Estrus cycle effect on muscle tyrosine kinase activity in bitches

Estrus cycle is a well recognized cause of insulin resistance in bitches. The insulin receptor (IR) as well as the insulin-like growth factor-I receptor belong to the same subfamily of tyrosine kinase (TK) receptors. The objective of this study was to evaluate basal TK activity in muscle tissue of bitches during the estrus cycle. Twenty-four bitches were used in the study (7 in anestrus, 7 in estrus, and 10 in diestrus). Muscle samples, taken after spaying surgery to determine TK activity, were immediately frozen in liquid nitrogen and then stored at −80°C until the membranes were prepared by sequential centrifugation after being homogenized. TK activity was determined by Poly (Glu 4:Tyr 1) phosphorylation and expressed in cpm/μg of protein. TK activity was significantly lower (P < 0.001) in the animals in estrus (104.5 ± 11.9 cpm/μg of protein) and diestrus (94.5 ± 16.9 cpm/μg of protein) when compared with bitches in anestrus (183.2 ± 39.2 cpm/μg of protein). These results demonstrate, for the first time, lower basal TK activity in the muscle tissue of female dogs during estrus and diestrus, which may represent lower insulin signaling capacity, opening a new field of investigation into the molecular mechanisms of insulin resistance in dogs.     

Chlamydia psittaci: a suspected cause of reproductive loss in three Victorian horses

Chlamydia psittaci was detected by PCR in the lung and equine foetal membranes of two aborted equine foetuses and one weak foal from two different studs in Victoria, Australia. The abortions occurred in September 2019 in two mares sharing a paddock northeast of Melbourne. The weak foal was born in October 2019 in a similar geographical region and died soon after birth despite receiving veterinary care. The detection of C. psittaci DNA in the lung and equine foetal membranes of the aborted or weak foals and the absence of any other factors that are commonly associated with abortion or neonatal death suggest that this pathogen may be the cause of the reproductive loss. The detection of C. psittaci in these cases is consistent with the recent detection of C. psittaci in association with equine abortion in New South Wales. These cases in Victoria show that C. psittaci, and the zoonotic risk it poses, should be considered in association with equine reproductive loss in other areas of Australia.     

Top 20 environmental weeds for classical biological control in Europe: a review of opportunities, regulations and other barriers to adoption

Classical biological control remains the only tool available for permanent ecological and economic management of invasive alien species that flourish through absence of their co‐evolved natural enemies. As such, this approach is recognized as a key tool for alien species management by the Convention on Biological Diversity (CBD), the European and Mediterranean Plant Protection Organization (EPPO) and the European Strategy on Invasive Alien Species (ESIAS). Successful classical biological control programmes abound around the world, despite disproportionate attention being given to occasional and predictable non‐target impacts. Despite more than 130 case histories in Europe against insect pests, no exotic classical biological control agent has been released in the EU against an alien invasive weed. This dearth has occurred in the face of increasing numbers of exotic invasive plants being imported and taking over National Parks, forests and amenity areas in this region, as well as a global increase in the use of classical biological control around the world. This paper reviews potential European weed targets for classical biological control from ecological and socioeconomic perspectives using the criteria of historical biological control success, taxonomic isolation from European native flora, likely availability of biological control agents, invasiveness outside Europe and value to primary industry and horticulture (potential for conflicts of interest). We also review why classical biological control of European exotic plants remains untested, considering problems of funding and public perception. Finally, we consider the regulatory framework that surrounds such biological control activities within constituent countries of the EU to suggest how this approach may be adopted in the future for managing invasive exotic weeds in Europe.     

Carbon monoxide measurements in the troposphere

During the second flight of the space shuttle, the measurement of air pollution from satellites (MAPS) experiment in the OSTA-1 payload acquired approximately 35 hours of radiometric measurements of the carbon monoxide mixing ratio in the middle troposphere, upper troposphere, and lower stratosphere. A gas filter radiometer operating in the 4.67-micrometer band was used to acquire the data over the region from 38 degrees N to 38 degrees S during both daytime and nighttime. The performance of the measurement system was excellent. The data reduced to date indicate the presence of significant gradients in the middle tropospheric carbon monoxide mixing ratio with both latitude and longitude over the North Atlantic, the Mediterranean Sea, and the Middle East. On the basis of comparisons with directly measured values, the accuracy of the measurements is approximately 15 percent. Comparisons of data taken on successive orbits over the same geographic region indicate that the repeatability of the measurements is approximately 5 percent.     

Effects of ruminal fill on short-term herbage intake rate and grazing dynamics of beef heifers

The impact of manipulating ruminal fill (RF) on intake rate of herbage and grazing dynamics was measured with three rumen‐cannulated beef heifers grazing Bermudagrass pastures individually. The treatments compared were removal of proportions of rumen contents of 0 (treatment RF0), 0·33 (treatment RF33), 0·66 (treatment RF66) and 1·00 (treatment RF100). Treatments were randomly applied in a 3 × 4 Youden‐square design. The rumens were emptied before and after planned grazing sessions (30 min) to set up the treatments, and to estimate intake rate and bite mass, respectively. Measurements were made of bite rate, bites per feeding station, feeding stations per minute, intake per feeding station, time per feeding station, eating and searching step rates and times. Apparent bite area and area grazed per feeding station were calculated. Ruminal fill affected short‐term intake rate and changed grazing dynamics. As RF increased, step rates, searching times, bite mass, apparent bite area, bites per feeding station, area grazed per feeding station, time per feeding station and intake per feeding station decreased (P < 0·01) while step times, eating step rates and bite depth increased (P < 0·01). The results of the present study indicate that RF is an important factor governing the intake characteristics and behaviour of grazing beef heifers.