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61.
Two varieties of avocado leaves (Persea americana var Guatemalan and var Mexican) were administered to lactating goats. The Mexican variety was without effect. The Guatemalan variety in doses exceeding 20 g fresh leaf per kg bodyweight, produced damage to the mammary gland with decreased milk production. The lesions were characterised by oedema and reddening, with clots in the large ducts. Microscopically, there was widespread degeneration and necrosis of the secretory epithelium, the necrotic cells sloughing into the lumen. There was no significant cellular inflammatory response. Concentrations of antitrypsin in the milk, indicating changes in vascular permeability, increased rapidly 15 h after a single high dose, coinciding with palpable oedema. Concentrations of NAGase, indicating cell damage, increased after 24 h. Goats given multiple doses followed a similar pattern but the initial response was delayed. The toxic principle, and its mode of action in selectively damaging mammary secretory cells, remains to be determined.  相似文献   
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• Identification of bacteriocin sources• Classification of bacteriocins• Antiviral pathways of bacteriocinsThe COVID-19 infections caused by SARS-CoV-2 have resulted in millions of people being infected and thousands of deaths globally since November 2019. To date, no unique therapeutic agent has been developed to slow the progression of this pandemic. Despite possessing antiviral traits the potential of bacteriocins to combat SARS-CoV-2 infection has not been fully investigated. This review summarizes the mechanisms by which bacteriocins can be manipulated and implemented as effective virus entry blockers with infection suppression potential properties to highly transmissible viruses through comprehensive immune modulations that are potentially effective against COVID-19. These antimicrobial peptides have been suggested as effective antiviral therapeutics and therapeutic supplements to prevent rapid virus transmission. This review also provides a new insight into the cellular and molecular alterations which have made SARS-CoV-2 self-modified with diversified infection patterns. In addition, the possible applications of antimicrobial peptides through both natural and induced mechanisms in infection prevention perspectives on changeable virulence cases are comprehensively analyzed. Specific attention is given to the antiviral mechanisms of the molecules along with their integrative use with synthetic biology and nanosensor technology for rapid detection. Novel bacteriocin based therapeutics with cutting-edge technologies might be potential substitutes for existing time-consuming and expensive approaches to fight this newly emerged global threat.  相似文献   
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Objective   To measure associations between body weight, growth rate, sex, time of shearing and post-weaning mortality of Merino sheep.
Design   Uni- and multivariable survival analyses of sheep mortality during the first year after weaning, using records (n = 3657) from two field experiments conducted in Western Victoria from 1996 to 2003.
Results   Overall mortality was 14.3% (range 4.5–26.8%) and mean maximum mortality rate was 29 deaths/1000 weaners/month. Increased mortality risk was associated with decreases in fleece-free body weight and mean weaner growth rate, particularly at low weights and growth rates. Weaners in the lightest weaning weight quintile had a hazard ratio of 3.5, compared with the middle quintile. The hazard ratio for a 2-kg decrease in weaning weight was 1.2 to 1.7 for weaners lighter than 22 kg. The hazard ratio for a reduction in mean weaner growth rate in the first 5 months after weaning of 0.25 kg/month was 1.1 to 6.8 if mean growth rate was less than 1 kg/month, but did not differ significantly from 1 at greater growth rates. The hazard ratio for wether weaners was approximately 1.5 compared with ewe weaners. The hazard ratio for weaners shorn between December and May, compared with unshorn weaners, was 1.2 to 3.5, with the greatest risk difference associated with shearing in March (45 deaths/1000 weaners/month).
Conclusion   Improving the body weight and mean growth rate of weaner sheep is likely to reduce post-weaning mortality. Lightweight weaners in a flock should be managed separately from the main portion after weaning. In southern Australia, not shearing spring-born Merino weaners between December and May may assist in reducing overall post-weaning mortality.  相似文献   
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Sperm DNA fragmentation (sDF) is an important parameter to assessing sperm quality. Information about sperm quality is not available for donkeys, especially in some breeds at risk of extinction. The objectives of this research were to test the four commercial variants of sperm chromatin dispersion test (SCD; sperm Halomax test), originally developed to assess sDF in boars, bulls, rams and stallions, in order to scrutinize their applicability in the study of sDF in a donkey breed at risk of extinction (Zamorano-Leonesa), for which there is no specific test available to analyze sperm at present. Only the SCD test, originally developed for stallions, produced stable and consistent results, and was deemed suitable to assess DNA fragmentation in sperm samples from donkeys. Image analysis was used to compare differences between the SCD methodology applied to stallion and donkey semen samples processed under the same experimental conditions. The extent of SCD in the SCD test was approximately 20% lower in donkey sperm than in stallion sperm. Yet, the ratio of chromatin sperm dispersion achieved in fragmented and unfragmented nuclei did not differ significantly between species. These data suggest that a similar protein depletion treatment can cause differences in protein removal in equivalent cells from different species and that sperm chromatin may be organized differently in stallions and donkeys.  相似文献   
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抗旱保水剂在紫花苜蓿种植中应用的试验报告   总被引:5,自引:0,他引:5  
用抗旱保水剂对土壤和紫花苜蓿种子处理后,进行种植试验。结果表明,使用抗旱保水剂出苗每平方米较对照地增加24.25株,存苗增加35.62株,苗高平均增加0.32cm,根长平均增长0.69cm,鲜草每平方增加0.41kg。  相似文献   
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SUMMARY: The productivity of Merino ewes treated with ivermectin and a controlled-release capsule containing albendazole was compared with untreated ewes grazing the same pastures on each of 3 farms. Treated breeding ewes had significantly increased greasy fleece weights (GFW, 6.5% and 7.1%) compared with untreated breeding ewes, on 2 of 3 farms but treatment caused no significant increase in the GFW of non-breeding ewes. Other benefits of treatment on all farms were a significant increase in body weight gain (from 1.7 to 3.7 kg) and a significant decrease in the weight of dag removed at crutching (from 42 to 622 g). These benefits occurred despite the presence on each farm of worms resistant to benzimidazoles. One disadvantage of treatment was an increase in mean fibre diameter of wool from treated ewes of from 0.12 to 0.41 μm. This increase reduces the value of the wool. Partial budgets indicated a net loss of from 8 to 62 cents per ewe for treatment. However, potential benefits such as increased growth rate and wool production from lambs of treated ewes were not included in the analysis. On one farm ewes were classified as ‘susceptible’ to severe dag if they had a dag score ≥ 4 at the time of capsule treatment. Ewes classified as ‘susceptible’ were about 7 times more likely to develop severe dag than were other ewes. There was no significant difference between the GFW of untreated ‘susceptible’ ewes and untreated ewes not classified as ‘susceptible’. Additionally, the response of GFW to treatment was no different to the response seen in ewes that were not classified as ‘susceptible’. The direct cost of diarrhoea and dag formation in Merino ewes was estimated to be 18, 30, 53, 86, 98 and 145 cents per head for ewes with a dag score of 0, 1, 2, 3, 4 and 5, respectively. This cost did not include potential benefits from reduced risk of breech strike, or intangible benefits associated with the improved welfare of sheep.  相似文献   
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AIMS: To investigate the production responses and cost-benefit of administering a controlled-release anthelmintic capsule (CRC) to pregnant yearling ewes prior to lambing.

METHODS: Yearling ewes from two commercial sheep flocks (A, n=489; B, n=248) in the North Island of New Zealand were enrolled in the study. Prior to lambing, CRC containing albendazole and abamectin were administered to half the ewes while the other half remained untreated. Ewe liveweights and body condition scores were measured prior to lambing, at weaning and, for Flock B, prior to subsequent mating. Lambs were matched to dams shortly after birth and the weight and number of lamb weaned per ewe were determined. A cost-benefit analysis was undertaken for Flock B considering the increased weight of lamb weaned per ewe, and the weight of ewes at the next mating and the benefit in terms of lambs born.

RESULTS: The mean weight at weaning of treated ewes was greater for treated than untreated ewes by 2.76 (95% CI 0.64–4.88)?kg in Flock A (p<0.001) and 2.35 (95% CI ?0.41–5.12)?kg in Flock B (p=0.003); the weight of lamb weaned per ewe was greater for treated than untreated ewes by 1.43 (95% CI ?0.71 to –3.49)?kg in Flock A (p=0.041) and 3.97 (95% CI 1.59–6.37)?kg in Flock B (p<0.001), and ewe liveweight prior to subsequent mating was greater for treated than untreated ewes in Flock B by 4.60 (95% CI 3.6–5.6)?kg (p<0.001). There was no difference in the percentage of lambs reared to weaning between treated and untreated ewes in either flock (p>0.8). The overall cost-benefit of treatment for Flock B was NZ$9.44 per treated ewe.

CONCLUSIONS AND CLINICAL RELEVANCE: Pre-lambing CRC administration to yearling ewes resulted in increased ewe weaning weights and weight of lamb weaned in both the flocks studied. There was an economic benefit in the one flock where this was assessed.  相似文献   

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