共查询到20条相似文献，搜索用时 578 毫秒
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Conformation is defined as the form or outline of an animal and is sometimes expanded to include a relationship of form to function. In the course ofa studentproject,25 traits were measured in each of 20 Thoroughbreds as 3-year-olds in training. "Winners" were three year olds who had won a listed race in 1990 as two year olds. "Others" were three year olds who had raced but not won in listed races in 1990 as two year olds. Twelve of these Waits were evaluated using a linear assessment scoring system; 13 traits were measured using a steel tape, vernier calipers or an improvised compass. This short communication confines itself to two measured waits, intermandibular width and cannon bone length. 相似文献
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Peter Mckenzie 《The Journal of small animal practice》1977,18(5):359-364
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Despite studies on range shifts being abundant, the problem of dispersal barriers limiting climate migrants’ movement is yet to be fully included into any modeling framework. For this reason, we introduce a novel concept whereby the interplay of range shifts and dispersal barriers of a particular spatial configuration can threaten the persistence of populations under a climate change scenario. We named this concept “C‐trap,” based on the topographic shape of such barriers. After elaborating on the theoretical features of C‐traps, we provide a simple method that combines environmental data and future climate projections to locate them spatially. We use this method to determine where high C‐trap densities have the potential to further threaten the conservation of endangered, endemic animals across the world's terrestrial realm, in a climate change scenario. Our methodology detected potential C‐traps for the study system, with areas of high density mostly located in east Europe, south Asia and North America. However, finer‐scale analyses are required to assess the magnitude of the threat locally. Dispersal barriers add an additional dimension to range shift studies and can ultimately prevent otherwise successful climate migrants from tracking their climatic niche. The methodology presented here is simple and flexible enough to be adapted to a wide range of taxa and locations as well as the fast development of range shift modeling. Therefore, we encourage researchers to include the effects of anthropogenic dispersal barriers in range shifts models and in the planning of effective conservation strategies with reference to climate change. 相似文献
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Francis Dov POR 《Integrative zoology》2007,2(2):57-59
Imprecise and faulty taxonomic identification of the biological objects of many ecological and experimental studies renders these studies irreproducible. Incomplete identification to the species level and excessive use of vernacular species names are additional problems. Good science must be able to be falsified. I recommend that publications and granting agencies use and mention the names of the zoologists or botanists who identified the species. Voucher specimens should be marked and deposited in scientific museums for future checking. 相似文献
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There are three major sources of uncertainty in the times for which drugs can be detected in a horse's blood or urine. First, horses are treated with drugs at one million-fold different doses, and they eliminate these doses at rates that vary about 300-fold. Second, the sensitivity of the tests that the analyst uses to detect these drugs can vary up to 100-fold or more. Third, horses treated with exactly the same doses of drugs can “spread out” or distribute the plasma levels of these drugs about50-fold in a skewed or irregular manner. In this distribution, a large proportion of horses show lowerblood levels of drugs, but a small proportion of horses show relatively much higher blood levels of drugs. Beyond this, the different pH (acidity) values of urine samples can cause urinary levels of drugs to vary by at least 200-fold. These factors cause large uncertainties concerning the blood or urinary levels of drugswhich are found even after the same doses of the same drug. These uncertainties result in considerable technical difficulties for the regulatory process of medication control. 相似文献
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Yen Hui Chen DVM Drmedvet Rudolf Stolla Prof Drmedvet 《Journal of Equine Veterinary Science》2006,26(5):219-224
Embryonic death plays an important role in infertility in mares, and most of embryonic mortality occurs at an early stage (before day 40) of pregnancy. Previous investigations focused on B-mode sonographic images to determine abnormal pregnancy; however, no study has provided a quantitative and objective method to diagnose embryonic death. Here we developed a new index, “Uterine Index,” using color Doppler sonography to describe alterations of uterine blood flow in physiological and pathological gestations during early gestation. Six Trotter mares were used in this study. The pregnancies were interrupted with a prostaglandin F2α (PGF2α) analog (tiaprost) at days 25, 30, and 40. Three gestations were investigated in each stage. After the PGF2α administration, these mares were examined every 8 hours until the embryonic vesicles were not visible on ultrasound. In the control group, three pregnancies were examined daily from days 12 to 60. The embryo size was measured in B-mode sonography, and the blood flow in uterine arteries was examined in Doppler ultrasound. The resistance index (RI) and uterine index (UI) were calculated. In the control group, the RI values of uterine artery were lower in pregnant side compared with that of the non-pregnant side from day 15 on, and the difference became greater as the pregnancy advanced (P < .05). The UI was close to 0 before week 3 and increased to approximately 10 after week 4. In the PGF2α-treated group, the UI values reduced from pregnancy level to approximately 0. As early as 32 hours before embryonic death, we observed a significant difference of UI values between control and treated mares. On the contrary, the embryo size of treated mares was not different from that of normal mares. Through the analysis of all recorded UI values, we suggest that the UI values 10 and 5 are good values for distinguishing normal pregnancy (UI >10) from embryonic death (UI < 5). If the UI values are located between 10 and 5, a reexamination at intervals of 1 to 3 days is recommended. Our findings demonstrate that the UI is a useful method to diagnose and predict embryonic death in mares by providing reliable and objective information. 相似文献
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