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1.
The horses studied were of the Swiss Warmblood breed and most were ELA-typed to assess a possible association of dermal hypersensitivity to insect bites with the major histocompatibility complex. Firstly, the occurrence of the condition was examined in 304 half-siblings sired by six stallions (A to F). Fourteen cases of dermal hypersensitivity were recognized and all were in the 153 offspring of Stallions C, E and F. Most animals of this group were also investigated for chronic hypersensitivity bronchitis: none of the sires displayed clinical signs of dermal hypersensitivity, but Stallions D, E and F were affected by chronic bronchitis. Among the animals investigated for both conditions only one horse showed coincidence of the two diseases as can be expected when the diseases are not correlated. The frequency of manifest dermal hypersensitivity and/or chronic hypersensitivity bronchitis varied in the half-sibling groups of individual sires. These findings suggest that the allergic conditions are independent entities. Secondly, the occurrence of dermal hypersensitivity was studied in three generations of horses at a stud at which Stallion C had exerted a particularly strong influence. A total of 302 animals, all born and raised at this stud, were surveyed over a period of 12 years. The descendants of Stallion C showed a significantly higher incidence (P less than 0.01) of dermal hypersensitivity (two daughters out of 19; eight second generation offspring out of 103; one third generation offspring out of 85) than did the controls of the same age classes but unrelated to Stallion C at the same stud (0 out of 95).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

2.
Polish Arabian horses are one of the most important populations of this breed in the world. Their post‐war history can be divided into two periods, with the dominant role of state studs until 1989, and the increasing significance of private breeding in the next years. The goal of the study was to evaluate genetic diversity and structure of the population under a new breeding policy. The analyses of breeding and microsatellite data from 1996 to 2012 provide a coherent picture of the population with constant flow of horses only in one direction from state to private studs. An increase in the number of broodmares was observed, from 396 mares in 1996 to 1021 mares in 2012. The proportion of foreign sires used in Polish studs also increased, from 7.1% to 37.0%. An increasing number of alleles and progressive differentiation in mares were observed. STRUCTURE analysis indicated that the Polish horses were clearly separated from foreign horses used in Polish breeding, although only one of the 75 alleles found can be considered as typically Polish. The high heterozygosity is an important feature of the Polish population; however, the decrease of heterozygosity in state broodmares was noted. This issue needs to be studied further.  相似文献   

3.
This study presents the estimates of heritability for spondylosis deformans in the boxer based on 353 offspring from 24 randomly selected sires, each with at least three radiographically investigated offspring. The estimated heritability (h2) for maximum degree of osteophyte development was high, both when estimated by paternal half-sib correlation (0·42) and by the regression of offspring based on the parents (0·62). The heritability for the number of affected discs estimated by paternal half-sib correlation was also high (0·47). The estimate of heritability for the number of affected discs based on regression of offspring on the parents was lower at 0·13. All heritabilities had large standard errors. A positive phenotypic correlation between spondylosis deformans and hip dysplasia was observed. Assuming a significant portion of the correlation is genetic, this fact may permit selection against spondylosis deformans without negatively influencing the incidence of hip dysplasia. Since the incidence of spondylosis deformans is high even in young dogs, it should be possible to detect a large proportion of genetically predisposed animals by radiographic examination of the spine at one year of age; at the same time that dogs are presented for a routine test for hip dysplasia.  相似文献   

4.
Different modes of selection in dogs were studied with a special focus on the availability of disease information. Canine hip dysplasia (CHD) in the German shepherd dog was used as an example. The study was performed using a simulation model, comparing cases when selection was based on phenotype, true or predicted breeding value, or genomic breeding value. The parameters in the simulation model were drawn from the real population data. The data on all parents and 40% of their progeny were assumed to be available for the genetic evaluation carried out by Gibbs sampling. With respect to the use of disease records on progeny, three scenarios were considered: random exclusion of disease data (no restrictions, N), general exclusion of disease data (G) and exclusion of disease data for popular sires (P). One round of selection was considered, and the response was expressed as change of mean CHD score, proportion of dogs scored as normal, proportion of dogs scored as clearly affected and true mean breeding value in progeny of popular sires in comparison with all sires. When no restrictions on data were applied, selection on breeding value was three times more efficient than when some systematic exclusion was practised. Higher selection response than in the exclusion cases was achieved by selecting on the basis of genomic breeding value and CHD score. Genomic selection would therefore be the method of choice in the future.  相似文献   

5.
The objective of this study was to investigate the possibility of genotype x environment interactions for weaning weight (WWT) between different regions of the United States (US) and between Canada (CA), Uruguay (UY), and US for populations of Hereford cattle. Original data were composed of 487,661, 102,986, and 2,322,722 edited weaning weight records from CA, UY, and US, respectively. A total of 359 sires were identified as having progeny across all three countries; 240 of them had at least one progeny with a record in each environment. The data sets within each country were reduced by retaining records from herds with more than 500 WWT records, with an average contemporary group size of greater than nine animals, and that contained WWT records from progeny or maternal grand-progeny of the across-country sires. Data sets within each country were further reduced by randomly selecting among remaining herds. Four regions within US were defined: Upper Plains (UP), Cornbelt (CB), South (S), and Gulf Coast (GC). Similar sampling criteria and common international sires were used to form the within-US regional data sets. A pairwise analysis was done between countries and regions within US (UP-CB vs S-GC, UP vs CB, and S vs GC) for the estimation of (co)variance components and genetic correlation between environments. An accelerated EM-REML algorithm and a multiple-trait animal model that considered WWT as a different trait in each environment were used to estimate parameters in each pairwise analysis. Direct and maternal (in parentheses) estimated genetic correlations for CA vs UY, CA vs US, US vs UY, UP-CB vs S-GC, UP vs CB, and S vs GC were .88 (.84), .86 (.82), .90 (.85), .88 (.87), .88 (.84), and .87 (.85), respectively. The general absence of genotype x country interactions observed in this study, together with a prior study that showed the similarity of genetic and environmental parameters across the three countries, strongly indicates that a joint WWT genetic evaluation for Hereford cattle could be conducted using a model that treated the information from CA, UY, and US as a single population using single population-wide genetic parameters.  相似文献   

6.
Insemination results of technicians and dairy bulls in AI were studied using 87112 first inseminations from 283 bulls by 37 technicians. The traits studied were 28- and 56-day non-return rates. Models were compared on the basis of the correlation between solutions obtained from a reference model and reduced models.Age at first service in heifers and calving to first service interval in cows did not affect the ranking of sires and technicians. Routine monthly evaluation of non-return rates of sires required a correction for parity of cow and month of insemination. In addition genetic group and number of inseminations should be considered. Monthly evaluation of technicians could be based on deviations within studs.Annual evaluation of sires and technicians should consider a herd effect as well. The correlation between solutions (56-day non-return) for models with and without herd effect was 0.94 for both sires and technicians, whereas the absolute average change was 0.5%.  相似文献   

7.
Broomfield Corriedales originate from a 15-year programme of selective breeding from sheep that evaded footrot when deliberately subjected to field challenge. To determine whether this policy may have resulted in improved resistance to footrot, trials were set up in which representative animals from the Broomfield blood-line were challenged with footrot by either experimental or natural infection, together with Corriedale sheep of similar age and sex but from flocks in which the disease is not known to occur. In another approach, the occurrence of footrot was compared in the offspring of Broomfield and of non-Broomfield sires mated with randomly selected ewes in a commercial Corriedale flock in which the condition was prevalent. Finally, the effects of natural challenge in Broomfield lambs were compared with those in a selection line of Corriedale lambs of which both parents had a history of chronic footrot disease. Footrot affected significantly fewer sheep of the Broomfield blood-line and to a markedly lesser degree than those chosen for comparison under identical challenge conditions. Where present, foot infections in Broomfield animals also tended to be less invasive and less persistent. Reduced footrot prevalence was also demonstrated in three birth cohorts of first-cross offspring of Broomfield sires relative to the offspring of other sires, though differences were not significant at all inspections. These findings, considered as a supplement to the historical development of the Broomfield flock, offer encouraging prospects for breeding programmes to enhance the resistance of sheep to footrot disease.  相似文献   

8.
OBJECTIVE: To determine the mode of inheritance of congenital proportionate dwarfism in Angus and Angus crossbred cattle, initially detected in two commercial beef herds in northern New South Wales. DESIGN: Matings of normal carrier sires to unrelated cows of diverse breeds, and of one carrier sire to his unaffected daughters. An unrelated Piedmontese bull was also mated to unaffected daughters of the carrier sires. PROCEDURE: Two carrier Angus bulls and nine unaffected daughters, all of whom were completely indistinguishable from normal animals, were purchased for controlled breeding studies under known nutritional and disease conditions. Affected and carrier individuals were examined for the presence of obvious chromosomal abnormalities. RESULTS: Angus dwarfism has been successfully reproduced under controlled experimental conditions over successive years using unrelated dams and is undoubtedly heritable. The high frequency of occurrence of affected individuals (23/61 = 0.38 +/- .06) among the progeny of matings of the Angus sires to unrelated females of diverse breeding is not compatible with recessive inheritance, because of the negligible frequency of proportionate dwarfism in the breeds of the dams. Both paternal and maternal transmission of the defect was demonstrated, so that imprinting in the strict sense of a gene that is only expressed when received from the male parent appears not to be involved. Tested individuals showed no evidence of gross chromosomal abnormality. Dominant autosomal inheritance with incomplete penetrance was indicated by the lack of expression of the defective gene in the two Angus sires and in three unaffected daughters who produced dwarf calves from matings to the Piedmontese bull. CONCLUSIONS: The mode of inheritance is that of a single autosomal dominant gene with a penetrance coefficient of 0.75 +/- 0.12, estimated from the observed incidence of 23/61 affected offspring of the two carrier Angus bulls mated to unrelated dams. Simple genetic models involving either (i) an unstable mutant which changes at high frequency to the expressed dominant dwarfing allele during gametogenesis, or (ii) a dominant allele with penetrance determined by an unlinked modifying locus, are shown to be compatible with the experimental data. Both models indicate that penetrance of the dwarfing gene may possibly be higher in matings involving carrier daughters of the two Angus bulls.  相似文献   

9.
A study was conducted to define the mode of inheritance of lateral luxation of the superficial digital flexor (SDF) tendon in different lines of Shetland sheepdogs by examination of pedigree data. This pedigree analysis included affected and unaffected dams, sires, and offspring; common clinical signs; and age at onset. The clinical, histopathologic, and radiographic features of the disease were also studied. Of the 14 offspring from five matings of an affected sire to unrelated affected females, 100% were affected with lateral luxation of the SDF tendon. Of the 59 offspring from the same affected sire to unrelated, unaffected females, 44% were affected. The mating between normal parents produced 61% unaffected and 39% affected offspring. Application of the phenotypic findings in this study to a Mendelian genetic model of inheritance suggests that lateral luxation of the superficial digital tendon in Shetland sheepdogs is inherited as a simple autosomal recessive trait.  相似文献   

10.
DNA fingerprinting techniques were used to try to resolve the parentage of an Exmoor pony foal. Three young Exmoor ponies, one female and two males, shared a paddock and the female subsequently became pregnant. The two possible sires were three-quarter siblings and were also half-siblings to the dam. Southern hybridisation of Exmoor pony DNA with human mini-satellite probes resolved the disputed parentage in spite of the fact that there was a 70 per cent band share between the individuals involved. Colt M6 was 2.06 times more likely to be the father than an uncle, and Colt M3 was 477 times more likely to be an uncle than the father.  相似文献   

11.
Angus, Polled Hereford and Santa Gertrudis bulls from ages 1 through 5 and 7 yr were assigned to 26 two-sire breeding groups. Each year, straightbred and crossbred cows of these breeds were allotted at random within breed composition, age of dam and calving date to breeding groups on pasture. Sires within each breeding group or pair were the same age at breeding and were two of the three breeds of sires. Neither calving rate nor the proportion of calves born by one vs the other sire in the two-sire breeding groups was affected by sire age among breeding groups. For a given breed, there was no uniformity among the sires in the proportion of calves they sired in their two-sire breeding groups. The proportion of calves born for the 26 sire pairs averaged .64 vs .36 (SE = 0.4 for either high or low value) for one vs the other sire in a sire pair with no indication that calving rate was affected by unequal proportions of calves by sires within sire pairs. Cows calved significantly earlier in the calving period (b = -.775 +/- .127) as calving rate increased among sire pairs. The number of days from the start of the breeding period to calf birth was affected by differences between sires in sire pairs for 8 of the 26 pairs, but there were no significant differences due to sire pair or breed of sire because of interaction between these two variables.  相似文献   

12.
The aim of the present study was to analyse the genetic subdivision of the Old Kladruber horse population compared to the historically close Lipizzan breed and to estimate genetic relatedness between them. A set of 13 microsatellites was used for genotyping a total of 270 Old Kladruber horses representing grey and black colour varieties and 418 Lipizzan horses from Slovak and Slovenian studs. The proportion of obtained heterozygosity indicates no major loss of genetic diversity within them. At the individual level across analysed populations, the formation of clusters in respect to breed’s origin and particular studs was observed. The Wright’s FST and genetic distances indicated genetic segregation of both colour varieties at the intraspecific level of the Kladruber breed. Moreover, the membership probability outputs showed that the frequencies of alleles varied across the three main regions represented by both Old Kladruber varieties and Lipizzan, depending on breeding history and strategy of studs.  相似文献   

13.
Strangles in horse studs: Incidence, risk factors and effect of vaccination   总被引：2，自引：0，他引：2  
A questionnaire survey of 179 horse studs in New South Wales was conducted to estimate the incidence of strangles during 1985 to 1988, to identify risk factors for strangles outbreaks and to assess the effect of strangles vaccination. Forty-nine of the studs (27.4%) had at least one strangles outbreak during this period and 62 studs (34.6%) had at least one case of strangles. The average incidence of strangles was 2.1 cases per 100 horses per year. The risk of strangles increased progressively with the total horse population and rose markedly when more than 100 mares had been served in the 1988-89 season. Certain types of feeders, fences and water sources were also significantly associated with outbreaks of strangles. Strangles vaccine was used on 63 studs (35.2%). Thirty-seven of these (58.7%) used the manufacturer's recommended vaccination regime. When other risk factors were taken into account, vaccination had no significant effect on the likelihood of a strangles outbreak.  相似文献   

14.
It has been known for many years that the offspring of scrapie affected ewes are at increased risk of developing scrapie but whether this is simply the result of an increased genetic susceptibility or transmission of infection has always been unclear. To contribute to clarify this we analysed the data collected in a detailed study of scrapie occurrence in a number of naturally affected commercial sheep flocks in Great Britain (GB) to investigate the association between PrP genotype and parental scrapie status and the incidence of scrapie. Our analyses confirmed the strong association between PrP genotype and the incidence of scrapie found in previous studies and a low incidence of scrapie in animals carrying the ARR allele and a high risk in homozygous VRQ animals. However, we also demonstrate an increased incidence of scrapie in the offspring of scrapie affected ewes controlling for the confounding effect of PrP genotype, but no increased scrapie incidence in the offspring of scrapie affected sires. Our results suggest that some of the increased incidence of scrapie in the offspring of scrapie affected ewes is the result of transmission of infection from mother to offspring. Our results confirm that a breeding policy aimed at decreasing the genetic susceptibility of the population should decrease the incidence of scrapie and that removing the offspring of scrapie affected animals from affected flocks could contribute to the control of this disease.  相似文献   

15.
A study was conducted to investigate the clinical aspects and to define the mode of inheritance of idiopathic epilepsy in the Bernese mountain dog. Pedigree analyses were carried out on an open, non-preselected population of 4005 dogs. Five different subpopulations with 50 epileptic dogs from 13 generations were included. Almost all epileptic patients showed generalised seizures of the grand-mal type with a well-defined prodromal and postictal phase. The majority (62 per cent) of the epileptic dogs had had their first seizures at between one and three years of age and it was found that the age at first seizure was significantly (P < 0.05) lower in dogs from affected parental animals than in dogs from healthy parental animals. A clear predisposition for males was also noted. Additionally, there was no correlation between inbreeding coefficient and age at first seizure or incidence rate of seizures. The increased occurrence of the disease in different subpopulations and different families of the same sires or dams showed that there was a genetic basis for the condition in the Bernese mountain dog. Furthermore, the results of the pedigree analyses and binomial test support the hypothesis that idiopathic epilepsy has a polygenic, recessive mode of inheritance in the breed. Additional objective test-mating programmes would however be necessary to define the exact mode of inheritance.  相似文献   

16.
Diseases involving the reproductive tract of bulls are a significant cause of economic and genetic loss to beef (eg, cow-calf units) and dairy (eg, bull studs) cattle producers. Injury or infectious disease may cause these abnormalities. Some injuries are amenable to surgical treatment. Surgical restoration of breeding bulls allows preservation of genetics and economic productivity for the owner of affected bulls. Accurate selection of surgical candidates is necessary to optimize prognosis.  相似文献   

17.
There was a high incidence of neonatal scours in 38 litters of pigs born at Compton in a four month period during 1978. The most important cause of the disease was an enteropathogenic Escherichia coli strain which possessed the K88 antigen. The Compton herd has been bred to produce pigs of three genotypes with respect to the presence or absence of the intestinal receptor for the K88 antigen. These are homozygous dominants (SS) and heterozygotes (Ss) susceptible to infection by virulent K88-positive E coli, and homozygous recessives (ss) resistant to the disease. The highest incidence of diarrhoea was in the susceptible progeny of resistant dams and susceptible sires. There was no K88 associated diarrhoea in resistant progeny or in susceptible progeny of susceptible dams.  相似文献   

18.
The study investigates the genetic diversity present as well as its development in the Brown Cattle population of Switzerland from pedigree information. The population consisted of three subpopulations, the Braunvieh (BV), the original Braunvieh (OB) and the US‐Brown Swiss (BS). The BV is a cross of OB with BS where crossing still continues. The OB is without any genetic influence of BS. The diversity measures effective population size, effective number of ancestors (explaining 99% of reference genome) and founder genome equivalents were calculated for 11 reference populations of animals born in a single year from 1992 onwards. The BS‐subpopulation consisted of animals and their known ancestors which were used in the crossing scheme and was, therefore, quite small. The youngest animals were born in 2002, the oldest ones in the 1920s. Average inbreeding was by far the highest in BS, in spite of the lowest quality of pedigrees, and lowest in OB. Effective population size obtained from the difference between average inbreeding of offspring and their parents was, mostly due to the heavy use of few highly inbred BS‐sires, strongly overestimated in some BV‐reference populations. If this parameter was calculated from the yearly rate of inbreeding and a generation interval of 5 years, no bias was observed and ranking of populations from high to low was OB – BV – BS, i.e. equal to the other diversity parameters. The high genetic diversity found in OB was a consequence of the use of many natural service sires. Rate of decrease of effective number of ancestors was steeper in BV than OB was, however, equal for founder genome equivalents. Founder genome equivalents were more stable than effective population sizes calculated from the difference between average inbreeding of offspring and parents. The five most important ancestors contributed one‐third of the 2002‐reference genomes of BV and OB, in BV all were BS‐sires. The relative amount of BS‐genes in the BV‐genome increased from 59.2% to 78.5% during the 11 years considered.  相似文献   

19.
Two horse farms, on which there was a high incidence of proven and suspected equine degenerative myeloencephalopathy (EDM), were studied. Symmetric ataxia and paresis, along with laryngeal adductor, cervicofacial, local cervical, and cutaneous trunci hyporeflexia, characterized the syndrome. Serum vitamin E concentration reflected a deficient state in affected and unaffected horses on both farms when compared with selected reference groups and with published values. A high incidence of the disease was evident in offspring of two particular sires on one farm. Vitamin E supplementation resulted in correction of the deficient state in most horses and was associated with a drastic reduction in the incidence of EDM on one farm from 40% to less than 10% the year following vitamin E supplementation. In addition, during the last year, the severity of signs in the few cases was dramatically reduced. This information substantiates the hypothesis that EDM is a vitamin E-responsive disorder of Equidae with a possible familial predisposition.  相似文献   

20.
The objective of this study was to detect QTL associated with the incidence of multiple pathogenic diseases in offspring from half-sib bovine families. Four F(1) sires were used to produce offspring: Brahman x Hereford (BH; n = 547), Piedmontese x Angus (PA; n = 209), Brahman x Angus (n = 176), and Belgian Blue x MARC III (n = 246). Treatment records for bovine respiratory disease, infectious keratoconjunctivitis (pinkeye), and infectious pododermatitis (footrot) were available for all of the offspring from birth to slaughter. The incidences of these 3 microbial pathogenic diseases were combined into a single binary trait to represent an overall pathogenic disease incidence. Offspring diagnosed and treated for 1 or more of the previously mentioned pathogenic diseases were coded as a 1 for affected. Cattle with no treatment record were coded as 0 for healthy. A putative QTL for pathogenic disease incidence was detected in the family derived from the BH sire at the genome-wise suggestive level. This was supported by evidence, in the same chromosomal region, of a similar QTL in the family derived from the PA sire. The maximum F-statistic (F = 13.52; P = 0.0003) was located at cM 18. The support interval of the QTL spanned from cM 9 to 28. Further studies should explore this QTL by using other bovine populations to further confirm the QTL and refine the QTL support interval. Offspring inheriting the Hereford allele, in the family from the BH sire, and the Angus allele, in the family from the PA sire, were less susceptible to incidence of pathogenic diseases, when compared with those inheriting the Brahman allele and Piedmontese allele, from the BH and PA sires, respectively.  相似文献   

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