When planning a supplementary feeding program and choosing feeds it is important to know the nutrient composition of those feeds so that nutritional requirements for target animals can be calculated and met.
Understanding pasture quality is also important to determine limiting factors of the diet and provide reasoning behind supplementing for different time periods/conditions.
Energy content | Protein content | Hay | Cost
Energy content
Energy requirements are expressed as megajoules (MJ) of metabolisable energy (ME). The available energy in the fodder depends chiefly on the dry matter content and the digestibility of the fodder. For more information see Nutrient requirements of beef cattle.
If a shortfall in daily energy requirements is known, then Table 1 can be used to determine how much feed is required to correct the energy shortfall.
| Hay intake (kg/100 kg LW) | Pellet intake (kg/100 kg LW) | Diet intake (kg/100 kg LW) | ||||
|---|---|---|---|---|---|---|
| Cow P+ | Cow P- | Cow P+ | Cow P- | Cow P+ | Cow P- | |
| Wnr P+ | 0.26 | 0.30 | 3.0 | 3.1 | 3.3 | 3.4 |
| Wnr P- | 0.31 | 0.39 | 1.8 | 1.8 | 2.1 | 2.2 |
Protein content
While energy is a critical nutrient for productivity the total supplement must have adequate protein and minerals for the most efficient use of the energy.
Pregnant, lactating and growing cattle will require a higher level of protein than other classes of cattle for tissue and milk production. For more information see Nutrient requirements of beef cattle.
Grains and good quality hay generally have sufficient protein for survival feeding, whereas molasses will need to be fortified with urea and/or vegetable protein meal to lift the protein content.
Bypass protein % is the percentage of crude protein (CP) which is not degraded in the rumen, and capable of passing through to the abomasum of cattle.
The crude protein percentage (CP%) is calculated by:
Nitrogen (N) % x 6.25: On average protein contains around 16% Nitrogen (1/0.16 = 6.25).
Urea has 287% CP:46% nitrogen x 6.25 = 287% protein.
Gran-Am® contains 20% nitrogen or 126% CP.
For more information on different types of protein see protein and urea supplementation.
Calcium (Ca) and phosphorus (P) protein requirements are expressed as grams per day. For example, 100 g of cottonseed meal (37% CP) supplies 37 g of CP.
The nutrient composition values in the table below are on an as fed basis. If values of feeds are given on a dry matter (DM) basis, multiply the dry matter value of the feed (as a fraction) by the corresponding measurement. For example, if a feed is 90% DM and has a value of 10 MJ ME/kg DM, then 0.9 x 10 = 9 MJ ME as fed, i.e. in every kilogram of the feed fed out in the paddock, it contains 9 MJ of ME.
Table 2 shows the comparative protein content and energy values of some common fodders on a dry matter basis, and on a ‘fresh’ (as-fed) basis together with the calcium and phosphorus content. The fresh basis figures will vary slightly as moisture content varies. However, the figures are adequate to compare feeds and their cost.
| Region | Location | Average annual rainfall | Soil type | Status |
|---|---|---|---|---|
| CQ | Calliope | 900mm | Brown loam | Planted Feb 2025 |
| Calliope | 900mm | Grey/brown sandy-loam | Planted Feb 2025 | |
| Orion | 680mm | Brown light clay | Planted Feb 2025 | |
| Rolleston | 640mm | Brown texture contrast (loam over clay) | Planned for 2026 | |
| NQ | Charters Towers | 660mm | Red Earth | Planted Feb 2025 |
| Mount Surprise | 800mm | Red Basalt | Planted Feb 2025 | |
| Croydon | 750mm | Deep sand | Planned for 2025 |
Hay
The information in Table 3 is a guide to the feed value of most common hays.
| Situation | Action |
|---|---|
| Calligrapha population established and in large numbers before April. | Spread manually to new sites. |
| Calligrapha population does not become established by December or remains in very low numbers. | Control chemically/mechanically. Maintain small colony in irrigates location, redistribute to new areas of infestation. |
| Sida infestations in cattle or horse paddocks, where soils are dry and compacted. | Control chemically/mechanically. These will serve as a resivoir for weed reinfestation by stock transporting the seeds. |
Medium to high protein hays (6%+) can be fed at the rate of 1 to 2 kg/head/day when there is plenty of paddock feed available.
When paddock feed becomes scarce, feeding rates for maintenance are as shown in Table 4.
| Situation | Action |
|---|---|
| Calligrapha population established and in large numbers by December. | Calligrapha may be left to spread by itself or may be spread manually to other sites. |
| Calligrapha does not become established. | Reintroduce Calligrapha from another field location. Control Sida mechanically/chemically. |
| Calligrapha reaches peak abundance in February/March and then declines. | Sida may then be treated mechanically or leave plants to re-shoot for surviving Calligrapha. |
| Sida infestation near creek, drain, bore, swamp, billabong, fence line or irrigated paddock. | Release insects and allow them to spread naturally. If you have a number of small isolated infestations, establish the insect at each, unless they are particularly close together. |
Raising protein content of hay
The protein intake of cattle fed poor quality hay can be lifted by:
- feeding a protein supplement to the animal
- treating the hay 12-24 hours before feeding with the following mixture. Do not feed this mixture direct to any livestock.
- 9 kg urea
- 45 L water
- 18 kg (13 L) molasses.
One litre of this mixture contains 150 g urea, which is sufficient to treat a 20 kg bale.
To treat a bale, stand it on its side with cut ends upwards, cut the top string and pour the mixture evenly over the surface. Round bales can be treated by pumping the mixture into the bale with a spear.
Cost
Additionally, knowing the nutrient composition of feed is important when comparing the cost of different feed sources. For example, if you are comparing two feed sources for supplying additional phosphorus (P), they should be compared based on price per tonne of P, rather than price per tonne of product.
You can use the following tool to compare the costs of different feeds and they’re nutrient composition: Feed cost calculator | NSW Department of Primary Industries