In this experiment, we used four male llamas that were three to four years of age from the Khara race. They were divided into two ad libitum feeding groups. The digestible energy (ED) was determined using samples that were sent to the laboratory. These samples were derived from a conventional in vivo assay using the method of total fecal collection in order to determine the difference between energy consumed and energy excreted. Metabolizable energy was calculated by deducting digestible energy, energy loss in the urine and energy loss in the gases (methane). Urinary energy was determined through the measurement of nitrogen in the urine as urea. Other studies have reported the energy values of alfalfa hay and barley as 414.05 Kcal/100g and 405.11 Kcal/100g, respectively. Additionally, alfalfa hay and barley have been recorded as having gross energy values of 6,973.92 Kcal/day and 4,373.65 Kcal/day, respectively. In this study, the energies excreted in the feces were 2,365.42 Kcal/day for alfalfa and 1,643.26 Kcal/day for barley. In order to determine the value of metabolizable energy, it is first necessary to obtain the urinary energy values (EU) by measuring the amount of nitrogen excretion as well as the energy of the gases (methane). Then, by deducting the energy calculated from the digestible energy, metabolizable energy may be estimated. The nitrogen content in urinary excretions from the llamas tested was highly variable from one treatment to another. With barley, the observed content was 0.59 g/day whereas with alfalfa hay it was 7.36 g/day. According to the data obtained for nitrogen content in urinary excretions, the amount of urea excreted each day was also obtained. It was also found to be variable from one food to another. Values of urea excretion for alfalfa and barley were 15.76 and 1.27 grams of urea/day respectively. By multiplying the daily amount of urea excreted by its caloric value (2.528 Kcal/g), the energy lost in the urine was determined to be 38.84 Kcal/day for alfalfa and 3.23 Kcal/day for barley. It was not possible to determine the energy of the gases. Instead, we used data obtained from llamas fed with forage (Engelhardt and Schneider, 1977). The data established that the energy loss as methane gas is approximately 7.1% of the gross energy. With this value as a reference for llamas, the energy losses as methane gas in this study were 495.08 Kcal/Kg/MS for alfalfa hay and 310.53 Kcal/Kg/MS for barley. By definition, the metabolic energy (EM) is the amount of energy from food that is calculated by determining the difference between the digestible energy (ED) and the energy lost in urine (EU) and gases (EG) according to the following equation (NRC, 1981): EM = ED - (EU + EG). Based on the equation, the metabolizable energy of alfalfa hay and barley are as follows: EB = 4140.49 Kcal/Kg/MS and EM = 2408.43 Kcal/Kg/MS for alfalfa compared to EB = 4051.20 Kcal/Kg/MS and EM = 2061.32 Kcal/Kg/MS for barley.
| Identifer | oai:union.ndltd.org:BGMYU2/oai:scholarsarchive.byu.edu:etd-6441 |
| Date | 01 January 2006 |
| Creators | Ugarte Huanca, Edwin Gonzalo |
| Publisher | BYU ScholarsArchive |
| Source Sets | Brigham Young University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Coverage | Oruro (Bolivia) |
| Rights | http://lib.byu.edu/about/copyright/ |
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