ANSC
Exam 1 Notes.docx

Lactation high levels of milk production require

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Lactation- high levels of milk production require highest levels of nutrient composition, except for a sustained period of extremely high exercise Requirements for all nutrients are increased during lactation and directly related to the level of production. Among all physiological states, is the most nutrient demanding function o Energy is the capacity for biochemical work, not a nutrient o Species lactation differs greatly typically in the 3 rd trimester of gestation. Some species in 3 rd trimester is dried up where as some are not. o Ex. Dairy cows lactate for 305 days. It is remarkable what the dairy cow can produce per day in milk. Lbs of protein and lactose and etc. this is reflected in the nutrient requirements. Reproduction- nutrient needs of animals for reproduction are generally less critical than for rapid growth or heavy lactation, but they are more critical than for maintenance Nutrient deficiencies prior to breeding may result in sterility, low fertility, silent estrus, or failure to establish or maintain pregnancy Work- studies indicate that work (physical exercise) increases energy demand, proportional to the level of work being done. Dietary CHO are utilized as energy sources in mammals, more efficiently than fats or proteins Nitrogen excretion has been shown to increase as a result of muscular activity o Methods for assessing nutrient content of feeds Proximate analysis is the most common analysis performed on feed samples A series of analyses performed to estimate the nutrient characteristics of a feed
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Includes dry matter, CP, ether extract, crude fiber, ash, and nitrogen free extract o The dry matter in a feedstuff or a food. If we are not careful as we think about the effect of moisture. Adds mass and dilutes. o Ex. Corn Grain: has about 10% moisture. 90% dry matter. On the moisture containing basis, as is as fed the corn will have about 9% protein. If the water is removed, the nutrient level increases. Adding the water back, there is a dilution that effects the level of protein or nutrients. o Ether is a nonpolar solvent that is used to dissolve the crude fat. Crude fat is called that upon ether abstraction. o Assessing nutrient content of feeds dry matter (DM) Water is a useful substance to an animal; but its presence in feed acts as a diluent. And it adds mass Most data on feeds are reported either on a dry matter basis or an as is basis With information reported on its moisture content Dry matter is determined by drying the sample in an oven of one type or another o Assessing nutrient content of feeds crude protein (CP) Protein level is estimated by a procedure called the Kjeldajl method, which measures nitrogen content of the feed, irrespective of source The feed sample is digested in hot, concentrated sulfuric acid, which converts all the carbon containing compounds to CO2 N is trapped, measured and expressed as percentage The Kjeldahl procedure provides only an estimate of the quantity of N
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  • Spring '18
  • Russel Muntifering
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