Unit 5:Feeds

 

Unit 5.

Feeds

Feed (s): Edible materials(s) which are consumed by animals and contribute energy and/or nutrients to the animals diet.

We can conveniently classify feeds into three main types:

(1) roughages,

(2) concentrates, and

(3)  mixed feeds.

Roughages include pasture forages, hays, silages, and byproduct feeds that contain a high percentage of fiber.

Concentrates are the energy-rich grains and molasses, the protein- and energy-rich supplements and byproduct feeds, vitamin supplements, and mineral supplements.

Mixed feeds may be either high or low in energy, protein, or fiber; or they may provide “complete” balanced rations.

·                 Complete feed: a nutritionally adequate feed for animals; by specific formula           compounded to be fed as the sole ration and is capable of maintaining life and /     or promoting production without any additional substances except water

·                 Concentrate:  a feed used with another to improve the nutritive balance of the t     total and intended to be further diluted and mixed to produce a supplement or a      complete feed.

·        Supplement: a feed used with another to improve the nutritive balance or performance of the total and intended

·        Premix:  a uniform mixture of one or more microingredients with diluents.

·        Additive: An ingredient or combination of ingredients added to the basic feed mix or parts thereof to fulfil a specific need. Usually used in micro quantities and requires careful handling and mixing

·        Compound feed: A mixture of products of vegetable or animal origin in their natural state, fresh or preserved, or products derived from the industrial processing thereof, or organic or inorganic substances, whether or not containing additives, for oral feeding in the form of a complete feed

Feed ingredients are broadly classified into cereal grains, protein meals, fats and oils, minerals, feed additives, and miscellaneous raw materials, such as roots and tubers.

 

 

Processing of feeds

Objective of the processing

1.     To make more profit: feed efficiency can be improved by 10% and occasionally by 15-20% by changing the methods of processing

2.     To alter particle size: increased feed intake or digestibility

3.     To change moisture content: make safer to store (reduced at 10% level)

    4.         To change the density of feed: bulky feed reduce feed intake. Grains are flaked               rather than ground or pelleted

5.     To change palatability: to increase acceptability and feed intake. Molasses and fats are added to improve flavor of the feed

6.     To increase nutrient content: when feed alone in their natural state, few feedstuffs meet the requirements of animals

7.     To increase nutrient availability: starch and protein appear to be less available in            jowar than other grains but processing improves feeding value of jowar

8.     To detoxify or remove undesirable ingredients: considerable control of gossypol is possible by heating

    9.          To improve keeping quality: high moisture grains may be preserved by either d             drying or chemical treatment (adding an organic acid)

10.                       pellete feed procing method

 

 

 

 

11.                       To lesson moulds, salmonella and their harmful substances: feeds are subjected to a certain process to ensure safety and avoid contamination especially from moulds and salmonella.

 

Mills used in the feed industry

1.     Hammer mills: these mills are used impact grinding principle to reduce particle size of feeds. Hammer mills are used for both concentrates and forages. It has been used for farm, commercial and custom grinding for many years.

2.     Roller mills: these are used in feed processing for the crimping or crushing of grains. The roller mill consists of two rolls rotating in opposite directions at the same speed or at different speeds. If the rolls are operated at the same speed, the reduction is crushing, and if different then cutting and shearing takes place.

 

Mixing of feeds

The compounding of animal feed includes processing of raw materials of wide ranging physical, chemical and    nutritional characteristics into a homogenous mixture suitable to obtain a desired nutritional response from the animals. Cereals, oil seedcakes, soybean meal, meat meal, blood meal, fishmeal undergo processing prior to their inclusion into a compounded feed.

 

Mixing

1.     Mixing of ground materials: Small quantities of animal feed can be adequately mixed manually. The ground raw materials should be layered one above another, and then mixed and turned to form one heap. Mixing of the heap at least 3-4 times may produce an acceptable product. Micronutrients such as vitamins, minerals, antibiotics and others are first mixed with diluents such as wheat bran and then it is added to ensure uniform mixing.

2.     Feed mixtures

·        Vertical mixer: it is used in thousands of feed mills and farms. They may be single crew or double for elevation the material, however single crew is popular. These are relatively inexpensive and do good job of mixing most ingredients.

·        Vertical mixer

·         

·        Horizontal mixer: commonly used in larger feed mills. This mixture has right and left hand augers which convey the materials from one end to the other while it is tumbled within mixture.

        Merit and demerits of the mixers

Attribute	Vertical	Horizontal
1.  Cost	Inexpensive and do a good job of dry mixing	Expensive and do a good job of dry  and liquid mixing
2.  Use	Used in  medium feed mills and farms	Used in small mills as well as a larger feed mills
3. Floor space	Required less floor space	Required more floor space
4. Time	Require  20 minutes or more time per batch mixing	Require 3-5 minutes per batch mixing
5.  Power requirements	Consumes less power	Consumes more power
6. Discharge of mixed feed	Opening at one place	Opening at several places
7.  Cleanout	Lesser extent	Generally 100% and is more efficient
8.  Mixing efficiency	Lower  mixing efficiency	Higher mixing efficiency
9. Liquid addition	Liquids such as molasses, fats cannot be effectively mixed	Molasses , fats etc  can be mixed effectively

 

Liquid addition

 

The addition of various liquids to feeds is a normal practice. These include molasses, vegetable and animal fats, fish soluble, phosphoric acid, choline chloride, etc. These are added to enhance palatability (molasses), energy (fats) and other nutrient content of the ration. Liquids are preheated to reduce their viscosity. Molasses are heated to 95-100⁰F while fat to 140-210⁰F.

When liquids are added to the mixer, they should be sprayed over the entire length of the mixture.

 

Packaging

 

Compound feeds, whether in meal or pellet form are packed in bags. Bags may be filled directly from mixers, pelleted coolers or holding bins and weighed before sealing. Bags may be of jute, cotton, paper or plastic and can be hand or machine stitched or tied with string.

 

Storage of feed

• Feed ingredients which are dry before processing should be kept dry and cool and used on a first-in, first-out basis. As a general rule the moisture percentage should be less than 13% particularly in humid and/or tropical areas
• The tanks in which these ingredients are commonly stored should be cleaned monthly, or as indicated by experience, to prevent the build-up of dust and fragments of feedstuffs. Such build-up creates habitat for mould (and therefore the possible production of mycotoxins) and insects which will quickly destroy the food value of the products being stored; heat is also produced by these organisms and spontaneous combustion resulting in serious ingredient losses, and possible property losses may occur. The elevator legs, other conveying equipment and spouting should also be routinely inspected and cleaned out for the same reasons.
• While processing may dilute or kill concentrations of mould and insects, keeping equipment and storage free of dust and build-up of old feedstuffs will prevent or at least reduce the possibility of contamination of the finished feed.
• Liquid ingredients such as tallow, amino acids, and molasses should be stored in accordance with manufacturers’ recommended procedures to protect freshness.
• Fats and oils may need to be heated for ease of handling and/or have antioxidants added (to prevent lipid peroxidation and control off-flavors in food animals) to maintain quality
• In general, aquafeeds are usually composed of some highly perishable and often very expensive ingredients and care must be taken to keep both the feed ingredients and the finished feed away from contamination including heat and light, as well as biological factors such as mildew, insects, birds and rodents (Cruz, 1996; O’Keefe, 2000).
• Propionic acid and other antifungal agents may be used during processing, but these chemicals may adversely affect palatability and efficacy of the feed. Both the feed miller and the farmer/end user of the feed need to remember that heat, light, and moisture can damage feed and that sacked feed should be stored off the ground on pallets, and out of direct sunlight due to the damaging effects of ultraviolet rays (New, Tacon and Csavas, 1995).
• Depending upon the source and nature of bulk feedstuffs, ingredient cleaning may be necessary. Most feed mills have grain cleaning systems, designed to remove broken seed, tramp metal, and other foreign materials which contaminate inbound ingredients from time to time.
• It is wise for the buyer to specify that dust (fines) and other contaminants shall not exceed a certain level. Inbound ingredients should be subject to rejection if contamination levels exceed specification.
• Aquatic animals are particularly sensitive to low levels of, for example, fumigants, and possibly mycotoxins, and for that reason great care must be taken in the choice, sourcing and handling of feed ingredients for aquaculture (Cruz, 1996).
• Bins, silos, warehouses, and ingredient handling systems should be designed so that moisture, rodents, birds and other pests are denied access. Regular cleaning of storage facilities will go a long way toward assuring a high quality finished product.
• One of the main components of receiving and storing is proper scheduling of the arrival of ingredients so as to minimize storage time and handling of the ingredients. Quality of ingredients, be they sacked supplements and/or medications, or bulk corn, or soybean meal, for example, may lose nutrient value or efficacy from excessive handling. Handling also invites problems with shrink.
• Misformulated, damaged or returned feed must be stored such that it cannot contaminate other feeding stuffs. Confirming analysis should be made to determine if such waste feed can be reprocessed, or must be destroyed. Here again a paper trail is important, especially for medicated feeds.

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