مصطلحات هامة جدا للسادة المتخصصين فى دراسة علم الانتاج الحيوانى ------------------------------------------------------------------------- General (see below for terms used particularly in energy and protein nutrition) ADF / Acid detergent fi bre availability That proportion of a stated concentration and amount of mineral in the diet, or of a particular mineral added in defi ned chemical form, that can be absorbed and utilised by the animal to meet its net requirement. CF / Crude fi bre CS / Condition score diet The feed that is eaten by the animal. Synonymous with feed if selection by the animal does not occur. digestibility The intake of DM or a component (e.g. OM, CP), or its GE content, minus the amount in the corresponding faeces, expressed as a proportion of the intake (or as a percentage). General usage in this Report is synonymous with apparent digestibility, for which no allowance is made for endogenous material in the faeces (see true digestibility). DM / Dry matter DMD / Dry matter digestibility DMI / Dry matter intake DOM / Digestible organic matter DOMD / The DOM in the feed (or diet) DM. DOMI Digestible organic matter intake EBG / Empty bodyweight gain EBW / Empty body weight (i.e. live weight minus the contents of the gastro-intestinal tract) EE / Ether extract (crude fat); used to express the oil content of a feed or the fat content of the body feed That which is offered to the animal to consume, whether as pasture for grazing or as a feedstuff or mixture of feedstuffs. Synonymous with diet if selection by the animal is not possible. FW / Live weight of the animal after a fast of specifi ed duration (see FHP) L Level of feeding; the quantity of feed eaten by the animal expressed as a multiple of the amount suffi cient for maintenance of zero ER, when L = 1 LWC / Liveweight change LWG / Liveweight gain maintenance At the maintenance level of feeding, the requirements of the animal for nutrients for the continuity of vital processes within the body (including the Glossary xix replacement of obligatory losses in faeces and urine and from the skin) are exactly met so that the net gain or loss of tissue substances by the animal as a whole is zero. Maintenance is not synonymous with zero change in weight (see also under Energy). MADF / Modifi ed acid detergent fi bre MW / Metabolic weight; W0.75 NDF / Neutral detergent fi bre OM / Organic matter OMD / Organic matter digestibility OMI / Organic matter intake requirement The amount of energy or any given nutrient that must be supplied in the diet to meet the needs of the animal. SCFA / Short-chain fatty acids; synonymous with VFA SRW / Standard Reference Weight; which, in concept, is the live weight of an animal (excluding fl eece and conceptus) when skeletal development is complete and the condition score is in the middle of the range. true digestibility For this measure, account is taken of endogenous material in the faeces; only the amount of material of direct dietary origin in the faeces is compared with the amount in the feed (see digestibility). In this Report true digestibility is employed only in the recommendations for protein nutrition. TSS / Total soluble salts in water VFA / Steam-volatile fatty acids; synonymous with SCFA W Live weight less conceptus and fl eece Energy BMR / Basal metabolic rate: heat production by a fasting animal in a postabsorptive state in a thermoneutral environment and at rest DE Digestible energy (MJ); synonymous with apparently digestible energy and calculated as the GE in the diet minus the GE in the corresponding faeces DEm / The DE required by the animal for maintenance EB, ER / Energy balance or retention (equivalent terms); MEI – H Ecold The additional energy required by the animal in cold stress. Egraze The additional energy expenditure incurred by grazing compared with confi ned animals. FHP Fasting heat production: represents the minimum energy requirement for maintenance; BMR + energy for minimal activity FM Fasting metabolism: the FHP plus the GE of the urine excreted during its measurement (synonymous with fasting catabolism) FMEI The intake of rumen-fermentable ME, calculated by deducting the energy contents of ether extract and UDP from the MEI. GE Gross energy; synonymous with heat of combustion H Heat production by the animal k(subscript) The net effi ciency of use by the animal of ME (i.e. NE/ME) for energy maintenance(km), for NE retained as weight gain (kg), as milk produced (kl) and in wool (kwool). xx Nutrient Requirements of Domesticated Ruminants kc Measures the gross effi ciency of use of ME for all energy costs incurred in the growth of the conceptus, because it includes the NE gain in the foetus and associated tissues and also the energy costs of their maintenance and of the enhancement of maternal metabolism. maintenance At the maintenance level of feeding (L = 1) the energy requirements of the animal are exactly met so that EB = 0; not synonymous with live weight maintenance. At other levels of feeding, this Report allows that there is variation in the energy requirement for the maintenance component of total energy expenditure. M/D Megajoules (MJ) of ME per kg of feed DM ME Metabolisable energy: the GE of the feed minus the GE of the corresponding faeces, urine and methane. At the maintenance level of feeding the heat production (H) by the animal exactly equals its ME intake; thus ME – H = ER = 0. MEI Metabolisable energy intake MEm The ME required by the animal for maintenance MEp The ME used by or available to the animal for production (i.e. = MEI – MEm) NE Net energy. The NE value of a feed (MJ/kg DM) is the increase in the ER of the animal promoted by an increment in the intake of that feed. Although the energy value of any particular feed is standardly described by a single M/D value, its NE value varies with the purpose for which its ME is used, because of differences between the km, kg and kl values for that feed. The NE requirement of the animal for maintenance is equal to the amount of energy that would be lost from the body by tissue catabolism if the animal were fasted (see FHP, FM), and for production is the GE of gain in tissue mass and of milk produced. Protein ADIP Acid detergent insoluble protein (the N present in ADF × 6.25) CP Crude protein, being total N × 6.25 (or × 6.38 for milk) CPI Crude protein intake CPLS Crude protein leaving the stomach through the pylorus to the duodenum; the (NAN × 6.25) in digesta in the form of MCP, plus UDP dg Degradability of CP estimated in sacco DPLS Truly digested protein leaving the stomach; made up of 0.6 MCP plus DUDP DUDP Truly digested UDP Edg The proportion of the CPI degraded in the rumen at a specifi ed rumen outfl ow rate, estimated from dg and fractional outfl ow rate EFP Endogenous faecal protein (N × 6.25) EUP Endogenous urinary protein (N × 6.25) FOM Fermented organic matter; the diet OM truly digested in the rumen MCP Microbial crude protein, being the (N × 6.25) incorporated in the microbial population in the rumen during its growth. It is assumed that of the MCP, 0.15 is in the form of nucleic acids and 0.25 is indigestible, leaving 0.6 as digestible true protein. NAN Non-ammonia nitrogen Glossary xxi NDIP Neutral detergent insoluble protein PLS True protein leaving the stomach through the pylorus to the duodenum; equals 0.85 MCP plus UDP RDP Rumen degraded protein (= CPI × Edg); may be used by microbial population in the rumen to synthesize MCP true digestibility For this measure, account is taken of endogenous material in the faeces; only the amount of protein of direct dietary origin in the faeces is compared with the amount in the feed (see digestibility). UDP Undegraded dietary protein; equals CPI
Posted on: Thu, 24 Oct 2013 16:48:10 +0000
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