High Number Of Animals Research Articles

Avaliação da dor pós-intervenção em três métodos de esterilização de cães machos

The objective of this project was to evaluate the post-intervention pain due to three methods of male sterilization. Twenty seven dogs participated in the study and were distributed in three groups: (OT) dogs submitted to orchiectomy; (ZG) dogs submitted to intratesticular injections of zinc gluconate; and (VT) dogs submitted to vasectomy. Pain was evaluated with the dog post-surgical pain evaluation scale from Melbourne. There was no significant difference amongst median pain scores for the groups. In the group ZG, 44% of the animals needed sedation during the application, and 11% showed secondary complications, with ulceration and swollen testicles. The maximum pain score was higher for the ZG group, requiring post-intervention analgesia for one dog. The results motivate studies with higher number of animals regarding zinc gluconate, suggesting that the dogs be closely monitored during 15 days post-intervention.

Can sheep replace indigenous antelope as seed dispersers in the Kalahari?

The Southern Kalahari Duneveld is an arid savannah, which has been used for permanent stock farming since around 1900. Farming with high numbers of animals has led to changes in the vegetation which have been associated with excessive grazing and trampling. To determine whether altered seed dispersal could be an alternative or additional explanation, we investigated how replacing antelope with sheep affects seed dispersal. We determined the dispersal potentials of plant species by various vectors using standardized experiments and studied the variation of dispersal potential along a grazing intensity gradient and among different habitats.Wind dispersal potential was low, but diaspores of many plant species were well adapted to dispersal by water. Biotic long-distance dispersal potentials were relatively high and varied between sheep and antelope: the species of plants dispersed differed, as did the number of seeds transported and the time of year that seeds were dispersed in.The importance of zoochory and the differences found between antelope and sheep dispersal suggest that dispersal is affected by a change of animal type. Thus, sheep can not replace antelope as seed dispersers. Therefore, sustainable grazing management or restoration efforts should benefit from seed input of sensitive species where antelope are rare.

Biotopic distribution, population structure, and some features of small mammal reproduction in Chisinau City

Comparative analysis of species composition, biotopic distribution, population structure, and reproduction of rodents and insectivores in Chisinau City was performed in October–November 2008 (3029 traps days, 715 animals). Sylvaemus sylvaticus appeared to be the most numerous and widely distributed species, the reproductive strategy of which consisted of intense reproduction in the summer. The second most abundant species was Microtus rossiaemeridionalis, which had a different reproductive strategy, with part of its population continuing to reproduce actively in the autumn. Urban woodlands are the most close to natural biotopes by the species composition. The highest number of animals was defined for meadows and gardens. No rodents and insectivores are found on lawns and waste grounds.

The Romanian agrofood industry between challenge and performance

Europe 2020 relies on smart growth. Romanian food industry is competitive in terms of possible integration of domestic agricultural production and increase of employment. There was no territorial correlation between agricultural production and the absorption capacity of the food industry, and any reference to the final consumer. The animal production is being used in totally other counties than those who really have the highest number of animals.

Immune Status and the Development of Listeria monocytogenes Infection in Aged and Young Guinea Pigs

Consuming even low numbers of the foodborne pathogen, Listeria monocytogenes, places the elderly at risk for severe illness. The impact of immunomodulation on the development of listerial infection within a young and aged population after low dose challenge with L. monocytogenes was investigated. Animals received daily supplementation of vitamin E for a period of 21 days to promote immunomodulation, and were then orally challenged with 100 CFU of L. monocytogenes. Levels of CD8+, CD4+ and CD3+ T cells were used as markers to determine the influence of daily supplementation with vitamin E on immune response; the spleen and liver were harvested for microbiological analysis. Higher numbers of animals became infected in control groups than in vitamin E-treated group. During the post-challenge period, vitamin E-treated aged animals showed faster CD8+ T cell proliferation than control aged animals. Daily supplementation with vitamin E was more beneficial in young compared with aged animals in mitigating listerial infection. Results suggest exposure to even low numbers of L. monocytogenes can result in infection in both healthy young and aged populations.

Reduction in the Number of Animals and the Evaluation Period for the Positive Control Group in Tg.rasH2 Short-Term Carcinogenicity Studies

The lack of a clear guidance on the adequate number of animals used for positive controls in the short-term (26-weeks) transgenic mouse carcinogenicity studies has resulted in the use of high number of animals. In our earlier Tg.rasH2 studies, 25 mice/sex were used in the urethane-positive control dose groups that were sacrificed by 18 weeks. Based on a robust response, several of our protocols for Tg.rasH2 studies with 15 mice/sex and terminal sacrifice at 17 ± 1 weeks were submitted and accepted by the Carcinogenicity Assessment Committee of the US Food and Drug Administration since we demonstrated close to 100% response for the development of lung and splenic tumors (target organs) in 500 mice/sex. These 500 mice/sex included 17 groups of 25 mice/sex and 5 groups of 15 mice/sex. The objective of this investigation was to determine whether the number of animals can be further reduced along with the shortened duration of exposure to urethane. Accordingly, 10 Tg.rasH2 mice/sex/group were administered a total of 3 intraperitoneal (IP) injections of urethane (1000 mg/kg per day) on study days 1, 3, and 5, and the presence of tumors in the lungs and spleen was evaluated after 8, 10, 12, 14, or 16 weeks. Our results demonstrate that 100% of the mice at 8 weeks had developed lung tumors, whereas close to 100% of the mice at 14 weeks had developed splenic tumors. Based on the development of lung tumors alone in 100% of the mice, we recommend that 10 mice/sex are sufficient and that these mice can also be sacrificed as early as 10 ± 1 weeks following the administration of urethane.

Improved Statistical Modeling of Tumor Growth and Treatment Effect in Preclinical Animal Studies with Highly Heterogeneous Responses In Vivo

Preclinical tumor growth experiments often result in heterogeneous datasets that include growing, regressing, or stable growth profiles in the treatment and control groups. Such confounding intertumor variability may mask the true treatment effects especially when less aggressive treatment alternatives are being evaluated. We developed a statistical modeling approach in which the growing and poorly growing tumor categories were automatically detected by means of an expectation-maximization algorithm coupled within a mixed-effects modeling framework. The framework is implemented and distributed as an R package, which enables model estimation and statistical inference, as well as statistical power and precision analyses. When applied to four tumor growth experiments, the modeling framework was shown to (i) improve the detection of subtle treatment effects in the presence of high within-group tumor variability; (ii) reveal hidden tumor subgroups associated with established or novel biomarkers, such as ERβ expression in a MCF-7 breast cancer model, which remained undetected with standard statistical analysis; (iii) provide guidance on the selection of sufficient sample sizes and most informative treatment periods; and (iv) offer flexibility to various cancer models, experimental designs, and treatment options. Model-based testing of treatment effect on the tumor growth rate (or slope) was shown as particularly informative in the preclinical assessment of treatment alternatives based on dietary interventions. In general, the modeling framework enables identification of such biologically significant differences in tumor growth profiles that would have gone undetected or had required considerably higher number of animals when using traditional statistical methods.

The bovine oocyte in vitro maturation model: A potential tool for reproductive toxicology screening

Reproductive toxicity testing according to the present guidelines requires a high number of animals. Therefore, the development of alternative in vitro methods is urgently required. The aim of the present study was to investigate the applicability domain of the bovine oocyte in vitro maturation assay (bIVM) to study female reproductive toxicology. Therefore, bovine oocytes were exposed to a broad set of chemicals of two distinct biological function groups: (a) affecting female fertility and (b) affecting embryonic development and having a broad range of physical and chemical properties. The endpoints evaluated were the oocyte nuclear maturation (progression of meiosis) and general cytotoxicity. The oocyte nuclear maturation was negatively affected by all compounds tested and the effect was observed at concentrations lower than the cytotoxic ones. The bIVM assay correctly predicted the classification of compounds between those predefined groups. Additionally, the bIVM model contributes significantly for the 3R principle, since no test animals are used in this assay. In conclusion, the bIVM is a sensitive and valuable alternative assay to identify potential chemical hazard on female fertility.

Risk factors for Psoroptes ovis mange on Belgian Blue farms in Northern Belgium

The parasitic mite Psoroptes ovis causes important economic losses in Belgian Blue cattle. Because mange problems vary significantly between farms, a cross-sectional questionnaire survey and subsequent farm visits were performed to identify potential risk factors for P. ovis infections on Belgian Blue farms in Flanders, Belgium.The questionnaire was sent to 1800 beef farms to evaluate the presence and severity of psoroptic mange in the herd and to assess farm management practices, including antiparasitic treatments. Subsequently, about 10% of the farms with a completed questionnaire were visited to validate the questionnaire and to retrieve supplementary information on additional management parameters, such as barn infrastructure and climate. Associations between parasitism and putative risk factors were assessed by logistic regression.Out of 1800 contacted farms, 680 (38%) completed questionnaires were received. Data were collected from 238 barns during 66 farm visits. The questionnaire results demonstrated a high farm prevalence of mange (74%; 95% CI (70.7–77.3)) and half of the farmers declared that the problem was difficult to control. Nevertheless, in only 14% of the barns a high scratching index was recorded and in most of the sampled animals (80%) the affected body surface was less than 10%. This indicates that despite the high prevalence and the difficulty to control the infection, clinical signs were often quite moderate.Logistic regression analyses of the questionnaire and the farm visit data suggested that heavily infested farms treat more intensively against mange. On most farms mange occurred the whole year round and more problems with mange were found on farms where a higher number of animals were purchased per year. In addition, the disease was more prevalent when the animals had a lower hygiene score. This score was strongly correlated with environmental hygiene, indicating that transmission of mites from the environment to the animals should not be underestimated. Conflicting results were obtained on the effect of supplementing minerals on the occurrence of mange. In this study, temperature, light intensity and relative humidity in the barns, ventilation systems, barn infrastructure, animal stocking rate and blood mineral levels were not indicated as risk factors for mange. In conclusion, maintaining a good animal hygiene and if possible, avoiding introduction of cattle may help to control psoroptic mange in Belgian Blue cattle.

Einfluss der extrakorporalen Perfusion auf die Biodistribution 99mTc- HMPAOmarkierter Granulozyten

SummaryAim of the study was to evaluate the influence of an extra corporal perfusion (cardiopulmonary bypass operation – cpb) on activation and biodistribution of 99mTc labelled granulocytes in pigs with and without inhibition of the granulocytes by a leukocyte inhibition module (LIM). The cpb is often related to an activation of granulocytes resulting in an inflammatory answer. The biological mechanisms are unsolved yet. First trials of our group showed that LIM may inhibit the activation of neutrophils and therefore antagonize a cpb-caused impairment of cardiac function. This study is the continuation of these experiments with a higher number of animals and the focus on scintigraphic imaging. Animals, material, methods: 39 German landrace pigs were subdivided into three groups: group A (control) median sternotomy without cpb, group B with cpb, group C with LIM in addition to cpb. After labelling with 99mTc-HMPAO autologues granulocytes were reinjected. Subsequently to cpb, the animals underwent scintigraphic imaging. Quantification was performed with ROI evaluation and with tissue samples (section analysis) examined in a well counter. Results: A high uptake of 99mTc-HMPAO was found in the liver. The count rates in brain, heart, lung, spleen and kidneys were far below. The amount of 99mTc-activity in the organ related to the half life corrected administered activity [%] was for the tissue samples (group A/B/C): brain 0.01/0.02/0.03; lung 12.1/8.3/11.5; heart 0.35/0.54/0.42; kidney 1.24/0.87/1.02; spleen 4.0/4.0/4.5, liver 16.8/20.9/19.6. The count rates determined by ROI-evaluation of the scintigraphic images related to the total count rate in the image [%] were (group A/B/C): brain 1.1/0.9/1.0; lung 15.6/10.4/12.2; heart 4.0/3.5/3.4; kidney 4.0/2.9/3.2; spleen 7.6/7.7/9.5, liver 23.1/36.7/31.4. A significant difference in the tracer uptake between the groups could neither be detected by scintigraphic imaging nor evaluation of tissue samples. Conclusion: Scintigraphic imaging as well as section analysis showed a comparable biodistribution of the tracer. Therefore, the initial results of our group were not confirmed with a considerably higher number of animals. Neither cpb nor the use of the LIM influenced distribution of 99mTc-labelled granulocytes in pigs significantly.

Soil water repellency in rangelands of Extremadura (Spain) and its relationship with land management

Abstract Soil water repellency reduces infiltration capacity, enhancing overland flow and even runoff production, and may produce patchiness in water infiltration at the hillslope scale. Knowledge about hydrophobicity in rangelands of Mediterranean type climate and its relation with vegetation cover and land management is sparse. The objectives of the present work are to determine the degree and spatial occurrence of soil water repellency and to define its relationship with site characteristics, such as soil, vegetation and land management in rangelands of SW Spain. Field work was conducted in September 2009 in 22 environmental units belonging to 10 farms, distributed throughout the region of Extremadura. The Molarity of an Ethanol Droplet (MED) method was used for measuring water repellency of the soil surface. A total of 725 points were sampled and the study was combined with a detailed vegetation survey, the determination of soil properties and of land use and management characteristics. More than 70% of the measurement points were hydrophilic, however differences between farm units were found. The highest values of hydrophobicity were observed on soil surfaces below the canopy of holm oaks, as compared to the low values found below shrub canopies ( Retama sphaerocarpa ) and in open areas. With respect to ground cover, water repellency was highest at sites covered by holm oak litter. At soil surfaces covered by cork oak litter, dry grass and mosses the degree of repellency was lower. Almost all sites with a bare soil surface were hydrophilic, independent of whether these were located below a tree canopy or in open areas. A significant positive relationship between livestock density and the degree of bare soil existed, and consequently, areas with high animal numbers were dominantly hydrophilic. No significant relationships were encountered between the degree of soil water repellency and soil properties.

Levantamento e identificação dos aspectos epidemiológicos da raiva canina no município de Cuiabá - MT

Reconhecida desde a antiguidade, a raiva é uma infecção aguda do sistema nervoso central que acomete mamíferos, sendo causada por um RNA vírus da família Rabidoviridae, gênero Lyssavírus. O Brasil, desde a implantação do programa de controle da raiva em áreas urbanas, vem apresentando um declínio de casos de raiva em cães e em seres humanos. Em Cuiabá, as atividades realizadas pelo Centro de Controle de Zoonoses voltadas para o controle da raiva como: vacinação antirrábica animal, bloqueios de foco, captura de animais errantes, entre outros, permitiu o bloqueio da circulação do vírus na espécie canina. Desde 2008, o município de Cuiabá não registra nenhum caso da doença na espécie canina. Com o objetivo de conhecer a distribuição temporal da raiva canina em Cuiabá- MT, assim como identificar os aspectos epidemiológicos dos cães infectados pelo vírus rábico e verificar as medidas de profilaxia para a raiva canina, adotadas pelo Centro de Controle de Zoonose do município de Cuiabá no período de janeiro de 2002 a dezembro de 2008, realizou-se o presente estudo. Para o estudo observacional descritivo foi empregado o banco de dados referente à série histórica do CCZ e do Laboratório de Apoio a Saúde Animal - LASA ambos situados no município de Cuiabá- MT. O período de estudo foi de janeiro de 2002 a dezembro de 2008. Neste período foram examinadas 1021 amostras de cérebro de cães, destas 8,71% (89/1021) foram positivas e 91,29% (932/1021) negativas para a raiva. Os meses de maior incidência da doença foram os meses de janeiro 15,05% (14/93), fevereiro 12,5% (9/72), março 12,5% (9/72), abril 14,14% (9/72) e dezembro 13,69% (10/73). O maior número de cães doentes era macho 59,55% (53/89) com idade acima de dois anos 50,55% (45/89) e não domiciliados 67,41% (60/89). Em relação à imunoprofilaxia, a maioria dos cães 99,63% foi vacinada em campanhas. A cobertura vacinal ficou acima dos 80% exceto em 2006. Entre os animais que apresentaram a enfermidade o maior número, 67,41% (60/89), foi de cães não domiciliados, os chamados cães errantes. O percentual de cães domiciliados infectados pelos VR foi igual a 32,58% (29/89). As campanhas de vacinação, portanto, são fundamentais para a imunização do maior número de animais possível e a sociedade deve se conscientizar sobre a importância da raiva e as medidas que devem ser tomadas para controlá-la.

Efeito de diferentes dispositivos intravaginais na sincronização estral e taxa de gestação em ovelhas deslanadas submetidas à IATF via cervical superficial com sêmen refrigerado

The aim of this study was to evaluate the effect of different intravaginal devices in estrus synchronization and pregnancy rate in woolless sheep submitted to FTAI via superficial cervical with fresh chilled semen. Forty crossbreed ewes were used and randomly distributed into two groups: Group 1, ewes treated with the device CIDR®; Group 2, ewes treated with sponges impregnated with 60 mg of medroxyprogesterone acetate (MAP). The devices remained in the animals for 14 days and the TFAI via superficial cervical was performed 55 h after the devices were removed. The TFAI was performed using fresh chilled semen from rams with proven fertility. The average interval between the end of treatment and the onset of estrus was 29 ± 0.59 h (CIDR®) and 34 ± 2.7 h (MAP), showing a significant anticipation (P < 0.05) at the onset of the estrus in animals treated with CIDR®, in comparison to MAP. The pregnancy rate and prolificity was 80% and 1.8 in the group of sheep treated with sponges with MAP and 25% and 1.6 for the CIDR®. Once the high number of animals in estrus in the CIDR® group did not result inperfect synchronization, resulting in low pregnancy rate, it is recommended the use of sponges impregnated with MAP for TFAI in woolless ewes, 55 h after the intravaginal device removal.

Distribution and reproductive biology of the little cuttlefish Sepiola atlantica (Cephalopoda: Sepiolidae) around Anglesey, North Wales

Sepiola atlantica were captured in seine nets at twelve locations around the coast of Anglesey, UK. Animals were most abundant on the very sheltered shore of Y Foryd Bay and the wave-exposed shore of Traeth Penrhos, and these two locations were further sampled seasonally to examine the seasonal occurrence, population structure and reproductive biology of S. atlantica. Sepiola atlantica (5–28 mm dorsal mantle length (DML)) migrated inshore seasonally and first appeared in July where they attained peak abundances between July and August at seawater temperatures of 17°C. Numbers declined between September and October as temperatures fell below 15–16°C, and in late October, they migrated offshore. Male S. atlantica was significantly smaller and matured at a smaller DML than females. The number of spermatangia on the bursa copulatrix of female S. atlantica varied seasonally attaining maximum numbers in October with a mean of 22 spermatangia on the bursa copulatrix of Y Foryd Bay females. At Y Foryd Bay and Traeth Penrhos, the number of spermatophores in male and potential fecundity in female S. atlantica ranged between 1 and 147 and 25 and 141, respectively. The spermatophoric complex and gonadosomatic index showed a high degree of variability in individuals of similar wet body weight with the female gonad constituting a far greater percentage of the total wet body weight than the male gonad. It is concluded that S. atlantica of all sizes and maturity stages congregate in the shallow waters around Anglesey between July and October when environmental conditions are favourable for enhanced growth and maturation and where the high numbers of animals enhance opportunities for mating.

Genomic selection for carrier-state resistance in chicken commercial lines

BackgroundSalmonella propagation by apparently healthy chicken and subsequent food security concerns could be decreased by the selection and use of chicken lines more resistant to carrier-state. In the present study we applied the first steps of the genomic selection methodology to assess the interest of including genetic markers for the genetic evaluation of hen lines infected with Salmonella Enteritidis.MethodsWe studied commercial laying hen lines divergently selected for resistance to Salmonella carrier-state at two different ages. A total of 600 animals were typed with 1536 SNP markers and artificially infected with S. Enteritidis. Phenotypes were collected four weeks (young animals) or five weeks (adults) later. Two types of variance component analyses, including or not including SNP data, were performed and compared. All variance components were estimated by Bayesian methods and Gibbs sampling.ResultsThe comparison of both genetic analyses shows that SNP are efficient in capturing genetic variation, although none of them captures a large affect on the traits studied. Average accuracies do not change between analyses, showing that using SNP data does not really increase information.ConclusionsThese preliminary results show that genomic selection for Salmonella carrier-state resistance in laying hens is promising, although a denser SNP coverage of the genome on a higher number of animals is needed to assess its feasibility and efficiency compared to classical pedigree evaluation.

The effect of the farm size on milk traits of cows

Objective of this study was to analyze the effect of the dairy farm on milk traits of cows in Vojvodina. The research was carried out on small farms with 10 to 20 cows, medium farms with 20 to 50 cows, and large farms with over 50 dairy cows. The study included registered animals of Simmental (SM) and Holstein-Friesian breed (HF; including Red Holstein) in the first lactation for traits of milk yield and yield and content of milk fat. Total of 1323 first lactations were analyzed. The average milk yield (both breeds) in the first lactation of 305 days was 6295 kg of milk with 234,3 kg of milk fat and average milk fat content of 3,74%. Milk performance of cows varied significantly (CV=22,9% and SD=1447,8), as well as milk fat yield (CV=21,6% and SD=50,8). Large farms produced in average 6534 kg of milk, medium farms 6347kg and small farms 4717kg. Size of the farm exhibited significantly high effect on all observed traits, and the tendency was that farms with higher number of animals realize also higher average of production. Farm management and various breeding-zootechnical conditions present on farms had significant effect on milk performance of cows.

Transcriptomic Profile Indicative of Immunotoxic Exposure: In Vitro Studies in Peripheral Blood Mononuclear Cells

Investigating the immunotoxic effects of exposure to chemicals usually comprises evaluation of weight and histopathology of lymphoid tissues, various lymphocyte parameters in the circulation, and immune function. Immunotoxicity assessment is time consuming in humans or requires a high number of animals, making it expensive. Furthermore, reducing the use of animals in research is an important ethical and political issue. Immunotoxicogenomics represents a novel approach to investigate immunotoxicity able of overcoming these limitations. The current research, embedded in the European Union project NewGeneris, aimed to retrieve gene expression profiles that are indicative of exposure to immunotoxicants. To this end, whole-genome gene expression was investigated in human peripheral blood mononuclear cells in response to in vitro exposure to a range of immunotoxic chemicals (4-hydroxy-2-nonenal, aflatoxin B1, benzo[a]pyrene, deoxynivalenol, ethanol, malondialdehyde, polychlorinated biphenyl 153, and 2,3,7,8-tetrachlorodibenzo-p-dioxin) and nonimmunotoxic chemicals (acrylamide, dimethylnitrosamine, 2-amino-3-methyl-3H-imidazo[4,5-F]quinoline, and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine). Using Agilent oligonucleotide microarrays, whole-genome gene expression profiles were generated, which were analyzed using Genedata's Expressionist software. Using Recursive Feature Elimination and Support Vector Machine, a set of 48 genes was identified that distinguishes the immunotoxic from the nonimmunotoxic compounds. Analysis for enrichment of biological processes showed the gene set to be highly biologically and immunologically relevant. We conclude that we have identified a promising transcriptomic profile indicative of immunotoxic exposure.

An assessment of the efficiency of PrPsc detection in rectal mucosa and third-eyelid biopsies from animals infected with scrapie

In classical scrapie, detection of PrPsc on lymphoreticular system is used for the in vivo and post mortem diagnosis of the disease. However, the sensitivity of this methodology is not well characterised because the magnitude and duration of lymphoid tissue involvement can vary considerably. The aim of the present study was to evaluate the efficiency of detecting PrPsc in rectal mucosa and third-eyelid biopsies. A total of 474 genetically susceptible sheep and 24 goats from three scrapie infected flocks were included in this study. A sample from rectal mucosa and a sample from third-eyelid lymphoid tissue were collected from each animal. Biopsy samples were fixed in formaldehyde and processed for immunohistochemical examination. Animals with negative biopsy results were studied more closely through a post mortem examination of central nervous and lymphoreticular systems and if there was a positive result, additional biopsy sections were further tested. The sensitivity of rectal mucosa and third-eyelid assays were 36% and 40% respectively on initial examination but increased to 48% and 44% respectively after retesting. The results of this field study show a high percentage of infected animals that do not have detectable levels of PrPsc in the biopsied lymphoid tissue, due mainly to the relatively high number of animals with minimal or no involvement of lymphoid tissue in the pathogenesis of the disease.

Assessing the effectiveness of intubation as a challenge model in contagious bovine pleuropneumonia vaccine experiments

A study was carried out to assess the effectiveness of a bronchoscope in administering a pathogenic field strain of Mycoplasma mycoides subsp. mycoides (MmmSC) in cattle challenge experiments. Out of 16 animals inoculated using the bronchoscope, 10 (62.2%) showed clinical disease as evidenced by fever and 15 (93.8%) displayed typical lesions of CBPP from which MmmSC was isolated. Serum samples collected weekly were tested by Complement Fixation Test (CFT) and competitive enzyme-linked immunosorbent assay (c-ELISA). Antibodies to MmmSC were detected in 10 out of the 16 animals by the CFT and 11 out of the 16 animals by c-ELISA. The onset of clinical disease was as early as 2 days post-inoculation, and most of the animals developed clinical disease 2 to 3 weeks post-infection. These results clearly demonstrate that nasotracheal inoculation of pathogenic strain of MmmSC with the aid of a bronchoscope can lead to early onset of clinical disease; similar to previous studies but with higher numbers of animals showing clinical disease. This is in contrast with previous studies where early clinical disease was observed in as little as 15% of inoculated animals. This nasotracheal inoculation method using a bronchoscope can, therefore, be adopted for use in experimental challenge infections of cattle. This method is found to be a better replacement to the contact transmission method whose drawback includes extra cost of donor animals and unpredictable rate and timing of transmission from intubated to challenge animals.

Sexual ratio, reproductive period and seasonal variation of the gonochoric shrimp Hippolyte obliquimanus (Caridea: Hippolytidae)

Hippolyte obliquimanus is a small, gonochoric shrimp found in algal substrates along the western Atlantic coast of Brazil, particularly in association with seaweed of the genus Sargassum. We studied population features (sexual ratio, reproductive period and temporal distribution) of H. obliquimanus in southeastern Brazil, including its relationships with the seasonality of banks of this alga. Specimens were collected at two-monthly intervals from March 2005 to January 2006, in Ubatuba Bay. The sex of individuals was checked, and the carapace length measured. In total, 668 individuals were collected: 211 males (0.70–2.50 mm carapace length), 341 non-ovigerous females (0.55–2.90 mm), and 116 ovigerous females (1.55–3.20 mm). Hippolyte obliquimanus showed seasonal–continuous reproduction and variable continuous recruitment. The highest number of animals (75%) was collected in fall–winter. The percentages of ovigerous females/total females (fall–winter: 27%; spring–summer: 26%) and the sexual ratio (fall–winter: 31%; spring–summer: 32%) were practically equal in both periods. The sexual ratio showed a predominance of females in almost all size classes, and we detected a new sex ratio pattern for this species. The seasonal variation in the number of individuals can be related to its migration to deeper areas, due to the decrease in the abundance of Sargassum sp. in shallower waters in spring–summer.