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PubMed2003

Parental selection, number of breeding populations, and size of each population in inbred development.

Some breeders select inbreds from many F(2) or backcross breeding populations, each with relatively few progenies. Other breeders select inbreds from only a few breeding populations, each with many progenies. My objectives were to: (1) determine the relative importance of parental selection, number of breeding populations, and size of each population, and (2) find optimum combinations between number and size of breeding populations. I assumed that a breeder has resources to test a total of 2,000 recombinant inbreds for a quantitative trait that was controlled by 100 additive loci and had a heritability of 0.20, 0.60, or 1.0. The parental inbreds had an inherent pedigree structure due to advanced cycle breeding. The parental inbreds were ranked according to their mean performance, and breeding populations were made among all parents, the top 25% of parents, and the top 10% of parents. I found that the issue of number versus size of breeding populations was only secondary compared with the ability to identify, prior to making the crosses, the breeding populations with the highest mean performance. For a given level of effectiveness of parental selection, the selection response was largest when the maximum number of breeding populations was used. The effect of the number of breeding populations was minor, however, when selection was practiced among the parents or when heritability was less than 1.0. The results suggested that, in practice, large selection responses could be obtained with a wide range of combinations between number and size of breeding populations.

Computer Simulation↗
PubMed1986

Increasing ovulation rate and lambing percentage by active immunization against androstenedione in dairy sheep breeds.

A total of 1200 ewes, two hundred from each of six dairy breeds-the Karagouniko (K), the Serres (S), the Vlachiko (V), the Florinis (F), the Kimis (Km) and the Chios (Ch)-were used to examine the efficacy of a new immunogen (androstenedione-7a-HSA + DEAE-dextran) in improving reproductive performance. Ewes of each breed were randomly allotted to two groups, the control and the treated. Treated ewes were given two injections of 2 ml immunogen three weeks apart, while the control ewes were untreated. Rams were introduced to all ewes after the second injection. Twenty ewes in each group for each breed were laparotimized 7 to 10 days post-mating. Incidence of estrus and mating, the ovulation rate (OR), lambing percentage (Lp. 100), litter size (LS), and lamb (LbW) and litter weight (LW) were recorded. The OR was increased in immunized ewes compared to controls from 1.60, 1.46, 1.50, 2.50, 2.50 and 2.90 to 2.50, 2.06, 2.20, 3.20 (P<0.05), 4.20 and 4.80 (P<0.01), respectively, in K, S, V, F, Km and Ch breeds. No significant difference on Lp. 100 was observed between control and treated ewes of all breeds. The LS was increased in immunized ewes by 17, 20, 18, 28, 57 and 0 lambs compared to control ewes in K, S, V, F, Km and Ch breeds, respectively; however, the increase was statistically significant (P<0.05) only in Km and F breeds. The LbW was decreased in immunized ewes compared to controls; however, the decrease was statistically significant (P<0.05) only in the V breed. When compared to control ewes the LW was greater in immunized ewes of S, K, Km and F breeds while in Ch and V breeds LW was smaller. It was concluded that an increase in ovulation rate by active immunization against androstenedione may not be reflected in an increase of litter size in dairy sheep. Breed differences must be considered when producers intend to use this technique to improve litter size.

Journal Article↗
PubMed2005

Unfolding of population structure in Baltic sheep breeds using microsatellite analysis.

Studies of domestic animals are performed on breeds, but a breed does not necessarily equate to a genetically defined population. The division of sheep from three native and four modern Baltic sheep breeds was studied using 21 microsatellite loci and applying a Bayesian clustering method. A traditional breed-wise approach was compared to that relying on the pattern of molecular diversity. In this study, a breed was found to be inconsistent with a distinct genetic population for three reasons: (i) a lack of differentiation between modern Baltic breeds, since the majority of the studied sheep formed a single population; (ii) the presence of individuals of foreign ancestry within the breed; and (iii) an undefined local Saaremaa sheep was referred to as a breed, but was shown to consist of separate populations. In the breed-wise approach, only the clearly distinct Ruhnu sheep demonstrated low within-breed variation, although the newly identified Saaremaa populations also have low variability. Providing adequate management recommendations for the Saaremaa sheep is not possible without further studies, but the potential harmful effects of inbreeding in the Ruhnu sheep could be reduced through the use of two genetically related Saaremaa populations. In other breeds, excessive crossing appears to be a larger concern than inbreeding. Assigning individuals into populations based on the pattern of genetic diversity offers potentially unbiased means of elucidating the genetic population structure of species. Combining these genetic populations with phenotypic and aetiological data will enable formulation of the most informed recommendations for gene resource management.

Animals↗
PubMed2000

Geographic and breed distribution of an Msp I PCR-RFLP in the bovine growth hormone (bGH) gene.

Information is presented on the frequency of the Msp I (-) allele in the third intron of the bovine growth hormone gene in a large number of cattle breeds. Consideration of the breed frequencies in relation to their geographic origin shows a low frequency for breeds originating in Northern Europe, moderate frequencies for breeds originating in Eastern Europe or the countries surrounding the Mediterranean basin, and very high frequencies for breeds originating in the Indian subcontinent. Consideration of breed frequencies in relation to breed type, shows low to moderate frequencies for the humpless breeds, high frequencies for the humped breeds. Various explanations for this distribution are discussed, among them the possibility that the Msp I (-) allele originated in the Bos indicus breeds of the Indian subcontinent, from which it diffused through the humpless Bos taurus breeds of Eastern Europe, the Mediterranean basin, eventually reaching Western, Northern Europe, Western Africa in low frequencies.

Alleles↗
PubMed2001

Genetic diversity among chicken breeds estimated through randomly amplified polymorphic DNA.

The randomly amplified polymorphic DNA (RAPD) markers were used to detect polymorphism among five breeds of chicken i.e. White Leghorn and Rhodes Island Red (selected for part period egg production and egg mass respectively), Red Cornish and White Plymouth Rock (selected for early body weights) and Kadaknath (native breed). Twelve of the fifty random primers screened yielded distinct polymorphic RAPD profiles. Of the total 96 fragments amplified, about 25% showed polymorphism. Using the RAPD data matrix, the within population and between population genetic similarity was estimated. The selected improved breeds showed higher within population genetic similarity in comparison to the native breed. The two meat type breeds showed a high level of genetic similarity between themselves. The White Leghorn breed showed a low genetic similarity with other breeds. The native breed showed highest similarity with Rhodes Island Red. The dendogram was constructed to show phylogenetic relationship among these breeds. As expected, the genetic distances were lowest within similar type breeds and were highest between dissimilar type breeds. The results indicated the effectiveness of RAPD in detecting polymorphism between chicken populations and their applicability in population studies and establishing genetic relationships among the chicken populations.

Animals↗
PubMed1984

Profiles of luteinizing hormone, follicle-stimulating hormone, testosterone and prolactin in rams of diverse breeds: effects of contrasting short (8L:16D) and long (16L:8D) photoperiods.

Mature rams of Polled Dorset, Finnish Landrace, Rambouillet and Suffolk breeding were maintained in a temperature-controlled environment and exposed to two consecutive cycles of short (8L:16D) followed by long (16L:8D) days. Serum hormone concentrations were determined in weekly samples and in 24-h profiles characterized at the end of each lighting schedule (i.e., 12, 24, 36 and 48 weeks). In all four breeds, the pituitary-testicular axis was more active during short days as compared with long days and the magnitudes of changes in serum luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone concentrations were greater for the two most seasonal breeds, Finnish Landrace and Suffolks. In comparison to other breeds, Finnish Landrace rams had significantly (P less than 0.05) higher mean LH levels, showed the greatest number of LH peaks/24 h, and had the highest mean testosterone levels at the end of both periods of short days, while Rambouillet rams had significantly (P less than 0.05) lower testosterone. Rambouillets also showed the smallest changes in pulsatile LH and testosterone secretion and displayed the least number of LH peaks/24 h following short days. Serum FSH levels were significantly (P less than 0.05) higher in Finnish Landrace and Suffolk rams than in Polled Dorsets and Rambouillets after 12 weeks of short days. Breed differences in serum LH, FSH and testosterone were not apparent following long days. Prolactin levels in Rambouillet rams were significantly (P less than 0.05) lower than in the other breeds following both periods of long days. These results indicate that breed differences exist in mature rams with regard to hormone secretory profiles. Breed differences in serum gonadotropin and testosterone are only apparent during short days when the hypothalamo-pituitary-testicular axis in rams is considered most active. Likewise, breed differences in prolactin are noticeable only during long days when secretion of this hormone is enhanced. Breed differences in LH, FSH and testosterone secretion in rams during short days might be related to seasonality of mating and/or fecundity of breed types.

Animals↗
PubMed2002

Why breed every other year? The case of albatrosses.

Albatrosses exhibit extremely low reproductive rates, each pair brooding only one egg and subsequent chick at a time. Furthermore, in several of the species, the majority of successful pairs breed only once every second year (termed 'biennial' breeding). Thus, on average, these latter species have an annual fecundity of about half an offspring per year, while other albatrosses produce an egg and chick every year. Using our 40-year bank of demographic data, we compared 12 species of albatrosses according to these two breeding strategies to examine potential causes of biennial breeding. Biennial breeding could be due to physiological constraints, larger animals breeding more slowly, or ecological constraints, more distant pelagic feeding trips being energetically costly, or both. We tested these hypotheses by looking for predicted associations between the duration of the rearing period, the distance to the oceanic feeding zone and breeding frequency. We also looked for associations of these variables with other life-history traits. Body size had a strong influence on the duration of the rearing period, but not on the distance that birds travelled to the feeding zone. Both the duration of the rearing period and distance to the feeding zone appeared to have direct influences on breeding frequency, as revealed by a path analysis, and thus both hypotheses to explain biennial breeding were supported. Finally, breeding frequency exhibited a strong trade-off with adult survival and age at maturity, indicating that slower breeders live through more breeding seasons, perhaps mitigating their lower annual reproductive output.

Age Factors↗
PubMed2004

Genetic diversity in German draught horse breeds compared with a group of primitive, riding and wild horses by means of microsatellite DNA markers.

We compared the genetic diversity and distance among six German draught horse breeds to wild (Przewalski's Horse), primitive (Icelandic Horse, Sorraia Horse, Exmoor Pony) or riding horse breeds (Hanoverian Warmblood, Arabian) by means of genotypic information from 30 microsatellite loci. The draught horse breeds included the South German Coldblood, Rhenish German Draught Horse, Mecklenburg Coldblood, Saxon Thuringa Coldblood, Black Forest Horse and Schleswig Draught Horse. Despite large differences in population sizes, the average observed heterozygosity (H(o)) differed little among the heavy horse breeds (0.64-0.71), but was considerably lower than in the Hanoverian Warmblood or Icelandic Horse population. The mean number of alleles (N(A)) decreased more markedly with declining population sizes of German draught horse breeds (5.2-6.3) but did not reach the values of Hanoverian Warmblood (N(A) = 6.7). The coefficient of differentiation among the heavy horse breeds showed 11.6% of the diversity between the heavy horse breeds, as opposed to 21.2% between the other horse populations. The differentiation test revealed highly significant genetic differences among all draught horse breeds except the Mecklenburg and Saxon Thuringa Coldbloods. The Schleswig Draught Horse was the most distinct draught horse breed. In conclusion, the study demonstrated a clear distinction among the German draught horse breeds and even among breeds with a very short history of divergence like Rhenish German Draught Horse and its East German subpopulations Mecklenburg and Saxon Thuringa Coldblood.

Animals↗
PubMedDate not supplied

Prevalence of primary breed-related cataracts in the dog in North America.

The objective of the study was to determine the prevalence of cataracts in dogs presented to veterinary medical teaching hospitals in North America between 1964 and 2003. A retrospective study of all dogs presented with cataracts to veterinary medical teaching hospitals in North America between 1964 and 2003 was conducted to determine cataract prevalence. The different decades, breeds, gender, and age at time of presentation with cataract were compared. The prevalence of dogs presented with cataract varied by decade and ranged from 0.95% (1964-73), 1.88% (1974-83), 2.42% (1994-2003), to 3.5% (1984-93). The total number of dogs presented with cataracts over the 40-year period was 39,229. From 1964 to 2003 the prevalence of cataract formation in this patient population increased by about 255%. Fifty-nine breeds of dogs were affected with cataracts above the baseline prevalence of 1.61% seen in mixed-breed/hybrid dogs. The breeds with the highest cataract prevalence included: Smooth Fox Terrier (11.70%), Havanese (11.57%), Bichon Frise (11.45%), Boston Terrier (11.11%), Miniature Poodle (10.79%), Silky Terrier (10.29%) and Toy Poodle (10.21%). The breeds with the largest number of cataractous dogs during the entire four decades were the Boston Terrier (11.11%), Miniature Poodle (10.79%), American Cocker Spaniel (8.77%), Standard Poodle (7.00%), and Miniature Schnauzer (4.98%). Gender ratios of cataractous dogs seemed to affect limited breeds. Age of presentation with cataract diagnosis varied among several breeds. In the mixed-breed/hybrid baseline population, cataract formation appeared to be age related with a higher frequency of cataract formation in dogs after 4-7 years. Cataract formation is one of the most prevalent eye diseases in the dog population, and in about 60 breeds of dogs the prevalence of cataract exceeds that of the baseline mixed-breed/hybrid group. The prevalence of cataract is also influenced by age in most purebred dogs and affects 16.80% of the 7-15+-year-old mixed-breed/hybrid dog population. Total and age-related cataract prevalence in dogs seems very similar to that in man.

Animals↗
PubMedDate not supplied

Renal calculi in dogs and cats: prevalence, mineral type, breed, age, and gender interrelationships (1981-1993).

Three hundred seventeen specimens of urinary calculi of renal origin from 214 female dogs and 103 male dogs, and 71 specimens of urinary calculi of renal origin from 38 female cats and 33 male cats were submitted for mineral analysis between July 1, 1981, and December 31, 1993. Among dogs, 45 breeds were affected with renal calculi. Thirty-three breeds and a crossbred group were represented among females, but 8 breeds and the crossbred group accounted for 81% of the total. Among male dogs, 30 breeds and a crossbred group were represented, but 7 breeds and the crossbred group accounted for 69% of the total. Among cats, 10 breeds and a crossbred group were represented. Dogs and cats with renal calculi were older than those of 2 comparison population groups. More than one-half of the renal calculi in both dogs and cats were from the 1st known episode of urolithiasis. The risk of formation of renal calculi was found to be higher for cats than for dogs, when compared to other stone-forming cats and dogs (approximately 4.95 per 100 stone-forming cats and 2.88 per 100 stone-forming dogs). Among dogs, breeds at highest risk of developing renal calculi were Miniature Schnauzers, Shih Tzus, Lhasa Aposos, Yorkshire Terriers, and female Pugs. Also at high risk were male Dalmatians and male Basset Hounds. Among small dogs, females generally were at higher risk of developing renal calculi than were males. Regardless of size, terrier breed males generally were at higher risk of developing renal calculi. Breeds of dogs at low risk for development of renal calculi included crossbreds. German Shepherd Dogs, Labrador Retrievers, Golden Retrievers, and female Dachshunds. When only 1 kidney was involved, the risk of left renal calculus was greatest for both dogs and cats, but bilateral renal involvement was relatively common in both species (19% and 9%, respectively). Among dogs, specimens composed of 1 mineral substance (e.g., struvite) occurred more often in males (58.3%) than in females (37.9%). Female dogs formed renal calculi containing struvite or oxalate more often than did males; males formed calculi containing urate more often than did females. Calculi containing oxalate, apatite, or some combination of these minerals predominated among cats; only 1 specimen from 38 female cats and only 4 specimens from 33 male cats contained neither oxalate nor apatite. Crossbred cats were significantly less likely to have renal calculi than were other breeds. A single renal calculus specimen was identified in several uncommon breeds including Tonkinese and Birman cats, and Affenpinscher, Clumber Spaniel, English Shepherd, and Field Spaniel dogs. No significant differences were observed between male and female dogs or between male and female cats with regard to mineral type of the specimen and the presence of urinary tract infection.

Age Distribution↗
PubMedDate not supplied

A novel method for the estimation of the relative importance of breeds in order to conserve the total genetic variance.

The need for conservation of farm animal genetic resources is widely accepted. A key question is the choice of breeds to be conserved. For this purpose, a core set of breeds was introduced in that the total genetic variance of a hypothetical quantitative trait was maximised (MVT core set). For each breed the relative contribution to the core set was estimated and the breeds were ranked for conservation priority according to their relative contribution. The method was based on average kinships between and within breeds and these can be estimated using genetic marker data. The method was compared to a recently published core set method that maximises the variance of a hypothetical population that could be obtained by interbreeding the conserved breeds (MVO core set). The results show that the MVT (MVO) core set favours breeds with a high (low) within breed kinship that are not related to other breeds. Following this, the MVT core set method suggests conserving breeds that show a large difference in the respective population mean of a hypothetical quantitative trait. This maximises the speed of achieving selection response for this hypothetical selection direction. Additionally, bootstrap based methods for the estimation of the breed's contribution to the core sets were introduced, substantially improving the accuracy of the contribution estimates.

Animals↗
PubMed2001

Androgen receptors are only present in mesenchyme-derived dermal papilla cells of red deer (Cervus elaphus) neck follicles when raised androgens induce a mane in the breeding season.

Red deer stags produce an androgen-dependent mane of long hairs only in the breeding season; in the non-breeding season, when circulating androgen levels are low, the neck hair resembles the rest of the coat. This study was designed to determine whether androgen receptors are present in deer follicles throughout the year or only in the mane (neck) follicles when circulating testosterone levels are high in the breeding season. Although androgens regulate much human hair growth the mechanisms are not well understood; they are believed to act on the hair follicle epithelium via the mesenchyme-derived dermal papilla. The location of androgen receptors in the follicle was investigated by immunohistochemistry and androgen binding was measured biochemically in cultured dermal papilla cells derived from mane and flank follicles during the breeding season and from neck follicles during the non-breeding season. Immunohistochemistry of frozen skin sections using a polyclonal antibody to the androgen receptor localised nuclear staining only in the dermal papilla cells of mane follicles. Saturation analysis assays of 14 primary dermal papilla cell lines using [(3)H]-mibolerone demonstrated high-affinity, low-capacity androgen receptors were present only in mane (breeding season neck) cells; competition studies with other steroids confirmed the specificity of the receptors. Androgen receptors were not detectable in cells from either the breeding season flank nor the non-breeding season neck follicles. The unusual biological model offered by red deer of androgen-dependent hair being produced on the neck in the breeding, but not the non-breeding season, has allowed confirmation that androgen receptors are required in follicle dermal papilla cells for an androgen response; this concurs with previous human studies. In addition, the absence of receptors in the non-breeding season follicles demonstrates that receptors are not expressed unless the follicle is responding to androgens. Androgen receptors may be induced in mane follicles by seasonal changes in circulating hormone(s).

Androgens↗
PubMed1997

A comparison of two collection methods for estimating abundance and parity of Anopheles albimanus in breeding sites and villages of southern Mexico.

The abundance and age structure of Anopheles albimanus populations were estimated by UV updraft light traps and human landing catches within villages and in nearby breeding sites of southern México. Four villages and 5 breeding sites were selected for the study. Light trap and human landing catches were simultaneously carried out in each breeding site and each village. Anopheles albimanus was the most abundant malaria vector caught in breeding sites and in villages. Significant differences in overall An. albimanus abundance among villages and among breeding sites were detected only by human landing catches. In both villages and breeding sites, more mosquitoes were captured by 1 human bait (34.3 +/- 6.3 and 14.6 +/- 2.9, respectively) than by one light trap (15.9 +/- 3.3 and 2.4 +/- 0.3 respectively) collection. After pooling, no significant differences were detected in the abundance estimated by each method in breeding sites and villages. A significant correlation of numbers of specimens between methods was detected. Age structure was different between samples from breeding sites and villages, with more gravid females collected in breeding sites, whereas more nulipars were collected in villages. By collection method, age structure was also different both in breeding sites and in villages. In breeding sites, the percentage of parous females was significantly higher in human landing catches, whereas the percentage of gravid females was significantly higher in light traps. In villages, only the percentage of gravid females was significantly higher in light traps. Our results suggests that UV light traps could be used to measure several entomological parameters of An. albimanus populations because both abundance variations and parity rates were similarly detected by both methods.

Animals↗
PubMed2000

The genetic structure of Spanish Celtic horse breeds inferred from microsatellite data.

Partition of the genetic variability, genetic structure and relationships among seven Spanish Celtic horse breeds were studied using PCR amplification of 13 microsatellites on 481 random individuals. In addition, 60 thoroughbred horses were included. The average observed heterozygosity and the mean number of alleles were higher for the Atlantic horse breeds than for the Balearic Islands breeds. Only eight percentage of the total genetic variability could be attributed to differences among breeds (mean FST approximately 0.08; P < 0.01). Atlantic breeds clearly form a separate cluster from the Balearic Islands breeds and among the former only two form a clear clustering, while the rest of Atlantic breeds (Jaca Navarra, Caballo Gallego and Pottoka) are not consistently differentiated. Multivariate analysis showed that Asturcon populations, Losina and Balearic Islands breeds are clearly separated from each other and from the rest of the breeds. In addition to this, the use of the microsatellites proved to be useful for breed assignment.

Animals↗
PubMed2001

Photoperiodic control of the concentration of luteinizing hormone, prolactin and testosterone in the male emu (Dromaius novaehollandiae), a bird that breeds on short days.

The objective of this study was to establish, for a short-day breeding bird, the male emu, whether the breeding season is principally controlled by changes in photoperiod, and to investigate the endocrine mechanisms involved. Two groups of adult males were subjected to three alternating periods of 150-185 days of 14 h light/day (LD) and 10 h light/day (SD) terminating in a 360-day period of LD or SD. Transfer from LD to SD led to increases in plasma concentrations of luteinizing hormone (LH) and testosterone, after 82 +/- 8 and 73 +/- 3 (SEM) days, and an increase in prolactin concentrations after 115 +/- 12 days. Concentrations of LH and testosterone began to decrease before transfer back to LD, at a time when prolactin concentrations were approaching peak values. Transfer from LD to 360 days of SD resulted in increases in LH and testosterone concentrations, and these terminated after an increase in prolactin concentrations. After transfer from SD to 360 days of LD, plasma concentrations of LH and testosterone began to increase, after delays of 222 +/- 24 and 225 +/- 13 days, and were high at the end of the study, while prolactin values remained depressed throughout. These observations clearly show that seasonal breeding in the emu is directly controlled by changes in photoperiod. The dynamics of the hormonal responses to change of photoperiod suggest that, despite being short-day breeders, the photoregulation of breeding in emus involves mechanisms that are currently accepted for birds, rather than mechanisms that have been proposed for short-day breeding mammals. The initiation of breeding in emus is due to dissipation of photorefractoriness by short days which leads to an increase in the secretion of gonadotrophins to levels that are sufficient to support full reproductive condition. The termination of breeding, while days are still short, is due to the antigonadotrophic action of prolactin which, unusually for birds, increases while the days are still short. In conclusion, breeding activity in male emus is strongly controlled by photoperiod. Emus are short-day breeders, but the central mechanisms that regulate the secretion of reproductive hormones seem to be similar to those previously proposed for long-day breeding birds. The pattern of prolactin secretion in emus suggests an important role for this hormone in the termination of the breeding cycle.

Animals↗
PubMed2004

Effect of breeder age and breeding season on egg production and incubation in farmed ostriches.

(1) This research was carried out to investigate changes in egg production and hatchability as influenced by age and breeding season of 10 trios (two females, one male) of ostrich (Struthio camellus) during 1998 to 2002. (2) Breeding season affected number of eggs laid per female per season, average egg weight, length of laying period and clutch sequence. (3) The number of eggs laid per female per season was 25 in the first breeding season and 57 by the fifth breeding season. The laying period lasted 169 d in the first season whereas it was 210 d by the fifth season. The breeding season became longer year by year. (4) The number of clutches was two in the first season, three in the second and 4 in the later breeding seasons: the mean interval between cycles was 9 to 10.6 d and the mean number of eggs in one cycle varied from 12 to 14.4. (5) The breeding season affected the hatchability of fertile eggs, chick weight at hatching, hatchability of total eggs, fertility, malpositioned embryos, deformed chicks and assisted chicks during hatching. The first 4 variables increased and the last three decreased, with each breeding season. (6) Weight loss of eggs and length of incubation were unaffected by the breeding season. Hatchability which was 64.3% in the first season increased progressively and reached 73.1% in the fifth breeding season.

Aging↗
PubMed2004

Effects of winning the Westminster Kennel Club Dog Show on breed popularity.

OBJECTIVE: To determine whether winning best in show at the annual Westminster Kennel Club Dog Show was associated with a subsequent increase in breed popularity. DESIGN: Analysis of archival data. STUDY POPULATION: Breed-specific numbers of individual purebred puppies registered with the American Kennel Club between 1946 and 2002. PROCEDURE: For breeds that had won the Westminster Show, the slope of the curve for number of new registrations per year for the 5 years prior to winning was compared with the slope of the curve for the 5 years after winning. In addition, the annual percentage change in number of new registrations for the breed that won each year was compared with the annual percentage change in number of new registrations for the nonwinning breed most similar in popularity to the winning breed. RESULTS: For breeds that had won the Westminster Show, the slope of the curve for number of new registrations per year for the 5 years prior to winning was not significantly different from the slope of the curve for the 5 years after winning. Annual percentage change in number of new registrations for the breed that won each year was not significantly different from annual percentage change in number of new registrations for matched nonwinning breeds. CONCLUSIONS: Results do not support the view that being named best in show at the annual Westminster Show results in a surge in popularity of winning breeds.

Animals↗
PubMed1997

Estimation of direct and maternal breed effects for prediction of expected progeny differences for birth and weaning weights in three multibreed populations.

Direct and maternal breed effects on birth and 200-d weights were estimated for nine parental breeds (Hereford [H], Angus [A], Braunvieh [B], Limousin [L], Charolais [C], Simmental [S], Gelbvieh [G], Red Poll [R], and Pinzgauer [P]) that contributed to three composite populations (MARC I = 1/4B, 1/4C, 1/4L, 1/8H, 1/8A; MARC II = 1/4G, 1/4S, 1/4H, 1/4A; and MARC III = 1/4R, 1/4P, 1/4H, 1/4A). Records from each population, the composite plus pure breeds and crosses used to create each composite, were analyzed separately. The animal model included fixed effects of contemporary group (birth year-sex-dam age), proportions of individual and maternal heterosis and breed inheritance as covariates, and random effects of additive direct genetic (a) and additive maternal genetic (m) with covariance (a,m), permanent environment, and residual. Sampling correlations among estimates of genetic fixed effects were large, especially between direct and maternal heterosis and between direct and maternal breed genetic effects for the same breed, which were close to -1. This resulted in some large estimates with opposite sign and large standard errors for direct and maternal breed genetic effects. Data from a diallel experiment with H, A, B, and R breeds, from grading up and from a top cross experiment were required to separate breed effects satisfactorily into direct and maternal genetic effects. Results indicate that estimation of direct and maternal breed effects needed to predict hybrid EPD for multibreed populations from field data may not be possible. Information from designed crossbreeding experiments will need to be incorporated in some way.

Aging↗