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At least 91 records · Page 5Linked to original sources
PubMed1999

Changes in rectal temperature and hematologic, biochemical, blood gas, and acid-base values in healthy Labrador Retrievers before and after strenuous exercise.

OBJECTIVE: To measure changes in rectal temperature and hematologic, biochemical, blood gas, and acid-base values before and after exercise. ANIMALS: 14 healthy adult Labrador Retrievers. PROCEDURE: Dogs exercised continuously for 10 minutes by repeatedly retrieving a dummy thrown approximately 40 to 50 yards on land. The ambient temperature during each exercise period was recorded. Rectal temperature, pulse, and respiratory rate were measured; CBC and serum biochemical profile were determined; and arterial blood gas tensions, acid-base status, and plasma lactate and pyruvate concentrations were measured at rest and immediately after exercise. Rectal temperature, pulse, respiratory rate, and lactate and pyruvate concentrations were evaluated at intervals up to 120 minutes after exercise. RESULTS: Immediately after exercise, rectal temperature increased markedly; ambient temperature did not affect rectal temperature. Arterial blood pH and PaO2 were significantly increased after exercise, and PaCO2 and bicarbonate concentration were significantly decreased after exercise. Also, statistically, but not clinically, significant increases were observed in RBC, WBC, and segmented neutrophil counts; hemoglobin, total protein, and serum sodium and potassium concentrations; PCV; anion gap; and creatine kinase activity. Plasma lactate and pyruvate concentrations increased significantly after exercise, but there was no change in the lactate-to-pyruvate ratio. CONCLUSION AND CLINICAL RELEVANCE: Reference values for healthy Laborador Retrievers during a standardized exercise protocol were established to compare data obtained from Laborador Retrievers with exercise intolerance and collapse. Important characteristics of lactate and pyruvate metabolism were documented that will enable more precise evaluation of exercise intolerance in this breed.

Acid-Base Equilibrium↗
PubMed2002

Aspects of the life history of Muspicea borreli (Nematoda: Muspiceidae), parasite of the house mouse (Mus domesticus) in Australia.

Prevalence of Muspicea borreli (Nematoda) infection in wild populations of Mus domesticus in forests in southeastern New South Wales and in rural Canberra, Australia was variable, relatively low and the parasite occurred predominantly in male mice. Experimental infection of BALB/c mice occurred only via subcutaneous inoculation but was achieved using i) adults containing embryonating eggs, ii) adults containing active larvae and iii) active larvae dissected from the uterus of female worms. Experimental infection was not established using adults containing unembryonated eggs and was not established via intraperitoneal, percutaneous nor oral routes. Evidence indicates that larvae develop to the infective stage in the uterus of the adult worm, suggests that an obligate developmental phase on the host skin does not occur and that autoinfection is possible. Experimental infection predominated in males; females rarely became infected. When male BALB/c mice were inoculated subcutaneously with M. borrelia, immediately paired with an uninoculated female and permitted to breed for 90 days, infection was found in male and female offspring only of the second and subsequent litters or in the breeding female partner. Transmission to the young occurred within 21 days of birth and fifth-stage M. borrelia were found in offspring of the second and subsequent litters only after 35 or more days. However, when a male was inoculated but mating delayed for 23 days, infection was found in progeny of the first and second litters. The life cycle is direct and the prepatent period in BALB/c mice is estimated at 50-60 days. The precise mode of transmission of the parasite in breeding pairs of mice was not determined but larvae remained active for approximately an hour in balanced saline solutions (pH = 7.2) and in human saliva but died under conditions emulating free-living (tap water pH = 7.1) and stomach (pepsin solution pH = 2) environments. Transmission was not effected by transplacental, transmammary nor transseminal routes. Consequently, it is difficult not to conclude that transmission may occur via penetration of skin or mucous membranes, and allogrooming behaviour may be particularly important in this regard.

Animals↗
PubMed2006

Fine-scale natal homing and localized movement as shaped by sex and spawning habitat in Chinook salmon: insights from spatial autocorrelation analysis of individual genotypes.

Natal homing is a hallmark of the life history of salmonid fishes, but the spatial scale of homing within local, naturally reproducing salmon populations is still poorly understood. Accurate homing (paired with restricted movement) should lead to the existence of fine-scale genetic structuring due to the spatial clustering of related individuals on spawning grounds. Thus, we explored the spatial resolution of natal homing using genetic associations among individual Chinook salmon (Oncorhynchus tshawytscha) in an interconnected stream network. We also investigated the relationship between genetic patterns and two factors hypothesized to influence natal homing and localized movements at finer scales in this species, localized patterns in the distribution of spawning gravels and sex. Spatial autocorrelation analyses showed that spawning locations in both sub-basins of our study site were spatially clumped, but the upper sub-basin generally had a larger spatial extent and continuity of redd locations than the lower sub-basin, where the distribution of redds and associated habitat conditions were more patchy. Male genotypes were not autocorrelated at any spatial scale in either sub-basin. Female genotypes showed significant spatial autocorrelation and genetic patterns for females varied in the direction predicted between the two sub-basins, with much stronger autocorrelation in the sub-basin with less continuity in spawning gravels. The patterns observed here support predictions about differential constraints and breeding tactics between the two sexes and the potential for fine-scale habitat structure to influence the precision of natal homing and localized movements of individual Chinook salmon on their breeding grounds.

Animal Migration↗
PubMed2001

Estimating genetic correlations in natural populations in the absence of pedigree information: accuracy and precision of the Lynch method.

Usually, genetic correlations are estimated from breeding designs in the laboratory or greenhouse. However, estimates of the genetic correlation for natural populations are lacking, mostly because pedigrees of wild individuals are rarely known. Recently Lynch (1999) proposed a formula to estimate the genetic correlation in the absence of data on pedigree. This method has been shown to be particularly accurate provided a large sample size and a minimum (20%) proportion of relatives. Lynch (1999) proposed the use of the bootstrap to estimate standard errors associated with genetic correlations, but did not test the reliability of such a method. We tested the bootstrap and showed the jackknife can provide valid estimates of the genetic correlation calculated with the Lynch formula. The occurrence of undefined estimates, combined with the high number of replicates involved in the bootstrap, means there is a high probability of obtaining a biased upward, incomplete bootstrap, even when there is a high fraction of related pairs in a sample. It is easier to obtain complete jackknife estimates for which all the pseudovalues have been defined. We therefore recommend the use of the jackknife to estimate the genetic correlation with the Lynch formula. Provided data can be collected for more than two individuals at each location, we propose a group sampling method that produces low standard errors associated with the jackknife, even when there is a low fraction of relatives in a sample.

Analysis of Variance↗
PubMed2026

Revealing potential biomarkers and metabolic mechanisms of ovarian aging in hens during late laying period based on machine learning and metabolomics.

Ovarian function decline during the late laying period represents a major bottleneck for the economic efficiency of the global poultry industry. However, the underlying metabolic mechanisms and reliable early-warning biomarkers for ovarian aging remain poorly understood. In this study, we performed the first untargeted LC-MS/MS metabolomics analysis of ovarian tissues from Taihe silky fowls at peak laying (30 weeks) and late laying (50 weeks) stages, and employed an ensemble machine learning strategy integrating LASSO, random forest, and support vector machine (SVM) algorithms to identify high-confidence core biomarkers of ovarian aging. Gene expression analysis was further conducted to validate the potential molecular mechanisms. Our results showed that the metabolic profiles of ovarian tissues differed significantly between the two groups. A total of 6 core biomarkers were identified, 4 of which were long-chain acylcarnitines. Mechanistic analysis revealed that downregulation of key genes in the carnitine shuttle system led to impaired mitochondrial fatty acid β-oxidation, which in turn triggered excessive oxidative stress and compromised ovarian endocrine function. In conclusion, this study identifies long-chain acylcarnitines as potential metabolic biomarkers for ovarian aging in Taihe silky fowls. These findings provide novel insights into the metabolic basis of poultry ovarian aging and lay a theoretical foundation for the precise regulation of reproductive performance in indigenous poultry breeds.

Animals↗
PubMed2005

The selectivity of canary HVC neurons for the Bird's Own Song: rate coding, temporal coding, or both?

The neuronal selectivity observed in the avian song system for the Bird's Own Song progressively emerged as an extraordinary fruitful model to investigate the neural code underlying the recognition of complex stimuli and the occurrence of learned behaviors. In adult zebra finch, neurons from the HVC (used as a proper name) show very selective auditory responses, firing more to presentation of the Bird's Own Song (BOS) than to reverse BOS or other conspecific songs. However, as adult zebra finches always produce the same stereotyped song, the presence of such highly selective neurons in birds with larger repertoire still remains an open question. Data presented here show that neurons selective for the BOS can be found in adult canary, a seasonal breeding bird which display a large repertoire. More precisely, we found that a large proportion of neurons (29/36) exhibits higher responses to presentation of the forward than to the reverse BOS, and that 22% of the cells were identified as selective on the basis of the d' value. For a cell that was extensively studied, we evaluated to what extent temporal stimulus-related structure predicts the acoustic stimulus using linear or non-linear artificial neural networks (ANN). These analyses indicated that the temporal structure contained in spike trains characterizes more accurately the stimulus than the firing rate. The limitations of applying ANN analyses to electrophysiological data are discussed and potential solutions to increase the confidence in these analysis are proposed.

Action Potentials↗
PubMedDate not supplied

Fragmented coronoid process and incomplete ossification of the humeral condyle in a rottweiler.

OBJECTIVE: To describe incomplete ossification of the humeral condyle and fragmentation of the medial coronoid process in a Rottweiler. STUDY DESIGN: Clinical report. ANIMAL POPULATION: A 4-year-old sexually intact male Rottweiler. METHODS: Physical examination, radiography, and computed tomography of both elbow joints were performed initially. Drill holes were made across the humeral condyle to promote ossification. Radiography and computed tomography were repeated 14 weeks later. Radiography was repeated 15 months later. A mild intermittent lameness remained. RESULTS: Preoperatively a radiolucent line was present across the right humeral condyle. This radiolucent line remained unchanged 14 weeks after drill holes were made across the condyle. CONCLUSIONS: Incomplete ossification of the humeral condyle is present in Rottweilers. CLINICAL RELEVANCE: Incomplete ossification of the humeral condyle is present in Rottweilers and may coexist with fragmentation of the medial coronoid process in that breed. The radiographic diagnosis may be difficult because precise positioning is required to see the area of incomplete ossification. Computed tomography may be required to confirm the presence of incomplete ossification of the humeral condyle. Drilling holes across the humeral condyle does not appear to lead to union of the area of incomplete ossification.

Animals↗
PubMed2006

A novel generic dipstick-based technology for rapid and precise detection of tetracycline, streptogramin and macrolide antibiotics in food samples.

Excessive use of antibiotics in veterinary medicine and as growth promoters in stock farming has been associated with the dramatically increasing prevalence of multidrug-resistant human pathogenic bacteria. European community legislators have therefore restricted the veterinary use of antibiotics and banned them as growth-promoting food additives in stock breeding (1831/2003/EC). The monitoring of such legislation requires technology for precise and straightforward on-site quantification of antibiotics in farm samples and food products without the need for extensive laboratory equipment and trained personnel. Capitalizing on bacterial transcriptional regulators (TetR, PIP, E), which are dose-dependently released from their cognate operators (tetO, PIR, ETR) upon binding of specific classes of antibiotics (tetracycline, streptogramins, macrolides) we have designed an easy-to-handle dipstick-based assay for detection of antibiotic levels in serum, meat and milk whose detection limits are up to 40-fold below licensed threshold values. The generic dipstick consists of either nitrocellulose, nylon or polyvinylidenfluorid (PVDF) membrane strips coated with streptavidin and immobilized biotinylated operator DNA, which acts as capture DNA to bind hexa-histidine (His(6))-tagged bacterial biosensors. Antibiotics present in specific samples triggered the dose-dependent release of the capture DNA-biosensor interaction, which, after dipping into two different solutions, results in a correlated conversion of a chromogenic substrate by a standard His(6)-targeted enzyme complex. This can be quantified by comparison of the dipstick to a standardized color scale or by assessing the terminal solution at 450nm. As demonstrated using serum, meat and milk samples spiked with 14 different antibiotics, the dipstick technology provided sensitive detection in a rapid assay format, and could be employed to monitor non-authorized use of antibiotics and to discover novel antibiotics.

Animals↗
PubMed2001

Identification of S-genotypes by PCR-RFLP in breeding lines of Brassica.

We developed a molecular method for the identification of the S-alleles of Brassicaceae, which belongs to the inbred line. This method is quicker and more precise than the existing methods. The genotype of the S-allele for 20 S-haplotypes of cabbage and 20 S-haplotypes of broccoli was determined by a pollination test. In order to identify the S-alleles, we performed PCR-RFLP with a mixture of the primers that are related to the S-locus glycoprotein (SLG) gene, which corresponds to the results of the pollination test. The selected primers amplified all of the single bands of about 1,150 bp in all 40 lines of cabbage and broccoli. Three out of 20 lines of cabbage were amplified by class I SLG specific primers, whereas all of the lines of the cabbage were amplified by class II SLG specific primers. Therefore, we could not classify class I and class II precisely by the class I and class II primers. However, 15 out of 20 lines of broccoli were amplified by the class I SLG specific primers. The remaining 5 lines were amplified with the class II SLG specific primers. We then digested the amplified PCR products with various restriction endonucleases and chose a restriction endonuclease, which accords exactly with the results of the diallel cross. The best one was HinfI. Its RFLP result was the same as that of the nucleotide sequence analysis. The 40 lines of cabbage and broccoli consisted of 16 different S-haplotypes. Therefore, the PCR-RFLP analysis was quicker and more precise in identifying the characteristics of S-haplotypes that are used in breeding. Also, we were able to check whether the lines could be mixed. The S-genotypes were difficult to determine due to the different flowering time.

Alleles↗
PubMed1991

[Study of the breed-forming process in sheep using multivariate methods of analysis of genetic and morphologic distances].

Comparison of biochemical genetic variation and morphological variation during formation of a new breed of sheep by means of multi-breed mating has been carried out. Genetic distances calculated by biochemical markers using various methods (by M. Nei, J.S. Rogers, I.I. Cavalli-Sforza and A.W.F. Edvards) have been discovered to significantly correlate with Manhattan and average taxonomic distances calculated on the basis of six morphological traits (r = 0.841-0.889, t = 2.98-2.99, P = 0.999). Nevertheless, it appeared that relationships between crossbred animals revealed with the help of methods for multidimensional analysis (principle component analysis and multidimensional scaling) on the basis of genetic distances matrix more precisely correspond to the real scheme and direction of breeding work than relationships described while using the given methods on the basis of morphological distances matrix. Greater correspondence of data on biochemical genetic variations of the animal groups studied to real processes of breeding, as compared with the data on morphological traits, is supposed to be connected with direct involvement of non-accounted phenotypic characters into the breeding work.

Animals↗
PubMed1989

Changes in plasma and pituitary levels of prolactin in the toad, Bufo japonicus, throughout the year with special reference to the breeding migration.

Monthly surveys of the plasma prolactin level in Bufo japonicus at two localities, one in Tokyo and the other in Saitama Prefecture, revealed that the level was highest during the month of breeding in early spring with an additional peak recognized in autumn. The level was lowest during the winter torpid period before breeding and during the spring torpid period after breeding. The pituitary prolactin content observed in Tokyo also showed an annual cycle similar to the plasma prolactin, except that the content in winter was higher than that in summer. A further precise survey of the plasma prolactin level before and during the breeding period revealed that the level in male toads migrating toward the pond for breeding was as low as the level in torpid toads, and also that the level was elevated in only about 50% of migrating female toads. In the pond, almost all female and male toads showed high plasma prolactin levels. Soon after the females finished breeding and returned to land, the level declined to the baseline without exception. In contrast, many males retained high levels on land. The present results indicate that prolactin is not a water drive factor, at least in B. japonicus. Prolactin may, however, play a role in toad osmoregulation in water. There is a possibility that the high prolactin level in some of the migrating female toads is related to oviductal secretion, as some female toads ovulate during migration.

Acclimatization↗
PubMed1986

Effect of misidentification on the estimation of breeding value and heritability in cattle.

For daughter groups of 15 test bulls, controls of paternity were performed by using blood group factors and biochemical polymorphisms. Data of incorrectly assigned daughters influenced the estimation of breeding values, heritabilities and correlations for milk performance traits. Formulae are given that show the effects of variable misidentification rates on estimation of breeding values, selection intensities, heritabilities, and genetic gains. For example, for milk fat yield, the genetic gains drop at a misidentification rate of 15% between 8.7% (for h2 = .5) and 16.9% (for h2 = .2) below values attained without misidentifications. Consequently, decreasing misidentification rates in progeny of test bulls can be used to diminish the progeny size per test bull for constant genetic gain, to achieve more precise ranking of all or distinct test bulls according to their "true" breeding values and(or) to increase the number of test bulls by using the same amount of test inseminations and the same precision of ranking. Actions to reduce misidentification rates in cattle populations are discussed.

Animal Identification Systems↗
PubMed2000

Determination of gestational age in medium and small size bitches using ultrasonographic fetal measurements.

A study was undertaken to estimate gestational age, in terms of days from parturition, in medium and small size dogs by ultrasonographic examination. Serial ultrasonographic examinations were performed in four medium size pregnant bitches throughout two consecutive pregnancies and three small size pregnant bitches throughout one pregnancy, in order to determine the range of variation in the size of selected fetal structures throughout gestation. Formulae were derived to estimate the expected delivery date for both groups of bitches by measuring anatomical fetal structures, so that this method could be applied to a large number of different breeds. The determination of gestational age could be achieved with reasonable precision by selecting fetal structures. Prediction of parturition date was accurate to within one day by ultrasonographic measurement of the diameter of the gestational sac in early pregnancy and the biparietal diameter in late pregnancy in both small size breeds and medium size breeds.

Animals↗
PubMed1999

[Veterinary recommendations for the handling of equine virus arteritis (EVA) in practical breeding care].

The equine virus arteritis (EVA) consistently epidemically varying throughout the different breeds of the horse breeding countries is up to now only of lower significance by means of the typical clinical manifestation as well as an abortion causing factor. The susceptibility of the sexual mature stallions against the equine arteritis virus (EAV) causes different infection response which may lead to some restrictions in their use in natural breeding especially in the artificial insemination. In a certain not precisely predictable part of the stallion population EAV infection will cause a transient or permanent virus presence in the accessorial apparatus of the genital tract with transient or permanent shedding of the virus via seminal secretions. This makes the stallion to one of the dominant factors of the propagation of the field virus. The use of EAV shedding stallions in natural breeding or AI is very risky and only justifiable under certain precautions and additional measurements e.g. in EAV-seropositive or vaccinated mares. A consistent progress in the defeat of the disease can be expected from vaccination of the seronegative stallions with dead or inactivated live vaccines as they are considered to be able to prevent the establishing of EAV shedder status.

Abortion, Veterinary↗
PubMed2000

Precise, highly female-biased sex ratios in a social spider.

It has been recognized for some time that the risk of producing maleless clutches should select for a lower than binomial variance in the sex ratio of organisms with female-biased sex ratios, small clutches and breeding groups containing the clutch of a single female. However, to date, precise sex ratios have only been reported for organisms with haplodiploid sex determination, a system which allows direct control of the sex of individual offspring. In contrast, under heterogametic sex determination chance is expected to play a crucial role in determining the sex composition of any one family, in particular when males are the heterogametic sex. Here, we present evidence of precise or underdispersed primary sex ratios in the Neotropical social spider Anelosimus domingo Levi. We show that this diplodiploid species with male heterogamety has not only beaten the odds of meiosis by producing mostly daughters, but has also attained relative precision in the proportion of sons and daughters produced in any one clutch. The latter finding suggests the existence of mechanisms that allow sorting of the two types of sperm in this spider species.

Animals↗
PubMed2000

Technical note: covariance adjustment in beef cattle research.

In randomized experiments, analysis of covariance is used to increase precision of treatment comparisons. However, for factors that are observational (e.g., breed) or for covariates measured after treatments are applied, it may not be biologically meaningful to calculate treatment means adjusted to a common value of the covariate. For example, in beef cattle trials, it may not be meaningful to compare hot carcass weights of medium- and large-framed breeds adjusted to a common weaning weight because the breeds have naturally different mean weights at weaning. If done, this would typically result in an undesirable downward adjustment of mean carcass weight for the large-framed breed and upward adjustment of the mean carcass weight for the small-framed breed. However, it is desirable to evaluate the mean carcass weight for two diets, adjusted to a common weaning weight. Because of randomization, the expected weaning weights of animals on the two diets are equal and hence the only effect of covariance adjustment is to increase precision of the diet comparison. This paper presents the statistical methodology for estimating covariance adjusted means (termed partially adjusted means) when the levels of some of the factors are compared at a common value of the covariate but the levels of other factors are compared at differing values of the covariate. The methodology is extended to include several covariates, several factors, and arbitrary interactions among covariates, among factors, and between factors and covariates. These methods can be implemented using existing statistical software for linear models. Data are presented from an experiment in which hot carcass weight was recorded for beef cattle. Analyses of these data illustrate that adjusted means, partially adjusted means, and unadjusted means may differ substantially in magnitude, significance, and in the ranking of treatments.

Analysis of Variance↗
PubMed2005

Polymerase chain reaction method to identify Down syndrome model segmentally trisomic mice.

The Ts65Dn segmentally trisomic mouse possesses an extra copy of a segment of chromosome 16 translocated to chromosome 17. This segment includes the mouse homolog of the Down syndrome critical region of human chromosome 21. The Ts65Dn mouse serves as a useful model to study the developmental regulation of the Down syndrome phenotype. To identify mice bearing the extra chromosome 16 segment, we developed a polymerase chain reaction (PCR) method as an alternative to karyotyping. Conditions under which segments of genes on chromosome 16 (App and Dyrk1a) could be coamplified with a control gene on chromosome 8 (Acta1) so that the yield of each PCR product was proportional to the amount of its template were determined. The amplification products were resolved and quantified by two methods. In the first method, the DNA segments were separated by agarose gel electrophoresis and stained with ethidium bromide. The fluorescence yields were quantified by photodensitometry. In the second method, the fragments were resolved and quantified by the high-performance DNA analysis system, a high-throughput, multichannel, microcapillary electrophoresis instrument. The results of both methods were within 10% of the expected ratio of 1.5. Application of these methods has allowed the maintenance of a Ts65Dn breeding colony through six generations and should permit the precise and efficient identification of trisomic and disomic animals at any developmental stage with minimally invasive procedures.

Animals↗
PubMed2004

Determination of genetic status in a closed colony of rhesus monkeys (Macaca mulatta).

The long-term management of breeding colonies requires some measure of genetic diversity in the animal population. For the maintenance of breeding colonies of monkeys used for biomedical research, known pedigrees supply precise data to determine the genetic status of colonies. We present data of genetic analyses in an old closed colony of rhesus macaques (Macaca mulatta) that was established in 1932 with 100 animals. For more than 40 years, the animals were kept on an isolated island and, in 1980, single-male breeding groups were established. A total of 333 DNA samples of these animals were typed to 20 microsatellite markers using multiplex PCR in order to verify inbreeding coefficient (alpha) and level of heterozygosity. We found an average heterozygosity of 64% and obtained alpha=-0.03293 (+/-0.00573). Our results indicate that the reproductive strategy used was effective because consanguineous breeding was avoided. A continuous genetic program must be carried out in order to obtain better quality primates for biomedical research.

Animals↗