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101.
Grace Delia Gilbert Jeff Randolph Thomas Kangethe Erastus 《Tropical animal health and production》2012,45(1):67-74
Individual interviews were conducted in 137 households using semi-structured questionnaires to determine the influence of socioeconomic factors on production constraints faced by indigenous chicken producers in the rural areas of South Africa. The major constraints to village chicken production were mortality (95 % of the households) followed by feed shortage (85 %) and low chicken sales (72 %). The logistic regression model showed that households that owned imported/crossbred chickens practiced extensive production system without housing structures and did not have vaccines were more likely to experience high levels of chicken mortality. Poor and youth-headed households with no supplements and vaccines had high probability of Newcastle disease. The probability of a household to experience chicken feed shortage was lower in households that owned indigenous chickens than those that owned imported/crossbred chickens (odds ratio, 11.68; 95 % confidence interval, 1.19–27.44). Youth-headed households that had small flocks and no access to veterinary services were not likely to sell chickens. It was concluded that gender, age, wealth status, production system, chicken flock size, type of chicken breed owned, accessibility of veterinary services, availability of supplements, vaccines and shelter influence village chicken farmer’s production constraints such as feed availability, chicken mortality, prevalence of diseases and chicken sales. 相似文献
102.
F Ytournel S Teyssèdre D Roldan M Erbe H Simianer D Boichard H Gilbert T Druet A Legarra 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2012,129(5):417-421
Simulations are a major tool to evaluate new statistical methods and optimize experimental designs in the genomic era. However, this can only be achieved when the simulations are close enough to reality, as well as diverse enough to be realistic. For mapping studies, it is thus critical to re-create as much as possible the forces generating linkage (mutation, random drift, changes in population sizes, selection and pedigree structure) and the mechanisms producing trait genetic architecture (additivity, dominance, epistasis). We present here a computer program (ldso) simulating these phenomena. Optional outputs provide statistics on the linkage disequilibrium (LD) structure and the identity by descent between chromosomal segments, facilitating further data analyses. Furthermore, ldso enables the simulation of genomic data in known pedigrees, which sticks as precisely as possible to recent population history and structures of the long-range LD, allowing optimization of fine-mapping strategies. 相似文献
103.
Machado VS Oikonomou G Bicalho ML Knauer WA Gilbert R Bicalho RC 《Veterinary microbiology》2012,159(3-4):460-469
The objective of this study was the use of metagenomic pyrosequencing of the 16S rRNA gene for the investigation of postpartum dairy cows' uterine bacterial diversity. The effect of subcutaneous supplementation of a trace mineral supplement containing Zn, Mn, Se, and Cu (Multimin North America, Inc., Fort Collins, CO) at 230 days of gestation and 260 days of gestation on dairy cows' uterine microbiota was also evaluated. Uterine lavage samples were collected at 35 DIM and were visually scored for the presence of purulent or mucopurulent secretion. The same samples were also used for the acquisition of bacterial DNA. The 16S rRNA genes were individually amplified from each sample. Pyrosequencing of the samples was carried at the Cornell University Life Sciences Core Laboratories Center using Roche 454 GS-FLX System Titanium Chemistry. The Ribosomal Database Project online tools were used for the analysis of the obtained sequences library. Bacteroides spp., Ureaplasma spp., Fusobacterium spp., Peptostreptococcus spp., Sneathia spp., Prevotella spp. and Arcanobacterium spp. prevalence was significantly (P<0.05) higher in samples derived from cows that had a higher uterine lavage sample score. Bacteroides spp., Ureaplasma spp., Fusobacterium spp., and Arcanobacterium spp. prevalence was significantly (P<0.05) higher in samples derived from cows that were not pregnant by 200 DIM. Anaerococcus spp., Peptostreptococcus spp., Parabacteroides spp., and Propionibacterium spp. prevalence was significantly (P<0.05) lower in samples derived from cows that were trace mineral supplemented. 相似文献
104.
Yazidhi Bamutaze Moses Makooma Tenywa Mwanjalolo Jackson Gilbert Majaliwa Veerle Vanacker Festus Bagoora Mathias Magunda Joy Obando John Ejiet Wasige 《CATENA》2010
Water infiltration is an important hydrological process that influences runoff and soil loss patterns in mountain ecosystems. In this paper, we present results on spatial variation in infiltration in croplands on the volcanic soils of Mt. Elgon, in Eastern Uganda. Twelve experimental sites with slope gradients ranging from 12 to 32% were established. Infiltration tests were carried out with a double ring infiltrometer and three measurements were taken at the upper, middle and lower sections of each experimental site to assess the local variability of infiltration. In addition soil information was collected on each experimental site. The soil infiltration data were then evaluated to fit to four commonly used water infiltration models: (1) Philip (1957), (2) Green–Ampt (1911), (3) Horton (1940) and (4) Kostiakov (1932). The twelve experimental sites cover two cropping systems: annual (6 sites) and perennial (6 sites) crops. Based on the results, we examine the spatial variability of infiltration, the relationship of infiltration to landscape position, and the influence of soil composition on infiltration rates on the slopes. The factors affecting spatial variability of soil infiltration were analysed using correlation and regression techniques. Steady state infiltration rates generally increased with the slope gradient and were crop type independent (P < 0.05). The performance of the four applied water infiltration models was generally good with mean R2 values ranging from 0.79 to 0.87, although all the models tended to over-predict the steady state infiltration rates at most sites. Overall, the Philip's and Kostiakov gave better results than the Horton and Green–Ampt models in reproducing the infiltration process on Mt. Elgon. 相似文献
105.
106.
Herv Garreau Julien Ruesche Hlne Gilbert Elodie Balmisse Florence Benitez Franois Richard Ingrid David Laurence Drouilhet Olivier Zemb 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2019,136(3):168-173
The aim of this experiment was to evaluate the significance of neonatal environment on feed efficiency. For that purpose, rabbits from a line selected for residual feed intake (RFI) during 10 generations (G10 kits) were cross‐fostered with non‐selected control does (i.e., G0 line), and reciprocally. In parallel, sibs were fostered by mothers from their original line. Nine hundred animals were raised in individual (N = 456) or collective (N = 320) cages. Traits analysed in this study were body weight at 32 days and at 63 days, average daily gain (ADG), feed intake between weaning and 63 days (FI), feed conversion ratio (FCR) and RFI. The maternal environment offered by does from the line selected for RFI deteriorated the FCR of the kits, independently of their line of origin, during fattening (+0.08 ± 0.02) compared to FCR of kits nursed by G0 does. The line, the type of housing and the batch were significant effects for all the measured traits: G10 kits were lighter than their G0 counterparts at 32 days (?82.9 ± 9 g, p < 0.0001) and at 63 days (?161 ± 16 g, p < 0.0001). They also had a lower ADG (?2.36 ± 0.36 g/day, p < 0.0001), RFI (?521 ± 24 g/day, p < 0.0001) and a lower FI (?855 ± 31 g, p < 0.0001), resulting in a more desirable feed efficiency (FCR: ?0.35 ± 0.02). There was no significant difference in the contrast of G10 and G0 performances between collective and individual/digestive cages (p > 0.22): ?2.35 g/day versus 2.94 g/day for ADG, ?0.39 versus ?0.40 for FCR, ?577 g versus ?565 g for RFI and ?879 g versus ?859 g for FI, respectively). Thus, no genotype‐by‐environment (housing) interaction is expected at the commercial level, that is, no re‐ranking of the animals due to collective housing. 相似文献
107.
Low-voltage organic transistors on plastic comprising high-dielectric constant gate insulators 总被引:1,自引:0,他引:1
CD Dimitrakopoulos S Purushothaman J Kymissis A Callegari JM Shaw 《Science (New York, N.Y.)》1999,283(5403):822-824
The gate bias dependence of the field-effect mobility in pentacene-based insulated gate field-effect transistors (IGFETs) was interpreted on the basis of the interaction of charge carriers with localized trap levels in the band gap. This understanding was used to design and fabricate IGFETs with mobility of more than 0.3 square centimeter per volt per second and current modulation of 10(5), with the use of amorphous metal oxide gate insulators. These values were obtained at operating voltage ranges as low as 5 volts, which are much smaller than previously reported results. An all-room-temperature fabrication process sequence was used, which enabled the demonstration of high-performance organic IGFETs on transparent plastic substrates, at low operating voltages for organic devices. 相似文献
108.
CL Gilbert 《Reproduction in domestic animals》1999,34(3-4):193-200
This paper will examine the augmentation of oxytocin (OT) secretion in the final day before parturition in the pig, and review the key endocrine systems of influence. Recent experiments have shown that increases in plasma OT above baseline secretion were not seen until 7 hours prior to the birth of the first piglet. Progesterone release begins to decline some days before birth and is unlikely to provide such acute control of OT release immediately before birth. The involvement of relaxin is complex but it is possible that the prepartum relaxin surge, which ends close to the OT rise, attenuates OT secretion to prevent excessive myometrial activity until cervical softening has occurred. Increasing myometrial electromyographic activity appears to be seen as relaxin concentrations decline and OT increase. Endogenous opioid peptides within the hypothalamus exert a profound influence upon OT secretion during birth, and some effects are also seen prepartum. It has been proposed that this system may allow parturition to be interrupted or slowed in response to changes in environment. The therapeutic choice of exogenous injections of OT to control the onset time of parturition will be discussed in the light of current physiological knowledge. 相似文献
109.
Mass selection for small‐sized cysts in Artemia franciscana produced in Vinh Chau salt ponds,Vietnam
Nguyen Thi Hong Van Nguyen Van Hoa Peter Bossier Patrick Sorgeloos Gilbert Van Stappen 《Aquaculture Research》2014,45(10):1591-1599
Unidirectional mass truncation selection for small‐sized cysts was carried out on brine shrimp (Artemia franciscana Kellogg 1906), Vinh Chau strain, Vietnam, through cyst sieving and then culturing the selected individuals (<5% of the population) under field and laboratory conditions over two successive generations (F1 and F2). The results showed that at both culture scales, the cyst size of the selected line was smaller (P < 0.05) compared with the control (non‐selected) line, illustrating that there was a response to selection. The cyst size decreased about 3% per generation and the accumulated gain on the target trait was in the range 5.82–6.07% at the end of the selection process compared with the base population. The realized heritability estimation (h2) for cyst size was 0.23 ± 0.06 and 0.74 ± 0.19 in the field trials and 0.34 and 0.51 in the laboratory test for the F1 and F2 generation respectively. The variations found between the respective trials may be explained as the result of environmental interaction with the selection process, but the results show that a selection program for small‐sized cysts in Artemia by mass selection is possible. 相似文献
110.
J. Scott Weese Roberta Poma Fiona James Gilbert Buenviaje Robert Foster Durda Slavic 《The Canadian veterinary journal. La revue veterinaire canadienne》2009,50(6):655-656
Staphylococcus pseudintermedius was implicated as the cause of rapidly progressive and fatal necrotizing fasciitis in a dog. The isolate was methicillin-susceptible and did not contain genes encoding the Panton-Valentine leukocidin. While Streptococcus canis is typically considered to be the main cause of necrotizing fasciitis in dogs, staphylococci should also be considered. 相似文献