Behavioral responses to ecological disturbances influence predation risk for a capital breeder

Landscape Ecology - Predation-risk and ecological disturbance regimes can both influence behavioral decisions by prey, yet few studies have simultaneously considered responses to these ecological...     

Incorporating habitat suitability,landscape distance,and resistant kernels to estimate conservation units for an imperiled terrestrial snake

Landscape Ecology - Wildlife distributions are often subdivided into discrete conservation units to aid in implementing management and conservation objectives. Habitat suitability models,...     

Bacteria as Mediators of Copper Sulfide Enrichment During Weathering

Supergene chalcocite enrichment during weathering is an economically vital natural process that may lead to severalfold increases in the copper content of sulfide deposits. A scanning electron microscope study of chalcocite (Cu2S) from major enriched copper deposits in northern Chile revealed myriad bacterioform bodies in original growth positions near replacement interfaces with remnant hypogene sulfide grains. These minute (0.03 to 0.2 micrometers) chalcocite bodies are interpreted as fossilized and metallized nannobacteria that promoted the fixation of mobilized copper ions. Bacterial activity may thus be a fundamental factor in supergene enrichment of copper deposits.     

Scanning Single-Electron Transistor Microscopy: Imaging Individual Charges

A single-electron transistor scanning electrometer (SETSE)-a scanned probe microscope capable of mapping static electric fields and charges with 100-nanometer spatial resolution and a charge sensitivity of a small fraction of an electron-has been developed. The active sensing element of the SETSE, a single-electron transistor fabricated at the end of a sharp glass tip, is scanned in close proximity across the sample surface. Images of the surface electric fields of a GaAs/AlxGa1-xAs heterostructure sample show individual photo-ionized charge sites and fluctuations in the dopant and surface-charge distribution on a length scale of 100 nanometers. The SETSE has been used to image and measure depleted regions, local capacitance, band bending, and contact potentials at submicrometer length scales on the surface of this semiconductor sample.     

Seasonal Changes in Testicular Cell Morphology in Domestic Male Cats (Felis catus)

The aim of this study was to asses the variation in the morphology of the seminal epithelium in relation to natural photoperiod in male cats. Tom cats (n = 240) were castrated every other week throughout the year. Each testis was fixed in Bouin's solution and cut into sections. The percentage of tubules with round spermatids (RS), elongated spermatids (ES), tailed spermatids (TS), mature spermatids (MS) and the number of Sertoli cells (SC) and Leydig cells (LC) were recorded in each sample. Testicles from males during short days (SHD) had a higher percentage of tubules with RS and ES compared to testicles from males during long days (LHD, 31.3 ± 0.6 vs 2.1 ± 0.6%, p < 0.001; 30.9 ± 0.7 vs 11.0 ± 0.7%, p < 0.001). Conversely, testicles from males during SHD had a lower percentage of tubules with TS and MS compared to testicles from males during LHD (24.5 ± 0.8 vs 29.7 ± 0.8%, p < 0.01; 13.1 ± 1.2 vs 57.0 ± 1.2%, p < 0.01). Furthermore, testicles from males during SHD had a higher number of SC and lower number of LC compared to testicles from males during LHD (11.4 ± 0.1 vs 8.0 ± 0.1%, p < 0.01; 19.2 ± 1.0 vs 38.0 ± 1.0%, p < 0.01). In conclusion, there are seasonal changes in testis cell morphology in the tom which may be related to seasonal sperm production.     

Ischaemic and haemorrhagic stroke in the dog

Cerebrovascular disease results from any pathological process of the blood vessels supplying the brain. Stroke, characterised by its abrupt onset, is the third leading cause of death in humans. This rare condition in dogs is increasingly being recognised with the advent of advanced diagnostic imaging. Magnetic resonance imaging (MRI) is the first choice diagnostic tool for stroke, particularly using diffusion-weighted images and magnetic resonance angiography for ischaemic stroke and gradient echo sequences for haemorrhagic stroke. An underlying cause is not always identified in either humans or dogs. Underlying conditions that may be associated with canine stroke include hypothyroidism, neoplasia, sepsis, hypertension, parasites, vascular malformation and coagulopathy. Treatment is mainly supportive and recovery often occurs within a few weeks. The prognosis is usually good if no underlying disease is found.     

Prolactin,Androstenedione and IGF1 Serum Concentrations During Induced Follicular Growth by eCG Administration in the Bitch

The oestrus cycle in the domestic bitch, a monoestrous species, differs considerably from that of other veterinary domestic animals species. In the bitch the combined use of eCG and hCG is effective to induce oestrus predictably and safely (Stornelli et al., Theriogenology, 78, 2012 and 1056). Although several studies were done to describe the hormonal changes during the canine oestrus cycle, to our knowledge none was done to describe the hormonal changes during induced follicular growth after the administration of eCG. The aim of this work was to study prolactin (PRL), insulin‐like growth factor (IGF1) and androstenedione (ANDR) serum concentrations during follicular growth induced by a single dose of eCG administered to late anoestrous bitches. PRL and ANDR concentrations were lower before than after eCG TRT (before eCG vs pro‐oestrus, oestrus and dioestrus; 4.3 ± 1.8 ng/ml vs 6.5 ± 1.6 ng/ml, p < 0.05; 0.08 ± 0.2 ng/ml vs 0.42 ± 0.16 ng/ml, p < 0.05). Conversely, IGF1 concentrations were similar before and after eCG TRT (286.0 ng/ml ±32.2, p > 0.53). Additionally, PRL concentrations were similar before oestrus compared to during oestrus and dioestrus (6.9 ± 1.7 ng/ml, p > 0.19). Furthermore, IGF1 concentrations were higher before and during oestrus compared to first day of dioestrus (286.1 ± 29.8vs 200.4 ± 29.2 ng/ml, p < 0.01). On the contrary, ANDR concentrations were lower before and during oestrus compared to first day of diestrum (0.35 ± 0.17 ng/ml and 0.38 ± 0.15 vs 0.68 ± 0.17 ng/ml, p < 0.05). These results show that treatment with a single injection of 50 IU/kg of eCG in late anoestrous bitches successfully induced changes in follicular growth which were paralleled with changes in PRL, IGF1 and ANDR serum concentration similar to those occurring during a normally occurring oestrous cycle. In addition, our results suggest that IGF1 in the bitch could play an important role in ovarian folliculogenesis.     

Confirmation of the occurrence of the chewing louse Bovicola (Lepikentron) breviceps (Insecta: Phthiraptera: Trichodectidae) on alpacas (Lama pacos) in New Zealand

Abstract

AIM: To investigate the cause of classical swine fever (CSF) virus-seropositive animals in a nucleus pig-breeding herd in New Zealand, where porcine circovirus-associated disease had been diagnosed.

CASE HISTORY AND CLINICAL FINDINGS: An exotic disease investigation was undertaken to exclude CSF and porcine reproductive and respiratory syndrome (PRRS) on a nucleus pig-breeding herd comprising approximately 300 breeding sows, 1,000 weaners, and 650 grower pigs. The herd was experiencing poor reproductive performance in sows, and breeding records showed a declining farrowing rate attributable to a single manager. The growing pigs (10–15 weeks old) were experiencing respiratory disease and wasting, and the mortality rate by pen varied between 9 and 20%. Post-mortem changes in affected grower pigs were consistent with circovirus-associated diseases.

DIAGNOSTIC TESTING: Serological screening using an IDEXX-ELISA gave negative results for PRRS virus antibodies, but two grower pigs and one sow tested positive for CSF virus antibodies. These three seropositive animals remained positive to CSF virus, using three commercial ELISA test kits, over 27 weeks. A newly developed virus neutralisation test (VNT), using a New Zealand isolate of border disease (BD) virus, demonstrated that the seropositive pig sera had higher antibody titres to BD virus than to bovine viral diarrhoea (BVD) virus and CSF virus.

PCR performed on tonsil, kidney, ileum and spleen gave negative results for CSF virus, and histopathology on lymph nodes, intestine, lung, kidney, liver and brain showed no evidence of the disease. Virus isolation performed on a number of samples was negative.

CLINICAL RELEVANCE: The seropositive samples for CSF virus found in this investigation were likely to be a cross reaction to a pestivirus other than CSF virus. The finding of a possible endemic pestivirus capable of being transmitted between sheep and pigs on this farm may explain findings from previous serological survey work in New Zealand, and supports experience elsewhere, where BD virus was found to be the predominant ruminant pestivirus infecting pigs. The results show that pestivirus cross reactivity can result in unexpectedly high titres, and that testing with a full set of (local) pestiviruses is necessary to reach the correct conclusion. The investigation has direct relevance where pig herds with a low seroprevalence are encountered during surveillance for CSF.