Effects of Exogenous Insulin on Luteolysis and Reproductive Cyclicity in the Mare

Insulin is a pancreatic hormone that classically regulates carbohydrate and fat metabolism, but also appears to play a role in various reproductive processes. A preliminary study suggested insulin production by day 10 to 18 equine conceptuses. The aim of the present study was to examine the hypothesis that insulin is the conceptus signal responsible for maternal recognition of pregnancy (MRP) in the mare, or otherwise influences reproductive cyclicity during the MRP period. Six Warmblood mares were treated daily during days 7 to 17 after ovulation of two successive oestrous cycles with either (short and intermediate acting) insulin or control saline. Mares were assigned randomly to treatment, and crossed over during the subsequent cycle. Time of ovulation and corpus luteum surface area were determined by serial transrectal ultrasonographic examination of the mares' ovaries, and daily jugular vein blood samples were analysed for progesterone and luteinizing hormone (LH) concentrations. On day 14 of dioestrus, the luteolytic drive was examined by measuring systemic 15-ketodihydroprostaglandin F_{2 α} (PG-metabolite) release in response to oxytocin challenge. In addition, yolk sac fluid recovered from 32 day 10 to 14 equine conceptuses was analysed for insulin concentrations. Insulin administration did not affect luteal size, dioestrus length, the interovulatory interval, or circulating LH concentrations. Insulin administration also failed to suppress oxytocin-induced PGF_{2 α} release, and tended to depress systemic progesterone concentrations. Finally, insulin could not be detected in the yolk sac fluid of day 10 to 14 equine conceptuses by radio-immunoassay. It is concluded that insulin administered daily during days 7 to 17 of dioestrus has little or no effect on reproductive cyclicity in the mare, and is unlikely to be the MRP signal.     

Sperm Pre-Incubation Prior to Insemination Affects the Sex Ratio of Bovine Embryos Produced in vitro

The objective of the present study was to determine whether sperm incubation prior to oocyte insemination in vitro affects the sex ratio of resulting blastocyst. Cumulus–oocyte‐complexes (COCs) collected from slaughterhouse ovaries were matured in vitro and inseminated with frozen‐thawed semen of three proven artificial insemination (AI) bulls pre‐incubated in vitro in Sperm‐Talp for 6 and 24 h. On day‐9 blastocysts were collected and processed for sex determination. More than 80% of blastocyst were successfully sexed. There were no significant differences in cleavage and blastocyst rates using sperm pre‐incubated for 6 h as compared with the 0‐h pre‐incubation control group. The cleavage and blastocyst rates were significantly lower in the 24‐h pre‐incubation group. The male to female ratio, when compared with the theoretical 1 : 1, differed significantly in favour of females among hatched (viable) blastocysts derived from sperm pre‐incubated for 24 h prior to insemination as well as among all blastocytsts in the 6‐h group. Moreover, when the sperm treatment was considered, the sex ratio was affected only among hatched blastocysts in 24‐h pre‐incubation group. It was concluded that prolonged sperm pre‐incubation influences the rate of development and the sex ratio among hatched blastocysts.     

Pulmonary alveolar microlithiasis in an alpaca (Vicugna pacos)

Pulmonary alveolar microlithiasis (PAM) is a rare, familial disease of unknown aetiology characterised by intra‐alveolar formation and accumulation of microliths. Multiple formalin‐fixed tissues were submitted from a 5‐month‐old female alpaca that died suddenly without significant clinical signs. No gross abnormalities were observed on postmortem examination. Histological findings included PAM and severe centrilobular hepatic necrosis. Although the hepatic lesion was the likely cause of death, PAM was an incidental finding that has not been reported previously in alpacas. An overview of PAM, including pathogenesis and histopathological characteristics, are discussed in relation to the concurrent hepatic disease in the present case.     

Toward a More Embedded Production System? Automotive Supply Networks and Localized Capabilities in Poland

The article addresses the embeddedness of automotive production in Poland in terms of supply networks. A comprehensive analysis of more than 550 suppliers, supported by company interviews, shows that foreign‐owned producers become embedded in Poland in the automotive supplier networks they have largely created themselves. Numerous local suppliers gain access to export markets and become integrated in a Europe‐wide production system. This trend has been accompanied by significant upgrading of foreign affiliates and domestic firms in terms of product quality, cost efficiency, adaptability, and fast response, but far less in nonproduction competences such as R&D. It is argued that the competences of automotive suppliers in Poland are built upon the localized capabilities, which are a product of the dynamic interplay between the activity of foreign firms and the changing local environment comprising various stakeholders. The localized capabilities constitute elements of a company's sunk costs and are embedding automotive producers in Poland. At the same time, the dependence on decisions and innovations from abroad and the limited development of local design and brands may constrain the future role of suppliers from the semiperipheral economy of Poland.     

Yersinia species isolated from sheep with enterocolitis

In 40 submissions to the Regional Veterinary Laboratory (RVL) Wagga Wagga from sheep in southern New South Wales from 1981 to 1989, 53 isolates of Yersinia sp were recovered from 45 sheep in 37 flocks. Of 53 isolates, 26 were identified as Y. pseudotuberculosis, 20 as Y. enterocolitica, 5 as Y. intermedia and 2 as Y. frederiksenii. Twelve isolates of Y. pseudotuberculosis tested in the slide agglutination test all belonged to serotype III. The 20 Y. enterocolitica isolates were categorised biochemically as biotype 5 strains and, of 6 isolates serotyped, all belonged to serogroup 2,3. Outbreaks of yersiniosis were most common in late winter and early spring and affected flocks often had experienced a change in husbandry. Infection with Yersinia sp was associated with diarrhoea, illthrift and mortality. At necropsy, congestion and occasionally thickening of the intestinal mucosa were observed in affected sheep. Gastrointestinal nematodiasis and coccidiosis often were concurrent findings. The characteristic histological lesion in sheep infected with Y. pseudotuberculosis was acute segmental suppurative erosive enterocolitis. There were no lesions consistently associated with Y. enterocolitica, Y. intermedia or Y. frederiksenii.