Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Breeding”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 937 records · Page 52Linked to original sources
PubMed2007

How slow breeding can be selected in seabirds: testing Lack's hypothesis.

The historical debate of the 1960s between group and individual selection hinged on how the slow breeding of seabirds could be explained. While this debate was settled by the ascendance of individual selection, championed by David Lack, explanations for slow breeding in seabirds remain to be tested. We examined the slowest breeding of these birds, the albatrosses and petrels (order Procellariiformes), using analyses that statistically controlled for variations in body size and phylogeny. Incubation and fledging periods appeared strongly correlated, but this turned out to be largely explained by phylogeny. Nonetheless, developmental and reproductive rates were associated with the distance to the foraging range, as predicted under the hypothesis of ecological constraints on breeding pairs, and these results were independent of body size and phylogeny. Slower breeding in these seabirds appeared associated with the rigors of farther pelagic feeding, as Lack originally hypothesized.

Animals↗
PubMed2004

Low frequency of the scrapie resistance-associated allele and presence of lysine-171 allele of the prion protein gene in Italian Biellese ovine breed.

Frequencies of polymorphisms at codons 136, 154 and 171 of the prion protein (PrP) gene were studied in 1207 pure-bred and cross-bred Italian Biellese rams, a small ovine breed of about 65 000 head in Italy. Aside from the five most common alleles (VRQ, ARQ, ARR, AHQ and ARH), the rare ARK allele was also found, with the highest frequency reported so far in an ovine breed (2.5 %). ARK/--- genotypes had a total frequency of 4.9 %. The resistance-associated ARR allele was seen at a low frequency (8.3 %). Only 1.4 % of animals examined had a resistant ARR/ARR PrP genotype. Semi-resistant (ARR/ARQ, ARR/ARH and ARR/AHQ) PrP genotypes had a total frequency of 12.6 % and PrP genotypes that are associated with high scrapie susceptibility (e.g. VRQ/VRQ and ARQ/ARQ) had a total frequency of 81.1 %. Statistical analysis comparing PrP allele frequencies between pure-bred and cross-bred animals showed that the ARR allele occurred at a significantly lower frequency in pure-bred rams. Furthermore, comparison of PrP allele frequencies between pure-bred rams over 18 months of age and those below 18 months of age showed a significant decrease in the ARR allele in breeding rams over 18 months of age. Based on these results, breeding for scrapie resistance in the Biellese breed will have to take into account the low frequency of the ARR allele, which also seems to be subject to negative selection by farmers. Further investigation is required to understand whether the ARK allele is also associated with resistance to transmissible spongiform encephalopathies.

Alleles↗
PubMed2004

Extensive and breed-specific linkage disequilibrium in Canis familiaris.

The 156 breeds of registered dogs in the United States offer a unique opportunity to map genes important in disease susceptibility, morphology, and behavior. Linkage disequilibrium (LD) is of current interest for its application in whole genome association mapping, since the extent of LD determines the feasibility of such studies. We have measured LD at five genomic intervals, each 5 Mb in length and composed of five clusters of sequence variants spaced 800 kb-1.6 Mb apart. These intervals are located on canine chromosomes 1, 2, 3, 34, and 37, and none is under obvious selective pressure. Approximately 20 unrelated dogs were assayed from each of five breeds: Akita, Bernese Mountain Dog, Golden Retriever, Labrador Retriever, and Pekingese. At each genomic interval, SNPs and indels were discovered and typed by resequencing. Strikingly, LD in canines is much more extensive than in humans: D' falls to 0.5 at 400-700 kb in Golden Retriever and Labrador Retriever, 2.4 Mb in Akita, and 3-3.2 Mb in Bernese Mountain Dog and Pekingese. LD in dog breeds is up to 100x more extensive than in humans, suggesting that a correspondingly smaller number of markers will be required for association mapping studies in dogs compared to humans. We also report low haplotype diversity within regions of high LD, with 80% of chromosomes in a breed carrying two to four haplotypes, as well as a high degree of haplotype sharing among breeds.

Animals↗
PubMed2004

Natural breeding places of phlebotomine sandflies.

Methods of finding larvae and pupae of phlebotomine sandflies (Diptera: Psychodidae) are described and the known types of breeding sites used by sandflies are listed. Three ways of detecting sandfly breeding places are the use of emergence traps placed over potential sources to catch newly emerged adult sandflies; flotation of larvae and pupae from soil, etc., and desiccation of media to drive out the larvae. Even so, remarkably little information is available on the ecology of the developmental stages of sandflies, despite their importance as vectors of Leishmania, Bartonella and phleboviruses affecting humans and other vertebrates in warmers parts of the world. Regarding the proven or suspected vectors of leishmaniases, information on breeding sites is available for only 15 out of 29 species of sandflies involved in the Old World and 12 out of 44 species of sandflies involved in the Americas, representing approximately 3% of the known species of Phlebotominae. Ecotopes occupied by immature phlebotomines are usually organically rich moist soils, such as the rain forest floor (Lutzomyia intermedia, Lu. umbratilis, Lu. whitmani in the Amazon; Lu. gomezi, Lu. panamensis, Lu. trapidoi in Panama), or contaminated soil of animal shelters (Lu. longipalpis s.l. in South America, Phlebotomus argentipes in India; P. chinensis in China; P. ariasi, P. perfiliewi, P. perniciosus in Europe). Developmental stages of some species (P. langeroni and P. martini in Africa; P. papatasi in Eurasia; Lu. longipalpis s.l. in South America), have been found in a wide range of ecotopes, and many species of sandflies employ rodent burrows as breeding sites, although the importance of this niche is unclear. Larvae of some phlebotomines have been found in what appear to be specialized niches such as Lu. ovallesi on buttress roots of trees in Panama; P. celiae in termite hills in Kenya; P. longipes and P. pedifer in caves and among rocks in East Africa. Old World species found as immatures in the earthen floor of human habitations include P. argentipes, P. chinensis, P. martini and P. papatasi. Much more information on sandfly breeding sites is required to facilitate their control by source reduction.

Animals↗
PubMed1977

Gene frequencies of blood groups in Dutch swine breeds.

Gene frequencies of blood groups at 6 loci were estimated within two Dutch breeds of swine, Dutch Landrace and Dutch Large White. At all loci there were significant differences between breeds. The relationship of the two breeds with, respectively, the Germany Landrace breed and the German Large White breed could be confirmed by the gene frequencies.

Animals↗
PubMed1982

Phenotype frequencies of vitamin D binding protein (Gc) and of posttransferrin-2 (Ptf-2) in Belgian cattle breeds.

The vitamin D binding protein (Gc) and posttransferrin-2 (Ptf-2) phenotypes have been determined in a number of Belgian cattle breeds. A very slow migrating variant of the Gc protein--Gc C--has been found in White and Red East Flemish breed. This variant was absent from the other breeds studied. This slow variant was identified as a vitamin D binding protein by autoradiography. The Gc C protein was shown to be controlled by a codominant autosomal allele Gc C at the Gclocus. The Gc C protein is probably identical with a previously described in buffalo and an Italian cattle breed. The allele frequencies for the Gc and Pft-2 systems are reported for several Belgian breeds of cattle.

Animals↗
PubMed1997

Analysis of genetic relationships between 10 cattle breeds with 17 microsatellites.

To guide genetic conservation programmes with objective criteria, general genetic variability has to be taken into account. This study was conducted to determine the genetic variation between 10 cattle breeds by using 17 microsatellite loci and 13 biochemical markers (11 blood groups, the transferrin and beta-casein loci). Microsatellite loci were amplified in 31-50 unrelated individuals from 10 cattle breeds: Charolais, Limousin, Breton Black Pied, Parthenais, Montbéliard, Vosgien, Maine-Anjou, Normande, Jersey and Holstein. Neighbor-joining trees were calculated from genetic distance estimates. The robustness of tree topology was obtained by bootstrap resampling of loci. A total of 210 alleles of the 17 microsatellites were detected in this study and average heterozygosities ranged from 0.53 in the Jersey breed to 0.66 in the Parthenais breed. In general, low bootstrap values were obtained: with the 17 microsatellites, the highest bootstrap values concerned the Holstein/Maine-Anjou grouping with an occurrence of 74%; with the biochemical markers, this node had an occurrence of 79% and the Charolais/Limousin grouping appeared with an occurrence of 74%; when microsatellites and biochemical polymorphism were analysed together, the occurrence of the Holstein/Maine-Anjou grouping was 90% and that of the Charolais/Limousin grouping was 42%. These results suggest that 30 microsatellites, a number currently considered as sufficient to distinguish closely related breeds is, in fact, probably insufficient.

Alleles↗
PubMed2005

Phylogenetic relationships among Spanish goats breeds.

We partially sequenced the mitochondrial hypervariable region 1 (HVR1) in 60 goats belonging to six Spanish breeds. The analysis of these and previously published sequences reveals a weak phylogeographical structure in the Iberian Peninsula breeds. Individuals from a single breed did not group into a single cluster. Furthermore, individuals from different breeds often shared single phylogenetic tree branches after UPGMA analysis. This could reflect the non-existence of breed isolation because of traditional seasonal pastoralism and annual long-distance migrations. Three goats belonging to the C maternal lineage were found, demonstrating a wider than previously thought distribution for this lineage.

Animals↗
PubMed1996

Different effects of somatostatin on in vitro growth hormone release in two porcine breeds with different growth rates.

A perifusion system of anterior pituitary (AP) tissue was used to investigate the temporal interaction of growth hormone-releasing factor (GRF) and somatostatin (SRIF) in the control of GH secretion in two pig breeds, Göttingen Miniature Pig (GMP), a small obese breed, and German Landrace (GLR), a conventional lean breed. AP tissue pieces derived from sexually mature ovariectomized animals were perifused (6 replicates per treatment) and fractions were collected at 10 min intervals. Basal GH release (ng.ml-1.mg-1 AP) in GLR was twice that of GMP (P < 0.001). Exposure to 10 min pulses of 1 nM GRF repeated 3 times at 2 h intervals resulted in rapid stimulatory GH responses (area under the curve) which became attenuated (P < 0.05) over time in GMP but not in GLR. Surprisingly, during and following the exposure of AP tissue from GMP to 10-, 20-, or 40-min pulses of 10 nM SRIF alone, GH release was markedly stimulated (P < 0.05), while AP tissue from GLR only showed a weak rebound GH release after SRIF pulses. With AP tissue from GLR low concentrations (0.1 nM SRIF) amplified GRF-induced GH release, whereas 1 nM or 10 nM SRIF inhibited GRF-induced GH release. However, concomitant exposure of AP tissue from GMP to 0.1, 1 or 10 nM SRIF during a GRF pulse markedly enhanced the GH response (P < 0.05), compared to 1 nM GRF alone, except for 1 nM SRIF which inhibited the GH response to the first GRF pulse. Thus the presence of SRIF, and not only its withdrawal, is an important factor in setting the timing and duration of GH pulses in both breeds. In GLR the concentration of SRIF is more important than the duration and/or type of SRIF pulse. In contrast, in GMP type and/or duration of SRIF pulses seem to be crucial to optimize pulsatile GH release and even determine peak height of GH pulses caused by GRF. These findings indicate clear breed differences in the role of SRIF and in the control of GH release by the interplay of GRF and SRIF. The "paradoxical' effect of SRIF suggests that the role of SRIF is much more complex than that of a mere inhibitor and whose real role could be a modulator either of GH pulse and/or GRF action on GH release.

Animals↗
PubMed1977

Characterization of extract of dog hair and dandruff from six different dog breeds by quantitative immunoelectrophoresis. Identification of allergens by crossed radioimmunoelectrophoresis (CRIE).

An extract of mixed dog hair and dandruff from six different dog breeds (alsatian, boxer, collie, poodle, and long-haired and short-haired dachshund) was obtained by mild extraction, centrifugation, dialysis and freeze-drying. Extract of hair and dandruff from the individual dog breeds was obtained in the same way, but the material was not freeze-dried. Examination and characterization of the mixed extract by means of crossed immunoelectrophoresis revealed a precipitation pattern composed of 25 antigens, some of which were mutually partially identical, and a high content of dog serum proteins was found. Quantitative and qualitative differences between the individual dog breeds were demonstrated. Partial identity of the antigens of the mixed extract with antigens of serum, antigens of extracts of hair and dandruff from cat, cow, horse and guinea pig, and antigens from extract of house dust was also observed. By means of crossed radioimmunoelectrophoresis, using sera from 21 patients who were RAST-positive to dog hair and dandruff extract, the specific IgE-binding to antigens of the mixed extract was examined. On the basis of these results major and minor allergens were identified. Dog albumin was found to be a very important major allergen, but alpha1-antitrypsin and gamma-globulin were also identified. Furthermore, four non-serum proteins were shown to be allergens. No breed-specific allergens could be identified in the extracts from the individual dog breeds.

Adult↗
PubMedDate not supplied

Correlation of clinical, radiographic, and surgical localization of intervertebral disc extrusion in small-breed dogs: a prospective study of 50 cases.

OBJECTIVE: To compare prospectively clinical, radiographic, and surgical findings of intervertebral disc extrusion (IDE) localization in small-breed dogs and to determine the best means of lesion localization for the purpose of hemilaminectomy. STUDY DESIGN: Clinical, radiographic, and surgical findings of small-breed dogs with thoracolumbar IDE were prospectively compared for agreement on lesion localization. SAMPLE POPULATION: 50 small-breed dogs with IDE treated at the three participating veterinary hospitals were included in the study if no other confounding diseases were identified and if the owner gave permission for diagnostic tests and surgery. METHODS: Clinical and surgical findings were recorded by the surgeon assigned to the case. Radiographic studies were evaluated independently by two radiologists blinded as to the clinical and surgical findings. kappa values and 95% confidence intervals were calculated for agreement on lesion localization by clinical, radiographic, and surgical means and for agreement between radiologists. RESULTS: kappa values for agreement of lesion localization were as follows: clinical versus surgical, 0.595; radiologist A versus radiologist B, 0.81; radiologist A versus surgical findings, 0.60; radiologist B versus surgical findings, 0.71. Both radiologists' interpretation of IDE localization agreed with surgical localization in 60% of cases. CONCLUSIONS: Clinical lateralization of IDE was found to be the least reliable factor of those studied for determining on which side the hemilaminectomy should be performed. Results of this study differ from those of previous studies examining the reliability of myelography to localize the site of IDE accurately. The results of this study further suggest that surgery may not be an absolute standard for determination of the localization of IDE in small-breed dogs. CLINICAL RELEVANCE: Intervertebral disc extrusion in small-breed dogs frequently results in bilateral distribution of extruded material. Computed tomography or magnetic resonance imaging may be necessary to delineate completely the distribution of extruded disc material in IDE.

Animals↗
PubMed1993

Fine structure of the free-living parakeet pineal in relation to the breeding cycle.

Seasonal changes in the ultrastructure of the free-living Rose-Ringed Parakeet Psittacula krameri pineal were examined in relation to the sub-tropical environment and seasonal reproduction. Dark and light pinealocytes of the presumptive neuroendocrine cell line predominated, while supporting cells, ependymal cells, myelinated and non-myelinated nerve fibers with nerve endings, and regressed photoreceptor elements were also observed. Unlike in pineals of many animals, particularly mammals, the presence of dense-core vesicles (DCVs) with varying core density, and absence of clear vesicles and vacuoles with flocullent material, indicate the involvement of DCVs in the synthesis and secretion of pineals principle/s. In November (pre-breeding) when the day length registered a drop to LD 10:14, pinealocytes showed significantly decreased and smaller DCVs and mitochondria, nuclei with heterochromatin, and greater distribution of glycogen and lipid droplets, all indicating low pineal metabolic activity. During the shortest day regime from December to March, when the birds peaked breeding, the number and size of DCVs and mitochondria increased, and Golgi body-endoplasmic reticulum-lysosome complex (GERL) was very well defined. Images of DCVs suggested possible secretion of pineal principle/s by dissolution, and exocytosis. Coincidence of these features with peak gonadotrophic (circulating LH) and spermatogenic and testicular endocrine activity described previously suggested an active turnover of pineal products during this short day length regime when parakeets breed. In contrast, during the post-breeding season (April onwards), when the day-length increased to LD 13:11 and hypophyseal-gonadal function was down, nuclei and RER continued to show active profile, the Golgi body and associated complex were moderately seen, and the DCVs and mitochondria were significantly smaller and lesser. It is therefore probable that the pineal is an important relay to translate cues related to less drastic sub-tropical environmental change into DCV-linked neurohormones that in turn may be involved in modulating seasonal breeding in parakeets.

Animals↗
PubMed2006

Selective breeding for catalepsy changes the distribution of microsatellite D13Mit76 alleles linked to the 5-HT serotonin receptor gene in mice.

Catalepsy (pronounced motor inhibition) is a natural defensive reaction against predator. Recently, the quantitative trait locus for catalepsy was mapped on mouse chromosome 13 near the 5-HT(1A) serotonin receptor gene. Here, the linkage between catalepsy and the 5-HT(1A) receptor gene was verified using breeding experiment. Selective breeding for high predisposition to catalepsy was started from backcross BC[CBA x (CBA x AKR)] generation between catalepsy-prone (CBA) and catalepsy-resistant (AKR) mouse strains. CBA and AKR strains also differed in the 5-HT(1A) receptor functional activity. A rapid increase of cataleptic percentage from 21.2% in the backcrosses to 71% in the third generation of selective breeding (S3) was shown. The fragment of chromosome 13 including the 5-HT(1A) receptor gene was marked with D13Mit76 microsatellite. Breeding for catalepsy increased the concentration of CBA-derived and decreased the concentration of AKR-derived alleles of microsatellite D13Mit76 in the S1 and S2. All mice of the S9 and S12 were homozygous for CBA-derived allele of D13Mit76 marker. Mice of the S12 showed CBA-like receptor activity. These findings indicate that selective breeding for behavior can involve selection of polymorphic variants of the 5-HT(1A) receptor gene.

Animals↗
PubMed1982

Breeding for resistance to Boophilus microplus in Australian Illawarra Shorthorn and Brahman x Australian Illawarra Shorthorn cattle.

Breeding for resistance to the cattle tick Boophilus microplus was undertaken in a herd of Australian Illawarra Shorthorn (AIS) cattle from 1961 to 1978 and in a herd of Braham x AIS cattle from 1970 to 1979. Breeder cows and their progeny were assessed for tick resistance during October to January. Resistance levels were determined as the average percentage mortality of female ticks from two artificial infestations with cohorts of c 20,000 larvae. Resistance increased from 89.2% to 99% in the AIS breeding herd, as a result of the yearly introductions of more resistant individuals and culling of less resistant ones. Concurrently resistance in the AIS progeny increased from 93.7% to 97.7%, thus demonstrating that the selection and breeding of the cows and bulls resulted in genetic improvement in the resistance of the progeny. Milk production tests on heifers from the selected AIS herd during 1975 to 79 indicated that selection for tick resistance did not select against milk production. Resistance of the Brahman x AIS increased from 98.4% to 99.3% in the breeding herd and from 97.6% to 99.6% in the progeny. Female calves of both breeds were more resistant than males.

Animal Husbandry↗
PubMed2001

Energetic and fitness costs of mismatching resource supply and demand in seasonally breeding birds.

By advancing spring leaf flush and ensuing food availability, climatic warming results in a mismatch between the timing of peak food supply and nestling demand, shifting the optimal time for reproduction in birds. Two populations of blue tits (Parus caeruleus) that breed at different dates in similar, but spatially distinct, habitat types in Corsica and southern France provide a unique opportunity to quantify the energetic and fitness consequences when breeding is mismatched with local productivity. As food supply and demand become progressively mismatched, the increased cost of rearing young pushes the metabolic effort of adults beyond their apparent sustainable limit, drastically reducing the persistence of adults in the breeding population. We provide evidence that the economics of parental foraging and limits to sustainable metabolic effort are key selective forces underlying synchronized seasonal breeding and long-term shifts in breeding date in response to climatic change.

Adaptation, Physiological↗
PubMed1983

Comparison of infarct size produced by coronary artery occlusion in purebred beagle and mixed-breed dogs.

This investigation demonstrated a significant difference in infarct size following coronary artery occlusion between purebred beagles and mixed-breed dogs. Myocardial infarctions were produced by a two-stage ligation of the left anterior descending artery (LAD). Myocardial infarct size, expressed as percent of left ventricular mass, was determined at 24 h by nitro blue tetrazolium staining. Infarct size was significantly smaller (12.5 +/- 3.4%) and more variable (coefficient of variation 72%) in beagles than in mixed-breed animals (28.0 +/- 2.4% infarct size, 23% coefficient of variation) (p less than 0.001). Ectopic activity at 24 h was similar for both beagles and mixed breed, 92 +/- 7 and 92 +/- 2% of total heart rate, respectively. Thus this study indicates that the breed of dog (i.e., purebred beagles versus mixed-breed animals) can be an important variable in the study of infarct size resulting from coronary artery occlusion.

Animals↗
PubMedDate not supplied

Genetic variability of six French meat sheep breeds in relation to their genetic management.

Some demographic parameters, the genetic structure and the evolution of the genetic variability of six French meat sheep breeds were analysed in relation with their management. Four of these breeds are submitted to more or less intense selection: the Berrichon du Cher (BCH), Blanc du Massif Central (BMC), Charollais (CHA) and Limousin (LIM); the other two breeds are under conservation: the Roussin de La Hague (RLH) and Solognot (SOL). Genealogical data of the recorded animals born from 1970 to 2000 and of their known ancestors were used. The most balanced contributions of the different flocks to the sire-daughter path was found in the SOL. In the BCH, a single flock provided 43% of the sire-AI sire path, whereas the contributions of the flocks were more balanced in the BMC and LIM (the only other breeds where AI is used to a substantial amount). The distribution of the expected genetic contribution of the founder animals was found to be unbalanced, especially in the BCH and LIM. The effective numbers of ancestors (founders or not) for the ewes born from 1996 to 2000 were equal to 35 (BCH), 144 (BMC), 112 (CHA), 69 (LIM), 40 (RLH) and 49 (SOL). Inbreeding was not analysed in the BMC, due to incomplete pedigree information. From 1980 on, the rates of inbreeding, in percentage points per year, were +0.112 (BCH), +0.045 (CHA), +0.036 (LIM), +0.098 (RLH) and +0.062 (SOL). The implications of the observed trends on genetic variability are discussed in relation to the genetic management of each breed. The need for a larger selection basis in the BCH, the efficiency of the rules applied in the SOL to preserve the genetic variability and the need for a more collective organisation in the CHA and RLH are outlined.

Animals↗
PubMed2002

Sequence analysis of the NRAMP1 genes from different bovine and buffalo breeds.

The natural resistance associated macrophage protein 1 (Nramp1) has been reported to confer resistance or susceptibility to Mycobacterium bovis, Salmonella typhimurium, and Leishmania donovani in the mouse, Mus musculus. A Gly and Asp substitution at position 169 of the mouse Nramp protein is invariably associated with the resistant and susceptible phenotypes, respectively. The present study aimed to detect polymorphisms in the NRAMP1 gene from different cattle and buffalo breeds. Genomic DNAs from five breeds of cattle and four breeds of buffalo were used in the study. Sequencing showed two nucleotide substitutions found in intron 4, three in exon V, and ten in intron 5. An amino acid substitution was observed at nucleotide position 1202 in exon V of the Japanese black, Angus, Philippine and Bangladesh swamp-type buffaloes which coded for Thr, while the Korean cattle, Holstein, African N'dama, Indonesian swamp-type buffalo and the Bangladesh river-type buffalo had Ile. All the breeds of cattle and buffaloes tested in this study coded for Gly at the position in exon VI which corresponds to the same amino acid of the murine Nramp1-resistant phenotype at position 169. The phylogenetic relationship among the different breeds showed a cluster comprised mainly of cattle and another one mainly of buffaloes.

Animals↗