Diets Premix

FFF Feeds, feed crops, forages, roughages, animal diets, premixes, concentrates. 

The most critical factor to dietary studies is the proper preparation of the test chemicals-diet admixtures. The range of physical and chemical characteristics of test materials requires that appropriate mixing techniques be determined on an individual basis. Standard practices generally dictate the preparation of a premix, to which is added appropriate amounts of feed to achieve the proper concentrations. 

Dietary preparation involving liquid materials frequently results in either wet feed in which the test article does not disperse or formation of gumballs feed and test material that form discernible lumps and chemical hotspots. Drying and grinding of the premix to a free-flowing form prior to mixing the final diets may be required however, these actions can affect the chemical nature of the test article. 

Gross necropsy lesions of a selenium deficiency are identical to those of a vitamin E deficiency (NRC, 1994) and include exudative diathesis and myopathy of the gizzard. Paleness and dystrophy of the skeletal muscles (white muscle disease) are also common. The incidence and degree of selenium deficiency may be increased by environmental stress. Selenium is generally included in trace mineral premixes. Common sources for supplementation of poultry diets are sodium selenite and sodium selenate. Selenium yeast is also used in conventional diets. 

Many producers wish to mix their own diets on-farm so that they have complete control over the formula (Fig. 5.1). This is particularly relevant when one or more protein feedstuffs is available on-farm in addition to a supply of suitable grain. In this case it is necessary only to purchase a premix, examples of which are shown later in this chapter. 

The premixes outlined above can be used for other stock, i.e. the chicken premixes can be used for waterfowl diets and the turkey premixes can be used for quail and ratite diets. Alternatively, specific premixes can be formulated for these species, based on the estimated requirements set out in Chapter 3. 

Table 5.14. Composition of a trace mineral premix to provide the NRC (1994)-estimated trace mineral requirements in chicken grower and layer diets when included at 5kg/t.

The use of purified vitamins and vitamin premixes as supplements to animal feeds has increased the economy of animal feeding. Vitamin premixes are composed of required vitamins and a suitable carrier and are given to animals together with feedstuffs providing energy and protein. Vitamin E is generally added to premixes for most domestic and laboratory animals (Combs, 1998). They are added as esters, because they are more stable than free tocopherols. Free tocopherols are known to stabilize other vitamins such as vitamin A in premixes. As an example, practical diets for chicks contain 5500 pg a-tocopherol equivalents/g (Combs, 1998). 

Diets are often deficient in minerals compared to animal requirements. They must be corrected either by incorporating a premix in the diet (monogastrics), or by the distribution of a mineral feed (ruminants). 

Providing adequate nutrition to broodstock is critical for ensuring eggs are of the highest possible quality. As outlined by Mourente and Tocher (2002), little is known about the exact nutritional requirements of tuna broodstock and, in the absence of such data, broodstock are typically fed on diets that closely mimic what they feed on in the wild (either directly or on locally available substitutes) and usually supplemented with a general vitamin and mineral premix (Wexler et aL, 2003 Hutapea and Permana, 2007). An early... 

A total of 196 composite milk samples from seven Holstein cows have been analyzed (20). The samples have been collected for 28 days, consecutively, beginning on the seventh day after calving. Cows were fed a ration containing corn silage, Timothy hay, commercial concentrate mixture (corn, barley, alfalfa meal, beet pulp, and CaCOs), trace minerals, and vitamins premix, and soybean meal provided 48% of total CP of the diet. The average BW of the cows was 552 kg. Animals were fed twice daily ad libitum and always had access to drinking water. Three of the examined cows had been healthy, with SCC lower than 137,000 cells/ml. One cow had been mastitic during the entire experimental period—the measured SCC varied from 204,000 to 11,876,000 cells/ml. Three cows had mastitic and healthy periods (SCC between 80,000 and 4,737,000 cells/ml). 

A filler material which is mixed with some of the minerals and/or vitamins required in a diet. The mix, which is sometimes called a premix, makes it easier to measure the correct amounts of the trace nutrients providing that they are homogenously distributed in the carrier material. 

Often a premixed powder or solution for feeding infants, or in some cases special diets for adults, is called a formula. 

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