| Summary: | 碩士 === 國立中興大學 === 動物科學系所 === 98 === Eight finishing female goats of Nubian crossbred with Taiwan Black (32.7 ± 3.25 kg of body weight) were used to determine the effect of copper supplementation on nutrient digestibility, growth performance, rumen parameters and copper metabolism. Goats were located in individual pens and randomly assigned to four dietary treatments by a completely randomized design. The treatments consisted of basal diet containing (1) 0 mg, (2) 5 mg, (3) 25 mg and (4) 50 mg of copper supplemented/kg DM with copper (II) carbonate dihydroxide (Cu2(OH)2CO3). The copper chemical was dissolved in ammonia water and sprayed on concentrate to make its copper content doubled of being required and kept at 4oC. Basal diet was consisted of 50% concentrate (17.5 ± 1.75 mg Cu/kg DM) and 50% pangola hay (7.62 ± 0.78 mg Cu/kg DM). The results revealed that average daily gain and feed efficiency were not different among the treatments. The digestibilities of ADF varied among the duration days such that measurements on day 16 and day 23 were higher (P < 0.04) than those on the day 9 but not differed from those on day 2. Crude fat digestibility was the highest on the day 23 and lowest (P = 0.0108) on the day 9. Ruminal osmolarity was the highest in goats fed diet 2 and the lowest (P = 0.0204) in goats fed diet 4. Ruminal bacteria and protozoa population as well as pH were not different among the treatments. Content of total rumen volatile fatty acids were decreased (P < 0.01) as copper supplementation increased but no difference was observed between goats fed diet 1 and diet 2. Ruminal propionate content was the highest and the lowest (P = 0.0325) in goats fed with diet 3 and diet 4, respectively. Ruminal fluid and fecal copper concentration increased (P < 0.001) when dietary copper supplementation increased. Copper content in urine tended (P = 0.0537) to increase as dietary copper concentration increased. Copper contents in whole blood and plasma were not different among the treatments whereas iron content in whole blood in the goats fed diet 4 and diet 1 was the highest and the lowest,
respectively. Fecal contents of molybdenum and sulfur positively correlated with whereas rumen fluid contents of these elements negatively correlated with the dietary copper supplementation levels. In conclusion, current range of dietary copper supplementation exerts no effect on the growth performance and copper status but increases the blood iron concentration and reduces the absorbabilities of molybdenum and sulfur by animals. Dietary copper supplementation exerts little, if any, effect on nutrient digestibility and ruminal parameters in finishing meat goats.
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