1,720,981 research outputs found
Misuriamo i vantaggi "reali" della genotipizzazione femminile
No full textFare progresso genetico implica scegliere soggetti miglioratori che, con la loro superiorità, vadano a costruire il futuro livello genetico dell’azienda. Più alta è la media dei riproduttori selezionati sia maschi che femmine, più alto è il livello di miglioramento genetico atteso nella progenie. Delle 4 vie di selezione che contribuiscono al progresso genetico (la cui velocità dipende da variabilità genetico-additiva, intensità di selezione, accuratezza e intervallo generazionale) due sono di pertinenza dei Centri di F.A.: Scelta Padri di Toro e Scelta Madri di Toro, mentre due sono quelle sulle quali può agire l’allevatore direttamente in azienda e cioè: Scelta dei Padri delle Vacche (i tori da usare in azienda), Scelta delle Madri delle Vacche (la scelta della rimonta). Sino ad oggi le strategie genetiche dell’allevatore consistevano nell’utilizzo di tutte le femmine in azienda per produrre la rimonta; oggi invece la tecnologia mette a disposizione nuovi scenari e si può abbinare l’utilizzo del seme sessato abbinato alla genotipizzazione delle femmine
ICS-PR: una nuova selezione per la Frisona Italiana
No full textCon l’uscita di Dicembre 2018 ANAFI pubblicherà il terzo indice di selezione nazionale della Frisona Italiana da affiancare al PFT e allo IES. Questo indice, sviluppato su specifica richiesta del Consorzio del Formaggio Parmigiano Reggiano, prenderà il nome di Indice Caseificazione e Sostenibilità – Parmigiano Reggiano (ICS-PR), e sarà finalizzato a massimizzare il reddito dell’allevatore in un contesto di produzione del latte destinato alla trasformazione casearia
Revision of the aggregate fertility index for Italian Holstein-Friesian dairy cattle
No full textThe aggregate fertility index was added to the national Holstein breeding objective in 2009, and is a linear combination of five selection criteria: angularity, milk yield (MY), interval calving-first service (DTFS), 56 days non-return rate (NR56), and calving interval. The objective of the present study was to include new traits, measured in both productive cows and heifers, to such aggregate index, by exploiting information from linear scoring and fertility-related events. Six subsets of ~15,000 animals calving since 1994 were extracted from the national database. Traits identified were: age at first insemination in heifers (AFI), interval first-last insemination (IFL), NR56, and conception rate (CR) in heifers and cows, and DTFS, MY, and body condition score (BCS) in cows. A multiple-trait animal model was employed to estimate (co)variances of these phenotypes, separately for cows and heifers. Fixed effects per trait were: herd-year of birth (AFI), month of birth (AFI), herd-year-season of birth (IFL, NR56, CR in heifers), month-year of insemination (IFL, NR56, CR in heif-ers), herd-year-season of calving (MY, DTFS, IFL, NR56, CR in cows), month of calving (DTFS, IFL, CR in cows) or insemination (NR56 in cows), age-year of calving (DTFS, IFL, NR56, CR in cows), herd-year-season of classification (BCS), age-stage of lactation at linear scoring (BCS), and year of calving (BCS). Animal additive genetic and residual were treated as random terms. The pedigree was traced back 5 generations. Estimates of G and R matrixes of all the six subsets were averaged to apply selection index methodology for deriving appropriate index weights, by fixing CR in cows and heifers as the only breeding goals. Heritability of cow fertility traits ranged from 0.013 (NR56) to 0.076 (DTFS), whereby estimates of heifer traits were between 0.012 (CR) and 0.071 (AFI). Relative emphasis placed in the selection criteria of the aggregate index for cows were: 0.55 (IFL), 0.16 (DTFS), 0.13 (NR56), 0.09 (MY), and 0.07 (BCS). Index weights for heifer traits were 0.47 (IFL), 0.43 (NR56), and 0.10 (AFI). Both indexes were scaled to have mean 100 and standard deviation 5. The aggregate fertility index published in the official genetic evaluation release is a combined index which includes both indexes by placing 90% emphasis on cow aggregate index and 10% emphasis on heifer aggregate index
EFFECT OF LIVE WEIGHT, DAILY GAIN AND PARENT AVERAGE FOR ILQM ON TIME FOR PROGENY TESTING OF ITALIAN FRIESIAN YOUNG BULLS
No full textHeritability of alternative somatic cell count traits in Italian Holstein cows
No full textMastitis is one of the most costly diseases in the dairy herd. The direct collection of data on clinical mastitis is not widely implemented worldwide and thus most countries refer to somatic cell score (SCS), i.e. the log transformation of milk somatic cell count (SCC, cells mL-1), as indirect measure to select against mastitis. Recently, alternative SCC traits have been proposed to improve udder health. The aim of this study was to estimate heritabilities of alternative SCC traits in Italian Holstein dairy cattle breed. The dataset of SCC was retrieved from the Italian Holstein Association (ANAFI) and included test-day records of first lactation cows (20 to 40 mo of age) calving between 1999 and 2014 in herds of Padova province. The dataset was edited to include records collected between 5 and 305 days in milk (DIM). Moreover, cows with less than 3 test-day records of SCC, with the first test-day beyond 60 DIM and with interval between two consecutive test-days greater than 70 DIM were discarded. Contemporary groups were defined as cows calving in the same herd-year-season (HYS) and HYS with less than 5 animals were removed. After editing procedure, 46,304 cows from 303 herds were available for subsequent analysis. Five SCC traits were defined: 1) SCSTOT, the lactation-mean SCS, 2) SCS150, the average SCS from 5 to 150 DIM, 3) SCS305, the average SCS from 151 to 305 DIM, 4) infection, a dichotomous trait (0/1), where 1 indicates that the cow had at least one SCC higher than 100,000 cells ml-1 during the lactation, and 5) severity (%), the ratio between the number of lactation test-days on which SCC was greater than 100,000 cells mL-1 and the total number of lactation test-days. Heritability of the aforementioned traits were estimated using an animal model that considered HYS, classes of age of the cow at calving, and number of lactation testdays as fixed effects, and additive genetic animal and residual as random factors. The pedigree included 144,255 animals. Means for SCSTOT, SCS150, SCS305, infection, and severity were 3.43, 3.10, 3.38, 0.82 and 39.0%, respectively, and all traits exhibited large variability. Estimates of heritability for SCSTOT, SCS150, SCS305, infection and severity were 10.6%, 6.4%, 10.3%, 2.9% and 13.2%, respectively. Despite low, these estimates suggest that selection for alternative SCC traits is feasible and they may potentially contribute to improve mastitis resistance in dairy cows
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
Empirical economic values of production and functional traits in the Italian Holstein population
No full textBlood parameters predicted from milk spectra are candidate indicator traits of hyperketonemia—A retrospective study in the Italian Holstein population
No full textAt the onset of lactation, high-producing dairy cows commonly face a negative energy balance and metabolic disorders, such as hyperketonemia. Blood concentrations of nonesterified fatty acids (NEFA), BHB, cholesterol, glucose, and urea provide valuable information about the metabolic, health, and nutritional status of lactating cows. Milk mid-infrared (MIR) spectroscopy has been successfully used for the prediction of several health traits in the last years, including blood metabolite concentrations, even though the model accuracy is moderate. In fact, MIR-predicted blood parameters are useful for population screening and may be used for selective breeding if they are heritable and genetically variable within a population. In the present study, we estimated h2 and genetic correlations of BHB, NEFA, glucose, cholesterol, and urea and assessed their genetic correlations with milk yield and composition traits in the Italian Holstein population using phenotypes of 9,943 cows in 460 herds. Two datasets were considered: early lactation (8,277 test-day records between 5 and 35 DIM) and whole lactation (105,293 test-day records, between 5 and 305 DIM). The h2 and genetic variability of blood traits were greater in early than whole lactation, suggesting that there is room to manipulate metabolic disease incidence in the transition period through tailored genetic strategies. Blood BHB was the most heritable trait, regardless of the lactation stage (with h2 of 0.13 and 0.08 in early and whole lactation), whereas blood NEFA was the least heritable trait, with h2 not significantly different from zero. Blood BHB was positively genetically correlated with NEFA, whereas glucose was negatively correlated with BHB, NEFA, and urea. The milk fat-to-protein ratio was correlated with BHB, NEFA, and cholesterol, whereas a negative correlation was calculated between lactose content and BHB and between SCS and BHB. Estimated breeding values of sires with at least 20 daughters with phenotypes available were extrapolated for a posteriori evaluation of the observed performance. The progeny of the top 5 sires exhibited a lower incidence of hyperketonemia compared with the other cows, with only 2.16% of cows having BHB concentrations above the conventional threshold (1.20 mmol/L). Conversely, the prevalence of hyperketonemia was 5 times higher in the offspring of the bottom 5 bulls (10.55% of cows with BHB above the threshold of 1.20 mmol/L). These findings suggest that, despite the low h2 estimates, there is room to identify animals with low or high genetic merit for traits linked to metabolism. Therefore, selection toward healthier and metabolically resistant cows is pursuable, with MIR-predicted blood traits being potential auxiliary traits for selective breeding
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