Rumen, cattle

Because feed comprises over 80% of the cost of producing and fattening cattle, the maximum utilization of ever increasingly expensive rations is of upmost importance (179). Monensin under the trade name of Rumen sin (Elanco Products) was introduced in 1976 at a recommended level of 30 ppm in cattle feed. Lasalocid having the trade name Bovatec (Hoffmann-LaRoche, Inc.) was marketed some years later. 

FIGURE 7.28 Giraffes, cattle, deer, and camels are rmninant animals that are able to metabolize cellulose, thanks to bacterial celln-lase in the rumen, a large first compartment in the stomach of a ruminant. 

Pantothenic acid is found in extracts from nearly all plants, bacteria, and animals, and the name derives from the Greek pantos, meaning everywhere. It is required in the diet of all vertebrates, but some microorganisms produce it in the rumens of animals such as cattle and sheep. This vitamin is widely distributed in foods common to the human diet, and deficiencies are only observed in cases of severe malnutrition. The eminent German-born biochemist Fritz Lipmann was the first to show that a coenzyme was required to facilitate biological acetylation reactions. (The A in... 

A current area of interest is the use of AB cements as devices for the controlled release of biologically active species (Allen et al, 1984). AB cements can be formulated to be degradable and to release bioactive elements when placed in appropriate environments. These elements can be incorporated into the cement matrix as either the cation or the anion cement former. Special copper/cobalt phosphates/selenates have been prepared which, when placed as boluses in the rumens of cattle and sheep, have the ability to decompose and release the essential trace elements copper, cobalt and selenium in a sustained fashion over many months (Chapter 6). Although practical examples are confined to phosphate cements, others are known which are based on a variety of anions polyacrylate (Chapter 5), oxychlorides and oxysulphates (Chapter 7) and a variety of organic chelating anions (Chapter 9). The number of cements available for this purpose is very great. 

The requirements of dairy cattle for B-vitamins, determined almost half a century ago, concluded that a ruminant animal does not require an exogenous supply of B-vitamins because its rumen microflora should synthesise enough of these compounds to avoid deficiency. Since then, dairy cows have greatly increased their average milk and milk component yields. More recent studies have shown that B-vitamin supply in dairy cows is increased by supplementation, although losses in the rumen are extensive (Santschi et al., 2005). Whilst there are few reports of B-vitamin supplementation affecting milk quality, supplemental biotin has been shown to directly improve milk yield (Majee et al., 2003). 

In studies with normal adult animals, orally administered radiocerium moves rapidly through the gastrointestinal tract. About 0.96 of a cerium nitrate solution administered orally to rats was excreted within 24 hours (Sagan and Lengemann, 1973). However, external irradiation of the gastrointestinal tract with a 137Cs source (800 R) delayed excretion of the radiocerium. Only about 0.85 of the administered cerium was excreted by 3 days but 0.992 was excreted by 4 days. In swine, 0.98 of an oral dose of radiocerium was excreted by 3 days (Miller et al., 1969) while in cattle, radiocerium placed in the rumen required 3.7 days for 0.9 of the dose to be excreted. Fecal excretion of the cerium still occurred after 4 days. When radiocerium was placed in the abomasum of cattle, it was almost entirely voided in 1.2 days. 

The need to include a variety of minerals in experimental diets has already been mentioned this was especially stressed (1920-1930) by Boyd-Orr, the director of the Rowett Institute for Animal Nutrition in Scotland. Increasingly refined food sources led to the identification of large numbers of trace elements (e.g., Cu, Mn, Mo, Zn) whose importance in the diet was suggested from hydroponic experiments with plant seedlings. Cobalt is an example of such a trace element. Vitamin Bj2 is synthesized by bacteria in the rumens of sheep and cattle but is absent from their fodder. In Australia, sheep feeding on cobalt-deficient pastures failed to thrive because vitamin B12 could no longer be made. 

Mo use is not confined to prokaryotes similar enzymes are also formd in eukaryotes (including humans). Mo deficiency is rare, as are disorders of Mo metabolism, but symptoms may be induced if diets are rich in Cu or W, which are Mo antagonists. The direct toxicity of Mo is low, but Mo is an antagonist for Cu in cattle, where thiomolybdates formed in the rumen act as high-alfinity ligands for Cu. Hence intake of foods high in Mo can induce the disease molybdenosis (Mills and Davis 1987). 

The waste products of a home include paper, containers, tin cans, aluminum cans, and food scraps, as well as sewage. The waste products of industry and commerce include paper, wood, and metal scraps, as well as agricultural waste products. Biodegradable wastes, such as paper fines and industrial biosludge, into mixed alcohol fuels (e g., isopropanol, isobutanol, isopentanol). The wastes are first treated with lime to enhance reactivity. Then, they are converted to volatile fatly acids (VFAs) such as acetic acid, propionic acid, and butyric acid, using a mixed culture of microorganisms derived from cattle rumen or anaerobic waste treatment facihties. 

RunUnococcus albus and Ruminococcus flavefadens. These bacteria are important cellulose-degraders found in the rumen of cattle and sheep (2). Most isolated strains ferment cellulose and xylan and all ferment cellobiose. Fermentation of glucose and some other carbohydrates depends on the particular strain. R flavefadens and B. succinogenes can ferment the highly ordered crystalline cellulosic su trates but R albus cannot. No evidence has been found for extracellular cellulase production by R albus, but Ohmiya et al. purified cellobiosidase from this culture 17). Laboratory growth of R albus has been conducted at pH 7.0 and 37 C. 

Monensin was tested in a rumen fermentation assay at the Lilly Laboratories, and it was found to produce the desired shift in the fermentation (9). Monensin has been licensed in the U.S. for use in beef cattle for improved feed efficiency, where it is administered at 5 to 30 g/ton in a complete feed. In this application, the rate of growth is not increased, but the cattle consume about 10% less food. It is also licensed for increased rate of weight gain in cattle weighing more than 400 lb. and on pasture, where it is fed in a supplement at a rate of 50 to 200 mg per head per day. Lasalocid and salinomycin have also been licensed for use in cattle. 

Three broad groupings, of the antibiotic substances presently used in animal production, include (a) broad-spectrum antibiotics, including penicillins and tetracyclines, which are effective against a wide variety of pathogenic and non-pathogenic bacteria (b) several narrow-spectrum antibiotics that are not used in human medicine and. (c) the ionophore antibiotics, monensin. lasalocid and salinomycin Monensin and lasalocid are used as rumen fermentation regulators in beef cattle, and the three ionophores are used as coccidiostats in poultry production. The ionophores. which are not used in human medicine, were first introduced in the 1970 s and account for most of the increase in antibiotic usage in animal production since the 1960 s. 

When planning for Tilley and Terry digestibilities, it is common practice to ensure that the sheep or cattle have been fed for a couple of weeks on a basal diet similar to the test samples to be analysed. This is to ensure a buildup of the appropriate rumen flora resulting in a corresponding optimal activity. Whether or not this is necessary is open to question, and this and other sources of error have been discussed by Ayres (1991). It is also customary not to feed the animal on the morning planned for extracting the rumen liquor. 

The second largest use of sodium bicarbonate, accounting for approximately 25% of total production, is as an agricultural feed supplement. In cattle it helps maintain rumen pH and aids fiber digestibility for poultry it helps maintain electrolyte balance by providing sodium in the diet, helps fowl tolerate heat, and improves eggshell quality. 

Bauchop T (1979) Rumen anaerobic fungi of cattle and sheep. Appl Environ Microbiol 38 148-158... 

Following its oral administration, niclofolan is metabolized to some degree in the rumen of cattle (45). Niclofolan passes into the milk of cattle at concentra-... 

Bithionol is used for the treatment of tapeworm infections in poultry, and tapeworm and rumen fluke infections in sheep, cattle, and goats. An oral dose of approximately 200 mg/kg bw is used in sheep and goats, whereas two treatments, 4 days apart, of 200 mg/kg bw are used for chickens. Tlie drug is administered to poultry with tire feed, whereas to other animals it is administered in the form of gelatin capsules, tablets, or boluses. 

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