FEED
REFERENCE
STANDARDS
CHAPTER VII
NUTRITIONAL DEFICIENCIES IN
LIVESTOCK AND POULTRY
In general, a nutritional deficiency may be considered simple or multiple in which case the total feed intake may contain an insufficient amount of one or more of the essential nutrients. Likewise, a given deficiency may be borderline, marked, or absolute. A borderline deficiency usually results in poor feed efficiency, or slightly decreased growth and production performance. An absolute deficiency of any important nutrient can lead to cessation of animal production or growth, and eventually death. An overt disease usually results from a marked deficiency of one or more essential nutrients.
The deficiency of a single nutrient may bring about inanition and the subsequent starvation may cause multiple deficiencies. Also, a nutrition deficiency may exist without the appearance of definite signs. In most common field conditions, the deficiency may be only slight or borderline, which makes the diagnosis difficult.
A simple uncomplicated nutrient deficiency in most farm animals as observed in controlled experiments, is rarely if ever seen in the field. More likely, a deficiency of several nutrients contributes to the signs observed. Many signs of nutrient deficiencies are non-specific and often are the result of a low plane of nutrition.
The variability in the nutrient composition of most feed ingredients present in the animal ration is an important factor leading to nutritional deficiency problems. A diet, that by feed analysis, appears to contain just enough of one or more nutrients may actually be deficient to some degree in those nutrients. Stress factors due to either microbial infections, extreme temperature and humidity and drugs may either interfere with the absorption of a nutrient or increase the quantity required. Moreover, an anti-nutrient present in the feed may destroy, or render unavailable to the animal, a particular nutrient that is present in the diet at normally adequate levels. The interactions of one nutrient with another and with other dietary constituents also contribute to the development of nutritional deficiencies.
The diagnosis of nutritional deficiencies by observation of signs alone is not complete. Observing the response to nutritional supplementation is not always evident particularly for chronic cases of deficiencies. For most nutritional deficiencies, the signs are not specific. Since many deficiency diseases result in the same clinical signs (e.g. stunted growth, poor appetite and unthriftiness) a nutritional deficiency problem could only be confirmed after observance of several of the clinical signs expected, and a careful review of the dietary, disease, and management histories of the animal.
The pages below are under
construction
Please refer to 2nd Edition
of the
FEED REFERENCE STANDARDS
for complete information
Copies available for PhP650.00
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Mr. Jerry Dean Concepcion
President, PHILSAN
jericho@skyinet.net
NUTRIENT DEFICIENCIES IN POULTRY
NUTRIENT DEFICIENCIES IN SWINE
NUTRIENT DEFICIENCIES IN RUMINANTS