Fundamentals of Applied Animal Nutrition
Gordon Dryden
- 288 páginas
- English
- ePUB (apto para móviles)
- Disponible en iOS y Android
Fundamentals of Applied Animal Nutrition
Gordon Dryden
Información del libro
If you have ever wondered why animals prefer some foods and not others, how poor feeding management can cause conditions such as laminitis, rumenitis or diarrhoea, or how to construct a diet to optimise animal performance and health, then this book will introduce you to the fundamentals of animal nutrition and their practical implementation.While giving a comprehensive and practical overview of the principles that underpin the design and management of farm animal feeding systems, this book: - Covers a wide range of topics from digestive function, nutrients and feed composition, to intake, feed related disorders, grazing behaviour and management, as well as how animals influence climate change and the environment.- Contains hints, tips and practical advice on animal feeding.- Includes links to the latest data on feed composition and nutrient requirements.- Is a companion book to the author's book titled Animal Nutrition Science.With its evidence-based approach and emphasis on the practical throughout, this is a valuable textbook for undergraduate and graduate animal science students studying the feeding of farm animals. It is also an essential reference for early practitioners, veterinarians, farm managers and advisers in animal feed companies.
Preguntas frecuentes
Información
1 Nutrients and important feed constituents and their functions
Introduction
Why do animals need feed?
The chemical composition of feeds
Food constituent | Analytical method |
---|---|
Dry matter (DM) | Measured by heating the feed, usually at 100°C for several hours; fresh forages may be dried at 50–60°C to avoid heat damage to proteins and loss of carbohydrates and other constituents |
Organic matter (OM) | Determined as the loss of mass after ashing (see below) |
Fibre (acid detergent fibre, ADF; neutral detergent fibre, NDF; and crude fibre, CF) | ADF and NDF are the residues which are resistant to the actions of either acid detergent (cetyltrimethylammonium bromide in sulphuric acid) or neutral detergent (sodium dodecyl sulphate in a pH 7 solution). Early methods of fibre analysis used a sequential extraction with acid and alkali to give a residue called CF. This analysis is now not often used and has been replaced with the more reliable detergent methods |
Protein (crude) (CP or Prot.) | Determined by measuring the total N content (using the Kjeldahl or Dumas methods) and multiplying this by 6.25. This method assumes that all the feed N is from protein, and that all proteins contain 16% N. Neither of these assumptions is completely correct, so CP values often overestimate the actual protein content. The individual amino acids which make up proteins are measured by chromatography |
Non-structural carbohydrates (NSC) or water-soluble carbohydrate (WSC) | These are carbohydrates which are not part of the plant cell wall. NSC includes starch and WSC. WSC is simple sugars (see text), β-glucans and fructans. These compounds are measured by polarimetry, ethanol extraction, and enzymatic methods |
Fat (crude) (EE, for ‘ether extract’) | Diethyl ether, petroleum ether, or hexane are used to extract fats and other substances such as phospholipids, waxes, fat-soluble vitamins, and pigments. This constituent is also called ‘ether extract’. Individual fatty acids are measured by chromatography |
Minerals (ash) | Ash is measured by burning a sample at 500°C or more for several hours. The ash contains most of the minerals – although some are lost by volatilization; this analysis is now more used for determining the organic matter content (see text). Data on individu... |