Effect of exogenous progesterone administration on luteal sensitivity to PGF during the early development of the corpus luteum in mares and cows

The objective of this study was to determine the effect of exogenous progesterone administration at ovulation and during the early development of the CL, on its future sensitivity to a single administration of PGF2a in mares and cows. Horse Retrospective reproductive data from an equine clinic in the UK during three breeding seasons were used. Mares were divided into: control group, cycles with single ovulations; double ovulation group cycles with asynchronous double ovulations; and PRID group: cycles with single ovulations and treatment with intravaginal progesterone device (CIDR) immediately after the ovulation. All mares were treated with d‐cloprostenol (PGF) at either: (i) 88 hr; (ii) 96 hr; (iii) 104 hr; or (iv) 112 hr after the last ovulation. Cattle A total of nine non‐lactating Holstein cows were used. All cows were administered PGF14 d apart and allocated to one of two groups control group GnRH was administered 56 hr after the second PGF administration. CIDR group CIDR was inserted at the same time of GnRH administration. All cows were administered PGF at 120 hr post‐ovulation. The complete luteolysis rate of mares with double ovulation (66.7%) and those treated with exogenous progesterone (68.4%) was significantly higher than the rate of mares with single ovulation (35.6%) at 104 hr. In the cow, however, the treatment with CIDR did not increase the luteolytic response in cows treated at 120 hr post‐ovulation. In conclusion, the degree of complete luteolysis can be influenced by increasing the concentration of progesterone during the early luteal development in mares.     

Equine amnionitis and fetal loss: The case definition for an unrecognised cause of abortion in mares

A series of abortions occurred in mares in New South Wales during 2004 that involved similar and unusual findings on post mortem examination of aborted fetuses and fetal membranes. The term Equine Amnionitis and Fetal Loss (EAFL) was developed to describe the condition. This form of abortion had not been previously recognised in Australia. The pathology alone is not specific for EAFL and diagnosis requires demonstration of a combination of certain pathological and bacteriological features. The purpose of this paper is to describe patterns considered consistent with EAFL cases as a working case definition for use by veterinarians and veterinary pathologists in identifying future cases of EAFL. More detailed papers are in preparation to fully describe the epidemiological, histopathological, and microbiological aspects of EAFL.     

Serological analysis of Chlamydophila abortus in Australian sheep and implications for the rejection of breeder sheep for export

Objective   To examine the incidence of positive results in a complement fixation test (CFT) and enzyme-linked immunosorbent assay (ELISA) for Chlamydophila abortus in Australian sheep and how this incidence differs with state of origin, age, sex, breed and property. To examine the consequences in relation to rejection of breeder sheep for export.
Design   Collection of blood samples from 891 sheep on 109 properties in southern Australia. All samples had a unique, coded property identification.
Procedure   The samples were tested using the Institut Pourquier Chlamydophila abortus antibody ELISA (rELISA) and a CFT. Residual maximum likelihood analyses of the sample to positive ratio of the corrected optical density for the rELISA and generalised linear mixed model analyses of the CFT outcomes were carried out.
Results   The sample to positive ratio of the corrected optical density values of the rELISA did not differ between sex, age, breed or state of origin, but differed greatly between properties. The CFT outcome did not differ between age, breed or state of origin, but differed greatly between properties and was more often positive with rams than with ewes.
Conclusion   Positive outcomes to C. abortus antibody tests are very common in Australia. Rams have a particularly high incidence of positive results with the CFT. Rejection of sheep and property consignments is likely to be very common with all tests and situations examined except for the CFT (at 1:32 dilution) in ewes.     

Effect of the Medium Replacement Interval on the Viability,Growth and In Vitro Maturation of Isolated Caprine and Ovine Pre‐Antral Follicles

The aim of the present study was to evaluate the effects of different medium replacement intervals on the viability, antral cavity formation, growth and in vitro maturation (IVM) of oocytes from caprine and ovine pre‐antral follicles. Pre‐antral ovarian follicles (≥150 μm) were isolated from the ovarian cortex of goats and sheep and were individually cultured for 24 days using two different medium replacement intervals [2 days (T₁) or 6 days (T₂)]. Follicle development was evaluated on the basis of antral cavity formation, increases in follicular diameter and the presence of healthy cumulus oocyte complexes and fully grown oocytes. For caprine species, results showed a higher percentage (p < 0.05) of viable follicles in T₁ than T₂ from day 6 until the end of the culture. In addition, when comparing both treatments after the same culture duration, the rate of antrum formation was significantly higher in T₁ than in T₂ from day 12 onwards. Yet, in ovines, when both treatments were compared on day 24 of the culture, there were more viable follicles in T₂ than in T₁ (p < 0.05). In the caprine species, percentages of fully grown oocytes (≥110 μm) acceptable for IVM after 24 days of culture were significantly higher in normal follicles cultured in T₁ (30.0%) than in T₂ (6.7%; p < 0.05). On the other hand, in ovines, at the end of the culture, the percentage of oocytes destined for IVM was higher in T₂ than in T₁ (23.5% vs 2.9%; p < 0.05). In conclusion, under the same conditions, the frequency of medium replacement significantly affected the in vitro development of caprine and ovine pre‐antral follicles. To improve the efficiency of the culture system, the medium must be replaced every 2 and 6 days for goat and sheep pre‐antral follicles, respectively.     

Getting lost in the matrix? On how the characteristics and arrangement of linear landscape elements influence ecological connectivity

Landscape Ecology - Linear landscape elements (LLEs) such as ditches and hedgerows can increase the ecological connectivity of habitat embedded within agricultural areas by acting as corridors for...     

Squamous Cell Carcinoma Arising in Chronic Discoid Lupus Erythematosus Nasal Lesions in Two German Shepherd Dogs

Résumé— Un épithélioma spinocellulaire s'est développé sur des lésions chroniques incontrôlées de lupus erythémateux discoïde chez deux chiens bergers allemands. Les chiens n'avaient reçu ni traitement ni photoprotection pour leurs lésions de lupus discoïde durant les 4 à 6 ans précédant l'apparition clinique d'épithéliomas spinocellulaires. [Scott, D.W., Miller, W.H., Jr. Squamous cell carcinoma arising in chronic discoid lupus erythematosus nasal lesions in two German Shepherd Dogs (Un épithélioma spinocellulaire suivenant sur des lesions de lupus erythémateux discoïde chroniques chez deux bergers allemands).
Resumen— Dos perros de raza Pastor Alemán desarrollaron carcinomas de células escamosas en lesiones crónicas del tipo lupus eritematoso discoide. Estos animales no habian recibido tratamiento ni protección solar del cuadro de lupus eritematoso discoide en los 4 a 6 años previos al desarrollo del carcinoma escamoso. [Scott, D.W., Miller, W.H., Jr. Squamous cell carcinoma arising in chronic discoid lupus erythematosus nasal lesions in two German Shepherd Dogs (Carcinoma de células escamosas a partir de lesiones crónicas nasales del tipo lupus eritematoso discoide en dos perros Pastor Alemán).
Abstract— Squamous cell carcinoma developed in the chronic, uncontrolled nasal lesions of discoid lupus erythematosus in two German Shepherd Dogs. The dogs had received no treatment nor photoprotection for their discoid lupus erythematosus for 4–6 years prior to the clinical onset of squamous cell carcinoma.     

Detection of papillomaviruses in cutaneous fibromas of white-tailed and mule deer

Naturally occurring cutaneous fibromas affecting white-tailed deer (Odocoileus virginianus) and mule deer (O hemionus), and cutaneous fibropapillomas of domestic cattle were tested for papillomavirus using indirect immunofluorescence (IF), peroxidase-antiperoxidase (PAP), and negative-stain electron microscopic techniques. Papillomavirus was consistently detected using rabbit antiserum against papillomavirus group-specific antigen in all mule deer fibromas and bovine fibropapillomas; only 16 of 28 white-tailed deer fibromas tested by IF and 9 of 15 tested by PAP were detected. Normal skin from white-tailed deer or cattle was consistently negative for virus. Similar results were obtained by negative-stain electron microscopic examination of partially purified tumor homogenates. Using deer fibroma virus or bovine papillomavirus type 1-specific antisera, viruses were typed by IF, PAP, and immunoelectron microscopy.     

Cooling of broiler hatching eggs during incubation

1. Broiler hatching eggs were cooled to 22°C for periods of 8 or 24 h on day 16 of incubation. Cooling had no significant effects on hatchability or chick quality compared with controls.

2. Cooling to 22°C for 24 h on days 14, 15, 16, 17 or 18 yielded similar results but cooling on day 13 increased late embryonic mortality.

3. When eggs were cooled to 22°C on day 16 of incubation there were no major differences in hatchability up to 48 h of cooling but chick quality deteriorated rapidly after 30 h and the limit for embryonic survival at this temperature was about 72 h.

4. There were no significant differences when eggs were cooled on day 16 and held for 24 h at 21.1, 23.9 or 26.7°C but hatchability and late deaths were significantly affected by cooling to 18.3°C.     

Genetic consequences of forest fragmentation by agricultural land in an arboreal marsupial

Context

Increasing demands on land for agriculture have resulted in large-scale clearance and fragmentation of forests globally. In fragmented landscapes, species that tolerate or exploit the matrix will persist, while those that do not, frequently decline. Knowledge of matrix use is therefore critical to predicting extinction proneness of species in modified landscapes and defining the value of land for conservation management.

Objectives

In a fragmented landscape consisting of seven remnant patches surrounded by agricultural land and a large Eucalyptus forest, we explored (i) population connectivity of common ringtail possums, Pseudocheirus peregrinus, to determine the permeability of the agricultural matrix, and (ii) genetic consequences of forest fragmentation.

Methods

238 common ringtail possums were screened at 14 microsatellite markers and analysed using a range of genetic techniques.

Results

We observed significant genetic differentiation among all patches and limited dispersal through the agricultural matrix, even between neighbouring patches. Consequences of this were a six- to ten-fold increase in genetic dissimilarity over an equivalent geographic distance across patches compared with sites in the continuous forest and a significant reduction in genetic diversity, particularly in patches that were geographically more isolated from their neighbours.

Conclusions

We conclude that the agricultural matrix has a number of characteristics that make it unsuitable for facilitating movement of possums through this landscape, and recommend several management strategies to mitigate the impacts of fragmentation on this and other arboreal species for their conservation.