Reproductive seasonality in Saanen goats kept under tropical conditions

Tropical Animal Health and Production - This study aimed to verify the reproductive seasonality in Saanen goats from distinct parity orders (nulliparous, primiparous, and pluriparous) throughout an...     

Rainfall Interception by Singleleaf Piñon and Utah Juniper: Implications for Stand-Level Effective Precipitation

The expansion of piñon and juniper trees into sagebrush steppe and the infilling of historic woodlands has caused a reduction in the cover and density of the understory vegetation. Water is the limiting factor in these systems; therefore, quantifying redistribution of water resources by tree species is critical to understanding the dynamics of these formerly sagebrush-dominated rangelands. Tree canopy interception may have a significant role in reducing the amount of rainfall that reaches the ground beneath the tree, thereby reducing the amount of available soil moisture. We measured canopy interception of rainfall by singleleaf piñon (Pinus monophylla Torr. & Frém.) and Utah juniper (Juniperus osteosperma [Torr.] Little) across a gradient of storm sizes. Simulated rainfall was used to quantify interception and effective precipitation during 130 rainfall events ranging in size from 2.2 to 25.9 mm hr^? 1 on 19 trees of each species. Effective precipitation was defined as the sum of throughfall and stemflow beneath tree canopies. Canopy interception averaged 44.6% (± 27.0%) with no significant difference between the two species. Tree allometrics including height, diameter at breast height, stump diameter, canopy area, live crown height, and width were measured and used as predictor variables. The best fit predictive model of effective precipitation under canopy was described by stump diameter and gross precipitation (R² = 0.744, P < 0.0001). An alternative management model based on canopy area and gross precipitation predicted effective precipitation with similar accuracy (R² = 0.741, P < 0.0001). Canopy area can be derived from various remote sensing techniques, allowing these results to be extrapolated to larger spatial scales to quantify the effect of increasing tree canopy cover on rainfall interception loss and potential implications for the water budget.     

So much for the city: Urban–rural song variation in a widespread Asiatic songbird

Song plays a fundamental role in intraspecific communication in songbirds. The temporal and structural components of songs can vary in different habitats. These include urban habitats where anthropogenic sounds and alteration of habitat structure can significantly affect songbird vocal behavior. Urban–rural variations in song complexity, song length and syllable rate are not fully understood. In this study, using the oriental magpie‐robin (Copsychus saularis) as a model, we investigated urban–rural variation in song complexity, song length, syllable rate, syllable length and inter‐syllable interval. Comparing urban and rural songs from 7 countries across its natural Asiatic range (Bangladesh, India, Malaysia, Nepal, Singapore, Sri Lanka and Thailand), we found no significant differences in oriental magpie‐robin song complexity. However, we found significant differences in temporal song variables between urban and rural sites. Longer songs and inter‐syllable intervals in addition to slower syllable rates within urban sites contributed the most to this variance. This indicates that the urban environment may have driven production of longer and slower songs to maximize efficient transmission of important song information in urban habitats.     

Multi-scale Mexican spotted owl (<Emphasis Type="Italic">Strix occidentalis lucida</Emphasis>) nest/roost habitat selection in Arizona and a comparison with single-scale modeling results

Context

Organisms commonly respond to their environment across a range of scales, however many habitat selection studies still conduct selection analyses using a single-scale framework. The adoption of multi-scale modeling frameworks in habitat selection studies can improve the effectiveness of these studies and provide greater insights into scale-dependent relationships between species and specific habitat components.

Objectives

Our study assessed multi-scale nest/roost habitat selection of the federally “Threatened” Mexican spotted owl (Strix occidentalis lucida) in northern Arizona, USA in an effort to provide improved conservation and management strategies for this subspecies.

Methods

We conducted multi-scale habitat modeling to assess habitat selection by Mexican spotted owls using survey data collected by the USFS. Each selected covariate was included in multi-scale models at their “characteristic scale” and we used an all-subsets approach and model selection framework to assess habitat selection.

Results

The “characteristic scale” identified for each covariate varied considerably among covariates and results from multi-scale models indicated that percent canopy cover and slope were the most important covariates with respect to habitat selection by Mexican spotted owls. Multi-scale models consistently outperformed their analogous single-scale counterparts with respect to the proportion of deviance explained and model predictive performance.

Conclusions

Efficacy of future habitat selection studies will benefit by taking a multi-scale approach. In addition to potentially providing increased explanatory power and predictive capacity, multi-scale habitat models enhance our understanding of the scales at which species respond to their environment, which is critical knowledge required to implement effective conservation and management strategies.

     

Use of an insect cell culture growth medium to isolate bacteria from horses with effusive, fibrinous pericarditis: a preliminary study

Effusive, fibrinous pericarditis is an uncommon disease entity in horses. In 2001, pericarditis occurred in conjunction with an epizootic in central Kentucky that was associated with exposure to eastern tent caterpillars (ETCs). Bacterial isolation from equine pericardial fluid samples was attempted using an insect cell culture growth medium (ICCGM). Using previously cultured, stored frozen samples from four horses with fibrinous pericarditis, inoculation of 10% blood agar plates yielded no growth, whereas simultaneous inoculation of ICCGM resulted in the isolation of Proprionibacterium acnes, Staphylococcus equorum, a Streptococcus sp. and Pseudomonas rhodesiae from pericardial fluid samples. A similar or novel caterpillar-associated bacteria was not identified; however, use of an ICCGM might enhance isolation of bacteria from equine pericardial fluid.     

Feeding Saccharomyces cerevisiae fermentation products lessens the severity of a viral–bacterial coinfection in preweaned calves

We have previously reported that supplementation with Saccharomyces cerevisiae fermentation products (SCFP) ameliorates clinical signs and lung pathology following experimental bovine respiratory syncytial virus (BRSV) infection in preweaned dairy calves. The objectives of this study were to determine the effect of SCFP supplementation on the metabolic and endocrine responses, and disease outcome of a viral–bacterial coinfection in preweaned calves. Twenty-seven, 1- to 2-d-old Holstein-Angus cross calves were enrolled in the study; one SCFP calf was removed from the trial during the pre-challenge phase due to complications from nephritis. Calves were assigned to two treatment groups: control or SCFP-treated, base milk replacer with 1 g/d SCFP (Smartcare, soluble formula) and calf starter top dressed with 5 g/d SCFP (NutriTek, insoluble formula). Calves were infected with BRSV on day 21, followed 6 d later by intratracheal inoculation with Pasteurella multocida (PM). Calves were euthanized on day 10 post-viral infection. Calves receiving SCFP had reduced thoracic ultrasonography scores on day 7 post-viral infection (P = 0.03) and a tendency toward reduced scores on day 10 post-viral infection (P = 0.09). Calves receiving SCFP also had less severe lung pathology scores at necropsy (P = 0.06). No differences between treatments were observed in lung viral loads (P = 0.48) or bacterial lung recovery (P = 0.34); however, there was a distinction in the lung location for PM recovery, with PM isolated more frequently from the cranial lobes in SCFP-treated calves, but more frequently from the caudal lobes of control calves. Calves treated with SCFP tended (P = 0.07) to have higher serum IL-6 concentrations following the coinfection. Calves treated with SCFP had lower concentrations of serum nonesterified fatty acids and beta-hydroxybutyric acid compared with controls following experimental challenge (P = 0.03 and P = 0.08, respectively), suggesting metabolic changes favoring growth and development. There were no differences between groups in gene expression of insulin receptor, insulin-like growth factor 1 (IGF-1), IGF-1 receptor (IGF-1R), growth hormone receptor, or haptoglobin in the liver. Results from this study suggest that supplementing with SCFP may moderate the impact of a respiratory viral–bacterial coinfection on preweaned calves through metabolic and immune modifications.     

Validation of enzyme-linked immunosorbent assay for measurement of faecal cortisol in fish

Quantification of glucocorticoid (GC) levels in faeces has become an established method for the non-invasive assessment of adrenocortical activity. These hormones are frequently determined in plasma samples as parameters of adrenal activity and response to stress. Because GCs are metabolized and excreted with both intact hormone and their metabolites present in faeces, the concentration of GCs can be measured in excreta. Faecal samples present the advantages of easy collection, no stress to the animal and elimination of the issue of potentially misleading acute GC spikes. The aim of this study was to determine if an enzyme-linked immunosorbent assay (ELISA) for cortisol was appropriate for monitoring adrenocortical activity in faecal casts of fishes. Performance of the cortisol ELISA was validated by comparison to high-performance liquid chromatography, which is an established method for measuring free GCs and GC metabolites in faeces. Parallelism and sample extraction efficiency were compared for the two methods. Pearson's correlation across samples for these methods was 0.996. Results demonstrated that the ELISA was an efficient, sensitive and reliable method for cortisol measurement in faecal extracts, which should permit integration of non-invasive stress monitoring into studies of fish behaviour and physiology.