificially (dependent on the weather). It is cut at a relatively late stage of maturity and is typically of variable quality in colour and smell, and nutritive value. There are various types of hay such as ryegrass, meadow, and timothy.
| DM (%) | ME (MJ/kg DM) | CP (g/kg DM) | |
|---|---|---|---|
| Hay | 80 - 90 | 7.5 - 10.5 | 50 - 150 |
Associated Problems
Moulds/mycotoxins.
Straw
Characteristics
Straw (usually barley or oat for feed) can be treated with alkali, urea or ammonia. It is commonly used as a roughage source for growing ruminants, and especially animals being reared in cereal beef systems.
| DM (%) | ME (MJ/kg DM) | CP (g/kg DM) | |
|---|---|---|---|
| Straw | 86 - 88 | 6.1 - 7 | 34 - 38 |
| Straw (ammoniated) | 84 - 88 | 7.4 - 7.8 | 68 - 75 |
Associated Problems
Moulds/mycotoxin. Impaction within GI tract (especially horses). High intakes of straw (+ grains) are associated with hypomagnesaemic tetany (due to high K levels in grain and straw)
Whole-Crop Cereal Silage
Characteristics
Maize whole-crop silage has high energy concentration while having a low protein concentration. It is harvested when grain is in the late dough stage. Barley, oats, wheat, and triticale are also used for whole-crop cereal silage either as monocultures or mixed with legumes (e.g. peas) to improve protein content. They are also high in energy while low in protein. Whole-crop cereal silages are fed as sole forage or mixed with grass silage.
| DM (%) | ME (MJ/kg DM) | CP (g/kg DM) | |
|---|---|---|---|
| Maize whole-crop silage | 22 - 35 | 10.5 - 12 | 65 - 110 |
| Barley whole-crop silage | 30 - 40 | 9 - 11 | 80 - 110 |
Associated Problems
Clostridia. Listeriosis. Acidosis. Poor fermentation (pH > 4.8) or too acidic (pH < 3.8).