Search results for " Sheep"
showing 10 items of 101 documents
Parentage verification of Valle del Belice dairy sheep using multiplex microsatellite panel
2013
Abstract The aim of this work was to develop and evaluate a PCR based microsatellite markers multiplex system for parentage verification of Sicilian Valle del Belice dairy sheep. A total of 85 samples of blood and hair were collected and genotyped for 24 microsatellite markers in multiplex electrophoresis runs. A total of 269 alleles were detected across the 24 loci investigated. The PIC considering all loci was equal to 0.736, showing that this microsatellite panel was very polymorphic and highly informative. A parentage test was performed on 64 families generated with multiple sires. Results indicated 20.3% and 29.7% misidentification rates for females and males, respectively. In 8 cases,…
Evidence for cryptic glacial refugia from North American mountain sheep mitochondrial DNA
2006
The separation of populations by ice sheets into large refugia can account for much of the genetic diversity found in present day populations. The evolutionary implications of small glacial refugia have not been as thoroughly explored. To examine refugial origins of North American mountain sheep Ovis spp., we analyzed a 604 bp portion of the mitochondrial DNA (mtDNA) control region from 223 O. dalli and O. canadensis. Major refugia were identified in eastern Beringia and southern North America, and we found evidence for two smaller refugia situated between the Laurentide and Cordilleran glaciers. Our results are the first to demonstrate support for survival of any organism in the latter two…
The quality of Valle del Belice sheep’s milk and cheese produced in the hot summer season in Sicily
2013
In response to the growing consumer demand for fresh cheese in summer, this investigation was aimed to evaluate the chemical and microbiological characteristics of sheep’s milk and cheese produced in Sicily in the hot summer months. A total of 810 bulk milk samples collected from 17 farms rearing ewes of the Valle del Belice breed were analysed for chemical composition, somatic cell count, total bacterial count and clotting parameters. Samples (n = 18) of Protected Designation of Origin Vastedda della valle del Belice cheese produced in six dairies were collected in summer, autumn and spring and analysed for chemical composition, microbiological profile and fatty acid (FA) composition. Univ…
Occurrence of aflatoxins in feedstuff, sheep milk and dairy products in Western Sicily
2003
Samples of feedstuffs (15), milk (40), and cheese (30) coming from sheep and dairy farms (23) or market in WesternSicily were analyzed for their respective content of aflatoxin B1 (AFB1) and M1 (AFM1) to evidence any possible indirectmycotoxin contamination risk to the consumer. Analyses using HPLC and fluorescence detection were performed afterimmunoaffinity column sample extraction and cleanup; AFM1 was detected in 30% of the milk samples at levels rangingfrom 4 to 23 ng/l and in 13% of the cheeses from 21 to 101 ng/kg; in the feed the AFB1 ranged from None of the contaminated samples exceeded the legal limits set down by the European Union for milk (50 ng/l) and feed(5 μg/kg ), or tha…
Genome-wide scan for Runs of Homozygosity in Valle del Belice sheep
2017
The current availability of very large numbers of single nucleotide polymorphisms (SNPs) throughout the genome makes these markers particularly suitable for the detection of genomic regions where a reduction in heterozygosity occurred and offers new opportunities to improve the accuracy of inbreeding (F) estimates. Runs of homozygosity (ROH) are contiguous lengths of homozygous segments of the genome where the two haplotypes inherited from the parents are identical. Here, we investigated the occurrence and the distribution of ROH in medium-density SNP genotypes (~ 50 000) in order to characterize autozygosity in 512 individuals of Valle del Belice sheep and identify the regions of the genom…
A population genomics analysis of the native Irish Galway sheep breed.
2019
SUMMARYThe Galway sheep population is the only native Irish sheep breed and represents an important livestock genetic resource, which is currently categorised as “at-risk”. In the present study, comparative population genomics analyses of Galway sheep and other sheep populations of European origin were used to investigate the microevolution and recent genetic history of the breed. These analyses support the hypothesis that British Leicester sheep were used in the formation of the Galway breed and suggest more recent gene flow from the Suffolk sheep breed. When compared to conventional and endangered breeds, the Galway breed was intermediate in effective population size, genomic inbreeding a…
A Comparative Analysis of Copy Number Variation of the Sheep and Goat Genomes
2010
Recent studies have shown that copy number variants (CNVs) are important sources of variability of mammalian genomes. We applied a cross species array comparative genome hybridization (aCGH) experiment using as reference the cattle genome to investigate, for the first time, variability in the sheep and goat genomes derived from copy number variation and identified 431 and 358 CNVs, respectively. A comparison of these results to those obtained in other mammals for similar experiments is reported. The identified CNVs could be important in determining phenotypic and production differences between and within breeds. Further studies will be carried out to evaluate the identified CNVs from both f…
Relationship between beta lactoglobulin and subclinical mastitis in Valle del Belice sheep breed
2010
The objective of the following research was to determine the effect of LGB genotypes on subclinical mastitis in Valle del Belice dairy sheep. Ewes were classified as affected or not by subclinical mastitis within a lactation based on i) a positive culture in one of the test-days and ii) more than 750,000 somatic cells. Generalized linear mixed models were fitted to assess the significance of LGB genotypes on MTB and MTC. The LGB genotypes significantly affected MTB (p=0.0387), and showed a tendency on MTC (p=0.1104). Least square means showed that in the analysis for MTB, individuals with genotypes BB and AB had a higher frequency of subclinical mastitis. Moreover, the least square differen…
Effects of ewes grazing sulla or ryegrass pasture for different daily durations on forage intake, milk production and fatty acid composition of cheese
2016
Sulla (Sulla coronarium L.) forage is valued for its positive impact on ruminant production, in part due to its moderate content of condensed tannin (CT). The duration of daily grazing is a factor affecting the feed intake and milk production of ewes. In this study, the effects of grazing sulla pasture compared with annual ryegrass, and the extension of grazing from 8 to 22 h/day, were evaluated with regard to ewe forage intake and milk production, as well as the physicochemical properties and fatty acid (FA) composition of cheese. During 42 days in the spring, 28 ewes of the Comisana breed were divided into four groups (S8, S22, R8 and R22) that grazed sulla (S) or ryegrass (R) for 8 (0800…
Detection of genomic regions underlying milk production traits in Valle del Belice dairy sheep using regional heritability mapping
2021
The aim of this study was to identify genomic regions underlying milk production traits in the Valle del Belice dairy sheep using regional heritability mapping (RHM). Repeated measurements for milk yield (MY), fat percentage and yield (F% and FY) and protein percentage and yield (P% and PY), collected over a period of six years (2006-2012) on 481 Valle del Belice ewes, were used for the analysis. Animals were genotyped with the Illumina 50k SNP chip. Variance components, heritabilities, and repeatability within and across lactations were estimated, fitting parity, litter size, season of lambing, and fortnights in milk, as fixed; and additive genetic, permanent environment within and across …