ALWAYS READ THE LABEL
Users of agricultural (or veterinary) chemical products must always read the label and any Permit before using the product, and strictly comply with the directions on the label and the conditions of any Permit. Users are not absolved from compliance with the directions on the label or the conditions of the Permit by reason of any statement made or not made in this publication.
DISCLAIMER
The product trade names in this publication are supplied on the understanding that no preference between equivalent products is intended and that the inclusion of a product does not imply endorsement by NSW Agriculture over any other equivalent product from another manufacturer.
Purpose of the ration
A feedlot ration should be designed to give maximum weight gains and fattening rates at the lowest cost with minimum digestive upset.Daily feed intake
In many cases, differences in individual feed capacities probably vary more within a group of similar cattle than between different categories.
Most feedlot rations tend to be based on grain, plus dry roughage, with an average dry matter content of around 90%. Therefore, when preparing a budget, calculations can be simplified if you use an intake capacity of 3% of liveweight to calculate the actual weight of feed required. This applies to a ration that is around the 90% dry matter.
However, if using a silage or green chop based ration, with an average dry matter less than 80%, or designing a ration to provide energy and crude protein requirements, calculations should be made on a dry matter basis; see ‘Dry matter’ and table 6 below, table 8 in Suitability of feedstuffs, and table 9 in Buying feed on a feed value basis.
Table 6 provides details of daily feed capacities, metabolisable energy and crude protein requirements on a dry matter basis, for various categories and liveweights of cattle.
Dry matter
Dry matter refers to the amount of dry material in a given feed. Green chop consists of about 15–20% and silage about 30–40% dry matter, while grain is about 90% dry matter. Most feeds used in feedlot rations have a dry matter content of around 90%.
A beast needs between 2.7% and 3.0% of its liveweight as dry matter intake per day. Cattle in low condition may eat 3% of their body weight, while cattle with a high degree of finish have a lower capacity (table 6).
To find how much to feed, calculate as dry material and divide by the dry matter percentage to get weight. For example, a silage consists of about 30% dry matter. If we need 3 kg of dry matter, then calculate as follows:
3 × (100 ÷ 30) = 10 kg of wet silage
Roughage
Roughage is required for the satisfactory functioning of the digestive system. Generally, a ration containing 75:25 or 80:20 grain/roughage gives satisfactory weight gain at minimum risk, although rations can vary from 50:50 to 90:10.
The higher the percentage of grain in the ration, the higher weight gain potential, but the risk of digestive upsets is greatly increased when more than 80% grain is fed.
When high levels of roughage are fed—for example, starter rations—good-quality roughage should be used. Poorer-quality roughages are acceptable when low-roughage high-grain rations are fed.
Energy
High-energy rations should be fed for maximum weight gains. Energy is measured as megajoules (MJ) of metabolisable energy (ME) per kilogram of feed.
For efficient fast-fattening, steers under 12 months of age need a ration containing about 12 MJ/kg, and yearling cattle require a ration containing about 11 MJ/ kg. Grains are rich in ME (about 13 MJ/kg) and stubbles are low (about 5 MJ/kg).
Protein
Protein is measured as crude protein (CP). Protein is essential for the health, growth and appetite of the animal. Young cattle require higher levels of protein than older cattle. A range of CP from 11% to 15%, depending on age and weight, will be required (see table 6).
| Type | Liveweight (kg) | Daily dry matter % of liveweight | ME (MJ/kg) | CP % in ration | Daily weight gain |
|---|---|---|---|---|---|
| Weaners | 150 | 2.6 | 12.0 | 15.0 | 1.0 |
| 200 | 2.7 | 11.5 | 13.0 | 1.0 | |
| Yearlings | 250 | 2.9 | 11.5 | 12.0 | 1.3 |
| 300 | 2.8 | 11.0 | 11.5 | 1.3 | |
| 400 | 2.6 | 11.0 | 11.0 | 1.3 | |
| Steers | 350 | 2.9 | 10.8 | 11.2 | 1.4 |
| 400 | 2.8 | 10.8 | 11.0 | 1.4 | |
| 500 | 2.6 | 10.8 | 11.0 | 1.4 | |
| Yearling heifers | 250 | 3.0 | 11.5 | 12.0 | 1.2 |
| 300 | 2.9 | 11.0 | 11.5 | 1.2 |
Where a high proportion of grain is fed and the roughage is of good quality, there is often adequate protein in the ration. If not, the addition of 1% urea will effectively boost the protein level and aid digestion. Rations for young cattle might be low in protein. If so, you can add a high-protein meal such as sunflower meal, linseed meal or cottonseed meal. Because young cattle require a high proportion of their protein intake from true proteins, these protein meals must be used in preference to urea to raise the protein level of the ration. As cattle slow their growth and become more finished, intake capacity often eases slightly. Weight gain may also ease as more of the energy consumed is converted into fat (higher energy content) rather than muscle. The preferred minimum entry weight for feedlot cattle is 250 kg (liveweight). Cattle can go on to the feedlot at lighter weights, but their protein requirements are so high that the ration becomes expensive and the time on feed is extended to achieve a marketable (although often not profitable) weight. Other componentsOther components of the feedlot ration include minerals, vitamins, salt, non-protein nitrogen and rumen modifiers.MineralsCattle need minerals to maintain good health. The most important are phosphorus and calcium. Grain is high in phosphorus and low in calcium, so with a high-grain ration, add calcium as ground limestone at a rate of about 1% (10 kg limestone/tonne) of the ration. This amount can be halved when lucerne hay is used as the roughage component. Extra phosphorus is sometimes added to weaner rations, usually at the rate of 0.1% (1 kg/tonne). Sulfur is often added to rations that include urea, while zinc and cobalt often improve the action of rumen micro-organisms. Other minerals could be needed, but deficiencies are unlikely to occur in short feeding periods (less than 100 days). Salt is added at the rate of 0.2% (2 kg/tonne) of the ration to supply the recommended daily allowance for sodium of 0.08% (0.8 kg/tonne). Non-protein nitrogen (NPN)Urea is cheap and physically easy to feed. However, it is toxic in excess, and inexperienced operators should not attempt to use more than 1% in their ration. See ‘Urea poisoning’ in Cattle health in feedlots. Feed at 1% by weight of the total ration. Because urea can be toxic if fed to excess, take care that this amount does not exceed 2% and that it is thoroughly mixed in the ration. Introduce it gradually, starting with 0.5% by weight (5 kg/tonne) of the total ration for the first 5 days. WARNING: If urea is added to the feed in a powder form and trough cleaning is inadequate, urea may settle to the bottom of the feed bunk. If the trough is not emptied for several days and cattle then eat it out, there is a danger of individual animals eating excessive quantities of urea. This can be lethal. Always use prilled and not granulated urea. VitaminsVitamin A and E supplementation will be necessary for animals on feed for greater than 60 days. The supplementation may be required even earlier if animals entering the feedlot have been on dry feed or in drought conditions. Premixes should contain the recommended daily allowance of vitamin A as retinol (1000 µg/kg) or its precursor, ß carotene (4500 g/kg). Stored grains contain approximately one-third of vitamin E requirements for growth. Therefore vitamin E should be added at a minimum of 20 mg/kg. Thiamine (vitamin B1) may be necessary to prevent polioencephalomalacia (brain swelling). Consult your veterinarian. Cobalt deficiency can lead to B12 deficiency. Cobalt should be incorporated in the vitamin/mineral premix if feed is grown in a cobalt-deficient area. Animals with a diagnosed deficiency can be treated with vitamin B12. Achieving even distribution of vitamins by directly adding vitamin requirements to the ration is very difficult, because of the very small quantities involved. Commercial premixes that contain the desired variety and proportion of vitamins are available and make an even distribution more achievable. Guides to nutrient drenches and injections and to vitamin and mineral premixes were published in ALFA Lotfeeding in June 1997. Other additivesVarious substances can be added to the ration to improve feed conversion efficiency or daily weight gain. As a general recommendation, make sure that adequate animal performance is obtained from the basic ration before including additives; they can mask feed or management problems which could otherwise be more readily noticed and rectified. A ‘feed additive’ is generally defined as a feed ingredient of a non-nutritive nature that will stimulate growth or other types of performance, improve the efficiency of feed use, or benefit in some way the health or metabolism of the animal. Rumen modifiers and in-feed antimicrobialsCertain antimicrobial agents have been used as feed additives. These are not HGPs. Antimicrobials are used in feedlots to improve animal performance in terms of growth rate or feed conversion efficiency or both.
The use of antimicrobial feed additive growth promoters, notably the ionophores (e.g. lasalocid, monensin, salinomycin), has resulted in liveweight gains of about 5% and improvement in feed conversion efficiency of 3–4%. Research organisations and industry are investigating other substances for use as growth promotants in beef cattle. New products may become available following clearance and registration. Sodium bentoniteSodium bentonite has been used successfully in the past. It acts as a buffer against grain sickness (acidosis) particularly during the build-up phase, when it should be fed at 2% of the ration. However, in the late 1990s, a number of commercial alternatives have become available, including virginiamycin. Virginiamycin (Eskalin®) When added to the feed, this product can prevent the build-up of lactic acid in the rumen and hence grain poisoning. It has been found to reduce grain poisoning when mixed effectively into the ration. This is a new product, which has only recently become commercially available in Australia. Initial observations reinforce the need for thorough mixing. Virginiamycin is an antimicrobial and it is important that the manufacturer’s recommendations are strictly followed.Proprietary mineral and vitamin premixes or concentratesIn the past many small feedlotters have sourced a variety of micro-ingredients and mixed them into a premix or concentrate, which is added to the ration at a rate of 1.5–4%. Today there are many proprietary premixes, concentrates or preparations available in a variety of forms, including pellets and molasses-based mixes and suspensions. Besides saving trouble, a commercial premix or concentrate may be a more reliable preparation to ensure each animal receives its daily requirements. A vitamin–mineral premix for domestic trade cattle should cover all but the most extreme situations. It should supply the following to the diet:
There are a large number of commercial preparations available, at varying prices (e.g. Rumevite®, Feedlot 80®, Eskape®, Beef Power®). Before selecting a premix, work out what ingredients you need for your operation and make sure they’re available. What other ingredients are included? Do you need them? Proprietary premixes generally incorporate salt, calcium, phosphorus, sulfur, cobalt, copper and magnesium, and may also contain urea, rumen modifiers, sodium bentonite and assorted vitamins. Check whether virginiamycin or other rumen modifiers are included. This document forms part of the publication Opportunity lotfeeding of beef cattle, a NSW Agriculture Feedlot Services publication, which is available for sale in print form from NSW Agriculture. The information contained in this web page is based on knowledge and understanding at the time of writing (6 January 2000). However, because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check currency of the information with the appropriate officer of New South Wales Department of Agriculture or the user’s independent adviser. © NSW Agriculture 2002 |
I enjoyed your post and found it to be well written and informative. In cattle feedlot, it is very important to read the product labels prior to mixing. Failure to so may cause possible hazard to the livestock.
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