莱茵鹅15项血清生化指标的测定及分析

为了更有效地保护和利用莱茵鹅的优良基因,对北方种鹅场和双鸭山种鹅场的莱茵鹅血清进行了15项生化指标的测定及分析。结果表明:北方种鹅场和双鸭山种鹅场莱茵鹅血清三酰甘油、肌酐、直接胆红素、氯、镁、尿素氮、白蛋白和钙等血清生化指标之间的差异达到了极显著水平(P<0.01);血清总蛋白和总胆红素之间的差异达到了显著水平(P<0.05);而葡萄糖、高密度脂蛋白胆固醇、总胆固醇、无机磷和尿酸含量之间差异不显著(P>0.05)。研究还初步建立了莱茵鹅15项血清生化指标的参考值及参考范围。     

Including an additional systematic environmental effect within a generation in an evaluation model improves accuracy of prediction of breeding values in a closed herd of pigs

The present study evaluated the advantage of mixed‐model techniques over a selection index under different magnitudes of an additional systematic environmental effect (ASEE) in terms of accuracy of prediction and expected genetic gain. The data attempted to simulate a closed herd in a pig breeding program. The base population (G₀) consisted of 10 males and 50 females. Six generations (G₀ to G₅) were selected by using a selection index of three traits without overlapping. Additional systematic environmental constants with four levels in a generation were assigned from a uniform distribution at different ranges. Breeding values of animals in the last generation (G₅) were estimated on the basis of an index of individual phenotype (SI‐U), SI‐U adjusted for ASEE using a least‐squares mean (SI‐A), best linear unbiased prediction using an animal model excluding ASEE (AM‐E), and an animal model including ASEE (AM‐I). Accuracy of prediction and expected genetic gain were larger by the animal model than by the selection index, even if heritability of the traits selected was high and ASEE was set to zero. When ASEE was zero, the accuracy of prediction and expected genetic gain given by SI‐U and AM‐I were similar to those given by SI‐A and AM‐E, respectively. However, the differences in accuracy and expected gain between SI‐U and AI‐A and between AM‐I and AM‐E increased as the range of ASEE increased. It was concluded that selection based on an animal model was more effective than index selection, even if the herd environment was uniform and traits with high heritability were selected, and that it should be always included in an evaluation model, however slight any systematic environmental effect may be in a closed herd.     

青藏高原高寒草甸草地资源环境及可持续发展研究

通过青藏高原地理位置、气侯条件和高寒草甸草地资源、生态环境现状及发展趋势的分析表明，草地生态结构不合理，经营管理水平落后，超载过牧、鼠虫危害、水土流失以及人类活动干扰是草地退化、生态环境恶化、阻碍草地畜牧业持续发展的主要因素。合理利用天然草地，优化草地生产结构，培育家育优良品种，开展季节畜牧业生产，建立稳产高产人工草地，并建立健全草地资源监测、预测预报和开展可持续发展的示范研究是防治草地退化，促进生态系统良性循环和提高草地畜牧业经济效益的有效途径。     

野生小灵猫捕获初期对环境适应能力的观察

本文采用观察、统计的方法 ,收集了捕获初期的小灵猫在采食、运动、生长发育、繁殖率及对外伤和疾病的抵抗力等方面的数据和行为特征。分析出外界因子对小灵猫适应性的影响 ,总结出遮光、安静和引诱进食对捕捉初期小灵猫驯化的重要性 ,形成了一套有利于在生产实践中加强小灵猫驯化和适应的实际方法     

Involvement of spleen components of mature fowl in the primary and secondary humoral antibody response following experimental EDS'76 virus infection

Summary

Cellular changes in spleens of mature fowl in relation to both the primary and secondary humoral antibody response following experimentalEDS'76 virus infection were studied. The influence of splenectomy on humoral antibody response was also examined.

Experimental fowl had been naturally infected with fowl adenovirus (FAV) but did not possess precipitins to these viruses at the time of EDS’ 76 virus infection. Since EDS'76 infection provokes a recall of the group antibody to FAV, this infection simultaneously induces a primary response against EDS’ 76 virus and a secondary response due to the recall of the group antibody to FAV.

HI and precipitating antibodies toEDS'76 virus (primary response) werefirst detected at 6 and 8 days p.i. respectively. Curves of HI, precipating and neutralising antibody titres were biphasic; the first peak (IgM peak) occurred at 10–11 days p.i., the second (IgG peak) at 16–28 days p.i.

Precipitating antibodies to FAV (secondary response) were demonstrated from 4 days p.i. The curve of these antibody titres was also biphasic, with peaks at the same times as in the primary response.

Based on HI and AGP testing of primary and secondary immune response in both splenectomised and non‐splenectomised fowl it is concluded that in the primary response the spleen of the adult fowl is involved significantly in only IgM secretion, while in the secondary response it is likely that bothIgM and IgG are secreted in considerable amounts.

Clusters of lymphoblasts and plasmablasts were observed at 3 days p.i. in the red pulp. It is very likely that antigen‐antibody complexes are formed from that time and circulate bound to the surface of lymphocytes. These antigen‐loaded lymphocytes are ‘picked up’ from the blood stream by

– red pulp macrophages, leading to enhanced formation of lymphoblasts in the red pulp. Great numbers of these cells (which are very probably IgM secreting cells) were present on days 6 and 7 p.i., but were no longer detectable after day 10 p.i.

– macrophages of the macrophagalellipsoidal corona (MEC), leading to significant enlargement of the periellipsoidal lymphoid tissue(PELT) by an increase of the number of lymphocytes observedfrom days 4–12 p.i. The MEC was significantly enlarged from 7–12 days p.i., very likely due to an increased number of macrophages.

Following deposition of antigen in the white pulp, formation of follicles begins. The number of small, intact follicles includingfollicle precursors increasedfrom 6 days p.i. From 15 days p.i. to the end of the experiment both the number and size of follicles increased significantly.

Uptake and processing of antigen by macrophages is probably accompanied by death of some of these cells. This might explain the degenerative changes observed in large mesenchymal cells, probably macrophages, at 3 and 5 days p.i. in the red pulp and at 5 and 6 days especially in the MEC. Splenitis which was present at 3 and 5 days p.i. and oedema observed in and around ellipsoidal cells at 5 days p.i. may be due to mediators released from these degenerative macrophages.

A significantly increased number of follicles with lymphoblasts was seen from 2–15 days p.i. while lymphoblasts and plasmablasts were present in the PELT from 5–15 days p.i., but predominantly at 6 and 7 days p.i. It is likely that disruption of follicles and blast transformation of white pulp lymphoid cells are secondary response events. White pulp lymphoblastsand plasmablastsare probably IgG secreting cells.

Splenomegaly was observed at 3, 5 and 6 days after infection and was mainly due to swelling of red pulp macrophages and infiltration of granulocytes in the red pulp. Ellipsoidal and periellipsoidal changes could contribute to the splenomegaly at 5 and 6 days p.i.     

Mussel shells as an environment enrichment and calcium source for floor-housed laying hens

Feather pecking is still a behavioral problem in laying hen flocks, resulting in impaired welfare and economic losses. Environment enrichment, e.g., providing access to litter, to increase foraging behavior in laying hens has been shown to decrease feather pecking. This study investigated the effect of spreading crushed mussel shells (particle size 10 to 20 mm) in the litter area as an environment enrichment and source of calcium for layers receiving a commercial feed and for layers given a feed with 40% less calcium. These treatments were compared with a control involving hens given the commercial feed, but no mussel shells in the litter. The study included 900 Dekalb White layers housed in a single-tier floor system during a production cycle (20 to 72 wk of age). The mussel shells were consumed to a lower extent than predicted, resulting in calcium deficiency in hens fed the low-calcium diet. This in turn was evident as increased degree of keel bone deviations and lower eggshell breaking strength. Daily addition of crushed mussel shells to the litter for laying hens on a balanced or calcium-deficient diets did not generate any positive effects on bird feather cover, eggshell quality, production performance, or fearfulness. Hence, with the particle size of mussel shells used in this study, there was no indication of improved welfare due to environment enrichment.     

畜禽及环境中沙门氏菌的PCR快速检测与控制

本文运用PCR技术检测家畜及环境中的沙门氏菌,25种沙门氏菌均获得特异性扩增,3种非沙门氏菌检测结果为阴性。表明PCR技术具有快速简便、敏感高和特异性强等优点,值得在沙门氏菌的快速检测中推广应用。并简要介绍了沙门氏菌的相关控制措施。     

浅谈农村环保型养鸡

针对农村养鸡现状与存在的问题，提出在选种、饲料的科学配合、饲养管理制度、合理用药以降低药物残留、加强养鸡场内外环境保护等方面，建立具有农村特色的环保型养鸡模式。