Concentrations of Prolactin, LH, Testosterone, TSH and Thyroxine in Normospermic Dogs of Different Breeds

Concentrations of prolactin (PRL), LH, testosterone (T), TSH and thyroxine (T₄) were determined before and at 20, 120 and 180 min after a single iv injection of thyrotropin-releasing hormone (TRH) in eight Beagles, eight Fox Terriers, six Labrador Retrievers and five Great Danes that were normospermic. Mean basal PRL concentrations were lower in the Fox Terriers compared with the Great Danes (p < 0.05). Mean LH concentrations were higher in the Fox Terriers than in the Beagles, and T was lower in the Fox Terriers at some times but not others (p < 0.05). Thyroid Stimulating Hormone (TSH) concentrations did not differ among breeds, while mean basal T₄ values were lower in Fox Terriers compared with Labrador Retrievers and Great Danes (p < 0.05). Stimulation of T₄ secretion 120 and 180 min after iv TRH injection was most pronounced in the Beagles and less in the Fox Terriers (p < 0.05). The results of the present study indicate that potential breed differences in circulating concentrations of PRL, LH, T, TSH and T₄ in male dogs with apparently normal fertility can be encountered, but further studies are needed to determine whether the observed differences are typical features of these breeds, reflect subsets of dogs within breeds, or are in part because of possible uncontrolled parameters such as sample timing, ambient photoperiod, housing conditions or diet.     

Scale and scope economies in small household rice farming in Vietnam

The Vietnamese agricultural sector has experienced a dramatic structural change based on increased specialization in rice cultivation. However, small-scale rice-farmers have continued to grow multiple crops, especially in less developed provinces. While the literature advocates crop diversification for reasons of both economic and ecological sustainability, there lacks empirical evidence as to whether crop diversification brings efficiency and productivity gains to small farms. The present study is the first applications of the input-oriented stochastic distance function approach in estimating scale and scope economies using data of multi-crop farming households in Vietnam. We find strong evidence of product-specific economies of scale. Scope economies are also present for rice, vegetable, and other annual crop production. This suggests that crop diversification enhances efficiency and productivity. However, there still exists significant technical inefficiency in crop production, indicating opportunities to expand farm output at the existing level of inputs and technologies. More specifically, our empirical results indicate that it is desirable to expand vegetable and other annual crop production in mountainous areas while rice cultivation can be further expanded in delta and coastal regions.     

Samenkonservierung und hormonelle Beeinflussung der Samenqualitat beim Kamel

Inhalt: Nach kuner Beschreibung des Eintritts der Geschlechtsrege beim Kamel wird auf die Samengewinnung, sowie die Flüssig- und Tiefgefrierkonservierung des Samens einge-gangen. Das männliche Reproduktionsverhalten sowie der Effect einer pulsatilen Verabreichung von GnRH mittels einer Hormonpumpe wird dargelegt.     

马铃薯晚疫病中心病株形成的观察

 自从1953年以来,我们注意到马铃薯晚疫病的流行无例外地是以少数的中心病株的出现并逐步往周围传染而开始的^[1]。去年许多地区应用观察中心病株的方法作为预测预报的根据也都获得了成功^[3]。     

Relaxin: an important indicator of canine pregnancy

In the present study the concentration of relaxin in peripheral blood plasma was assessed during canine pregnancy for its suitability as a pregnancy indicator, using a newly developed relaxin enzyme immunoassay. A significant relaxin increase was found in pregnancy at day 24 after ovulation. However, this relaxin increase did not correlate either with litter size or with body weight of the bitch. Induction of abortion with prostaglandin F2 alpha resulted in reduced peripheral relaxin levels, suggesting a damage of the placenta due to this medical intervention. Thus, the results confirm that relaxin, which is produced by the placenta, is a useful marker for early pregnancy diagnosis in the bitch. Relaxin measurement is recommended for detection of pregnancy either alone, or as supplement of ultrasonographic findings.