环境温度和饲粮营养浓度对生长期母兔代谢能利用率的影响

选用6只9周龄新西兰母兔,评定环境温度和饲粮营养浓度对生长期母兔代谢能利用率的影响。试验在密闭式的小动物呼吸测热柜中进行。分别对处于环境温度为20±2℃和30±2℃,采食两种不同营养浓度的试兔进行测试。饲粮营养水平实测值,分别为12.22kJ ME/g和13.49kJ ME/g;粗蛋白质(CP)分别为17.3％和21.6％;中性洗涤纤维(NDF)分别为23.7％和16.5％。结果表明:环境温度影响试兔的能量平衡,它与采食量间存在着显著的相关。20±2℃时,相关系数r=0.798;30±2℃时,相关系数r=0.875。在本试验设计范围内,饲粮营养浓度并不影响代谢能食入量(ME_I),热增耗(HP)和能量平衡(EB)。当环境温度为20±2℃和30±2℃时,表观代谢能转化率(NE/ME)分别为51％和71％;每天每兔每千克代谢体重代谢能维持需要分别为396 kJ和361 kJ。试验结果认为:环境温度影响营养物质消化率(P相似文献   

Predicting Acceptability of Jaguars and Pumas in the Atlantic Forest,Brazil

Jaguars and pumas are threatened species in Brazil’s Atlantic Forest, especially at the borders of protected areas. This article assessed the influence of emotions, attitudes, existence value, and agency credibility on acceptability of big cats among rural residents living adjacent to two protected areas in this forest. Data from self-administrated questionnaires (n = 326) indicated those with positive attitudes toward big cats (β = .28, p < .001), those who valued the existence of big cats (β = .14, p < .05), those who would feel sorrow if big cats disappeared (β = .21, p < .001), and those who considered the managing agency as credible (β = .16, p = .002) were more accepting of big cats. The model provided theoretical and practical insights into large carnivore conservation. For example, given the significance of agency credibility, a positive relationship between park authorities and residents is crucial for big cat conservation.     

Epidemiology of porcine non-specific colitis on Scottish farms

The objective of this study was to investigate epidemiological risk factors for porcine non-specific colitis (NSC). Forty-seven Scottish pig farms, with and without a clinical history of diarrhoea during the growing period (15-40 kg), were selected. The study included farm visits, clinical inspection of pigs, completion of farm management questionnaires, pathological tests into the cause of the diarrhoea and analysis of the non-starch polysaccharide (NSP) content of feeds. The results from 17 farms designated as NSC and 10 control farms suggest dietary associations with NSC. Farms with NSC fed diets with significantly higher levels of NSPs, especially containing the sugars glucose, arabinose and xylose. Few management factors were identified, although the high prevalence of infectious colitis reduced the power of the study.     

Quantitative analysis of production traits in saltwater crocodiles (Crocodylus porosus): II. age at slaughter

Crocodile morphometric (head, snout‐vent and total length) measurements were recorded at three stages during the production chain: hatching, inventory [average age (±SE) is 265.1 ± 0.4 days] and slaughter (average age is 1037.8 ± 0.4 days). Crocodile skins are used for the manufacture of exclusive leather products, with the most common‐sized skin sold having 35–45 cm in belly width. One of the breeding objectives for inclusion into a multitrait genetic improvement programme for saltwater crocodiles is the time taken for a juvenile to reach this size or age at slaughter. A multivariate restricted maximum likelihood analysis provided (co)variance components for estimating the first published genetic parameter estimates for these traits. Heritability (±SE) estimates for the traits hatchling snout‐vent length, inventory head length and age at slaughter were 0.60 (0.15), 0.59 (0.12) and 0.40 (0.10) respectively. There were strong negative genetic (?0.81 ± 0.08) and phenotypic (?0.82 ± 0.02) correlations between age at slaughter and inventory head length.