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B A Freking

Publications and source records attributed to B A Freking.

At least 19 recordsLinked to original sources
PubMed2004

Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds of sheep: IV. Survival, growth, and carcass traits of F1 lambs.

The objectives of this study were to estimate effects of sire breed (Dorset, Finnsheep, Romanov, Texel, and Montadale), and dam breed (Composite III and Northwestern whiteface) on survival, growth, carcass, and composition traits of F1 lambs. Effects of mating season (August, October, and December) were estimated for survival and growth traits. Data were collected on 4,320 F1 lambs sired by 102 purebred rams over 3 yr. Birth weight was recorded on all lambs, and subsequent BW were adjusted to 56 (weaning), 70, and 140 d of age (n = 3,713, 3,654, and 3,579 observations, respectively). Survival of dam-reared progeny (n = 4,065) to weaning was recorded. Each year, wethers from October matings were slaughtered in three groups at 25, 29, and 33 wk of age to obtain carcass data (n = 546). In addition to standard carcass traits, resistive impedance measurements were recorded on the warm carcass to predict lean mass. Dam breed (P = 0.37) did not influence lamb survival to weaning, but sire breed (P < 0.05) was important. Romanov-sired lambs excelled in survival rate to weaning (94.1%), followed by Finn-sheep (93.0%), Texel (90.7%), Dorset (90.0%), and Montadale (89.1%) sired progeny. Lower (P < 0.01) postweaning growth rate was observed for Texel (267 g/d) and Finnsheep (272 g/d) sired progeny than for Dorset (285 g/d), Montadale (282 g/d), and Romanov (278 g/d) sired progeny. Sire breed and dam breed were generally significant for most carcass traits. Breed differences in distribution of carcass fat and carcass shape were detected; however, carcass composition was similar for all sire breeds when compared at a constant carcass weight. When evaluated at a constant 12th-rib fat depth, carcasses of lambs from Finnsheep, Romanov, and Texel sires produced 1 to 1.5 kg less (P < 0.001) predicted lean mass per lamb than carcasses of lambs from Dorset and Montadale sires. These experimental results provide information about the direct breed effects for survival, growth, and carcass traits of these breeds and their potential use in crossbreeding systems.

Animals↗
PubMed2004

Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds of sheep: II. Reproduction of F1 ewes in fall mating seasons.

Objectives were to estimate effects of sire breed (Dorset, Finnsheep, Romanov, Texel, and Montadale), dam breed (Composite III and northwestern whiteface), mating season (August, October, and December), ewe age (1, 2, and 3 yr), and their interactions on reproductive traits of F1 ewes. A total of 1,799 F1 ewes produced 3,849 litters from 4,804 exposures to Suffolk rams during 35-d mating seasons over 3 yr. Ewes were weighed at breeding. Conception rate and ewe longevity (present or absent at 42 mo of age) were determined. Number born and litter birth weight were recorded, and number and weight at weaning and 20 wk of age were analyzed separately for dam- and nursery-reared litter mates. Total productivity through 3 yr of age for each ewe entering the breeding flock was calculated as the sum of 20-wk weights for dam- or nursery-reared lambs. Interactions of sire breed x mating season, sire breed x ewe age, and mating season x ewe age were generally significant, whereas interactions of sire breed, mating season, and ewe age x dam breed were seldom detected. Interactions of sire breed x mating season were often due to changes in rank as well as magnitude, indicating the importance of matching sire breed to a specific mating season. The number born to Dorset-, Texel-, and Montadale-sired ewes was not affected by dam breed; however, Finnsheep-sired ewes out of northwestern whiteface dams were more prolific than Finnsheep-sired ewes out of Composite III dams, and the opposite situation existed for Romanov-sired ewes. Least squares means of sire breeds (P < 0.001) for total productivity of dam-reared lambs were 98.5, 103.5, 106.9, 124.6, and 154.9 kg/ewe entering the breeding flock for Texel, Dorset, Montadale, Finnsheep, and Romanov, respectively. Superior reproduction of Romanov-sired ewes was due to greater conception rate and prolificacy for each mating season and ewe age, as well as greater ewe longevity. Total productivity of F1 ewes by Composite III dams (125.6 kg) was greater (P < 0.001) than for ewes born to northwestern whiteface dams (109.7 kg), and the effect of mating season increased (P < 0.001) from August to October to December. Litter weight at 20 wk of age of 2- and 3-yr-old ewes was similar but greater (P < 0.001) than for 1-yr-old ewes. Experimental results provide comprehensive information about the appropriate use of these breeds in crossbreeding systems to meet specific production-marketing objectives.

Age Factors↗
PubMed2004

Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds of sheep: III. Wool characteristics of F1 ewes.

An experiment was designed to evaluate the effects of five sire breeds (Dorset, Finnsheep, Romanov, Texel, and Montadale), two dam breeds (Composite III [CIII] and northwestern whiteface [WF]), and three shearing seasons (December, February, and April, corresponding to August, October, and December breeding seasons) and their interactions on wool and other characteristics of F1 ewes. Fleeces were collected and characterized from six 2-yr-old F1 ewes representing each of the 90 sire breed x dam breed x shearing season x year (three) subclasses. Characteristics measured objectively were grease and clean fleece weights, clean yield, mean fiber diameter and SD, and mean staple length and SD. Visual assessments of fleece color were also made. Data collected on the F1 ewes were analyzed using a mixed model analysis of variance procedure. The model included fixed effects of year of birth, sire breed, dam breed, shearing season, six two-way interactions, and the three-way interaction of sire breed x dam breed x shearing season. The random effect of individual sire within year of birth x sire breed was also fitted. Texel- and Montadale-sired ewes produced more clean wool (P < 0.05) (approximately 0.24 kg) than Dorset-, Finnsheep-, and Romanov-sired ewes. Texel-sired ewes produced the coarsest wool (28.7 microm) (P < 0.05), whereas Romanov-sired ewes produced the finest (24.9 microm) and longest (9.12 cm) fleeces (P < 0.05). Ewes from WF dams produced more and finer wool (0.15 kg and 2.7 microm) than ewes from CIII dams (P < 0.001). Ewes shorn in December produced more, coarser, and longer wool (P < 0.05) than those shorn in February and April. This trend in wool production is opposite to that in conception rate (reported previously). Romanov-sired ewes produced the lowest percentage of white fleeces (62.6%), whereas Dorset-sired ewes produced the most (P < 0.001) white fleeces (96.3%). Estimates of heritability were calculated for grease and clean fleece weights (0.36), percentage of clean yield (0.31), average fiber diameter and SD (0.86 and 0.42, respectively), and average staple length and SD (0.49 and 0.00, respectively). Although necessary for a thorough evaluation of these 10 types of crossbred ewes, it is estimated that wool income would only constitute a small portion (1 to 5%) of overall income from sheep of this type.

Analysis of Variance↗
PubMed2002

Single nucleotide polymorphism (SNP) discovery in porcine expressed genes.

High-throughput genotyping of swine populations is a potentially efficient method for establishing animal lineage and identification of loci important to animal health and efficient pork production. Markers were developed based upon single nucleotide polymorphisms (SNPs), which are abundant and amenable to automated genotyping platforms. The focus of this research was SNP discovery in expressed porcine genes providing markers to develop the porcine/human comparative map. Locus specific amplification (LSA) and comparative sequencing were used to generate PCR products and allelic information from parents of a swine reference family. Discovery of 1650 SNPs in 403 amplicons and strategies for optimizing LSA-based SNP discovery using alternative methods of PCR primer design, data analysis, and germplasm selection that are applicable to other populations and species are described. These data were the first large-scale assessment of frequency and distribution of porcine SNPs.

Animals↗
PubMed2002

An integrated comparative map of the porcine X chromosome.

The objectives of this study were to assign both microsatellite and gene-based markers on porcine chromosome X to two radiation hybrid (RH) panels and to develop a more extensive integrated map of SSC-X. Thirty-five microsatellite and 20 gene-based markers were assigned to T43RH, and 16 previously unreported microsatellite and 15 gene-based markers were added to IMpRH map. Of these, 30 microsatellite and 12 gene-based markers were common to both RH maps. Twenty-two gene-based markers were submitted to BLASTN analysis for identification of orthologues of genes on HSA-X. Single nucleotide polymorphisms (SNPs) were detected for 12 gene-based markers, and nine of these were placed on the genetic map. A total of 92 known loci are present on at least one porcine chromosome X map. Thirty-seven loci are present on all three maps; 31 loci are found on only one map. Location of 33 gene-based markers on the comprehensive map translates into an integrated comparative map that supports conservation of gene order between SSC-X and HSA-X. This integrated map will be valuable for selection of candidate genes for porcine quantitative trait loci (QTLs) that map to SSC-X.

Animals↗
PubMed2001

Comparative mapping of BTA15 and HSA11 including a region containing a QTL for meat tenderness.

The starting point of the present study was the reported identification of a chromosomal region on bovine Chromosome (Chr) 15 (BTA15) carrying loci affecting meat tenderness. A comparative linkage map of BTA15 and human Chr 11 (HSA11) was constructed to identify potential positional candidate genes and to provide a resource of genetic markers to support marker-assisted selection (MAS). Relative rearrangements between the bovine and human genomes for these chromosomes are the most complex observed in comparative mapping between the two species, with nine alternating blocks of conserved synteny between HSA11 and bovine Chrs 15 and 29. The results of this study were the addition of nine genes to the HSA11/BTA15 comparative linkage map, and development of five microsatellite markers within the quantitative trait locus (QTL) interval. One gene with known effects on muscle development (MYOD1) was mapped to the interval. A second gene (CALCA) involved in regulation of calcium levels, a key factor in postmortem tenderization, also mapped within the interval. Refinement of the comparative map and QTL position will reduce the interval on the human transcription map to be scanned in search of candidates, reducing the effort and resources required to identify the allelic variation responsible for the genetic effect.

Animals↗
PubMed2001

Sequence evaluation of four pooled-tissue normalized bovine cDNA libraries and construction of a gene index for cattle.

An essential component of functional genomics studies is the sequence of DNA expressed in tissues of interest. To provide a resource of bovine-specific expressed sequence data and facilitate this powerful approach in cattle research, four normalized cDNA libraries were produced and arrayed for high-throughput sequencing. The libraries were made with RNA pooled from multiple tissues to increase efficiency of normalization and maximize the number of independent genes for which sequence data were obtained. Target tissues included those with highest likelihood to have impact on production parameters of animal health, growth, reproductive efficiency, and carcass merit. Success of normalization and inter- and intralibrary redundancy were assessed by collecting 6000-23,000 sequences from each of the libraries (68,520 total sequences deposited in GenBank). Sequence comparison and assembly of these sequences was performed in combination with 56,500 other bovine EST sequences present in the GenBank dbEST database to construct a cattle Gene Index (available from The Institute for Genomic Research at http://www.tigr.org/tdb/tgi.shtml). The 124,381 bovine ESTs present in GenBank at the time of the analysis form 16,740 assemblies that are listed and annotated on the Web site. Analysis of individual library sequence data indicates that the pooled-tissue approach was highly effective in preparing libraries for efficient deep sequencing.

Animals↗
PubMed2001

An enhanced linkage map of the sheep genome comprising more than 1000 loci.

A medium-density linkage map of the ovine genome has been developed. Marker data for 550 new loci were generated and merged with the previous sheep linkage map. The new map comprises 1093 markers representing 1062 unique loci (941 anonymous loci, 121 genes) and spans 3500 cM (sex-averaged) for the autosomes and 132 cM (female) on the X chromosome. There is an average spacing of 3.4 cM between autosomal loci and 8.3 cM between highly polymorphic [polymorphic information content (PIC) > or = 0.7] autosomal loci. The largest gap between markers is 32.5 cM, and the number of gaps of > 20 cM between loci, or regions where loci are missing from chromosome ends, has been reduced from 40 in the previous map to 6. Five hundred and seventy-three of the loci can be ordered on a framework map with odds of > 1000 : 1. The sheep linkage map contains strong links to both the cattle and goat maps. Five hundred and seventy-two of the loci positioned on the sheep linkage map have also been mapped by linkage analysis in cattle, and 209 of the loci mapped on the sheep linkage map have also been placed on the goat linkage map. Inspection of ruminant linkage maps indicates that the genomic coverage by the current sheep linkage map is comparable to that of the available cattle maps. The sheep map provides a valuable resource to the international sheep, cattle, and goat gene mapping community.

Animals↗
PubMed2000

Comparative mapping of the ovine clpg locus.

We used a comparative mapping approach to identify segments of conserved synteny between human Chromosome 14 (HSA14), bovine Chromosome 21 (BTA21), and the portion of ovine Chromosome 18 (OAR18) that contains the clpg locus. A bovine radiation hybrid map of the region was constructed with available Type II genetic markers and seven candidate genes to establish the comparative interval between BTA21 and HSA14. We developed polymorphic microsatellite and SNP markers associated with five candidate genes and placed them on the ovine and/or bovine genetic maps by multipoint linkage analysis. Three additional genes were mapped by virtue of their physical linkage to genetically mapped makers. Development of integrated linkage and physical maps facilitates the selection of positional candidate genes from the gene rich human map. The physically linked candidate genes PREF-1 and MEG3 map to the interval containing the clpg locus. Comparative biology suggests imprinting of MEG3 and/or the influences of PREF-1 on cellular differentiation, should be examined for their role in the parent-of-origin dependent influence of mutant clpg alleles on sheep muscle characteristics.

Animals↗
PubMed2000

Evaluation of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds of sheep: I. Effects of ram breed on productivity of ewes of two crossbred populations.

Effects of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds for performance as sires were estimated in the initial phase of a comprehensive evaluation of these breeds as contributors to sheep crossbreeding systems. Objectives were to evaluate the effects of ram breed, ewe breed, season of mating, and two-way interactions. Rams from the five breeds were single-sire-mated with ewes from two breed types to produce lambs over a 3-yr period. Ewes were assigned to one of three distinct 35-d mating seasons initiated each year in August, October, and December. A different sample of six rams per breed was used each year across all three seasons, and each ram was penned with ewes of both breeds. Traits evaluated and number of ewe records were conception rate and litter weaning weight per ewe exposed (n = 3,261) and number born, litter birth weight, average birth weight, number weaned, and litter weaning weight per ewe lambing (n = 2,751). Ram breed and ewe breed interacted (P < .01) for conception rate and litter weaning weight per ewe exposed, implicating mating preferences, particularly of Romanov rams. In mixed groups of ewes exposed to Romanov rams, conception rate was 12.7% lower and litter weight weaned was 8.4 kg lower in the ewe breed presumably less preferred for mating by the rams. On a per ewe exposed basis, Romanov-sired litters produced either the largest or the smallest values for litter weaning weight, depending on the breed of ewe. Effects of ram breed on number born and litter birth weight interacted (P < .05) with season of mating. The largest litters within each ram breed were associated with the October mating season. Montadale and Romanov rams sired larger and heavier litters from August matings than from December matings, whereas the opposite was true for Dorset-sired litters. Texel- and Finnsheep-sired litters were similar in size and weight from August and December matings. Breed of ram differences affected per ewe lambing productivity measurements (P < .01). Differences between ram breeds for ewe productivity were noted, with increased number born and improved survival of crossbred progeny to weaning for Romanov-sired litters. These results may have implications for using these ram breeds as sires in different crossbreeding systems. Structured mating systems or the creation of new composite populations involving these breeds could be used to match the resources, environment, and market of specific production situations.

Animals↗
PubMed1999

Genomic organization and genetic mapping of the bovine PREF-1 gene.

As a potential regulator of nutrient partitioning in beef cattle, we have cloned and genetically mapped the bovine PREF-1 gene. A full-length PREF-1 cDNA was isolated by iterative purification from a mixed-tissue cDNA library to which adipose contributed mRNA. Analysis of partial cDNAs from this library revealed that the 3'-terminal exon of the bovine PREF-1 mRNA is spliced in a manner analogous to its murine ortholog. However, we have also detected a PREF-1 splice form apparently unique to cattle. Aside from this alternative selection of a splice donor in the bovine fifth exon, the exon/intron junctions of the bovine PREF-1 gene recapitulate those observed for mice. The sequences proximal to the bovine PREF-1 transcription start site are homologous to the mouse PREF-1 promoter. Importantly, the sequence experimentally identified as critical to PREF-1 "suppression in adipocyte differentiation" is conserved in the bovine gene. The bovine PREF-1 gene was mapped to the telomeric end of BTA 21 by virtue of a physically linked microsatellite with seven alleles and 285 informative meiosis.

Amino Acid Sequence↗
PubMed1999

Evaluation of the ovine callipyge locus: III. genotypic effects on meat quality traits.

A resource flock of 362 F2 lambs provided phenotypic and genotypic data to estimate effects of callipyge (CLPG) genotypes (NN, NC, CN, and CC) on meat quality traits. The mutant allele is represented as C, the normal allele(s) as N, and the paternal allele of a genotype is given first. Lambs of each genotype born in 1994 and 1995 were serially slaughtered in six groups at 3-wk intervals starting at 23 wk of age. Warner-Bratzler shear force and subjective evaluation of marbling were collected during both years from longissimus. Calpastatin activity was measured on longissimus from the 1994 group, and ELISA quantification of calpastatin protein was obtained from the 1995 group. Significant additive and paternal polar overdominance effects on meat quality traits were detected. This is in contrast to previous research that detected only polar overdominance effects on slaughter and carcass traits in this population. The magnitude of genotypic effects on shear force differed significantly between years; however, additive (P < .01), paternal polar overdominance (P < .001), and maternal dominance (P < .01) effects adjusted for variation in carcass weight were detected within each year. Shear force data adjusted to the mean slaughter age or carcass weight indicated that the means and variances of CN and CC genotypes were greater than values of NC and NN. Shear force values were greatest for CN and were intermediate for CC. The difference in shear force (adjusted for variation in slaughter age) between homozygous genotypes (additive effect) was supported by calpastatin activity data with 2-df F-tests of 3.66 (P < .05) and 11.84 (P < .001) at d 0 and 7 postmortem, respectively. Corresponding values for the paternal polar overdominance effects on calpastatin activity were 53.80 (P < .001) and 87.43 (P < .001). Calpastatin ELISA data (d 0, adjusted for slaughter age) exhibited a paternal polar overdominance effect exclusively with a 2-df F-test of 57.63 (P < .001). Additive and paternal polar overdominance effects on marbling adjusted for slaughter age had F-tests of 6.41 (P < .01) and 93.29 (P < .001), respectively. Consequences of increased longissimus shear force must be addressed if the advantages of CN lambs for dressing percentage and carcass composition are to be realized. Further research is needed to establish whether selection targeted at changing the background genome can mitigate the negative effects of the C allele on meat tenderness.

Animals↗
PubMed1998

Microsatellite evolution: testing the ascertainment bias hypothesis.

Previous studies suggest the median allele length of microsatellites is longest in the species from which the markers were derived, suggesting that an ascertainment bias was operating. We have examined whether the size distribution of microsatellite alleles between sheep and cattle is source dependent using a set of 472 microsatellites that can be amplified in both species. For those markers that were polymorphic in both species we report a significantly greater number of markers (P < 0.001) with longer median allele sizes in sheep, regardless of microsatellite origin. This finding suggests that any ascertainment bias operating during microsatellite selection is only a minor contributor to the variation observed.

Animals↗
PubMed1998

A second-generation linkage map of the sheep genome.

A genetic map of Ovis aries (haploid n = 27) was developed with 519 markers (504 microsatellites) spanning approximately 3063 cM in 26 autosomal linkage groups and 127 cM (female specific) of the X Chromosome (Chr). Genotypic data were merged from the IMF flock (Crawford et al., Genetics 140, 703, 1995) and the USDA mapping flock. Seventy-three percent (370/504) of the microsatellite markers on the map are common to the USDA-ARS MARC cattle linkage map, with 27 of the common markers derived from sheep. The number of common markers per homologous linkage group ranges from 5 to 22 and spans a total of 2866 cM (sex average) in sheep and 2817 cM in cattle. Marker order within a linkage group was consistent between the two species with limited exceptions. The reported translocation between the telomeric end of bovine Chr 9 (BTA 9) and BTA 14 to form ovine Chr 9 is represented by a 15-cM region containing 5 common markers. The significant genomic conservation of marker order will allow use of linkage maps in both species to facilitate the search for quantitative trait loci (QTLs) in cattle and sheep.

Animals↗
PubMed1998

Evaluation of the ovine callipyge locus: II. Genotypic effects on growth, slaughter, and carcass traits.

A resource flock of 362 F2 lambs provided phenotypic and genotypic data to estimate effects of callipyge (CLPG) genotypes on growth, slaughter, and carcass traits. Lambs were serially slaughtered in six groups at 3-wk intervals starting at 23 wk of age to allow comparisons at different end points. Probabilities of CLPG genotypes were calculated at a position 86 cM from the most centromeric marker of chromosome 18. A contrast of CLPG genotypic effects, based on the paternal polar overdominance model, was used to evaluate callipyge and normal phenotypes. Relationships of traits with slaughter age, carcass weight, or 12th-rib fat depth for callipyge and normal phenotypic groups were estimated by regression. Callipyge and normal lambs did not differ for growth traits measured from birth to slaughter. Callipyge lambs produced 55.9% of live weight as chilled carcass weight compared with 51.7% for normal lambs at the same mean live weight of 48.32 kg. Lighter pelt, kidney-pelvic fat, and liver weights contributed to this advantage of callipyge lambs for dressing percentage (P < .001). Estimated accretion rates of carcass protein at the mean slaughter age were 12.5 and 10.2 g/d for callipyge and normal carcasses, respectively. Corresponding values for carcass fat were 35.2 and 42.1 g/d. Compositional differences in favor of callipyge carcasses were detected at constant values of slaughter age, carcass weight, and 12th-rib fat depth. Callipyge carcasses had 2.56 kg greater fat-free lean and 1.39 kg less fat than normal carcasses at the same mean age of 214.9 d (P < .001). The majority of these differences were established before the initial group was slaughtered and were maintained as age increased. Callipyge carcasses consisted of 24.3% fat and 71.3% fat-free lean, compared with 31.5 and 64.0% for normal carcasses at 25.6 kg of carcass weight. When evaluated at .49 cm of 12th-rib fat depth, callipyge lambs were 15.4 d older and produced 4.1 kg heavier carcasses with 4.3% less fat (P < .001). Effects of CLPG genotypic groups on carcass composition were greater than virtually all reported breed substitution effects. Use of the CLPG mutant allele in structured mating systems can dramatically increase production of lean lamb.

Age Factors↗
PubMed1998

Evaluation of the ovine callipyge locus: I. Relative chromosomal position and gene action.

Genotypic and phenotypic data were collected to estimate chromosomal position of the callipyge (CLPG) gene and to test gene action. Nine Dorset rams of extreme muscling phenotype and 114 Romanov ewes composed the grandparent generation of a resource flock of 362 F2 lambs segregating at the CLPG locus. The parent generation consisted of eight F1 sires and 138 F1 dams. The F2 lambs were serially slaughtered in six groups at 3-wk intervals starting at 23 wk of age to allow comparisons at different end points. A linkage group of 25 marker loci (mean of 708 informative meioses per marker) spanning 87.2 cM was developed and improved the previous known coverage and precision of marker order and interval distance from available maps of ovine chromosome 18. Probabilities of each CLPG genotype were calculated at 1-cM intervals (0 to 107 cM). Statistical models included effects of year, sex, sire, regressions on genotypic probabilities, and genotype-specific linear and quadratic regressions on appropriate covariates. Orthogonal contrasts of CLPG genotypic effects evaluated additive, maternal dominance, and paternally derived polar overdominance models of gene action. The most parsimonious model did not include the additive and maternal dominance genetic contrasts. From analyses of four key traits, a consensus for position of CLPG was obtained at 86 cM relative to the most centromeric marker. An F-test with 3 df representing polar overdominance was maximum at position 86 cM (F = 407.4; P < .00001) with leg score as the dependent variable. These results are consistent with assignment of the CLPG locus to the telomeric region of chromosome 18 and support the polar overdominance model of gene action proposed by Cockett et al. (1996). Furthermore, recombinant individuals with definitive phenotypes confined the position of CLPG to a 3.9-cM interval, facilitating positional cloning experiments.

Animals↗