1,697 research outputs found
Genetic selection for reduced somatic cell counts in sheep milk: A review
Full text linkMastitis is an inflammation of the udder, mainly caused by bacteria, and leads to economic loss, due to discarded milk, reduced milk production, reduced milk quality, and increased health costs in both dairy sheep and cattle. Selecting for increased genetic resistance to mastitis can be done directly or indirectly, with the indirect selection corresponding to a prediction of the bacteriological status of the udder based on traits related to the infection. The most frequently used indirect method is currently milk somatic cell count (SCC) or somatic cell score (SCS). This review reports the state of the art relating to the genetic basis of mastitis resistance in sheep, and explores the opportunities to use SCC as selection criterion in a breeding programme to improve resistance to mastitis in sheep, discussing the actual situation and prospects for improvement. It has been stressed, in particular, that although it is unlikely that selection for mastitis resistance by the farmers on their own will be successful, there is good prospect for genetic improvement if reliable pedigree and performance recording is implemented across flocks, combined with breeding value estimation. To achieve this, a strong and well-structured organization to implement and support the program is essential
Schermi. Immagini, corpi, condivisioni
No full textIn this book the author investigates the digital image proliferation of our times from an interdisciplinary point of view. Starting from the Visual Culture theoretical frame, Valentina Mignano explores the ways in which we interact with the screen, dealing with the "screen experience" in the first years of the network societ
Genetic parameters for somatic cell score according to udder infection status in Valle del Belice dairy sheep and impact of imperfect diagnosis of infection
Full text linkAbstract Background Somatic cell score (SCS) has been promoted as a selection criterion to improve mastitis resistance. However, SCS from healthy and infected animals may be considered as separate traits. Moreover, imperfect sensitivity and specificity could influence animals' classification and impact on estimated variance components. This study was aimed at: (1) estimating the heritability of bacteria negative SCS, bacteria positive SCS, and infection status, (2) estimating phenotypic and genetic correlations between bacteria negative and bacteria positive SCS, and the genetic correlation between bacteria negative SCS and infection status, and (3) evaluating the impact of imperfect diagnosis of infection on variance component estimates. Methods Data on SCS and udder infection status for 1,120 ewes were collected from four Valle del Belice flocks. The pedigree file included 1,603 animals. The SCS dataset was split according to whether animals were infected or not at the time of sampling. A repeatability test-day animal model was used to estimate genetic parameters for SCS traits and the heritability of infection status. The genetic correlation between bacteria negative SCS and infection status was estimated using an MCMC threshold model, implemented by Gibbs Sampling. Results The heritability was 0.10 for bacteria negative SCS, 0.03 for bacteria positive SCS, and 0.09 for infection status, on the liability scale. The genetic correlation between bacteria negative and bacteria positive SCS was 0.62, suggesting that they may be genetically different traits. The genetic correlation between bacteria negative SCS and infection status was 0.51. We demonstrate that imperfect diagnosis of infection leads to underestimation of differences between bacteria negative and bacteria positive SCS, and we derive formulae to predict impacts on estimated genetic parameters. Conclusions The results suggest that bacteria negative and bacteria positive SCS are genetically different traits. A positive genetic correlation between bacteria negative SCS and liability to infection was found, suggesting that the approach of selecting animals for decreased SCS should help to reduce mastitis prevalence. However, the results show that imperfect diagnosis of infection has an impact on estimated genetic parameters, which may reduce the efficiency of selection strategies aiming at distinguishing between bacteria negative and bacteria positive SCS.</p
ENTREPRENEURSHIP AND FEMALE ENTREPRENEURSHIP IN MARAMURES COUNTY
Full text linkInitiating and developing a business involves a considerable risk and a sustained effort in order to defeat the inertia against what is new. The person initiating a business, assuming the responsibility and risk of its development and benefiting from theentrepreneurship, female entrepreneurship, profit, businesses
Genetic diversity and phylogenetic relationships among four breeds reared in Sicily using β-lactoglobulin promoter region polymorphisms
No full textThe aim of this work was to analyze the genetic diversity and the phylogenetic relationships among the Valle del Belice (VDB) breed and the other sheep breeds considered as ancestors, using -lactoglobulin (BLG) promoter region polymorphisms. The BLG promoter region of 50 randomly chosen animals from the four breeds (VDB n=20; Comisana (COM) n=10; Pinzirita (PIN) n=10; Sarda (SAR) n=10) were sequenced and aligned, and results showed the presence of 36 single nucleotide polymorphisms (SNPs) and one deletion. The number of polymorphic sites identified showed high variability within breeds. Nucleotide (π) and haplotype (Hd) diversity were estimated with DnaSP software, whereas PHASE software was used to infer and analyze haplotypes. A total of 22 haplotypes were found in “best” reconstruction and used for phylogenetic analysis with MEGA software (Neighbor-Joining algorithm). The SAR breed presented the lowest genetic diversity (π=0.00355±0.00151 and Hd=0.279±0.123), whereas the COM breed presented the highest one (π=0.00703±0.00055 and Hd=0.837±0.076). Comparing the nucleotide diversity among breeds, the highest value was obtained between VDB and PIN breeds (π=0.00566), whereas the lowest one between VDB and SAR breeds (π=0.00421). The phylogenetic tree showed the closest relationship between VDB and SAR breeds. Considering that polymorphisms in the BLG promoter region could have a functional role associated with milk composition, the lowest nucleotide diversity between VDB and SAR breeds may be related to a higher similarity of milk composition of these two breeds compared to the others. Further analyses will be conducted on a wider sample in order to confirm the obtained results
The use of initial tocolysis and maintenance tocolysis in preterm birth : guideline-based approach or off-label use - a survey on the current application in Switzerland
No full textAuthor Valentina Schedl, BscMasterarbeit Universität Linz 202
Estimation of genetic and phenotypic parameters for bacteriological status of the udder,somatic cell score,and milk yield in dairy sheep using a threshold animal model
Full text linkThe objective of this study was to estimate the genetic parameters for infection status (INF), as indicator of mastitis, SCS (i.e., log-transformed SCC), and milk yield (MY), by using a Gibbs sampling algorithm. The data comprised 17,843 test-day records of 2,040 ewes. The pedigree file included 2,948 animals. A bivariate variance component analysis was performed using the TM software. Fixed effects considered in the analysis were litter size, parity, flock by test-day interaction, year by season of lambing interaction, and stage of lactation; whereas the animal, and the permanent environmental effect within and across lactations were considered as random as well as the error. Flat priors were used for both fixed effects and variance components. Parameters were drawn from the posterior conditional distributions. The posterior means of heritability for MY, SCS and INF were equal to 0.14, 0.09, and 0.09, respectively; whereas the repeatability within lactation was around 0.30 for the three traits, and ranged between 0.29 and 0.41 across lactations. The genetic correlation between INF and SCS was equal to 0.93, suggesting that selection for low SCS would also lead to a reduced incidence of mastitis. On the other hand, the positive and moderate genetic correlation between mastitis and milk yield (0.59) confirms the antagonistic association between udder health and milk yield. Therefore, in breeding programs that emphasize milk yield, the unfavorable genetic correlation between milk yield and mastitis, may result in an increased incidence of the latter
Guido Crepax – Valentina – The Shape of Her Time
Full text linkThe paper will focus on the analysis of Guido Crepax revolutionary comic book character Valentina that belongs to the golden age of the Italian comic-book genre fumetto. The aim is to explore whether Guido Crepax Valentina character was a "living doll" filling male fantasies of her creator or she was a woman empowered by her author struggling for many of the values of the women's culture that feminists today are trying to introduce into the mainstream. It also addresses research questions that focus on comic books and gender and empowerment at the decade of sexual liberation.Through Valentina case study the present paper is going to study an approach on the concept of woman in comics, and touch the border of female empowerment issue in contemporary world taking in consideration that her revolutionary strong and independent figure was born in a society where women have been frequently viewed as passive and represented as inferior to men and where questions of sexuality were considered taboo. Despite the fact that she angered some feminists by the way she was portrayed as an object of male gaze or a damsel in distress, there is nothing anti-feminist about Valentina. The aim here is to uncover feminist themes in the stories of Valentina and to explore what empowered her and made her a contemporary icon of style and symbol of liberated women
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