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31.
Objective   To determine the efficacy of monepantel, a developmental compound from the amino-acetonitrile derivative class of anthelmintics, against field infections of gastrointestinal nematodes in sheep.
Procedures   Comparisons of efficacy (using standard faecal worm egg count reduction tests) and safety (on the basis of visual observations) were made in a large-scale field study in Australia, between groups of sheep treated with either an oral solution of monepantel or a registered anthelmintic. The sheep were naturally infected with the major gastrointestinal nematode genera present in Australia.
Results   The post-treatment efficacy results for monepantel were: at 7 days (±1 day) efficacy was >98%; at 14 days (±1 day) it was generally close to or >99%; and at 21 days (±1 day) efficacy was consistently >99%. A high proportion of the targeted nematode populations were confirmed as being resistant to one or more of the currently available anthelmintic classes.
Conclusions   Monepantel when used under field conditions at a minimum dose rate of 2.5 mg/kg was highly effective against mixed-genus natural field infections of the major gastrointestinal nematode genera including Haemonchus , Teladorsagia ( Ostertagia ), Trichostrongylus , Nematodirus , Chabertia and Oesophagostomum . This result included efficacy against some populations resistant to the currently available broad-spectrum anthelmintics. Few Cooperia spp. were present to allow confirmation of efficacy against this genus. On no occasion after treatment did any commercial anthelmintic-treated groups have significantly lower faecal egg counts than the monepantel-treated groups. Monepantel was safe for the target animals and human operators when used in a field situation.  相似文献   
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The objective of this study was to examine the follicular dynamics of five-eighths Girolando cows by observing the number of follicular development waves, days of emergence of those waves, diameters of the dominant and largest subordinate follicles and the processes of follicular selection and dominance. Ovarian follicle dynamics were monitored for 24 oestrous cycles in 12 cows, of 4 to 10 years of age, presenting regular oestrous cycles and with body scores between 3 and 4. Ovaries were observed daily for two consecutive oestrous cycles and follicles were measured with ultrasonographic equipment. The dominant follicle was considered to be that which presented a diameter ≥ 10 mm for three consecutive days and on the day of wave emergence, when a group of follicles measuring 3–5 mm in diameter would appear. Of the 24 cycles monitored, 62.5% presented two waves of follicular development and 37.5% presented three waves. The cycles presenting two waves had an average duration of 20 days, with the emergence of the waves on days 1 and 9, whereas the cycles presenting three waves had an average duration of 22 days, with emergences on days 1, 10 and 16. For cycles with two waves, both the first and second dominant follicles reached an average size of 13.8 mm, with the first regressing on day 10 and the second ovulating around day 20. For cycles with three waves, the dominant follicles of the first and second waves reached maximum diameters of 11.8 and 12 mm, respectively, with the first regressing on day 11 and the second regressing on day 17. The third dominant follicle reached a maximum diameter of 12.4 mm on day 20, and ovulated on day 22. These results lead to the conclusion that the follicular dynamics of five-eighths Girolando cows are characterized by the presence of two to three waves of follicular growth.  相似文献   
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Lizards have been reported as important pollinators on several oceanic islands. Here we evaluate the potential role of Galápagos lava lizards (Microlophus spp.) as pollinators across their radiation. Over 3 years, we sampled pollen transport by 9 lava lizard species on the 10 islands where they are present, including 7 single‐island endemics. Overall, only 25 of 296 individuals sampled (8.4%) transported pollen of 10 plant species, the most common being Prosopis juliflora, Exodeconus miersii, Sesuvium sp. and Cordia leucophlyctis. At least 8 of these plant species were native, and none were confirmed as introduced to the archipelago. Despite the low overall proportion of individuals carrying pollen, this was observed in 7 of the nine lizard species, and on 8 of the ten main islands (Española, Fernandina, Floreana, Isabela, Marchena, Pinta, Santa Cruz and Santiago), suggesting that this is a widespread interaction. The results reported here support the potential role of lava lizards as pollinators across their radiation, although they may represent a relatively modest contribution when compared with birds and insects. However, we cannot discard that lizards may be ecologically significant for particular plant species and ecosystems given the specific climatic condition and functional diversity of each island.  相似文献   
35.
A field experiment was carried out to investigate the effect of Rhizobium inoculation, sulphur, nitrogen and chicken manure on yield, 100-seed weight, cookability, non-soakers, total defects and hydration coefficient of faba bean. The results showed that sulphur, nitrogen and chicken manure treatments significantly (p 0.05) increased yield, 100-seed weight, non-soakers, and hydration coefficient, in the absence of Rhizobium inoculation. The results also showed that Rhizobium inoculation significantly (p 0.05) increased yield, 100-seed weight, cookability, but decreased non-soakers. A positive correlation (r=0.90) was observed between the non-soaker percent and the total defect percent. No correlation was found between non-soakers, hydration coefficient and cookability. The results of this investigation indicate that Rhizobium inoculation is a promising fertilizer because it is cheap, easy to handle and improves plant growth and seed quality. The efficiency of inoculation could be improved with the addition of biological, chemical or organic fertilizers. Generally, fertilization of faba bean with nitrogen, sulphur or chicken manure not only increased plant growth and yield, but also improved seed quality and nutritional value.  相似文献   
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Characterization of fecundity genes offers the opportunity to improve production efficiency, and the consequent increase in litter size in livestock industry, through utilizing them in breeding programs. The main objective of this study was to detect the BMPR‐IB, BMP15 and GDF9 gene mutations and to investigate whether these mutations are associated with litter size in Egyptian sheep breeds. To achieve this goal, 73 adult ewes representing Barki (n = 33) and Rahmani (n = 40) breeds were used. Polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) screening approach was used to detect the presence of FecB, FecXG and FecXI mutations in the two selected breeds. Results of this study showed that the three different candidate gene mutations, namely FecB, FecXG and FecXI are not present among these selected populations of the Egyptian breeds. Further studies regarding other mutations and/or other genes, which may influence ovulation rate, should be carried out to determine the type and mode of inheritance of such genes in Egyptian sheep breeds.  相似文献   
39.
The pharmacokinetics of enrofloxacin were determined in Desert sheep and Nubian goats after intravenous and intramuscular administration of Baytril at the dose of 5mgkg(-1) bodyweight. A two compartment open model best represented the intravenous plasma concentration versus time data in both species. Comparisons between the means of the pharmacokinetic parameters obtained after intravenous administration of enrofloxacin (Baytril) revealed a significantly smaller distribution rate constant (lambda(1)) and consequently a shorter half-life time of distribution in sheep (P<0.05). A larger volume of the central compartment (Vc) was observed in goats (P<0.05). Similar values were obtained for sheep and goats for the remaining parameters.Plasma concentrations versus time data of enrofloxacin after 5mgkg(-1) intramuscular administration of Baytril in sheep and goats were adequately described by one-compartment open model with first order absorption and elimination. There were no significant differences between sheep and goats in any of the estimated pharmacokinetic parameters.The results indicate that the pharmacokinetics of enrofloxacin did not differ significantly between sheep and goats; similar intravenous and intramuscular dose rates of enrofloxacin should therefore be applicable to both species. Owing to the high variations in MIC (minimal inhibitory concentration) of sensitive veterinary pathogens, it is recommended that enrofloxacin dosage regimens be calculated according to the sensitivity of the individual pathogen, site of infection and clinical response, than by following a preset dosage regimen.  相似文献   
40.
The objective of this study was to investigate (i) the effect of two different ovum pick-up (OPU) schemes (once vs twice weekly aspirations) on oocyte recovery rate, quality and subsequent in vitro embryo development, (ii) the influence of days post-partum on oocyte recovery and (iii) possible differences in OPU results from two different herds. In group A, OPU was performed twice weekly in two Holstein Friesian (HF) and three Danish Red and White (DRW) cows from a private herd. In the research herd, two groups of eight HF cows were investigated: group B (OPU once weekly) and group C (OPU twice weekly). The collected oocytes were subsequently submitted to in vitro embryo production. More oocytes were recovered from the private herd when compared with the research herd. In the research herd, the twice weekly scheme aspirated more oocytes than the once weekly scheme. The quality of the retrieved oocytes was significantly different between groups B and C but not between groups A and C, and HF cows yielded higher quality oocytes than DRW cows (p = 0.029). Oocytes from group C showed higher level of embryonic development than group B oocytes. No differences in blastocyst rates were observed between groups A and C. Session affected the number of retrieved oocytes and subsequent developmental rates, with these being lower in the first compared with the last sessions. Finally, there was no significant effect of days post-partum in the number and quality of the retrieved oocytes, likely because of the small group size and high variation between sessions.  相似文献   
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