Effect of virginiamycin supplementation on the performance of young grazing cattle

Three experiments have been conducted to study the effect of virginiamycin in young grazing-bulls (Experiment 1) and heifers (Experiments 2 and 3). Rotational grazing on permanent grassland was practised and animals were supplemented with 1 kg dried sugarbeet pulp per head daily. Control groups did not receive virginiamycin via the supplement, while it was incorporated at 120, 300 and 200 mg kg⁻¹ for the treatment groups in Experiments 1 to 3 respectively.
Average daily liveweight gain was significantly increased from 0·59 to 0·72 kg in Experiment 1 and from 0·73 to 0·81 kg in Experiment 3, but was not affected in Experiment 2 (0·51 vs 0·55 kg). Virginiamycin also increased liveweight gain per ha by 12, 7 and 13%, respectively, for the three experiments. Grazed area per animal was not enlarged to the same extent as the calculated daily energy allowances, which may suggest an improved digestibility and/or rumen fermentation.     

Assessment of impact of the introduction of exotic fish species in north-east Thailand

Abstract. Within the framework of a fisheries project in north-east Thailand, project MK/FSPC/069 entitled ‘The Fish Seed Production Centre, North East Thailand’, an assessment was carried out of the ecological impact of introducing exotic fish species (common carp, Cyprinus carpio L., Nile tilapia, Oreochromis niloticus (L.), and Chinese and Indian carps). For the assessment, the protocol of Kohler & Stanley (1984) was followed, covering feasibility of introduction, acclimatization potential, potential impact, and control potentials. Regarding the (ongoing) use of the proposed exotic species in aquaculture, it was concluded that so far no clear ecological impact has been reported from escapes to open water; the use of the exotic species has shown to be highly beneficial from a 9 socio-economic point of view. Regarding the proposed introduction of the exotic species into public waters (natural lakes and man-made reservoirs), it was concluded that earlier releases of these species in north-east Thailand did not provoke severe ecological impact in terms of deterioration of aquatic ecosystems. Incidental cases of minor ecological impact were reported for common carp and nile tilapia. Indications were obtained for niche competition between Chinese and Indian carps and indigenous carps, while similar niche competition was concluded for bighead carp, Aristichthys nobilis (Richardson), and indigenous pelagic zooplankton feeders. Observing the prolific development of the Nile tilapia in a number of reported cases, it was recommended not to include this species in stocking programmes for public water bodies, until more risk assessments are available.     

The Iron Ore Market in the Sino-Brazilian Trade

China has required a large quantity of commodities in order to keep with its economic growth path,driven by large exports,rapid urbanization and investment in fixed assets.Commodities exporter countries have benefited from China ’s immense"hunger"for commodities,especially during the 2000s.Brazil,for instance,has emerged in this scenario as one of the largest iron ore producers and exporters.However,the cooling down of the Chinese economy has brought doubts to the iron ore industry,which may remain strong in near future but one cannot claim for certain whether or not this trend will remain this positive in the long run.     

Comparison of the effects of etomidate and its fluoro analogue, R 8110, on plasma Cortisol, 11β-deoxycortisol, 17α-hydroxyprogesterone and testosterone concentrations in dogs

R 8110, an imidazole derivative, was shown to be clinically superior to etomidate for induction and maintenance of anaesthesia in dogs. The present study compared the effects of intravenous (i.v.) R 8110, etomidate and Ringer solution on cortisol biosynthesis by the adrenal gland in seven male labradors. A tetracosactide challenge was carried out 30 min after the i.v. injection of 3 mg/kg of both drugs and after i.v. Ringer solution (1 ml/kg). Etomidate and R 8110 both suppressed the cortisol response to tetracosactide almost completely and increased the plasma 11 beta-deoxycortisol levels more than 20 fold. Maximal 11 beta-deoxycortisol values were reached 120 min after R 8110, and not less than 300 min after etomidate. Plasma 17 alpha-hydroxyprogesterone and testosterone concentrations did not differ between placebo and R 8110 treatment, but they decreased after etomidate. These results indicate that the effects of R 8110 on steroid biosynthesis in dogs are less pronounced than those of etomidate and are largely limited to a temporary inhibition of the 11 beta-hydroxylase in the adrenal gland.     

Helminth parasites of freshwater fishes from Cuatro Ciénegas,Coahuila, in the Chihuahuan Desert of Mexico: inventory and biogeographical implications

As part of an ongoing inventory of the helminth parasites of freshwater fishes in Mexico, 570 individual fish were collected between Apr 2008 and Oct 2011 in 26 localities along the Cuatro Ciénegas region in Coahuila State, northern Mexico. Seventeen species of hosts, mostly corresponding to Nearctic freshwater elements, were studied. A total of 8324 individual worms were collected during this survey, representing 25 species of helminths, of which 9 were digeneans, 3 monogeneans, 3 acanthocephalans, 9 nematodes and 1 cestode. Most of the records in this checklist represent new host or locality records. The information provided in this checklist may be helpful for our understanding of the biodiversity and historical biogeography of this host–parasite system, because in the Cuatro Ciénegas region occur a Nearctic freshwater fish fauna, along with Neotropical and endemic elements, and from a biogeographical point of view, this may represent a transitional area.     

Effect of magnitude and direction of force on laryngeal abduction: Implications for the nerve‐muscle pedicle graft technique

Reasons for performing study: The nerve‐muscle pedicle graft technique is a treatment for recurrent laryngeal neuropathy (RLN), but the optimal placement of the pedicles within the cricoarytenoideus dorsalis (CAD) muscle is unknown. Hypothesis: The magnitude and direction of force placed on the muscular process of the left arytenoid cartilage affects the magnitude of laryngeal abduction. Methods: Five larynges were harvested from cadavers. Using increments of 0.98 N, a dead‐weight force generator applied a force of 0–14.7 N for 1 min each to the left muscular process at 0, 10, 20, 30, 40, 50, 60 and 70° angles. The rima glottis was photographed digitally 1 min after each force had been applied. Distances between biomarkers (Lines 1–4) and right to left angle quotient (RLQ) were used to assess the degree of left arytenoid abduction. Results: Increasing force from 0–14.7 N progressively and significantly increased the length of all lines and RLQ, indicating abduction. Furthermore, there was a significant interaction between force and angles. Applying forces of 7.84 N or greater (Lines 2–4 and RLQ) or 11.76 N or greater (Line 1) at angles 0, 10, 20 and 30° resulted in significantly greater abduction than applying the same forces at 40, 50, 60 and 70°. Angles of 0–30° correspond with the direction of pull exerted by the lateral compartment of the CAD muscle. Conclusion: In RLN, nerve‐muscle pedicle grafts should be placed preferentially in the lateral rather than in the medial compartment of the CAD muscle. Potential relevance: The information presented can be used to assist surgeons in the planning and application of the nerve‐muscle pedicle graft procedure.     

青藏高原高寒草甸草地NPK施肥组合研究

采用三因子二次正交旋转组合回归设计,以N、P和K3种肥料为因子,在青海省玉树州高寒草地进行施肥试验。结果表明,缺乏N和P的高寒退化草地,不缺K,3个施肥因素对牧草产量的影响顺序为NPK,草地牧草产量(Y,kg/hm2)可用其与N(kg/hm2)和P(kg/hm2)间的二元二次方程Y鲜重=11 027+742 N+728 P-2 540 N2-624 P2-1 055 NP和Y干重=3 706+243 N+232 P-716 N2-201 P2-306 NP很好地估测;牧草产量较优施肥组合为251.80 kg N/hm2+131.82 kg P/hm2和269.69 kg N/hm2+119.36 kg P/hm2。     

氮、磷添加对青藏高寒草甸土壤碳氮磷化学计量特征影响的Meta分析

为了解青藏高原高寒草甸土壤碳(Carbon,C)、氮(Nitrogen,N)、磷(Phosphorus,P)化学计量特征对氮、磷添加的响应,提高养分管理水平及草地生态系统的养分平衡。本研究严格筛选出21篇文章(612项数据)进行Meta分析,通过亚组分析分析了不同施肥方式(氮添加、磷添加、氮磷添加)、不同施肥强度(轻度、中度、重度)对青藏高原草地土壤C,N,P化学计量特征的影响。研究结果表明：养分添加显著增加了青藏高原草地土壤C,N,P含量;氮添加对土壤的增加效应随施肥强度增加而增加,磷轻度施肥(20g·m^-2以下)处理、氮磷添加轻度施肥处理下的土壤C,N,P含量及化学计量比增加效果最好。本研究结果总体反映出氮、磷添加对青藏高原高寒草甸土壤产生积极影响,研究结果可为青藏高原草地生态系统的保护提供科学依据。