Breeding Research Papers - Academia.edu (original) (raw)
Given current extinction trends, the number of species requiring conservation breeding programs (CBPs) is likely to increase dramatically. To inform CBP policies for threatened terrestrial vertebrates, we evaluated the number and... more
Given current extinction trends, the number of species requiring conservation breeding programs (CBPs) is likely to increase dramatically. To inform CBP policies for threatened terrestrial vertebrates, we evaluated the number and representation of threatened vertebrate species on the IUCN Red List held in the ISIS zoo network and estimated the complexity of their management as metapopulations. Our results show that 695 of the 3,955 (23%) terrestrial vertebrate species in ISIS zoos are threatened. Only two of the 59 taxonomic orders show a higher proportion of threatened species in ISIS zoos than would be expected if species were selected at random. In addition, for most taxa, the management of a zoo metapopulation of more than 250 individuals will require the coordination of a cluster of 11 to 24 ISIS zoos within a radius of 2,000 km. Thus, in the zoo network, the representation of species that may require CBPs is currently low and the spatial distribution of these zoo populations makes management difficult. Although the zoo community may have the will and the logistical potential to contribute to conservation actions, including CBPs, to do so will require greater collaboration between zoos and other institutions, alongside the development of international agreements that facilitate cross-border movement of zoo animals. To maximize the effectiveness of integrated conservation actions that include CBPs, it is fundamental that the non-zoo conservation community acknowledges and integrates the expertise and facilities of zoos where it can be helpful.
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- Biology, Breeding, Endangered Species, Medicine
Estimados colegas, éste es el primer número de Noticias de Reproducción Bovina, publicación que tiene como propósito ofrecer información para los Médicos Veterinarios Zootecnistas que están trabajando en el manejo reproductivo de hatos... more
Estimados colegas, éste es el primer número de Noticias de Reproducción Bovina, publicación que tiene como propósito ofrecer información para los Médicos Veterinarios Zootecnistas que están trabajando en el manejo reproductivo de hatos bovinos tanto lecheros como de carne. La información contenida proviene de publicaciones científicas periódicas de alto nivel y también de artículos de difusión técnica escritos por especialistas. Aquí podrán encontrar los resúmenes y la referencia para la consulta del artículo completo. La selección de la información está a cargo de los editores y se hace de acuerdo con el criterio de la utilidad práctica de la misma. El objetivo al iniciar con el primer número es ofrecer una publicación bimestral, la cual llegará en forma electrónica a los colegas inscritos en nuestras bases de datos y a todos aquellos que nos escriban solicitándola. Esta es una publicación sin fin de lucro y su único objetivo es ofrecer información actualizada para mejorar el desempeño de los Veterinarios y con ello contribuir al aumento de la productividad de los hatos bovinos de nuestro país.
The genetic structure of sheep reflects their domestication and subsequent formation into discrete breeds. Understanding genetic structure is essential for achieving genetic improvement through genome-wide association studies, genomic... more
The genetic structure of sheep reflects their domestication and subsequent formation into discrete breeds. Understanding genetic structure is essential for achieving genetic improvement through genome-wide association studies, genomic selection and the dissection of quantitative traits. After identifying the first genome-wide set of SNP for sheep, we report on levels of genetic variability both within and between a diverse sample of ovine populations. Then, using cluster analysis and the partitioning of genetic variation, we demonstrate sheep are characterised by weak phylogeographic structure, overlapping genetic similarity and generally low differentiation which is consistent with their short evolutionary history. The degree of population substructure was, however, sufficient to cluster individuals based on geographic origin and known breed history. Specifically, African and Asian populations clustered separately from breeds of European origin sampled from Australia, New Zealand, Europe and North America. Furthermore, we demonstrate the presence of stratification within some, but not all, ovine breeds. The results emphasize that careful documentation of genetic structure will be an essential prerequisite when mapping the genetic basis of complex traits. Furthermore, the identification of a subset of SNP able to assign individuals into broad groupings demonstrates even a small panel of markers may be suitable for applications such as traceability.
Italy counts several sheep breeds, arisen over centuries as a consequence of ancient and recent genetic and demographic events. To finely reconstruct genetic structure and relationships between Italian sheep, 496 subjects from 19 breeds... more
Italy counts several sheep breeds, arisen over centuries as a consequence of ancient and recent genetic and demographic events. To finely reconstruct genetic structure and relationships between Italian sheep, 496 subjects from 19 breeds were typed at 50K single nucleotide polymorphism loci. A subset of foreign breeds from the Sheep HapMap dataset was also included in the analyses. Genetic distances (as visualized either in a network or in a multidimensional scaling analysis of identical by state distances) closely reflected geographic proximity between breeds, with a clear north-south gradient, likely because of high levels of past gene flow and admixture all along the peninsula. Sardinian breeds diverged more from other breeds, a probable consequence of the combined effect of ancient sporadic introgression of feral mouflon and long-lasting genetic isolation from continental sheep populations. The study allowed the detection of previously undocumented episodes of recent introgression (Delle Langhe into the endangered Altamurana breed) as well as signatures of known, or claimed, historical introgression (Merino into Sopravissana and Gentile di Puglia; Bergamasca into Fabrianese, Appenninica and, to a lesser extent, Leccese). Arguments that would question, from a genomic point of view, the current breed classification of Bergamasca and Biellese into two separate breeds are presented. Finally, a role for traditional transhumance practices in shaping the genetic makeup of Alpine sheep breeds is proposed. The study represents the first exhaustive analysis of Italian sheep diversity in an European context, and it bridges the gap in the previous HapMap panel between Western Mediterranean and Swiss breeds.
- by P. Crepaldi and +4
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- Genetics, Zoology, Phylogeography, Breeding
Background: Identification of genomic regions that have been targets of selection for phenotypic traits is one of the most important and challenging areas of research in animal genetics. However, currently there are relatively few genomic... more
Background: Identification of genomic regions that have been targets of selection for phenotypic traits is one of the most important and challenging areas of research in animal genetics. However, currently there are relatively few genomic regions identified that have been subject to positive selection. In this study, a genome-wide scan using~50,000 Single Nucleotide Polymorphisms (SNPs) was performed in an attempt to identify genomic regions associated with fat deposition in fat-tail breeds. This trait and its modification are very important in those countries grazing these breeds. Results: Two independent experiments using either Iranian or Ovine HapMap genotyping data contrasted thin and fat tail breeds. Population differentiation using F ST in Iranian thin and fat tail breeds revealed seven genomic regions. Almost all of these regions overlapped with QTLs that had previously been identified as affecting fat and carcass yield traits in beef and dairy cattle. Study of selection sweep signatures using F ST in thin and fat tail breeds sampled from the Ovine HapMap project confirmed three of these regions located on Chromosomes 5, 7 and X. We found increased homozygosity in these regions in favour of fat tail breeds on chromosome 5 and X and in favour of thin tail breeds on chromosome 7.
- by John C McEwan
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- Genetics, Breeding, Adipose tissue, Tail
SUMMARY The duration of electrocardiograph wave forms and intervals were determined in 179 Spanish-bred (Andalusian) horses aged from 1 month to 17 years. The values were compared with those of other breeds, and the relationship between... more
SUMMARY The duration of electrocardiograph wave forms and intervals were determined in 179 Spanish-bred (Andalusian) horses aged from 1 month to 17 years. The values were compared with those of other breeds, and the relationship between electrocardiographic data and age was examined. High correlation coefficients were found between PR, ST and QT intervals and the age of the horses, and an inverted relation between heart rate and age was found. A multiple range analysis was made and the results suggest that significant changes in duration values and heart rate ocurred at the age of 6 months and in the second year of life.
A commercial dog breeding unit experienced problems with acute diarrhoea, often haemorrhagic, in young German Shepherd Dog litters. No aetiologic diagnosis had been made. In order to determine whether coccidial infections were implicated,... more
A commercial dog breeding unit experienced problems with acute diarrhoea, often haemorrhagic, in young German Shepherd Dog litters. No aetiologic diagnosis had been made. In order to determine whether coccidial infections were implicated, a survey was conducted to ascertain shedding of oocysts by dams, acquisition of coccidial infection by neonatal pups and to determine whether bouts of diarrhoea were associated with peak oocyst production. Oocysts of Isospora canis and I. burrowsi/I. ohioenis were recovered from 26.0% of faecal specimens from bitches and from 51.7% of similar specimens from litters. No association between shedding of oocysts by bitches and their litters could be demonstrated, nor was there consistent association between bouts of diarrhoea and peaks of oocyst shedding.
- by Banie Penzhorn
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- Breeding, Diarrhea, Dogs, Coccidiosis
Horse is a seasonal breeder and information on oocyte quality outside the breeding season is very limited. Ovaries obtained at the slaughterhouse are a convenient but often limited source of oocytes in this species. As the low quantity of... more
Horse is a seasonal breeder and information on oocyte quality outside the breeding season is very limited. Ovaries obtained at the slaughterhouse are a convenient but often limited source of oocytes in this species. As the low quantity of ovaries leads to an intensive use of all available material, it would be useful to know whether ovaries collected during the non-breeding season are suitable for in vitro maturation (IVM). In an attempt to characterize the effect of season on oocyte quality, we investigated the permeability of the gap junctions (GJ) present between cumulus cells and oocytes because of their important role in oocyte growth and maturation. We also compared the effect of supplementing the maturation medium with bovine serum albumin (BSA) or oestrus mare serum (EMS). A total of 645 oocytes isolated from 158 and 154 ovaries collected during the breeding and the non-breeding season, respectively, were used in this study. Oocytes were matured for 30 h in TCM 199 supplemented either with 10% EMS or with 4 mg/ml BSA. The presence of permeable GJs between cumulus cells and oocytes was investigated with the injection of a 3% solution of the fluorescent dye Lucifer yellow into the ooplasm. No differences in efficiency of oocyte retrieval or oocyte meiotic competence were detected between oocytes collected during the breeding and non-breeding season. The vast majority (90%) of the oocytes collected during the breeding season had fully functional communications with their surrounding cumulus cells but such communications were completely interrupted in 55.3% of the oocytes collected during the nonbreeding season. During the non-breeding season, the proportion of oocytes whose communications with cumulus cells were classified as closed or intermediate at the end of maturation was lower in the group matured with BSA than with EMS (71.4 vs 97.7, p < 0.05). The same trend, although not statistically significant, was observed during the breeding season also. The presence of BSA caused an incomplete cumulus expansion during both seasons. Our data indicate that oocytes collected during the non-breeding season do not show any meiotic deficiency but lack active communication with the surrounding cumulus cells at the time of their isolation from the ovary. No data are available at present for determining the consequences on the developmental competence even if data from other species suggest that this is likely.
Genomic selection estimates genetic merit based on dense SNP (single nucleotide polymorphism) genotypes and phenotypes. This requires that SNPs explain a large fraction of the genetic variance. The objectives of this work were: (1) to... more
Genomic selection estimates genetic merit based on dense SNP (single nucleotide polymorphism) genotypes and phenotypes. This requires that SNPs explain a large fraction of the genetic variance. The objectives of this work were: (1) to estimate the fraction of genetic variance explained by dense genome-wide markers using 54 K SNP chip genotyping, and (2) to evaluate the effect of alternative marker-based relationship matrices and corrections for the base population on the fraction of the genetic variance explained by markers. Two alternative marker-based relationship matrices were estimated using 35 706 SNPs on 1086 dairy bulls. Both pedigree- and marker-based relationship matrices were fitted simultaneously or separately in an animal model to estimate the fraction of variance not explained by the markers, i.e. the fraction explained by the pedigree. The phenotypes considered in the analysis were the deregressed estimated breeding values (dEBV) for milk, fat and protein yield and for...
- by Sergio Roman
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- Genetics, Technology, Genomics, Biology
- by Maria Cozzi and +1
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- Breeding, Italy, Germany, Dogs
The Green-legged Partridgelike (GP) fowl, an old native Polish breed, is characterised by reseda green-coloured shanks rather than yellow, white, slate or black commonly observed across most domestic breeds of chicken. Here, we... more
The Green-legged Partridgelike (GP) fowl, an old native Polish breed, is characterised by reseda green-coloured shanks rather than yellow, white, slate or black commonly observed across most domestic breeds of chicken. Here, we investigate the origin, genetic relationships and structure of the GP fowl using mtDNA D-loop sequencing and genomewide SNP analysis. Genome-wide association analysis between breeds enables us to verify the genetic control of the reseda green shank phenotype, a defining trait for the breed. Two mtDNA D-loop haplogroups and three autosomal genetic backgrounds are revealed. Significant associations of SNPs on chromosomes GGA24 and GGAZ indicate that the reseda green leg phenotype is associated with recessive alleles linked to the W and Id loci. Our results provide new insights into the genetic history of European chicken, indicating an admixd origin of East European traditional breeds of chicken on the continent, as supported by the presence of the reseda green phenotype and the knowledge that the GP fowl as a breed was developed before the advent of commercial stocks.
- by M. Siwek and +1
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- Genetics, Zoology, Breeding, Mitochondrial DNA
A case of juvenile nephropathy In a two-year-oid Weimaraner bitch Is reported. Although juvenile nephropathy has been described in several breeds of dogs, this is the flrst report In a Weimaraner. Clinical aspects, blood analysis, renal... more
A case of juvenile nephropathy In a two-year-oid Weimaraner bitch Is reported. Although juvenile nephropathy has been described in several breeds of dogs, this is the flrst report In a Weimaraner. Clinical aspects, blood analysis, renal pathology and extrarenai changes are described. The renal changes consisted of tubular as well as glomeruiar lesions, similar to those described in the miniature schnauzer. The main extrarenai lesion was degeneration and necrosis of subendocardial myocytes in the left atrial wail associated with an inflammatory reaction and focal necrotlsing arteritis.
Most wild and semi-wild species of the genus Gossypium are exhibit photoperiod-sensitive flowering. The wild germplasm cotton is a valuable source of genes for genetic improvement of modern cotton cultivars. A bi-parental cotton... more
Most wild and semi-wild species of the genus Gossypium are exhibit photoperiod-sensitive flowering. The wild germplasm cotton is a valuable source of genes for genetic improvement of modern cotton cultivars. A bi-parental cotton population segregating for photoperiodic flowering was developed by crossing a photoperiod insensitive irradiation mutant line with its pre-mutagenesis photoperiodic wild-type G. darwinii Watt genotype. Individuals from the F2 and F3 generations were grown with their parental lines and F1 hybrid progeny in the long day and short night summer condition (natural day-length) of Uzbekistan to evaluate photoperiod sensitivity, i.e., flowering-time during the seasons 2008-2009. Through genotyping the individuals of this bi-parental population segregating for flowering-time, linkage maps were constructed using 212 simple-sequence repeat (SSR) and three cleaved amplified polymorphic sequence (CAPS) markers. Six QTLs directly associated with flowering-time and photop...
A joint evaluation of all animals, uses all additive genetic relationships uses all data on all animal jointly It works as a linear model (correcting different effects for each other), jointly estimates animal effects and fixed effects... more
A joint evaluation of all animals, uses all additive genetic relationships uses all data on all animal jointly It works as a linear model (correcting different effects for each other), jointly estimates animal effects and fixed effects (herds) but has Selection Index properties (Regression with " heritability ") 1 0 0 0 1 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1
We have analysed the genetic information to be obtained from analysis of mitochondrial DNA (mtDNA) in domestic dogs studying the exclusion capacity in different populations and the correlation between mtDNA types and breeds or types of... more
We have analysed the genetic information to be obtained from analysis of mitochondrial DNA (mtDNA) in domestic dogs studying the exclusion capacity in different populations and the correlation between mtDNA types and breeds or types of dogs. The exclusion capacities for a 573 bp sequence of the mitochondrial control region was between 0.86 and 0.95 for dogs in Sweden, the UK, Germany, Japan and China. The direct correlation between mtDNA type and breed, type of dog, and geographical origin of breed was generally low, but in some cases certain mtDNA types were overrepresented in one breed, and for wider groupings such as morphologically similar breeds, some mtDNA types were in many cases found in a distinct group of breeds, often originating from the same geographic region. This type of information may be used as an indication of the breed and, with some degree of probability, to include or exclude certain breeds from being the source of evidence materials.
Genetic (co)variances between body condition score (BCS), body weight (BW), milk production, and fertilityrelated traits were estimated. The data analyzed included 8591 multiparous Holstein-Friesian cows with records for BCS, BW, milk... more
Genetic (co)variances between body condition score (BCS), body weight (BW), milk production, and fertilityrelated traits were estimated. The data analyzed included 8591 multiparous Holstein-Friesian cows with records for BCS, BW, milk production, and/or fertility from 78 seasonal calving grass-based farms throughout southern Ireland. Of the cows included in the analysis, 4402 had repeated records across the 2 yr of the study. Genetic correlations between level of BCS at different stages of lactation and total lactation milk production were negative (−0.51 to −0.14). Genetic correlations between BW at different stages of lactation and total lactation milk production were all close to zero but became positive (0.01 to 0.39) after adjusting BW for differences in BCS. Body condition score at different stages of lactation correlated favorably with improved fertility; genetic correlations between BCS and pregnant 63 d after the start of breeding season ranged from 0.29 to 0.42. Both BW at different stages of lactation and milk production tended to exhibit negative genetic correlations with pregnant to first service and pregnant 63 d after the start of the breeding season and positive genetic correlations with number of services and the interval from first service to conception. Selection indexes investigated illustrate the possibility of continued selection for increased milk production without any deleterious effects on fertility or average BCS, albeit, genetic merit for milk production would increase at a slower rate. (Key words: body weight, body condition score, fertility, selection index)
P á g i n a 4 5 L a C h i r i c o c a Siguiendo la reproducción del Aguilucho de cola rojiza (Buteo ventralis): Reseña de un estudio por Heraldo V. Norambuena y Victor Raimilla Aguilucho de cola rojiza (Buteo ventralis), hembra, 04... more
P á g i n a 4 5 L a C h i r i c o c a Siguiendo la reproducción del Aguilucho de cola rojiza (Buteo ventralis): Reseña de un estudio por Heraldo V. Norambuena y Victor Raimilla Aguilucho de cola rojiza (Buteo ventralis), hembra, 04 octubre 2008, foto Heraldo Norambuena. N°1 5 , D i c i e m b r e 2 0 1 2 L a C h i r i c o c a P á g i n a 4 6 N°1 5 , D i c i e m b r e 2 0 1 2
in the modification of agronomic performance. Data will be provided from a range of sources including details of Transgenic crops are now grown commercially on sevapplications for the field testing of experimental material, eral million... more
in the modification of agronomic performance. Data will be provided from a range of sources including details of Transgenic crops are now grown commercially on sevapplications for the field testing of experimental material, eral million hectares, principally in North America. To and from recent patent applications which make claims date, the predominant crops are maize (corn), soybean, to novel approaches to this problem. cotton, and potatoes. In addition, there have been field Throughout this review emphasis will be given to recent trials of transgenics from at least 52 species including publications, which should be consulted if additional all the major field crops, vegetables, and several herbinformation is required. aceous and woody species. This review summarizes recent data relating to such trials, particularly in terms of the trends away from simple, single gene traits Present status of transgenic crops such as herbicide and insect resistance towards more complex agronomic traits such as growth rate and The first transgenic plant product marketed commercially increased photosynthetic efficiency. Much of the was the well-known 'Flavr Savr' tomato which had been recent information is derived from inspection of patent modified to contain reduced levels of the cell wall databases, a useful source of information on commersoftening enzyme polygalacturonase. Tomato purée with cial priorities. The review also discusses the time scale a similar type of modification has been on the market in for the introduction of these transgenes into breedthe UK since February 1996. Since that time, however, ing populations and their eventual release as new there has been a massive expansion in the growth of varieties. transgenic field crops, particularly maize, soybean, oilseed rape, and cotton, such that in North America transgenic Key words: Genetic modification, field trials, photosynvarieties now represent the majority of the acreage of thesis, chlorophyll, stress responses. these crops. For example, it is now estimated that 70% of the Canadian oilseed rape crop in 1999 will be genetically modified. Most of the varieties grown to date have I would like to thank the Biotechnology and Biological Sciences Research Council (BBSRC) and ZENECA plc for financial support and other assistance during the preparation of this Public perception and acceptance review. Recent attention in the media and elsewhere has shown that many sections of the general public in the UK are uneasy about the safety of genetically modified crops and References food derived from such crops (see above) (Dunwell, 1998b). This issue is forcing a political reappraisal of the
Within-breed artificial insemination and between-breed embryo transfer were carried out in small pony (P) and large Thoroughbred (Tb) mares to create 4 types of horse pregnancy in which the fetus experienced spatial and nutritional... more
Within-breed artificial insemination and between-breed embryo transfer were carried out in small pony (P) and large Thoroughbred (Tb) mares to create 4 types of horse pregnancy in which the fetus experienced spatial and nutritional deprivation (Tb-in-P; n=8), luxury (P-in-Tb; n=7) or normality (Tb-in-Tb; n=7 and P-in-P; n=7) in utero. Measurement of equine chorionic gonadotrophin (eCG), total conjugated oestrogens and progestagen concentrations in serial peripheral serum samples recovered from all the mares throughout gestation showed that the amount of eCG produced during the first half of gestation was dependent upon the breed of the mare rather than the breed of the fetus being carried. In contrast, the mean total amounts of oestrogens produced, as measured by area under the curve, were significantly greater (P=0.003) in the two types of pregnancy in which a Thoroughbred fetus was being carried (Tb-in-Tb and Tb-in-P) than those in which a pony fetus was gestated (P-in-P and P-in-...
The present investigation was carried out using 51 diverse bitter gourd accessions as material for studying genetic diversity and relatedness using morphological and SSR markers. A wide variation was observed for morphological traits like... more
The present investigation was carried out using 51 diverse bitter gourd accessions as material for studying genetic diversity and relatedness using morphological and SSR markers. A wide variation was observed for morphological traits like the number of days to the first female flower anthesis (37.33–60.67), the number of days to the first fruit harvest (47.67–72.00), the number of fruits/plant (12.00–46.67), fruit length (5.00–22.23 cm), fruit diameter (1.05–6.38 cm), average fruit weight (20.71–77.67 g) and yield per plant (513.3–1976 g). Cluster analysis for 10 quantitative traits grouped the 51 accessions into 6 clusters. Out of 61 SSR primers screened, 30 were polymorphic and highly informative as a means to differentiate these accessions. Based on genotyping, a high level of genetic diversity was observed, with a total of 99 alleles. The polymorphic information content (PIC) values ranged from 0.038 for marker BG_SSR-8 to 0.721 for S-24, with an average of 0.429. The numbers of...
1. Quantifying the pattern of temporal and spatial variation in demography, and identifying the factors that cause this variation, are essential steps towards understanding the structure and dynamics of any population. 2. One critical but... more
1. Quantifying the pattern of temporal and spatial variation in demography, and identifying the factors that cause this variation, are essential steps towards understanding the structure and dynamics of any population. 2. One critical but understudied demographic rate is pre-breeding survival. We used long-term colour-ringing data to quantify temporal (among-year) and spatial (among-nest site) variation in pre-breeding survival in red-billed choughs (Pyrrhocorax pyrrhocorax) inhabiting Islay, Scotland, and identified environmental correlates of this variation. 3. Random-effects capture-mark-recapture models demonstrated substantial temporal and spatial process variance in first-year survival; survival from fledging to age 1 year varied markedly among choughs fledged in different years and fledged from different nest sites. Spatial variance exceeded temporal variance across choughs fledged from well-studied nest sites. 4. The best-supported models of temporal variation suggested that first-year survival was higher in years following high tipulid larvae abundance and when weather conditions favoured increased invertebrate productivity and/or availability to foraging choughs. These variables explained up to 80% of estimated temporal process variance. 5. The best-supported models of spatial variation suggested that first-year survival was higher in choughs fledged from nest sites that were further from exposed coasts and closer to flocking areas, and surrounded by better habitat and higher chough density. These variables explained up to 40% of estimated spatial process variance. 6. Importantly, spatio-temporal models indicated interactive effects of weather, tipulid abundance, local habitat and local chough density on first-year survival, suggesting that detrimental effects of poor weather and low tipulid abundance may be reduced in choughs fledged from nest sites surrounded by better foraging habitat and lower chough density. 7. These analyses demonstrate substantial temporal and small-scale spatial variation in pre-breeding survival, a key demographic rate, and indicate that this variation may reflect interactive effects of weather, prey abundance, habitat and geography. These patterns illustrate the value of holistic models of demographic variation, and indicate environmental factors that may limit the growth rate of Islay's protected chough population.
A permanent mapping population of rice consisting of 65 non-idealized chromosome segment substitution lines (denoted as CSSL1 to CSSL65) and 82 donor parent chromosome segments (denoted as M1 to M82) was used to identify QTL with additive... more
A permanent mapping population of rice consisting of 65 non-idealized chromosome segment substitution lines (denoted as CSSL1 to CSSL65) and 82 donor parent chromosome segments (denoted as M1 to M82) was used to identify QTL with additive effects for two rice quality traits, area of chalky endosperm (ACE) and amylose content (AC), by a likelihood ratio test based on stepwise regression. Subsequently, the genetics and breeding simulation tool QuLine was employed to demonstrate the application of the identified QTL in rice quality improvement. When a LOD threshold of 2.0 was used, a total of 16 chromosome segments were associated with QTL for ACE, and a total of 15 segments with QTL for AC in at least one environment. Four target genotypes denoted as DG1 to DG4 were designed based on the identified QTL, and according to low ACE and high AC breeding objectives. Target genotypes DG1 and DG2 can be achieved via a topcross (TC) among the three lines CSSL4, CSSL28, and CSSL49. Results revealed that TC2: (CSSL4 × CSSL49) × CSSL28 and TC3: (CSSL28 × CSSL49) × CSSL4 resulted in higher DG1 frequency in their doubled haploid populations, whereas TC1: (CSSL4 × CSSL28) × CSSL49 resulted in the highest DG2 frequency. Target genotypes DG3 and DG4 can be developed by a double cross among the four lines CSSL4, CSSL28, CSSL49, and CSSL52. In a double cross, the order of parents affects the frequency of target genotype to be selected. Results suggested that the double cross between the two single crosses (CSSL4 × CSSL28) and (CSSL49 × CSSL52) resulted in the highest frequency for DG3 and DG4 genotypes in its derived doubled haploid derivatives. Using an enhancement selection methodology, alternative ways were investigated to increase the target genotype frequency without significantly increasing the total cost of breeding operations.
Artificial neural networks learn how to solve new problems through a computationally intense and time consuming process. One way to reduce the amount of time required is to inject preexisting knowledge into the network. To make use of... more
Artificial neural networks learn how to solve new problems through a computationally intense and time consuming process. One way to reduce the amount of time required is to inject preexisting knowledge into the network. To make use of past knowledge, we can take advantage of techniques that transfer the knowledge learned from one task, and reuse it on another (sometimes unrelated) task. In this paper we propose a novel selective breeding technique that extends the transfer learning with behavioural genetics approach proposed by Kohli, Magoulas and Thomas (2013), and evaluate its performance on financial data. Numerical evidence demonstrates the credibility of the new approach. We provide insights on the operation of transfer learning and highlight the benefits of using behavioural principles and selective breeding when tackling a set of diverse financial applications problems.
In this study, genetic analyses of diversity and differentiation were performed on five horse breeds raised in Algeria (Barb, Arab-Barb, Arabian, Thoroughbred and French Trotter). All microsatellite markers were highly polymorphic in all... more
In this study, genetic analyses of diversity and differentiation were performed on five horse breeds raised in Algeria (Barb, Arab-Barb, Arabian, Thoroughbred and French Trotter). All microsatellite markers were highly polymorphic in all the breeds. A total of 123 alleles from 14 microsatellite loci were detected in 201 horses. The average number of alleles per locus was the highest in the Arab-Barb horses (7.86) and lowest in the thoroughbred breed (5.71), whereas the observed and expected heterozygosities per breed ranged from 0.71 (Thoroughbred) to 0.752 (Barb) and 0.71 (Thoroughbred) to 0.77 (Arab-Barb), respectively. The genetic differentiation between the breeds was significant (p < 0.01) based on the infinitesimal model (FST ). Three different approaches for evaluating the genetic relationships were applied. Genetic distances, the factorial correspondence analysis and structure analysis showed that a significant amount of genetic variation is maintained in the native horse...
Objective-To describe a method for radiographic measurement of the mechanical joint angles of the tibia in the sagittal plane and report reference ranges for a population of dogs with cranial cruciate ligament disease, and specifically... more
Objective-To describe a method for radiographic measurement of the mechanical joint angles of the tibia in the sagittal plane and report reference ranges for a population of dogs with cranial cruciate ligament disease, and specifically for Labrador Retrievers. Study Design-Retrospective evaluation of radiographs. Animals-Canine tibia (n ¼ 150) of dogs evaluated for cranial cruciate ligament disease; 104 tibiae were from Labrador Retrievers, 46 tibiae were from other medium-to large-breed dogs. Methods-Medial-lateral radiographs were used to establish anatomic landmarks and measure the mechanical cranial distal tibial angle (mCrDTA) and mechanical caudal proximal tibial angle (mCaPTA). Results-For all tibiae mean mCrDTA was 81.61 and mCaPTA, 63.61. For Labrador Retriever tibiae mean mCrDTA was 81.71 and mCaPTA, 63.81. For non-Labradors, means mCrDTA was 81.51 and mCaPTA, 631. Labrador Retrievers were significantly younger than non-Labradors in our study population. No significant differences were noted between Labrador Retrievers and non-Labradors for mCrDTA or mCaPTA and correlations between mCrDTA and mCaPTA were neither strong nor significant. Conclusion-A method was established for radiographic measurement of mechanical joint angles of the canine tibia in the sagittal plane. Reference ranges are reported for a population of Labrador Retrievers and a population of non-Labradors with cranial cruciate ligament disease. Clinical Relevance-Measurement method and reference ranges provided for mechanical tibial angles may be used to aid in diagnosis, surgical planning, and postoperative critique for hindlimb angular deformities.
This study was undertaken to determine management and seasonal effects on fertility in 1298 Finnish sow units over a 4-year period in 1992-1996. A multivariate analysis of the herd record data was undertaken to study the effect of various... more
This study was undertaken to determine management and seasonal effects on fertility in 1298 Finnish sow units over a 4-year period in 1992-1996. A multivariate analysis of the herd record data was undertaken to study the effect of various management factors on rebreeding rate. Factors found to have an effect were further subjected to time series plotting for seasonal effects. In addition, seasonal effects on the farrowing rate, age of gilts at first mating and littersize as well as the 3-week litterweight were studied. Year and month caused the most significant variation in the Ž rebreeding rate. Moreover, geographical area, herd and way of breeding mating vs. artificial . insemination were found to be significant determinants of rebreeding rate. Dry sows loosely housed were more likely to be rebred than sows housed in individual stalls. Sows receiving Ž . Ž . roughage feed hay, straw or bedding straw were less likely to require rebreeding. A significant seasonal fluctuation in farrowing rate was found with a nadir of 72.6% in August and a high of 80.9% in January. The average farrowing rate for the 4-year period was 77.7%. The age of gilts at Ž first mating showed seasonal variation of 11 days 229.9 " 0.5 days in March and 241.4 " 0.5 . days in November . In conclusion, this study indicates that group housing of dry sows increases the risk of rebreeding. In group housed sows, rebreeding more often occurs after an irregular oestrus-to-oestrus interval in summer-autumn whereas a not-in-pig seems to be a more common ) Corresponding author.
In a survey of 900 Dalmatian dogs, brainstem auditory-evoked responses (BAER) and clinical observations were used to determine the incidence and sex distribution of bilateral and unilateral BAER abnormalities and their association with... more
In a survey of 900 Dalmatian dogs, brainstem auditory-evoked responses (BAER) and clinical observations were used to determine the incidence and sex distribution of bilateral and unilateral BAER abnormalities and their association with heterochromia iridis (HI). To assess the efficacy of BAER testing in guiding breeding programs, data from 749 dogs (subgroup A), considered to be a sample of the population at large, were compared with data from a subgroup (subgroup B; n=151) in which selection of breeding stock had been based on BAER testing from the beginning of the 4-year survey. Brainstem auditory-evoked responses were elicited by applying click stimuli unilaterally, while applying a white noise masking sound to the contralateral ear. Under these conditions, BAER were either normal, unilaterally absent, or bilaterally absent. Dogs with bilaterally absent BAER were clinically deaf; dogs with unilaterally absent BAER were not clinically deaf but appeared dependent on their BAER-normal ears for their auditory-cued behavior. Dogs with unilaterally absent BAER often were misidentified as normal by uninformed observers. Among the 900 dogs, 648 (72.0%) were normal, 189 (21.0%) had unilateral absence of BAER, and 63 (7.0%) had bilateral absence of BAER or were clinically deaf and assumed to have bilaterally absent BAER (n=4). Total incidence in the population sampled was assumed to be higher, because some bilaterally affected dogs that would have been members of subgroup A undoubtedly did not come to our attention. Among females, 24.0% were unilaterally abnormal and 8.2% were bilaterally abnormal whereas, among males, 17.8% were unilaterally abnormal and 5.7% were bilaterally abnormal. These differences were significant (P=0.014). Dogs with grossly visible HI (any degree) had a significantly higher incidence of abnormality than dogs with completely pigmented iridial stromas (P=0.0001). Females had a significantly higher incidence of HI than did males (P=0.038). Subgroup B had a significantly lower incidence of BAER abnormality than did subgroup A (P=0.027); the difference was not attributable to subgroup differences associated with gender or HI status. (Journal of Veterinary Internal Medicine 1992; 6:166–174)
We have mapped the quantitative trait loci (QTLs) conferring resistance to sorghum downy mildew (Peronosclerospora sorghi; SDM) and Rajasthan downy mildew (P. heteropogoni; RDM), two species of DM prevalent throughout India. QTL mapping... more
We have mapped the quantitative trait loci (QTLs) conferring resistance to sorghum downy mildew (Peronosclerospora sorghi; SDM) and Rajasthan downy mildew (P. heteropogoni; RDM), two species of DM prevalent throughout India. QTL mapping was carried out on a backcross population of 151 individuals derived from a cross between CM139 (susceptible parent) and NAI116 (highly resistant to both SDM and RDM). Heritability estimates were 0.74 for SDM and 0.67 for RDM. Composite interval mapping combined with a linkage map constructed with 80 simple sequence repeat (SSR) markers resulted in the identification of three QTLs (one each on chromosomes 2, 3 and 6) for SDM resistance and two QTLs (one each on chromosomes 3 and 6) for RDM resistance, all of which were contributed by NAI116. The significance of the major QTL on chromosome 6 (bin 6.05) that confers resistance to diverse DMs in tropical Asia, including SDM and RDM in India, was also verified. The results confirmed that some common QTLs contribute to both SDM and RDM resistance, while additional loci might specifically govern resistance to SDM. The QTL information generated in this study provide information that will aid in undertaking an integrated breeding strategy for the transfer of resistance to SDM and RDM in maize lines using marker-assisted selection.
Plasma NT-proBNP has previously been evaluated in dogs with degenerative mitral valve disease (DMVD). However, reference intervals (RI) established according to the Clinical Laboratory and Standards Institute (CLSI) recommendations have... more
Plasma NT-proBNP has previously been evaluated in dogs with degenerative mitral valve disease (DMVD). However, reference intervals (RI) established according to the Clinical Laboratory and Standards Institute (CLSI) recommendations have never been provided. The objectives of this prospective study were to assess effects of breed, body weight, age, and sex on plasma NT-proBNP, and to establish RI according to CLSI for this biomarker in a large population of dogs predisposed to DMVD.
Canine hypoadrenocorticism is believed to be an immune-related condition. It is rare in the overall dog population but shows a breed-related predisposition with Standard poodles and Portuguese water dogs having a greater prevalence of the... more
Canine hypoadrenocorticism is believed to be an immune-related condition. It is rare in the overall dog population but shows a breed-related predisposition with Standard poodles and Portuguese water dogs having a greater prevalence of the condition. It shares many similarities with human primary adrenal insufficiency and is believed to be a naturally occurring, spontaneous model for the human condition. Short haplotype blocks and low levels of linkage disequilibrium in the human genome mean that the identification of genetic contributors to the condition requires large sample numbers. Pedigree dogs have high linkage disequilibrium and long haplotypes within a breed, increasing the potential of identifying novel genes that contribute to canine genetic disease. We investigated 222 SNPs from 42 genes that have been associated or may be implicated in human Addison's disease. We conducted case-control analyses in 3 pedigree dog breeds (Labrador retriever: affected n = 30, unaffected ...
- by Lorna Kennedy and +1
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- Genetics, Breeding, Heredity, Dogs
Evaluating the impact of plant domestication on the population structure of the associated pathogens provides an opportunity to increase our understanding of how and why diseases emerge. Here, we investigated the evolution of the... more
Evaluating the impact of plant domestication on the population structure of the associated pathogens provides an opportunity to increase our understanding of how and why diseases emerge. Here, we investigated the evolution of the population structure of the apple scab fungus Venturia inaequalis in response to the domestication of its host. Inferences were drawn from multilocus microsatellite data obtained from samples collected on (i) the Central Asian Malus sieversii, the main progenitor of apple, (ii) the European crabapple, Malus sylvestris, a secondary progenitor of apple, and (iii) the cultivated apple, Malus · domestica, in orchards from Europe and Central Asia. Using clustering methods, we identified three distinct populations: (i) a large European population on domesticated and wild apples, (ii) a large Central Asian population on domesticated and wild apples in urban and agricultural areas, and (iii) a more geographically restricted population in M. sieversii forests growing in the eastern mountains of Kazakhstan. Unique allele richness and divergence time estimates supported a host-tracking co-evolutionary scenario in which this latter population represents a relict of the ancestral populations from which current populations found in human-managed habitats were derived. Our analyses indicated that the domestication of apple induced a significant change in the genetic differentiation of populations of V. inaequalis in its centre of origin, but had little impact on its population dynamics and mating system. We discuss how the structure of the apple-based agrosystem may have restricted changes in the population structure of the fungus in response to the domestication of its host.
Selective breeding for disease resistance utilises proven animal breeding methods to improve animal health, welfare and productivity. Unsurprisingly, it is receiving more and more attention from livestock breeders. However, there are a... more
Selective breeding for disease resistance utilises proven animal breeding methods to improve animal health, welfare and productivity. Unsurprisingly, it is receiving more and more attention from livestock breeders. However, there are a number of largely theoretical arguments that have been raised as potential problems in selection for disease resistance. These can be classified under sustainability, feasibility and desirability. This review considers each of these areas in turn. Several examples show that enhanced resistance to disease is stable under natural selection and therefore deliberate selection for disease resistance should also be stable and sustainable. The feasibility of selective breeding depends in part upon the heritability of the trait or traits used to measure disease resistance, as well as the amount of variation among animals. The heritability of traits associated with resistance to many important diseases is often high and considerable variation among animals exi...
- by Michael Stear and +1
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- Breeding, Innate immunity, Animal Production, Veterinary
Plant-based foods offer an array of nutrients that are essential for human nutrition and promote good health. However, the major staple crops of the world are often deficient in some of these nutrients. Traditional agricultural approaches... more
Plant-based foods offer an array of nutrients that are essential for human nutrition and promote good health. However, the major staple crops of the world are often deficient in some of these nutrients. Traditional agricultural approaches can marginally enhance the nutritional value of some foods, but the advances in molecular biology are rapidly being exploited to engineer crops with enhanced key nutrients. Nutritional targets include elevated mineral content, improved fatty acid composition, increased amino acid levels, and heightened antioxidant levels. Unfortunately, in many cases the benefits of these "biofortified" crops to human nutrition have not been demonstrated. 401 Annu. Rev. Nutr. 2009.29:401-421. Downloaded from arjournals.annualreviews.org by Old Dominion University on 02/18/10. For personal use only.
First we remind general considerations concerning biodiversity on earth and particularly the loss of genetic biodiversity that seems irreversible whether its origin is directly or indirectly linked to human activities. Urgent and... more
First we remind general considerations concerning biodiversity on earth and particularly the loss of genetic biodiversity that seems irreversible whether its origin is directly or indirectly linked to human activities. Urgent and considerable efforts must be made from now on to cataloge, understand, preserve, and enhance the value of biodiversity while ensuring food safety and human and animal health. Ambitious integrated and multifield research programs must be implemented in order to understand the causes and anticipate the consequences of loss of biodiversity. Such losses are a serious threat to sustainable development and to the quality of life of future generations. They have an influence on the natural balance of global biodiversity in particularly in reducing the capability of species to adapt rapidly by genetic mutations to survive in modified ecosystems. Usually, the natural immune systems of mammals (both human and animal), are highly polymorphic and able to adapt rapidly to new situations. We more specifically discuss the fact that if the genetic diversity of the affected populations is low the invading microorganisms, will suddenly expand and create epidemic outbreaks with risks of pandemic. So biodiversity appears to function as an important barrier (buffer), especially against disease-causing organisms, which can function in different ways. Finally, we discuss the importance of preserving biodiversity mainly in the wildlife ecosystems as an integrated and sustainable approach among others in order to prevent and control the emergence or reemergence of diseases in animals and humans (zoonosis). Although plants are also part of this paradigm, they fall outside our field of study.
A u g u s t 2 0 0 7 Large-scale agriculture would become more sustainable if major crop plants lived for years and built deep root systems MODERN FOOD CROPS depend heavily on irrigation and other human inputs while depleting the land and... more
A u g u s t 2 0 0 7 Large-scale agriculture would become more sustainable if major crop plants lived for years and built deep root systems MODERN FOOD CROPS depend heavily on irrigation and other human inputs while depleting the land and polluting surrounding environments. Development of perennial versions, such as the experimental hybrid of intermediate wheatgrass and triticale shown on the opposite page, could reduce those burdens.
- by John Reganold
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- Soil, Breeding, Agriculture, Plant Roots
We developed two mutant populations of oilseed rape (Brassica napus L.) using EMS (ethylmethanesulfonate) as a mutagen. The populations were derived from the spring type line YN01-429 and the winter type cultivar Express 617 encompassing... more
We developed two mutant populations of oilseed rape (Brassica napus L.) using EMS (ethylmethanesulfonate) as a mutagen. The populations were derived from the spring type line YN01-429 and the winter type cultivar Express 617 encompassing 5,361 and 3,488 M 2 plants, respectively. A high-throughput screening protocol was established based on a two-dimensional 89 pooling strategy. Genes of the sinapine biosynthesis pathway were chosen for determining the mutation frequencies and for creating novel genetic variation for rapeseed breeding. The extraction meal of oilseed rape is a rich protein source containing about 40% protein. Its use as an animal feed or human food, however, is limited by antinutritive compounds like sinapine. The targeting induced local lesions in genomes (TILLING) strategy was applied to identify mutations of major genes of the sinapine biosynthesis pathway. We constructed locus-specific primers for several TILLING amplicons of two sinapine synthesis genes, BnaX.SGT and BnaX.REF1, covering 80-90% of the coding sequences. Screening of both populations revealed 229 and 341 mutations within the BnaX.SGT sequences (135 missense and 13 nonsense mutations) and the BnaX.REF1 sequences (162 missense, 3 nonsense, 8 splice site mutations), respectively. These mutants provide a new resource for breeding low-sinapine oilseed rape. The frequencies of missense and nonsense mutations corresponded to the frequencies of the target codons. Mutation frequencies ranged from 1/12 to 1/22 kb for the Express 617 population and from 1/27 to 1/60 kb for the YN01-429 population. Our TILLING resource is publicly available. Due to the high mutation frequencies in combination with an 89 pooling strategy, mutants can be routinely identified in a cost-efficient manner. However, primers have to be carefully designed to amplify single sequences from the polyploid rapeseed genome. Communicated by R. Visser. Hans-Joachim Harloff and Susanne Lemcke have equally contributed. Electronic supplementary material The online version of this article (
Congenital portosystemic shunts were definitively diagnosed in 62 dogs over a period of 15 years. Maltese and Australian Cattle Dogs were significantly overrepresented, accounting for 14 and 13 cases, respectively. Maltese invariably had... more
Congenital portosystemic shunts were definitively diagnosed in 62 dogs over a period of 15 years. Maltese and Australian Cattle Dogs were significantly overrepresented, accounting for 14 and 13 cases, respectively. Maltese invariably had a single extrahepatic shunt derived from the left gastric or gastrosplenic vein, whereas Cattle Dogs usually had large intrahepatic shunts involving the right liver lobes. The clinical syndromes resulting from anomalous portosystemic communications were indistinguishable in the 2 breeds. Fasting blood ammonia concentration was elevated in 20 of 22 dogs tested, providing a minimally invasive and effective means of diagnosis. Complete or partial shunt attenuation was performed successfully in all 9 Maltese and in 2 of 6 Cattle Dogs in which it was attempted. Aust Vet j 71:174 -178
- by Richard Malik
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- Breeding, Treatment Outcome, Dogs, Kidney
Data on breeding soundness and libido evaluations in Belgian Blue (BB) bulls are scarce. The present study compared results of breeding soundness and libido evaluations of young BB bulls to young Holstein Friesian (HF) bulls prior to... more
Data on breeding soundness and libido evaluations in Belgian Blue (BB) bulls are scarce. The present study compared results of breeding soundness and libido evaluations of young BB bulls to young Holstein Friesian (HF) bulls prior to acceptance into an AI program. Breed differences for breeding soundness exist between BB and HF bulls, as 93.7% of the young BB bulls failed the breeding soundness examination (BSE) compared to 59.3% of the HF bulls (P = 0.0005). Within the BB breed, differences were present between bulls of different ages, and bull selection for better fertility with increasing age apparently influenced the results. The number of reasons for which bulls failed the test differed between the age groups in the BB breed, whereas a tendency for more failure reasons in the BB breed was noticed in the breed comparison. The most important reasons for failure were sperm morphology and scrotal circumference (SC), but far more BB bulls failed for these traits compared to the HF breed (82.8% versus 56.0% and 43.8% versus 17.6% in the BB and the HF breed for sperm morphology (P = 0.0005) and SC (P < 0.0001), respectively). The high proportion of BB bulls with a substandard SC and poor sperm morphology might suggest an increased prevalence of testicular hypoplasia or degeneration within this breed. Concerning libido, the reaction time did not differ either between breeds or between age groups within the BB breed, whereas mounting enthusiasm, although not different between the two breeds, did decline with increasing age, probably due to the greater mating experience of the older bulls. All in all, libido did not seem to be different between the breeds.
The aim of this study was to compare the ecology of catalase-positive cocci (CPC) present in traditional fermented sausages produced using different breeds of pork, each of which was raised in two different environments and processed... more
The aim of this study was to compare the ecology of catalase-positive cocci (CPC) present in traditional fermented sausages produced using different breeds of pork, each of which was raised in two different environments and processed using two different technologies. Semi-quantitative molecular methods were used to determine bacterial identities. Almost all fermentations were characterised by a significant increase in CPC during the first few days of fermentation, reaching values of 10 5 e10 6 cfu g À1 within 3 days. Staphylococcus xylosus and Staphylococcus equorum species, which were detected over the course of fermentation, were found to be the predominant population in all the monitored fermentation. Staphylococcus haemolyticus, Staphylococcus lentus, Micrococcus luteus, Macrococcus caseolyticus and Staphylococcus succinus were also present, but their concentrations were found to vary under the different experimental conditions. Using cluster analysis, we concluded that a plant-specific CPC ecology existed. In addition, the breed of pork used for production was found to influence the presence of some CPC species. However, from this study, it was not possible to reach the same conclusion regarding the breeding system used.
This paper explores the many meanings attached to the designation,"the rodent in the laboratory" (rat or mouse). Generations of selective breeding have created these rodents. They now differ markedly from their wild progenitors, nonhuman... more
This paper explores the many meanings attached to the designation,"the rodent in the laboratory" (rat or mouse). Generations of selective breeding have created these rodents. They now differ markedly from their wild progenitors, nonhuman animals associated with carrying all kinds of diseases.Through selective breeding, they have moved from the rats of the sewers to become standardized laboratory tools and (metaphorically) saviors of humans in the ght against disease. This paper sketches two intertwined strands of metaphors associated with laboratory rodents.The rst focuses on the idea of medical/scienti c progress; in this context, the paper looks at laboratory rodents often depicted (in advertising for laboratory products) as epitomizing medical triumph or serving as helpers or saviors. The second strand concerns the ambiguous status of the laboratory rodent who is both an animal (bites) and not an animal (data).The paper argues that, par tly because of these ambiguous and multiple meanings, the rodent in the laboratory is doubly "othered"-rst in the way that animals so often are made other to ourselves and then other in the relationship of the animal in the laboratory to other animals.
Objectives: The aim of this study was to investigate whether contrast echocardiography could enhance the subcostal Doppler signal for aortic flow measurements and achieve myocardial opacification, in Boxer dogs with and without AS.... more
Objectives: The aim of this study was to investigate whether contrast echocardiography could enhance the subcostal Doppler signal for aortic flow measurements and achieve myocardial opacification, in Boxer dogs with and without AS. Background: In evaluating dogs for aortic stenosis (AS) subcostal Doppler echocardiography was used for measurement of the aortic flow velocity, a measurement that can sometimes be difficult to perform in Boxer dogs. Animals, materials, and methods: Cardiac auscultation, phonocardiographic and echocardiographic examinations, including a contrast study with Optison, were performed on 29 Boxer dogs selected based on previous examinations. Results: The initial subcostal Doppler signal was weak in 66% of the dogs and a marked improvement was seen in all dogs after contrast injection. The peak aortic flow velocity increased 5% from 2.58 AE 1.42 m/s before contrast to 2.71 AE 1.54 m/s after contrast (p ¼ 0.003). This corresponds to a 2.8 mmHg increase in the pressure gradient from 26.6 mmHg before to 29.4 mmHg after contrast. A dose of 0.05e0.1 mL of Optison administered intravenously resulted in approximately 4 min of Doppler signal enhancement. With the present technique contrast echocardiography did not achieve myocardial opacification.
- by Jens Häggström and +1
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- Breeding, Veterinary Cardiology, Echocardiography, Dogs
Abstract—Artificial neural networks learn how to solve new problems through a computationally intense and time consuming process. One way to reduce the amount of time required is to inject pre-existing knowledge into the network. To make... more
Abstract—Artificial neural networks learn how to solve new problems through a computationally intense and time consuming process. One way to reduce the amount of time required is to inject pre-existing knowledge into the network. To make use of past knowledge, we can take advantage of techniques that transfer the knowledge learned from one task, and reuse it on another (sometimes unrelated) task. In this paper we propose a novel selective breeding technique that extends the transfer learning with behavioural genetics approach proposed by Kohli, Magoulas and Thomas (2013), and evaluate its performance on financial data. Numerical evidence demonstrates the credibility of the new approach. We provide insights on the operation of transfer learning and highlight the benefits of using behavioural principles and selective breeding when tackling a set of diverse financial applications problems. Keywords—transfer learning, artificial neural networks, ge-netic algorithms, population studies, ...