1,720,969 research outputs found
Behaviour of laying hens of two genotypes in a cage-free system enriched with hay bales
Full text linkEnvironmental enrichment can play a positive role in cage-free systems by allowing hens to diversify their behavioural repertoire and reducing aggression among animals. Our study evaluated the effect of the enrichment with hay bales in an aviary system on the behaviour of 1,800 laying hens (Hyline Brown and Lhomann White) from 50 to 53 weeks of age. Behaviours, expressed as the percentage of hens observed on the floor, were scored through a 10-sec scan every 30 min per hour (05:30-20:30) and observations were grouped per day-time interval, i.e. early, midday, afternoon, and evening. Data were submitted to ANOVA with genotype, enrichment, and time interval (not discussed here) as main effects, and pen as a random effect. As for the enrichment, the presence of hay bales increased the number of hens on the floor and the rate of those interacting with the enrichment at the expenses of hens performing dustbathing, sitting, or walking. As for the genotype, a higher number of brown hens was recorded on the floor, with a higher rate of them sitting-inactive and preening compared to white hens which performed more dustbathing, interactions with hay bales, ground-pecking, and piling (P<0.01). In conclusion, hay bales attracted hens and reduced the expression of some comfort behaviours; white hens were more active and showed more risky behaviours such as piling compared to brown hens. Acknowledgements: This study was carried out within Agritech National Research Center and was funded by the European Union – NextGenerationEU (PNRR – Missione 4 Componente 2, Investimento 1.4 – D.D. 1032 17/06/2022, CN00000022), and by Unimpresa, University of Padova (call 2019)
Risk factors for navigation ability of laying hens at housing in an aviary system
No full textTo evaluate the risk factors for navigation ability of two genotypes of laying hens at housing in an aviary system, 1,800 pullets, half Lohmann White-LSL and half Hy-line Brown, were randomly allocated at 17 weeks of age in 8 pens of an experimental aviary (3 tiers), according to a bi-factorial arrangement, 2 genotypes (brown vs. white hens) × 2 types of pens (enriched or not enriched with additional perches). Data collected by video-recording at 17 and 20 weeks of age were used to assess the number of successful and unsuccessful landings from any part/equipment of the aviary to the floor. Risk factors related to failed landings were evaluated by multivariate logistic regression analysis through a forward stepwise selection using the PROC LOGISTIC of SAS. The regression coefficients were expressed as odds ratio (OR) with 95% confidence interval (CI). Compared to brown hens, white hens performed a significantly higher number of landings per hour in the observation interval (80.7 vs. 35.4; P<0.001) with a higher success rate (94.8% vs. 88.6%; P<001). Brown hens had higher odds of failed landings compared with white hens (OR: 6.65; 95% CI: 4.36-10.1). The logistic regression analysis showed significantly higher odds (OR: 1.90; P<0.001) of experiencing failed landings at 17 weeks compared to 20 weeks. No significant difference in the number or in the rate of success of landings was recorded between enriched and not enriched pens, where the logistic regression analysis only measured a trend (OR: 1.29; P=0.09). The odds of failed landings were greatly higher when comparing long with medium flight distance to floor (i.e. hens starting from the third vs. the second tiers of the aviary) (OR: 31.1; P<0.001) and lower comparing short (i.e. hens starting from the first tiers of the aviary) with medium flight distance (OR: 0.17; P<0.001). In conclusion, under the condition of the present study, white hens exhibited higher navigation activity and ability compared to brown hens since the first week after housing; the navigation ability improved four after housing weeks; the enrichment with additional perches played a minor role. Long-term effects on space use should be evaluated over the laying period
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Production and egg quality in brown hens kept in a cage-free system: effect of hen age and nest lighting
Full text linkThe study evaluated the effects of hen age and nest lighting on egg production and quality, and oviposition pattern from 26 to 45 weeks of age in 1800 Lohmann Brown-Classic hens housed in 8 pens of an aviary system. From 17 to 26 weeks of age, half pens had the nest opened with the inner led light turned on 1.5 h before turning on the installation light (5:30); the other half had the nests closed until turning on the installation light and without any inner led light. Measurements were taken weekly and monthly. As hen age increased, the oviposition rate (p < .001) increased from 89.1% housed hens (on average of 26–34 weeks) to 92.8% (34–45 weeks). Both the oviposition rate of broken and dirty eggs decreased from the first period (5.13% and 7.65% on average, respectively) to the second period (2.28% and 4.21%) (p < .001). The weight and width of the eggs increased and the shape index decreased as age increased (p < .001). As for oviposition pattern from 26 to 45 weeks, eggs laid in the first hours (5:30–7:30) decreased (76.4–45.8% of eggs laid in 24 h), whereas eggs laid in the rest of the day increased (p < .001). Moreover, eggs laid in the nest (as % eggs laid in each time interval) between 5:30 and 7:30 (77.9–86.4%) and between 7:30 and 9:30 (68.3–84.7%) increased from 26 to 45 weeks (p < .001). A significant decrease of broken eggs (% eggs laid in each time interval) was also recorded for the eggs laid within 9:30 when the hen age increased. The use of nest lighting from 17 to 26 weeks increased oviposition rate in the following period (26–45 weeks) from 90.1% to 92.3% (p < .001), decreased egg weight, width, and surface (p < .001) as well as the rate of broken (4.22–3.43%; p < .001) and dirty eggs (5.98–5.65%; p = .10), whereas the rate of defective eggs was not affected. The oviposition pattern (i.e. distribution of eggs laid in the different daily time intervals) did not change. In the first time interval (5:50–7:30), eggs laid in the nest were higher (83.2% vs. 80.2% eggs laid in the time interval; p < .01) and broken eggs lower (4.83% vs. 7.01%; p < .01) in the case of the presence of nest lighting. Based on the above results, changes in the oviposition during the day according to hen age must be considered in cage-free systems to assure a correct use of nests. As for early nest lighting, further investigation is worth in view of the positive effects on egg production and quality, and on nest use
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Color of nest curtains: effects on egg and hens position in an aviary system
No full textThe study evaluated the effects of the colour of nest curtains on hens preference based on egg and hen position in an aviary consisting of two tiers with collective nests and a third uppermost level with perches. To this purpose, 1,800 brown hens were housed in 8 pens according to four combinations (2 pens/group, 225 hens/pen): nests with red (R) or yellow (Y) curtains in all tiers; or nests with R and Y curtains on the first and second tier, respectively (R/Y); or nests with Y and R curtains on the first and second tier, respectively (Y/R). From 28 to 37 weeks of age, on average, eggs laid in the nest (nest eggs) were 80.9% of the total, 17.1% were laid on tiers out of the nest and 2.0% on the floor; additionally, 44.3% of eggs were laid at the first tier while 53.7% at the second tier. As for hen position, 33.6% of hens were observed on the floor, 18.5% on the first tier, 43.0% at the higher levels (30.9% at the second tier and 12.1% at perches of the uppermost level), and 5.0% in the nests (average of all recordings). As for the effect of curtain colour, the rate of nest eggs was higher in Y/R than in Y pens (81.4% vs. 79.9%; P<0.05), without differences with R and R/Y pens (81.0% and 81.1%, respectively). Then, the rate of eggs laid at the first tier was the lowest in R/Y pens (41.5% vs. 44.4% in Y/R, 45.3% in R, and 46.0% in Y pens; P<0.001), whereas an opposite trend was recorded at the second tier (56.5% in R/Y vs. 53.1% in Y/R pens, 52.0% in Y pens, and 52.8% in R pens; P<0.001). The highest rate of hens on the floor was observed in Y/R compared to R/Y pens (34.2% vs. 30.8%; P<0.05), whereas the other treatments showed similar values (32.9% and 32.5% in Y and R pens, respectively). Thus, the rate of hens on the top levels was the highest in R/Y (46.1%) compared to R pens (43.8%; P<0.05), whereas similar rates were observed in Y/R and Y pens (44.1% and 44.9%, respectively). Based on results of nest use and hen position, we could conclude that yellow curtains got the preference of hens and moved them on the tiers equipped with yellow curtains when red and yellow curtains were used in the same pen
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