1,720,964 research outputs found
Genetics of casein content in Brown Swiss and Italian Holstein dairy cattle breeds
No full textOver 2,000,000 records of casein contents were collected from herds of Brown Swiss (BS) and Italian Holstein Friesian (HF) dairy cows in northern Italy during routine milk recording. Variance components for casein and genetic correlations of casein with production and type traits considered in selection were estimated from a sample of 200,484 test day records for 26,279 BS cows and 376,652 for 41,543 HF cows. A multivariate multi-model REML estimation of variance components was made. Models for production included the fixed effects for herd-test day, year of evaluation, days in milk, month of calving and age at calving within parity. Models for type traits were defined accordingly to the model officially used for each breed for breeding value estimation. Breeding values for casein yield and content were calculated from estimated heritabilities (Brown 0.12; Holstein 0.09). Estimates were similar for protein and casein yield and content while genetic correlations with traits in the actual selection indexes differed between breeds. These differences, together with the greater emphasis now given to protein in the selection index of the Brown Swiss than in the Italian Holstein Friesian, suggest that a direct selection for casein could be more advantageous in Brown than in Holstein cows. The Brown breeders association could soon include casein yield and content directly in their selection criteria while that of Holstein cows would wait for a longer term casein data collection
Genetic parameters and selection for casein content in Italian Holstein and Brown Swiss
No full textA total of more than 2,000,000 records on casein contents were collected in Lombardia (Italy) during routine milk recording of Italian Holstein and Brown Swiss dairy cows. Variance components for casein were estimated as well as all the genetic correlations of casein with production and type traits considered in selection. According to the heritabilities estimated (12.4% for Brown and 9.36% for Holstein), breeding values were calculated for bulls and compared to the breeding values for total protein. The results of two different selection scenarios were compared for each breed when including protein or casein as selection criterion. Genetic progress expected for all traits selected were compared after 10 years of selection. The genetic variability of casein allows the use of this trait as selection criterion with the estimation of breeding values and its inclusion in selection indexes. Ranking of breeding values for casein and protein are very similar in both breeds. But some differences in genetic values for casein exist for the same level of breeding value for protein. Nevertheless results in genetic gain differ between breeds depending mainly on genetic correlations with the other traits selected. The positive results in selection response estimated for several traits suggest to the Brown Swiss Association the replacement of protein selection with casein. In contrast the smaller effects estimated for the Italian Holstein suggest to wait for more casein data collected before any change in selection program
Genetic parameters for casein and urea content in the Italian Brown Swiss dairy cattle
No full textA total of 137,753 test day records of 20,745 Italian Brown Swiss dairy cows from 26 provinces of Italy were used to estimate heritability for casein and urea content in milk and their genetic correlations with other production traits and milk somatic cell score. Milk component values were obtained by Fourier Transformed Infrared (IR) Spectroscopy from milk samples collected during national routine recording and were analysed using test day repeatability animal models. Fixed effects included 1,001 levels of herd-test date, 15 classes of days in milk, and 13 classes of age at calving within parity. The variation among cows was large for most of the traits. The heritability value for casein content was 0.31, as for protein content, and genetic and phenotypic correlations between these two traits were large (0.99 and 0.97 respectively). Milk urea content had a heritability of 0.17 and a positive genetic relationship with fat (0.12), null with protein (0.03) and casein (0.002) content and a negative genetic correlation with milk yield (-0.17) suggesting that the genetic improvement for milk urea content would be possible, but genetic gain would be affected by other traits included as selection criteria in the economic index and by their relative economic emphasis
Heritabilities and genetic correlations of body condition score and muscularity with productive traits and their trend functions in Italian Simmental cattle
No full textWith the aim to study the genetics of energy and muscle balance in the Italian Simmental breed, the objectives of this study were: i) the estimation of the genetic parameters for body condition score (BCS) and muscularity (MU) score; ii) the estimation of genetic correlations of BCS and MU with productive traits; iii) the estimation of the expected pattern of BCS and MU over lactation. A total of 47,839 records of first-parity lactating cows, collected from 1999 to 2007 in 2794 herds, were used. Two-trait animal models were analyzed using restricted maximum likelihood (REML) procedures to estimate (co)variance components. The expected patterns of BCS and MU along the lactation of first parity cows were estimated from the solutions of DIM fixed effect obtained from an univariate mixed model for both the traits. The heritability estimated was 0.18 for BCS, 0.38 for MU, and ranged from 0.13 to 0.18 for yield traits. The genetic correlations between BCS, MU and yield traits were negative (-0.17 to -0.63). The genetic correlation between BCS and MU was strongly positive (0.88), indicating that cows that genetically tend to have high BCS are more likely to have high values of MU. The genetic parameters estimated suggested that selection for BCS and MU in dual purpose breeds may be possible, and BCS may indirectly improve MU. The expected patterns for BCS and MU showed the trend of these two traits along the lactation and can help farmers in planning the best management of the lactating 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
Some of the main results of Quantomics EU project : CNV detection and GWA analysis in the Italian Brown Swiss dairy cattle
No full textSelenium (Se) and iodine (I) are veryimportant trace mineral for animals andhuman health. Selenium is an essential constituent of the antioxidant enzyme GSH-Px,while I as a thyroid hormone play a crucial rolein regulating body metabolism. The aim of thisstudy was to provide preliminary data on theSe and I status of two camel breeds (Majaheemand Maghateer:Camelus dromedaries) raisedunder the semi intensive system in SaudiArabia (SA). Ten Majaheem male camels andten maghateer, age 1.5±0.5 yrs old, wereslaughtered and blood and tissues (liver, kidney and meat) were collected. Blood serumsamples were analyzed for Se, thyroxine (T4),triiodothyronine (T3), glucose, cholesterol,true protein and albumin. Tissues sampleswere wet digested and analyzed for Se levelusing Atomic Absorption Spectrophotometer.Results showed a significant breed effect onserum and tissues Se with higher concentration of Majaheem compared with Maghateerbreed. The same trend was found for glucoseand total protein. Furthermore, serum Se wassignificantly correlated with liver Se (r2=0.698;P<0.01), meat Se (r2=0.453; P<0.05), T3(r2=0.527; P<0.05) and T4 (r2=0.476; P<0.05).Thyroxine was significantly correlated to T3(r2=0.693; P<0.01). In conclusion, a highly significant breedeffect was reported for Se metabolism. Thehighest Se concentration occurs in kidney followed by liver and meat
The QuaLAT project : mapping QTL for SCC and milk fatty acid content in the Italian Brown population and in the Israel Holstein Friesian
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