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11.
The development and implementation of a population supplementation and restoration plan for any endangered species should involve an understanding of the species’ habitat requirements prior to the release of any captive bred individuals. The freshwater pearl mussel, Margaritifera margaritifera, has undergone dramatic declines over the last century and is now globally endangered. In Northern Ireland, the release of captive bred individuals is being used to support wild populations and repatriate the species in areas where it once existed. We employed a combination of maximum entropy modelling (MAXENT) and Generalized Linear Mixed Models (GLMM) to identify ecological parameters necessary to support wild populations using GIS-based landscape scale and ground-truthed habitat scale environmental parameters. The GIS-based landscape scale model suggested that mussel occurrence was associated with altitude and soil characteristics including the carbon, clay, sand, and silt content. Notably, mussels were associated with a relatively narrow band of variance indicating that M. margaritifera has a highly specific landscape niche. The ground-truthed habitat scale model suggested that mussel occurrence was associated with stable consolidated substrates, the extent of bankside trees, presence of indicative macrophyte species and fast flowing water. We propose a three phase conservation strategy for M. margaritifera identifying suitable areas within rivers that (i) have a high conservation value yet needing habitat restoration at a local level, (ii) sites for population supplementation of existing populations and (iii) sites for species reintroduction to rivers where the mussel historically occurred but is now locally extinct. A combined analytical approach including GIS-based landscape scale and ground-truthed habitat scale models provides a robust method by which suitable release sites can be identified for the population supplementation and restoration of an endangered species. Our results will be highly influential in the future management of M. margaritifera in Northern Ireland. 相似文献
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Ayantunde AA Delfosse P Fernandez-Rivera S Gerard B Dan-Gomma A 《Tropical animal health and production》2007,39(3):207-216
Groundnut haulms along with cowpea hay are major crop residues used for animal fattening in the West African Sahel. In traditional
sheep fattening, feeds are always provided ad-hoc and in an unregulated fashion, which is rather wasteful. As a preliminary
study to establish the optimal feeding levels of groundnut haulms for profitable sheep fattening, a feeding trial was conducted
for 70 days with four levels of groundnut haulms (0, 150, 300 and 450 g/day) and a basal diet of bush hay. The effects of
supplementation with groundnut haulms on feed intake, water consumption, live weight changes and economic return were determined.
Twenty-four Peuhl Oudah rams with average initial weight of 28.6 kg (SD = 1.4) were randomly allocated to four treatments
defined by the four levels of groundnut haulms in the diet. Faeces and urine were collected in weeks 5 and 9 of the trial.
Digestible organic matter intake (g/(kg LW)0.75) and nitrogen intake (g/day) increased linearly with the level of groundnut haulms offered. Sheep that were fed only bush
hay lost 18.4 g/day, while those that were offered 150, 300 and 450 g of groundnut haulms gained 1.4, 19.3 and 40.2 g/day,
respectively. The gross return ranged from 1883 to 4946 FCFA per ram. Net benefit, after removing the feed and veterinary
costs from the gross return, ranged from 368 to 1400 FCFA per ram. 相似文献
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Bodyweight and carcass characteristics of somali goats fed hay supplemented with graded levels of peanut cake and wheat bran mixture 总被引:2,自引:2,他引:0
The experiment was conducted for ninety days of feeding trial at Haramaya University, Ethiopia using twenty four yearling male Somali goats weighing 20.4 +/- 2.02 (mean +/- SD) with the objectives to evaluate the effect of supplementation of peanut cake and wheat bran mixture (3:1) on body weight (BW) gain and carcass characteristics of Somali goats. The experiment was arranged with six blocks and four treatments in a randomized complete block design. The treatments were ad libitum feeding of hay (T1, control) and supplementation with 200 g (T2), 300 g (T3) and 400 g (T4) peanut cake and wheat bran mixture on dry matter (DM) basis. Supplementation reduced (P < 0.001) hay DM intake, but increased (P < 0.001) total DM intake at 300 g DM (T3) and 400 g DM (T4) level of supplementation compared to the control treatment. Daily BW gain, final BW, empty BW, hot carcass weight and dressing percent were higher (P < 0.001) in the supplemented treatments. Goats on the medium (T3) level of supplementation had significantly heavier (P < 0.001) liver and more muscle deposition, whereas those on hay alone (T1) exhibited heavier bone, head as well as gut contents (P < 0.05). It was concluded that supplementation of Somali goats with the different levels of peanut cake and wheat bran mixture promoted BW gain, dressing percentage and increased the proportion of edible offals. Similarity between the different levels of supplementation used in this study with regard to BW and carcass characteristics favours the use of the low (T2) or medium (T3) level than the high (T4) level of supplementation. 相似文献
15.
Effect of iodine supplementation on thyroid and testicular morphology and function in euthyroid rats
Seventy-five male weaner euthyroid rats, randomly divided into three equal groups were used to evaluate the effect of iodine
supplementation in the diet on growth and spermatogenesis. From the age of six weeks, the rat groups were fed normal diet
containing 0.05 mg iodine/Kg diet (A); normal diet supplemented with 0.5 mg/Kg iodine (B) and normal diet supplemented with
3.0 mg/Kg iodine for a period of 90 days. Thereafter, all three groups were fed the normal diet for another 60 days. Body
weight and feed consumption were determined; morphomeric studies of thyroid glands, testes and epididymes were carried out.
Spermatogenesis was evaluated with epididymal (ESC) and testicular sperm counts (TSC). Increasing iodine intake significantly
(p < 0.05) decreased mean body weight from day 30 of supplementation. Iodine supplementation influenced feed conversion ratio
and efficiency in feed utilization in an inconsistent pattern. Supplementation did not significantly (p > 0.05) alter the
size of thyroid glands, but increased the mean weights of the testes and epididymes to levels significantly (p < 0.05) higher
than values for non-supplemented rats at specific stages of the study, especially at the highest (3 ppm) level of iodine supplementation.
However, supplementation resulted generally in lower sperm counts, which was significant (p < 0.05) in the case of the epididymes.
The results of the study show that iodine supplementation to weaner, non-iodine deficient euthyroid rats at 3ppm not only
retard weight gain but could also reduce fertility by lowering epididymal sperm counts. 相似文献
16.
Robert A. McCleery Roel R. Lopez Nova J. Silvy William E. Grant 《Biological conservation》2005,124(1):27-33
We evaluated the effectiveness of supplemental stockings being proposed in the recovery of the federally endangered Key Largo woodrat (KLWR, Neotoma floridana smalli) using a stage-based, stochastic model. Supplemental stockings were evaluated with a population model using current trapping and telemetry data along with published and unpublished KLWR data. Model simulations predicted the KLWR had >70% probability of terminal extinction over the next 10 years even with the use of supplemental annual stockings. Supplemental stockings of KLWRs (?20 females) appear to delay the extinction of the species, but negative population trajectories accelerated after stockings cease. Model results illustrated the importance of determining limiting factors on the population prior to the use of supplemental stockings as a recovery option for this endangered woodrat population. 相似文献
17.
不同精料添加量对绵羊饲料瘤胃降解的影响 总被引:6,自引:0,他引:6
6只8月龄小尾寒羊公羊(平均体重为29.98kg),安装永久性瘤胃瘘管。采用对比试验设计,分150g/d、250g/d、350g/d、450g/d四个混合精粒水平,玉米秸自由采食。采用铬标记法测定饲料瘤胃流通量,采用尼龙袋法测定饲料瘤胃降解率。试验结果表明:玉米秸、玉米面、麸皮和棉仁粕的营养物质瘤胃有效降解率与精料水平之间以及饲料瘤胃流通速度(k)与精料水平之间均存在二次函数关系。饲料k值均在日喂250g精料时最大,之后又随精料水平的提高而下降,所测饲料营养成分瘤胃有效降解率在350-450g精粒水平之间最高,个别饲料营养成分瘤胃有效降解率在250-350g精料水平之间达最大值,因此,为提高秸秆利用率及日粮的合理利用,以精粒添加量不大于350g为宜。 相似文献
18.
David W. Horohov Stephen T. Sinatra Raj K. Chopra Stanley Jankowitz Alejandra Betancourt Richard J. Bloomer 《Journal of Equine Veterinary Science》2012
The inflammatory response to vigorous exercise ranges from the mild symptoms of delayed-onset muscle soreness to debilitating injuries affecting soft tissue, joint, and bone. Although there is a great deal of information available on the inflammatory response to exercise in human athletes, less information is available regarding the inflammatory response to exercise in young horses undergoing training for racing careers. Here, we assessed the cytokine response to exercise in a group of young Thoroughbred racehorses during their initial training. Because there is interest in nonpharmacologic approaches to control or ameliorate exercise-induced inflammation, we also examined the anti-inflammatory effect of a nutritional supplement fed to half of the horses undergoing training. Twenty-five Thoroughbred horses aged 2 years were followed through their initial race training. Peripheral blood samples were collected at various times during the exercise for the quantitation of lactic acid, oxidative stress, and inflammatory cytokine gene expression. There was an intensity-dependent effect of exercise on lactate, malondialdehyde, and proinflammatory cytokine gene expression. Although training itself was associated with an overall reduction in inflammatory markers, horses receiving the supplement exhibited further reductions in their indicators of inflammation. As such, this study provides novel evidence of nutritional supplementation reducing postexercise inflammation. 相似文献
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A. Sterk J.M.A.J. Verdonk A.J. Mul B. Soenen M.L. Bezenon M. Frehner R. Losa 《Livestock Science》2007,108(1-3):269-271
The effect of supplementing a cereal-based diet with xylanase on the apparent faecal digestibility was investigated in weanling piglets (9.7 kg body weight). Xylanase supplementation increased the apparent faecal digestibility coefficients of crude protein, crude fat, crude fibre, organic matter, nitrogen free extract (NFE) and nonstarch polysaccharides (NSP). The increased apparent faecal digestibility coefficients resulted in a higher energy value of the cereal-based diet supplemented with the xylanase. 相似文献