The incidence of genotypes at codon 171 of the prion protein gene (PRNP) in five breeds of sheep and production traits of ewes associated with those genotypes

Scrapie is one of several transmissible spongiform encephalopathies of livestock. Disease susceptibility is linked to polymorphisms in the normal prion protein gene that encodes the mammalian prion precursor. Codon 171 of this gene is a major determinant of scrapie susceptibility. Selection for arginine (R) at codon 171 is encouraged by the USDA to decrease the incidence of scrapie. Objectives of this study were to determine the frequency of R allele variants at codon 171 in a sample of sheep from five breeds (Columbia, Hampshire, Rambouillet, Suffolk, and Targhee) and western white-faced commercial ewes and to determine whether the R allele is associated with ewe and lamb production traits. Genotyping was performed on 532 ewes and 901 lambs from the University of Wyoming flock, in addition to 820 rams from 52 sheep producers from Wyoming and surrounding areas, using a DNA mismatch assay that discriminated the R allele from others at codon 171. Genotyping was performed by DNA sequencing on 127 rams representing all breeds, except Hampshire from the USDA Sheep Experiment Station at Dubois, ID. The 171R allele was found in all five breeds and in the commercial western white-faced ewes. Genotype frequencies varied (P < 0.001) by breed in ewe and ram populations. Influence of R-allele frequency on ewe lambing records and individual lamb records was analyzed for Columbia (62, 161, 121), Hampshire (89, 193, 162), Rambouillet (87, 179, 133), Suffolk (67, 178, 161), and commercial sheep (227, 463, 324) for numbers of ewes, total number of ewe production records, and individual lamb records, respectively. Suffolk ewes without the R allele (non-R/non-R) gave birth to more (P or= 0.08) by ewe genotype. Lamb birth and weaning weights were not influenced (P >or= 0.12) by lamb genotype in any of the breeds or in the commercial flock. In this population, ultimate lamb production was only influenced by genotype at codon 171 in the Suffolk flock.     

Associations of polymorphisms of the ovine prion protein gene with growth, carcass, and computerized tomography traits in Scottish Blackface lambs

The objective of this study was to investigate and estimate the associations of the ovine prion protein (PrP) genotypes with a wide range of performance traits in Scottish Blackface lambs. Performance records of up to 7,138 sheep of known PrP genotypes born from 1999 to 2004 in 2 experimental farms were utilized. Performance traits studied were BW at birth, marking (when the sheep were identified with permanent ear tags at an average age of 52 d), and weaning (average age of 107 d); slaughter traits (BW at slaughter, slaughter age, carcass weight, and carcass conformation); ultrasonic muscle and fat depths; and computerized tomography-predicted carcass composition and carcass yield at weaning. Different linear mixed models, including random, direct animal effect, and up to 3 maternal effects (genetic, permanent, and temporary environmental) were used for the different traits. The PrP genotype was included in the model as a fixed effect, along with other fixed factors with significant effects (P < 0.05). Five separate analyses were carried out for each trait, differing in the method of PrP genotypic classification. The first analysis was based on classifying the sheep into categories according to all 9 available PrP genotypes. In the other 4 analyses, sheep were categorized according to the number of each PrP allele carried. Results showed that there were no significant differences between PrP genotypes for any of the performance traits studied when all 9 genotypes were compared (first analysis). Similarly, performance of the lambs did not significantly differ between genotypes with different numbers of ARR copies. However, there were significant variations in a few traits with respect to the number of ARQ, AHQ, and VRQ alleles carried. Heterozygous lambs for the AHQ or the ARQ allele were significantly heavier at some ages than lambs of the other genotypes. Lambs carrying the VRQ allele required approximately 10 d longer finishing time (P = 0.01) and yielded carcasses approximately 0.5 kg heavier (P = 0.03) compared with noncarriers. The few significant associations found do not have a negative influence on performance when selecting against the most susceptible PrP allele (VRQ) or in favor of the most resistant one (ARR). Overall, there were no major associations of PrP genotypes with most lamb performance traits in Scottish Blackface sheep.     

Associations between prion protein genotype and type traits in East Friesian milk sheep

Linear models were used to analyse the relationships between the prion protein genotypes and the height at the withers and rump, the heart girth and the length of the trunk of 440 East Friesian milk sheep. Significant associations were found between the ARR allele and the height of the withers and rump, and heart girth. The average height at the withers of the homozygous ARR/ARR sheep was 1.9 cm less than that of ARQ/ARQ sheep and 1.6 cm less than in sheep heterozygous for ARR; the height at the rump, length of the trunk and heart girth were similarly smaller. In the ARR/ARR ewes, the average height at the withers was 2.6 cm less and the height at the rump was 1.9 cm less than in the ARQ/ARQ ewes.     

Development and usefulness of new polymerase chain reaction-based tests for detection of different alleles at codons 136 and 171 of the ovine prion protein gene.

OBJECTIVE: To develop new and improved tests to detect alleles at codons 136 and 171 of the ovine prion protein locus and to evaluate the frequency of these alleles. ANIMALS: 159 Suffolk sheep belonging to 3 flocks. PROCEDURE: Polymerase chain reaction (PCR) analysis that contained diagnostic restriction site variation for each allele were developed for the relevant gene regions. Alleles were determined by analyzing DNA isolated from buccal swab specimens or blood samples. RESULTS: At codon 136, frequencies of the alanine and valine alleles were found to be 97 and 3%, respectively. At codon 171, frequencies of the glutamine, arginine, and histidine alleles were found to be 57, 41, and 2%, respectively. CONCLUSIONS: Little variation was detected in codon 136, whereas noteworthy variation was found in codon 171; > 40% of the alleles at this locus coded for glutamine. Because the glutamine allele at codon 171 confers susceptibility to scrapie, reduction of its frequency is of importance to management of sheep flocks. CLINICAL RELEVANCE: Genotyping of sheep, using the tests reported here, should facilitate selective breeding programs designed to decrease the risk of scrapie.     

Associations between maternal milk protein genotypes with preweaning calf growth traits in beef cattle

The objectives of this study were to investigate milk casein polymorphisms in dams and to determine the impacts of maternal casein genotypes on growth traits of their sucking calves. Milk samples from 433 dams of the breeds German Angus (GA) and German Simmental (GS) were typed at the milk protein loci α _s1-casein (α_s1-CN), β-casein (β-CN), α _s2-casein (α_s2-CN), and κ-casein (κ-CN) via isoelectric focusing. Associations between casein genotypes in maternal milk with growth traits of their 1,872 calves were analyzed until the age of weaning using linear mixed models, considering either genotypes of individual casein loci (model 1) or composite α _s1-β-α _s2-κ-CN genotypes within the casein cluster (model 2). Besides environmental effects such as sex, age of the dam, and calving year-season, genetic effects (breed group and maternal and paternal effects) were considered in statistical models. The composite casein genotype BBǀA2A2ǀAAǀAB (order of genes on bovine chromosome 6: α _s1-ǀβ-ǀα _s2-ǀκ-CN) was associated with greater average daily weight gains (ADG) and heavier age-adjusted weaning weights (WW) of calves (P < 0.05). The effects of composite genotypes on birth weight of calves were similar (P > 0.05; model 2). With regard to individual casein loci, greater ADG and WW were observed for calves from dams with the genotypes κ-CN BB and α _s1-CN BB, respectively (P < 0.05; model 1). Age-adjusted WW was largest for calves from dams carrying the κ-CN genotype BB (215 kg) compared with calves representing the maternal AB and AA genotypes (both 204 kg). Results from the present study suggested selectable casein genotypes due to their nutritional value of milk (value in terms of offspring performances), offering new perspectives for breeding strategies in beef cattle to improve preweaning calf performance.     

Associations between polymorphisms in the chicken VIP gene,egg production and broody traits

1.?In this study, the vasoactive intestinal peptide (VIP) gene was screened for variations by cloning and sequencing to analyse the association with chicken egg production and broodiness traits.

2.?Sequencing revealed that 69 polymorphisms were found in a 9305-bp length of the chicken VIP gene, of which 39 were located in introns, 28 in 5′ regulatory region, 1 in exon 6 (synonymous) and 1 in 3′-UTR. The nucleotide diversity corrected for sample size was 1·96 × 10^?3.

3.?Five polymorphisms, C-3134T, “AGG” indel at ?2648 to ?2650, C + 338T, G + 780T and A + 4691G, were genotyped in 644 individuals of Ningdu Sanhuang chickens to evaluate their effects on egg production and broodiness traits. Marker-trait association analyses showed that the “AGG” indel was associated with total number of eggs from 90 to 300 d of age and total number of qualified eggs from 90 to 300 d of age. In contrast, C + 338T was associated with duration of broodiness.     

Associations between variants of bone morphogenetic protein 7 gene and growth traits in chickens

1. Enhancing bone strength to solve leg disorders in poultry has become an important goal in broiler production. Bone morphogenetic protein 7 (BMP7), a member of the BMP family, represents an attractive therapeutic target for bone regeneration in humans and plays critical roles in skeletal development.

2. The objective of this study was to investigate the relationship between BMP7 gene expression, single-nucleotide polymorphisms (SNPs) and growth traits in chickens. Here, a SNP (c.1995T>C) in the chicken (Gallus gallus) BMP7 gene was identified, that was associated with growth and carcass traits.

3. Genotyping revealed that the T allele occurred more frequently in breeds with high growth rates, whereas the C allele was predominant in those with low growth rates. The expression level of BMP7 in the thigh bone of birds with the TT genotype was significantly higher than in those with the CC genotype at 21, 42 and 91 d of age.

4. These findings suggest that selecting the birds with the TT genotype of SNP c.1995T>C could improve bone growth, could reduce leg disorders in fast-growing birds. The SNP c.1995T>C may serve as a selective marker for improving bone growth and increasing the consistency of body weights in poultry breeding.     

Associations of leptin gene polymorphisms with production traits in pigs

The associations of leptin (LEP) gene polymorphisms C798T, T2411C, T3266G and T3469C with production traits were investigated in a F2 pig population produced by divergent crosses. The statistical model included genotype, sex, batch and genotype by sex interaction as fixed effects and sire as random effect. Polymorphism C798T was associated with variation in total teat number (p < 0.02) and left teat number (p < 0.03), and polymorphism T3469C was associated with weight at 21 days (p < 0.03), 42 days (p < 0.05), 63 days (p < 0.02) and 77 days of age (p < 0.04) as well as feed intake (p < 0.01), average daily gain (p < 0.01), feed conversion (p < 0.01), bacon depth (p < 0.03) and slaughter weight (p < 0.03). Phenotypic associations were also performed by combining T3469C and C798T genotypes. Interaction between C798T genotypes and sex was observed for some traits. LEP genotypes had significant influence on performance traits, and can be considered as potential genetic markers for selection. However, these results have to be validated in commercial herds.     

The evidence of associations between prion protein genotype and production, reproduction, and health traits in sheep

The EU Commission issued a regulation in 2003, which requires all member states to implement a breeding programme for resistance to transmissible spongiform encephalopathies in sheep by selecting for specific alleles of the prion protein (PrP) gene. A key concern with regard to this regulation was that the intensive selection programmes, designed to increase resistance to scrapie, may have a negative impact on a range of other economically important production, reproduction, and disease traits in sheep. Such problems could arise for a number of reasons. Firstly, a number of breeds have a low frequency of the resistant PrP allele. Secondly, there may be a negative association between the resistant allele and animal performance. Thirdly, selection for scrapie resistance may reduce the rate of improvement towards current breeding goals. The evidence concerning the relationship between PrP genotype and reproduction, production, and disease traits is the subject of this review. We conclude that there is no evidence for a negative association between PrP genotype and reproduction traits (e.g. litter size), lamb performance traits (e.g. growth rate, conformation, carcass composition) or milk production. There is, however, a distinct paucity of information on the relationship between the PrP gene and disease traits. In this context it is noted that there are a number of genes located on chromosome 13, in close proximity to the PrP gene, that are involved in intracellular cell signalling, apoptosis, phagocytosis, and immune function. Thus further direct studies of key disease traits associated with sheep production systems are warranted.     

A real-time polymerase chain reaction assay to detect single nucleotide polymorphisms at codon 171 in the prion gene for the genotyping of scrapie susceptibility in sheep.

The objective of this study was to report a reliable real-time polymerase chain reaction assay compatible with the Roche LightCycler 2.0 capable of genotyping sheep for scrapie susceptibility at codon 171. The single nucleotide polymorphisms (SNPs) in the prion protein gene in sheep that may govern resistance to scrapie at codon 171 encode for lysine (K), histidine (H), glutamine (Q), and arginine (R). A modified proteinase K method for leukocytes or whole blood was used to isolate genomic DNA from sheep blood. Fluoresentric developed and optimized primers and probes for the codon 171 SNP assay. The assay was initially validated using 218 determinations from whole blood of known genotypes with 100% correct identity. The assay was further validated through a whole-blood check test provided annually by the National Veterinary Services Laboratory with a correct identification rate of 100%. From January 2005 to December 2006, 3,672 samples from blood were genotyped at codon 171. The genotypes were QR(171) (n = 1,838, 50.05%), RR(171) (n = 1,423, 38.75%), QQ(171) (n = 407, 11.08%), HR(171) (n = 2, 0.05%), and HQ(171) (n = 2, 0.05%). The combination of this simple extraction method and the novel Fluoresentric assay is very accurate, is capable of identifying all 4 SNPs at codon 171 in one reaction, and has proven to be a useful tool for producers in their selective breeding programs.     

Identification of a new leucine haplotype (ALQ) at codon 154 in the ovine prion protein gene in Spanish sheep

Genetic susceptibility to scrapie is closely linked to variations at codons 136, 154, and 171 of the prion protein (PRNP) gene. This association between the PRNP genotype and susceptibility to scrapie is the basis of breeding programs for scrapie resistance in different countries. In this paper, we describe the method used with 2 Spanish dairy sheep breeds (Churra and Castellana) to ascertain the initial status of protection against scrapie as a first step toward adapting their breeding schemes to include resistance as a complementary selection criterion. The procedure for genotype identification is based on multiplex minisequencing methodology and has been shown to be accurate, easy to interpret, and to have a medium throughput. The frequency of the ARQ allele was similar in the 2 populations at nearly 70%. The ARR allele, associated with resistance in the homozygous state, reaches around 23% in Churras and nearly 20% in Castellanas. The high-risk VRQ allele appeared at a relatively low frequency in both breeds. No other haplotypes were found in these 2 breeds. Furthermore, in this screening we found a new allele carrying leucine at codon 154. This new genetic variant might play a role in susceptibility to scrapie because codon 154 belongs to a region considered to have an important role in conformational conversion of the cellular to the pathogenic protein.     

GH基因遗传多态性与中国荷斯坦牛泌乳性状的遗传效应分析

为分析GH基因SNPs与中国荷斯坦牛泌乳性状的相关性。以Z32头中国荷斯坦牛为研究材料,采用PCRSSCP技术检测GH基因第5外显子及其相邻区域的多态性,并进行相关性分析。结果发现GH基因第4内舍子（2017bp处）存在C—T的碱基转换,该群体在此位点处于Hardy-Weinberg平衡状态,为中度多态。与泌乳性状的相关性分析表明,该多态位点与泌乳性状显著相关（P〈0．05）,TT型305d产奶量、305d乳脂量、305d乳蛋白量和305d乳糖量显著高于CC型（P〈0．05）;TC型与TT型、CC型之间305d产奶量、305d乳脂量、305d乳蛋白量差异均不显著（P〉0．05）,但TC型在数值上有优于CC型的趋势。建议将等位基因T作为提高奶牛产奶量、乳脂量和乳蛋白量的候选分子标记。     

Influence of prion protein gene polymorphisms on performance traits in German meat sheep breeds

PrP polymorphisms influence the scrapie susceptiblility of sheep. The objective of this study was to analyse the association between performance traits and the PrP genotype in the sheep breeds German black-headed and German white-headed mutton, Bleu du Maine, German mutton merino, Leine, Texel and Suffolk from Lower Saxony and Westphalia. We analysed performance traits such as scores for muscle mass, type and wool quality and the calculated daily weight gain using linear animal models. In all seven breeds no statistically significant associations were found between performance traits and the occurrence of ARR alleles, and the ARR/ARR genotypes, respectively. All genotyped sheep of all breeds investigated showed significantly superior performance traits in comparison to the non-genotyped animals.     

Association analyses between the prion protein locus and reproductive and lamb weight traits in Ripollesa sheep

The objective of this study was to analyze the association between the haplotypes of the prion protein (PrP) locus and several reproductive and lamb weight traits in Ripollesa sheep. Prion protein genotypes were available for a total of 310 sheep (7 rams, 114 ewes, and 189 lambs), all of them belonging to the purebred Ripollesa flock of the Universitat Autònoma of Barcelona, for which all sheep had a known pedigree. In addition, the genotype of 24 historical descendants of the previously genotyped adult individuals was reconstructed, provided that both parents were homozygous for PrP haplotypes. Only 3 haplotypes (ARR, ARQ, and ARH) were observed in the PrP locus of the sheep sampled. Reproductive traits included conception rate and litter size, whereas birth BW and 90-d BW were the lamb weight traits studied. The additive effect of PrP haplotypes was analyzed through Bayesian animal threshold and linear models, for reproduction and weight traits, respectively. Ewe reproductive data belonged to 89 ewes that gave 492 conception rate records and 440 litter size records. Analyses of BW at birth and at 90 d of age were made on 323 and 164 lamb records, respectively. No associations between PrP haplotypes and conception rate and BW traits were observed. For litter size, the effect of the ARH haplotype was greater than that of the ARQ haplotype. Differences between ARH and ARR haplotypes also suggested an advantage for the ARH. As a whole, our results indicated that the selection favorable to increase litter size in Ripollesa ewes may also increase the ARH haplotype frequency, which contradicts the recommendations of the current European Union legislation aiming to increase the genetic resistance to scrapie. As a consequence, scrapie genotyping needs to be included as a new selection criterion in the breed.     

Investigating the relationship between the prion protein locus and udder morphology traits and milk yield in Sardinian sheep

Different approaches were applied to investigate prion protein (PrP)-encoding gene effects on udder morphology and milk yield in Sardinian sheep. The PrP genotype of 23,077 animals (10,029 males) was determined. The direct effect of the PrP or a closely linked gene was analyzed at the population-wide level using 2 animal models, based on records from genotyped animals, including only the PrP genotype as a fixed effect. In the female model, the dependent variable was animal performance deviation, calculated as the sum of the individual random effects. The male model was based on daughter yield deviations. Both dependent variables were obtained from the national genetic evaluations of 2005. The significance of pairwise comparisons between genotypes was assessed by using the Tukey-Kramer multiple-comparison procedure. Within-family analyses were performed on sires heterozygous for the PrP gene to detect those genes that affect the traits of interest and are not in linkage disequilibrium with the PrP locus at the population-wide level. The overall results led us to exclude either a direct or a linkage gene effect of the PrP locus on udder morphology or milk yield in Sardinian sheep. A further analysis of males that neglected the relationship matrix was carried out to evaluate the effect on the loss of genetic gain of the different selection pressures applied on resistant and susceptible genotype classes. Significant differences between genotypes were detected for milk yield. These were due to the different selection pressures applied to the PrP genotype classes. Finally, no negative correlated genetic response on the selection traits is expected from the selection for scrapie resistance in the Sardinian breed. However, a loss of genetic gain for milk yield is likely to occur in the future due to the different selection pressures on resistant and susceptible males.     

Distribution of prion protein genotypes in breeds of sheep in New Zealand

AIM: To use an established high through-put genotyping procedure to gain an estimate of the frequency of alleles of the prion protein (PrP) gene in some common sheep breeds in New Zealand. METHODS: Using a genotyping procedure based on matrix-assisted laser desorption ionisation-time of flight (MALDI-TOF), DNA samples from 3,024 sheep from New Zealand, including breeds such as Romney, Texel, Coopworth, Merino and mixed breed, were isolated, genotyped and the results analysed. RESULTS: The 15 scrapie genotypes commonly reported, and derived from the five commonly reported allelic variants (ARR, ARQ, AHQ, ARH and VRQ), were all observed in the samples analysed. The estimates were indicative of the frequencies in the population of alleles present in breeds of sheep in New Zealand. There was a significant difference between the frequencies of alleles between breeds, but the ARQ, followed by the ARR allele, were, except in Carwell sheep, the most common alleles present. CONCLUSION: This study gave an indication of the percentages of PrP gene alleles in sheep in New Zealand, including data previously unreported from breeds in this country. It is of interest because of the relatively large size of the sheep population in New Zealand compared with many countries, and it provides some useful information on the genetic susceptibility or resistance of the sheep population in New Zealand to scrapie. The frequencies of the alleles can be different for an individual breed compared between countries.     

Distribution of prion protein genotypes in breeds of sheep in New Zealand

AIM: To use an established high through-put genotyping procedure to gain an estimate of the frequency of alleles of the prion protein (PrP) gene in some common sheep breeds in New Zealand.

METHODS: Using a genotyping procedure based on matrix-assisted laser desorption ionisation-time of flight (MALDI-TOF), DNA samples from 3,024 sheep from New Zealand, including breeds such as Romney, Texel, Coopworth, Merino and mixedbreed, were isolated, genotyped and the results analysed.

RESULTS: The 15 scrapie genotypes commonly reported, and derived from the five commonly reported allelic variants (ARR, ARQ, AHQ, ARH and VRQ), were all observed in the samples analysed. The estimates were indicative of the frequencies in the population of alleles present in breeds of sheep in New Zealand. There was a significant difference between the frequencies of alleles between breeds, but the ARQ, followed by the ARR allele, were, except in Carwell sheep, the most common alleles present.

CONCLUSION: This study gave an indication of the percentages of PrP gene alleles in sheep in New Zealand, including data previously unreported from breeds in this country. It is of interest because of the relatively large size of the sheep population in New Zealand compared with many countries, and it provides some useful information on the genetic susceptibility or resistance of the sheep population in New Zealand to scrapie. The frequencies of the alleles can be different for an individual breed compared between countries.     

Associations of the variation in the porcine myogenin gene with muscle fibre characteristics, lean meat production and meat quality traits

Pig breeding is aimed at improving lean meat production ability as well as meat quality, and muscle fibre characteristics may be important for enhancing these traits. Therefore, new molecular markers have been demanded for selecting lean meat production ability and meat quality in live animals. Myogenin belongs to the MyoD gene family, and is a candidate gene responsible for muscle fibre characteristics. We identified a new single nucleotide polymorphism (SNP) site in the 5' upstream region of the myogenin gene (nucleotides C and T). A total of 252 pigs of three breeds were genotyped by polymerase chain reaction–restriction fragment length polymorphism using BspCNI . Additionally, they were genotyped for the previously detected Msp I site in the 3'-flanking region (alleles A and B). The CCBB diplotype had the highest frequency over breeds, followed by TCBB and CCAB. The other diplotypes were not found in studied pigs. Association analysis performed for the markers found that the TCBB diplotype has desirable effects on the total number of fibres (p   < 0.002), fibre cross-sectional area (p   < 0.06), and loin eye area (p   < 0.001) than the other diplotypes. Moreover, the diplotype had the highest muscle pH value (p   < 0.07) and all meat quality traits were near the upper limit of the normal range as a reddish pink, firm and non-exudative (RFN) pork. Therefore, we suggest that selection for the myogenin diplotypes could improve total muscle fibre number, size and lean meat production ability with good meat quality.     

Associations between trichostrongylid worm egg count and productivity measures in Dorper lambs

Two flocks of pure bred Dorper lambs were managed separately according to sex (283 ewe lambs and 212 ram lambs) in southern Western Australia. Faecal sample collection, weighing and body condition assessments were performed for each lamb on 2 occasions, specifically pre-weaning (approximately 14 weeks of age) and post-weaning (approximately 9 months of age). Body condition score (BCS) was assessed using a scale of 1 (very thin, emaciated) to 5 (excessively fat). Faecal worm egg counts (WECs) were measured using a modified McMaster technique and larval cultures were performed to identify trichostrongylid nematode genera present. Eye muscle and c-site fat depths were measured using ultrasound at post-weaning. Lambs received an abamectin anthelmintic treatment at weaning (18 weeks of age). Worm egg count data was assessed for normality of data distribution and homogeneity of variance. This data was transformed using log(10)(WEC+25) to stabilise variances between groups prior to statistical analyses and general linear models were used to assess relationships between WEC and productivity measures. Mean WECs were 564 eggs per gram of faeces (EPG) and 514 EPG at pre- and post-weaning in the ewe flock and 552 EPG and 480 EPG at pre- and post-weaning in the ram flock. Teladorsagia (Ostertagia) circumcincta, Trichostrongylus spp. and Oesophagostomum spp. larvae were identified. No lambs with WEC<500 EPG pre-weaning had WEC>1000 EPG post-weaning. Ewe and ram lambs with WEC>1000 EPG at pre-weaning were 42 (12-145 95% CI) and 37 (9-153) times more likely to have WEC>1000 EPG at post-weaning than lambs with WEC 501-1000 EPG at pre-weaning. There were no significant relationships between WEC and live weight in the ram flock, while relationships between WEC and live weight were inconsistent in the ewe lamb flock. There was no relationship between WEC and eye muscle or c-site fat depth. Significant negative relationships between WEC and BCS were identified at pre- and post-weaning for both flocks. Lambs with WEC<500 EPG had 0.19-0.61 higher mean BCS than lambs with WEC>1000 EPG at pre- and post-weaning. In conclusion, high WEC was associated with lower body condition in Dorper lambs, however the relationship between WEC and live weight was inconsistent and there was no effect on eye muscle depth.