Supplementary Feeding Levels
It is vital to feed stock the right amount of supplements. You can achieve this by calculating the feed value of your ration. You should also monitor stock condition by weighing a sample every 2-3 weeks.
This article should help you assess the feed value of your supplements, and may highlight your best options in terms of both cost and feed value.
Energy is the main limiting nutrient for maintenance in animals, while protein is important with growing or lactating animals. As a rule, the protein concentration of a sheep's diet should be 6-8% for maintenance, 12-16% for young growing stock, and at least 15% for lactating ewes.
Ruminants obtain most of their energy from the digestion of sugars and starch (from inside cells), and from cellulose and lignin which comprise the walls of the cells. Any protein surplus to requirements for growth and lactation will be broken down with the nitrogen being passed out as urine. As well as energy and protein, there should be a balance of vitamins, minerals and water in the animal's diet.
High-quality pasture feeds (including hay, silage and balage) supply adequate concentrations of protein and energy. However, poor-quality conserved feeds may be deficient in energy and/or protein for young, growing or lactating animals. Getting samples tested for protein, metabolisable energy (ME) and neutral detergent fibre (NDF) will help decisions regarding adequacy of these feeds. Pasture can also be deficient in minerals and trace elements (eg selenium, magnesium, copper or cobalt).
Ruminants also need a certain amount of fibre (bulk) to aid digestion. Some very concentrated feeds may not contain enough bulk to allow the rumen to work efficiently. If the diet contains too much fibre, on the other hand, the rate of digestion drops. With feeds of low digestibility (less than 50%), stock are likely to need more energy than they obtain from these feeds.
The energy content of a feed is measured in megajoules of metabolisable energy per kilogram of dry matter (MJ ME/kg DM). Comparing different feeds in terms of energy rather than in terms of dry matter gives you a better comparison of the worth of a particular feed. As an example, 1 kg of ryegrass straw contains about 7.5 MJ ME/kg DM or 6.45 MJ on a wet matter basis, while 1 kg of barley grain contains about 12.5 MJ or 10.7 on a wet basis.
In the following table, some common feeds have been compared on both a relative price per kilogram dry matter as well as per megajoule of feed. In each case the price of the feed is on a per tonne basis. Depending on the source of the feed and the transport costs, adjustments will need to be made for each different situation.
When feeding supplements or pasture you must know the weight of the feed that you are both buying and feeding to get the best results. Either weigh the large bales on a set of load bars or run a bale across the nearest weighbridge. Typically medium square bales weigh 220-300 kg, so underfeeding or overfeeding is likely if the weight is guessed.
Feed value of common stock feeds
| Feedstuff | DM% | Relative to leafy pasture |
MJ ME/kg DM | % Crude Protein ( DM Basis) |
Price/tonne delivered |
Relative prices | |
|---|---|---|---|---|---|---|---|
| Cents/kg DM | Cents/MJME | ||||||
| Pasture -short leafy |
15 | 1.10 | 11.7 | 27 | 23 | 15.3 | 1.31 |
| Pasture -medium |
18 | 1.00 | 10.8 | 21 | 25 | 13.9 | 1.29 |
| Pasture -dry stalky |
28 | 0.80 | 8.1 | 10 | 30 | 10.7 | 1.32 |
| Green feed oats |
20 | 1.20 | 13 | 15 | 30 | 15.0 | 1.15 |
| Hay -good quality |
85 | 0.80 | 8.4 | 12 | 200 | 23.5 | 2.80 |
| Hay -poor quality |
85 | 0.70 | 7.3 | 10 | 170 | 20.0 | 2.74 |
| Lucerne hay | 85 | 0.80 | 9 | 17 | 230 | 27.1 | 3.01 |
| Barley straw | 86 | 0.70 | 7.1 | 5 | 170 | 19.8 | 2.78 |
| Ryegrass straw |
86 | 0.70 | 7.5 | 6 | 170 | 19.8 | 2.64 |
| Pea vine | 86 | 0.93 | 10.9 | 14 | 200 | 23.3 | 2.13 |
| Pea straw | 86 | 0.70 | 7.2 | 9 | 170 | 19.8 | 2.75 |
| Wheat balage | 40 | 0.97 | 10.5 | 13 | 150 | 37.5 | 3.57 |
| Barley balage | 40 | 0.94 | 10.1 | 12 | 150 | 37.5 | 3.71 |
| Balage -dry medium |
40 | 0.85 | 9.5 | 13 | 150 | 37.5 | 3.95 |
| Balage -wet good |
25 | 0.95 | 10.5 | 17 | 120 | 48.0 | 4.57 |
| Pasture Silage | 30 | 0.95 | 10.5 | 14 | 80 | 26.7 | 2.54 |
| Maize silage | 35 | 1.00 | 10.5 | 8 | 84 | 24.0 | 2.29 |
| Lucerne balage |
45 | 0.95 | 10.5 | 20 | 160 | 35.6 | 3.39 |
| Palm Kernel | 90 | 1.05 | 11.5 | 16 | 270 | 30.0 | 2.61 |
| Kibble maize | 86 | 1.25 | 13.6 | 8 | 400 | 46.5 | 3.42 |
| Molasses | 75 | 1.00 | 11.5 | 5 | 300 | 40.0 | 3.48 |
| Barley grain ( whole) |
85 | 1.20 | 13.1 | 12 | 350 | 41.2 | 3.14 |
| Barley grain ( crushed) |
85 | 1.20 | 13.1 | 12 | 370 | 43.5 | 3.32 |
| Oat grain | 86 | 1.10 | 12 | 13 | 380 | 44.2 | 3.68 |
| Wheat grain | 86 | 1.30 | 13.5 | 14 | 380 | 44.2 | 3.27 |
| Sheep nuts | 94 | 1.11 | 12 | 12.5 | 480 | 51.1 | 4.26 |
| Dairy meal (basic) |
85 | 1.2 | 12 | 15 | 500 | 58.8 | 4.90 |
Updated June 2007
Note: Feed cost will vary from district to district and different sources so these are a guide only. They are based on bulk purchased delivered on farm prices. Extra cost will occur in storage and feeding out. Pasture cost used are for grazing charges.
Key: DM = dry matter; MJME = megajoules metabolisable energy
Usually most farmers offer a range of feeds to stock, eg straw, some grain and a pick of pasture. This way they reduce the problems of some animals refusing to eat a certain feed, and the mix is more likely to supply all the nutrients and minerals as needed.
Calculate the Value of Your Supplementary Feed
Using the above table, if sheep weighing 50 kg are to be offered maintenance feed (which is 10 MJ ME/day), a mix of 0.5 kg barley straw, 0.5 kg barley and 0.2 kg of pasture will suffice.
Barley straw |
0.5 kg x 86% DM x 7.1 MJ |
= 3.0 |
Barley grain |
0.5 kg x 86% DM x 13.1 MJ |
= 5.6 |
Pick of pasture |
0.62 kg x 28% DM x 8.1 MJ |
= 1.4 |
Total |
= 10.0 |
The average protein in the diet is then 7.9%, which is adequate for a sheep in maintenance mode.
Gradually introduce any new feed over a week or more so the bugs in the rumen can adapt to handle it. Most farmers are aware that death from acidosis can occur from a heavy loading of the rumen with grain. Start gradually with only 50 gms per day and slowly build up. Kiwifruit contain many soluble sugars and an adaptation period of seven to ten days is recommended. Care is required: Sugar levels increase as the fruit ripens, making animals more prone to acidosis problems with riper fruit, and cattle can choke on fruit.
You can obtain a form for preparing a feed budget from your Agriculture New Zealand consultant.
Ken Muscroft-Taylor
Agricultural Consultant
Agriculture New Zealand
Darfield
Contact for Enquiries
Manager
North Island Regions
Sector Performance Policy
MAF Policy
Hamilton
NEW ZEALAND
Phone: +64 7 957 8313
Contact this person
