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Horse owners choose whether or not to train American Saddlebred horses ( ASHs) to perform the 4-beat gaits called rack and slow gait. The rack and slow gait are similar to ambling gaits shown to be associated with variation in the DMRT3 gene in other breeds but are trained rather than naturally occurring gaits. A premature stop codon in the DMRT3 gene ( DMRT3_Ser301 STOP) caused by the Ch23:g.22999655C>A SNP has an effect on the pattern of locomotion in horses and allows for the pacing gait and strong association with performance of ambling gaits in diverse breeds. We used horse show records to identify ASHs trained to perform as 5-gaited horses and compared them to other Saddlebreds for the prevalence of the A allele of the Ch23:g.22999655C>A SNP of DMRT3. Genomic DNA was typed using a PCR- RFLP technique for 5-gaited ASHs ( n = 55), 3-gaited or harness ASHs ( n = 64) and ASHs not shown ( n = 128). We did not observe differences in the frequencies of the Ch23:g.22999655C>A SNP of DMRT3 when comparing 5-gaited ASHs to other ASHs ( P > 0.22). These results suggest that DMRT3 alleles do not affect the choice of breeders to train and show ASHs as 5-gaited horses. [ABSTRACT FROM AUTHOR]

Introduction: Nellore cattle (Bos taurus indicus) is the main beef cattle breed raised in Brazil. This breed is well adapted to tropical conditions and, more recently, has experienced intensive genetic selection for multiple performance traits. Over the past 43 years, an experimental breeding program has been developed in the Institute of Animal Science (IZ, Sertaozinho, SP, Brazil), which resulted in three differentially-selected lines known as Nellore Control (NeC), Nellore Selection (NeS), and Nellore Traditional (NeT). The primary goal of this selection experiment was to determine the response to selection for yearling weight (YW) and residual feed intake (RFI) on Nellore cattle. The main objectives of this study were to: 1) identify copy number variation (CNVs) in Nellore cattle from three selection lines; 2) identify and characterize CNV regions (CNVR) on these three lines; and 3) perform functional enrichment analyses of the CNVR identified. Results: A total of 14,914 unique CNVs and 1,884 CNVRs were identified when considering all lines as a single population. The CNVRs were non-uniformly distributed across the chromosomes of the three selection lines included in the study. The NeT line had the highest number of CNVRs (n = 1,493), followed by the NeS (n = 823) and NeC (n = 482) lines. The CNVRs covered 23,449,890 bp (0.94%), 40,175,556 bp (1.61%), and 63,212,273 bp (2.54%) of the genome of the NeC, NeS, and NeT lines, respectively. Two CNVRs were commonly identified between the three lines, and six, two, and four exclusive regions were identified for NeC, NeS, and NeT, respectively. All the exclusive regions overlap with important genes, such as SMARCD3, SLC15A1, and MAPK1. Key biological processes associated with the candidate genes were identified, including pathways related to growth and metabolism. Conclusion: This study revealed large variability in CNVs and CNVRs across three Nellore lines differentially selected for YW and RFI. Gene annotation and gene ontology analyses of the exclusive CNVRs to each line revealed specific genes and biological processes involved in the expression of growth and feed efficiency traits. These findings contribute to the understanding of the genetic mechanisms underlying the phenotypic differences among the three Nellore selection lines. [ABSTRACT FROM AUTHOR]

In the past few decades, genomic selection and other refined strategies have been used to increase the growth rate and lean meat production of beef cattle. Nevertheless, the fast growth rates of cattle breeds are often accompanied by a reduction in intramuscular fat (IMF) deposition, impairing meat quality. Transcription factors play vital roles in regulating adipogenesis and lipogenesis in beef cattle. Meanwhile, understanding the role of transcription factors in regulating adipogenesis and lipogenesis in beef cattle has gained significant attention to increase IMF deposition and meat quality. Therefore, the aim of this paper was to provide a comprehensive summary and valuable insight into the complex role of transcription factors in adipogenesis and lipogenesis in beef cattle. This review summarizes the contemporary studies in transcription factors in adipogenesis and lipogenesis, genome-wide analysis of transcription factors, epigenetic regulation of transcription factors, nutritional regulation of transcription factors, metabolic signalling pathways, functional genomics methods, transcriptomic profiling of adipose tissues, transcription factors and meat quality and comparative genomics with other livestock species. In conclusion, transcription factors play a crucial role in promoting adipocyte development and fatty acid biosynthesis in beef cattle. They control adipose tissue formation and metabolism, thereby improving meat quality and maintaining metabolic balance. Understanding the processes by which these transcription factors regulate adipose tissue deposition and lipid metabolism will simplify the development of marbling or IMF composition in beef cattle., (© 2023 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

The Brangus cattle were developed to utilize the superior traits of Angus and Brahman cattle. Their genetic compositions are expected to be stabilized at 3/8 Brahman and 5/8 Angus. Previous studies have shown more than expected Angus lineage with Brangus cattle, and the reasons are yet to be investigated. In this study, we revisited the breed compositions for 3,605 Brangus cattle from three perspectives: genome-wise (GBC), per chromosomes (CBC), and per chromosome segments (SBC). The former (GBC) depicted an overall picture of the "mosaic" genome of the Brangus attributable to their ancestors, whereas the latter two criteria (CBC and SBC) corresponded to local ancestral contributions. The average GBC for the 3,605 Brangus cattle were 70.2% Angus and 29.8% Brahman. The K-means clustering supported the postulation of the mixture of 1/2 Ultrablack (UB) animals in Brangus. For the non-UB Brangus animals, the average GBC were estimated to be 67.4% Angus and 32.6% Brahman. The 95% confidence intervals of their overall GBC were 60.4%-73.5% Angus and 26.5%-39.6% Brahman. Possibly, genetic selection and drifting have resulted in an approximately 5% average deviation toward Angus lineage. The estimated ancestral contributions by chromosomes were heavily distributed toward Angus, with 27 chromosomes having an average Angus CBC greater than 62.5% but only two chromosomes (5 and 20) having Brahman CBC greater than 37.5%. The chromosomal regions with high Angus breed proportions were prevalent, tending to form larger blocks on most chromosomes. In contrast, chromosome segments with high Brahman breed proportion were relatively few and isolated, presenting only on seven chromosomes. Hence, genomic hitchhiking effects were strong where Angus favorable alleles resided but weak where Brahman favorable alleles were present. The functions of genes identified in the chromosomal regions with high (≥ 75%) Angus compositions were diverse yet may were related to growth and body development. In contrast, the genes identified in the regions with high (≥ 37.5%) Brahman compositions were primarily responsible for disease resistance. In conclusion, we have addressed the questions concerning the Brangus genetic make-ups. The results can help form a dynamic picture of the Brangus breed formation and the genomic reshaping. [ABSTRACT FROM AUTHOR]

Reducing age at first calving (AFC) has been a challenge in beef herds. There is anecdotal evidence that herd owners choose to calve heifers older because of the perceived consequences of calving heifers at 24 mo of age compared to 36 mo on performance traits in beef herds. The objective of this study was to estimate the association of calving heifers at younger ages on subsequent performance traits, calving interval, longevity, cow weight, dystocia, and progeny weaning weight for parities 1 to 5. Available to the study after data edits were 219,818 calving interval records, 219,818 longevity records, 118,504 cow live-weight records, 230,998 dystocia records, and 230,998 weaning weight records. Linear mixed models were used to quantify performance of each trait in AFC groups for each parity. As parity increased, there was a favorable reduction in calving interval and dystocia (P < 0.001), while the likelihood of cows surviving reduced (P < 0.001). Both cow live weight and progeny weaning weight increased as parity increased. Age at first calving only had a significant association with dystocia within parity 1 (P < 0.001), where older heifers at first calving subsequently had lower risk of calving. Calving interval for parity 1 cows was observed to be longer by 6 d in cows that calved for the first time at 33 to 36 mo compared to cows calved for the first time at 22 to 24 mo (P < 0.001). No statistical difference was observed for longevity between cows with an AFC of 22 to 24 mo compared to cows with an AFC of 33 to 36 mo (P > 0.05). Cows that calved at a younger age did wean lighter calves for their first three lactations (P < 0.01) but had no association with weaning weight for parity 4 and 5 cows (P > 0.05). Cows with a lower AFC were lighter for parity 1 to 4 (P < 0.001); at parity 5, AFC had no association with cow live weight (P > 0.05). The performance of mature cows for calving interval, longevity, calving difficulty, cow live weight, and weaning weight was not impacted by AFC. In conclusion, calving cows for the first time at younger ages do pose risks and associated performance loss but this risk and loss should be minimized by good management. [ABSTRACT FROM AUTHOR]

With regard to potential applications of genomic selection in small numbered breeds, we evaluated genomic models and focused on potential candidate gene annotations for weight and meat quality traits in the local Rotes Höhenvieh (RHV) breed. Traits included 6,003 birth weights (BWT), 5,719 200 d-weights (200dw), 4,594 365 d-weights (365dw), and 547 records for intramuscular fat content (IMF). A total of 581,304 SNP from 370 genotyped cattle with phenotypic records were included in genomic analyses. Model evaluations focused on single- and multiple-trait models with direct and with direct and maternal genetic effects. Genetic relationship matrices were based on pedigree (A -matrix), SNP markers (G -matrix), or both (H -matrix). Genome-wide association studies (GWASs) were carried out using linear mixed models to identify potential candidate genes for the traits of interest. De-regressed proofs (DRP) for direct and maternal genetic components were used as pseudo-phenotypes in the GWAS. Accuracies of direct breeding values were higher from models based on G or on H compared to A. Highest accuracies (> 0.89) were obtained for IMF with multiple-trait models using the G -matrix. Direct heritabilities with maternal genetic effects ranged from 0.62 to 0.66 for BWT, from 0.45 to 0.55 for 200dW, from 0.40 to 0.44 for 365dW, and from 0.48 to 0.75 for IMF. Maternal heritabilities for BWT, 200dW, and 365dW were in a narrow range from 0.21 to 0.24, 0.24 to 0.27, and 0.21 to 0.25, respectively, and from 0.25 to 0.65 for IMF. Direct genetic correlations among body weight traits were positive and favorable, and very similar from different models but showed a stronger variation with 0.31 (A), −0.13 (G), and 0.45 (H) between BWT and IMF. In gene annotations, we identified 6, 3, 1, and 6 potential candidate genes for direct genetic effect on BWT, 200dW, 365dW, and IMF traits, respectively. Regarding maternal genetic effects, four (SHROOM3 , ZNF609 , PECAM1 , and TEX2) and two (TMEM182 and SEC11A) genes were detected as potential candidate genes for BWT and 365dW, respectively. Potential candidate genes for maternal effect on IMF were GRHL2 , FGA , FGB , and CTNNA3. As the most important finding from a practical breeding perspective, a small number of genotyped RHV cattle enabled accurate breeding values for high heritability IMF. [ABSTRACT FROM AUTHOR]

The present study aimed to identify the genotype and the allele variety of the DMRT3 gene highly linked SNP with the horse breed. It aims as well as to determine the effective alleles, influencing the ability to perform alternate gaits, which causes a favorable effect on the harness racing performance (all that being based on the results discussed). The animals were selected via genotyping based on their breed, gaits, and racing performance. Some of these horses showed good racing performance, so we've used their performance traits. The RFLP analysis was carried out with specific endonuclease DdeI. The whole group of horses was genotyped for SNP (BIEC2_620109) via Sanger sequencing. In the study, the mutation was observed in horses from the following 5 harness breeds (Germany, Italian, Standardbred, French and Bulgarian trotters). In the breeds for a flat race, only the wild type was observed. SNP (BIEC2_620109) is highly linked with the A and C alleles of DMRT3_Ser301STOP mutation, except for only one horse of the Fresian breed. Both groups: young horses of 2 and 3 yo (years old), incl. a qualification test and horses older than 4 yo (years old)/of heterozygous genotype CA showed a better placing. The heterozygous genotypes (CA) have a positive effect on the winning results of the four-year-old ones. The heterozygous genotype (CA) has a negative effect on the qualification and the racing career of the young horses. These results indicate that this polymorphism may be useful for assisted selection for the gait type of the gaited breeds. [ABSTRACT FROM AUTHOR]

The objective was to estimate allelic and genotypic frequencies for loci associated with meat quality in a Mexican population of Braunvieh cattle. Information was obtained from 300 animals genotyped with the Genomic Profile Bovine LD chip of 30K and 50K SNPs. After the final edition, including quality control, the data contained information for 12 loci of the CAPN1, CAPN3, CAPN5, CAPN14, DGAT1, DGAT2, TG, ANK1, and MADH3 genes. Allelic and genotypic frequencies and Hardy-Weinberg equilibrium were estimated with the Cervus 3.0.7 software. The studied population markers were in Hardy-Weinberg equilibrium, except for those associated with CAPN1, DGAT1, and MADH3. Frequencies higher than those reported for other breeds were found for genotypes associated with meat softness, higher marbling score, lower quantity of saturated fatty acids, and lower shear force (CAPN1 and DGAT2). There were similarities with frequencies reported for Bos taurus breeds for the CAPN3 and TG genes. For the DGAT1 and ANK1 genes, the frequencies of the desired genotypes were low. A marker for DGAT1 and another for MADH3 were monomorphic. The results of this study are encouraging in terms of the potential of the Braunvieh population studied for breeding programs aiming to increase meat quality. The breed has strengths that could be used either by crossbreeding to generate heterozygous animals or by selection to increase frequencies of valuable alleles. [ABSTRACT FROM AUTHOR]

The aim was to disentangle gait characteristics from other qualities needed for racing performances with a genomic analysis of French trotters (FT). A sample of 1,390 horses were recruited, from which 46% were genotyped with Illumina chip of 54,602 SNPs, 49% with Affymetrix chip of 670,806 SNPs and 586 had a completed questionnaire on trotting technique. Racing performances cover the period 1996 to 2018. There were 252,368 FT‐born; 96,617 qualified and 83,962 which participated in a race. After quality control, 377,611 SNPs were retained and imputed. Questionnaire described trotting technique over 13 questions which were summarized, after principal component analysis in 3 traits: pacer, heavy trot/gallop and other defects. GWAS and genomic evaluation were performed using single‐step approach. We found 25 QTL for racing performances and 9 for trotting technique. Only DMRT3 mutation was significant for both traits. To tend to pace avoid the defect at gallop and lead to a better early career for earnings, less percentage of disqualified races at all ages and more harness than under saddle career. This is the portrait of AA genotype at DMRT3. We found 5 other QTL, not linked to gait traits, which might improve selection of genetically independent performance traits of earnings per races and percentage of finished races. For only earnings at different ages and in under saddle or harness races, genomic evaluation remains the best way to predict performances. [ABSTRACT FROM AUTHOR]

This study was conducted in Badri cattle using a double digest restriction-site associated DNA sequencing approach. The study aimed to identify and annotate high confidence single nucleotide polymorphisms (SNPs) and their mapping in candidate genes related to production and fertility in dairy cattle. A total of 7,168,552 genome-wide SNPs were initially identified in Badri cattle by alignment with the Bos indicus reference genome. After filtration of SNPs, 65,483 high confidence SNPs were retained and further used for downstream analysis. Annotation of high confidence SNPs revealed 99.197% SNPs had modifier impact, 0.326% SNPs were low impact, 0.036% were high impact, and 0.441% were moderate impact SNPs. Most SNPs in Badri cattle were found in intergenic, transcript and intronic regions. The candidate genes for milk production PRKCE, ABCG2, GHR, EPS8, CAST and NRXN1 were found to harbour maximum high confidence variants. Among candidate genes for fertility in cattle, ATP2B1, SOX5, WDR27, ARHGAP12, CACNA1D, ANKRD6, GRIA3, ZNF521 and CAST822 have maximum high confidence variants mapped in them. The SNPs found mapped in the candidate genes will be important genetic tools in the search for phenotype-modifying nucleotide changes and will aid in formulating relevant genetic improvement programmes for dairy cattle., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

Diacylglycerol acyltransferase1 (DGAT1) plays an important role in the metabolism of triglycerides which catalyze the final step of triglyceride synthesis in animals. The objective of this study was to investigate the single-nucleotide polymorphisms (SNPs) in 5'UTR, exon-1, and exon-2 of DGAT1 in two Iranian indigenous sheep breeds. A total of 309 animals including fat-tailed Lori-Bakhtiari (n=152) and thin-tailed Zel (n=157) were used in this study. The genotypic patterns were detected by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP). Five SSCP patterns were detected for 5'UTR and exon-1 fragment by PCR-SSCP and subsequently confirmed by sequencing PCR products. The sequencing results revealed that there are three novel polymorphisms in 5'UTR and exon-1fragment of DGAT1 at the studied breeds. Out of the detected polymorphisms only A277G substitution in exon-1 of DGAT1 leads to the changes in amino acids (p.Arg26Gly). There was significant correlation (P<0.05) between fat-tail weight (FTW) and back-fat thickness (BFT) and the observed genotypes in Lori-Bakhtiari breed; therefore, animals with G5 pattern had higher FTW and BFT compared to G1 pattern. The G1 and G5 genotypic patterns or haplotypes were different at their position 101 of 5'UTR region. No significant relationship (P<0.05) was found between the detected genotypes of 5'UTR and exon-1 fragment of DGAT1 in Zel breed and carcass traits. These results revealed that detected DGAT1 novel SNPs had significant effects on carcass traits and they can be used as a marker for these traits. [ABSTRACT FROM AUTHOR]

Cattle breeding routinely uses crossbreeding between subspecies (Bos taurus taurus and Bos taurus indicus) to form composite breeds, such as Brangus. These composite breeds provide an opportunity to identify recent selection signatures formed in the new population and evaluate the genomic composition of these regions of the genome. Using high-density genotyping, we first identified runs of homozygosity (ROH) and calculated genomic inbreeding. Then, we evaluated the genomic composition of the regions identified as selected (selective sweeps) using a chromosome painting approach. The genomic inbreeding increased at approximately 1% per generation after composite breed formation, showing the need of inbreeding control even in composite breeds. Three selected regions in Brangus were also identified as Angus selection signatures. Two regions (chromosomes 14 and 21) were identified as signatures of selection in Brangus and both founder breeds. Five of the 10 homozygous regions in Brangus were predominantly Angus in origin (probability >80%), and the other five regions had a mixed origin but always with Brahman contributing less than 50%. Therefore, genetic events, such as drift, selection, and complementarity, are likely shaping the genetic composition of founder breeds in specific genomic regions. Such findings highlight a variety of opportunities to better control the selection process and explore heterosis and complementarity at the genomic level in composite breeds. [ABSTRACT FROM AUTHOR]

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Arabian horses are commonly believed to be one of the oldest and most influential horse breeds in the world. The high financial benefits obtained from races tend to search for genetic markers strongly correlated with the results achieved. To date, the modern approaches such as transcriptome, miRNAome, and metabolome analyses have been used to investigate the genetic background of racing performance as well as endurance capacity in Arabians. The analysis of polymorphisms at the genome level has also been applied to the detection of genetic variants associated with exercise phenotype in the Arabian breed. The presented review summarizes these findings, with a focus on the genetics underlying flat racing and endurance performance traits in different Arabian horse populations. [ABSTRACT FROM AUTHOR]

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Heritability and direct and maternal genetic changes were estimated in Nellore cattle for the following traits: birth to weaning weight gain (BWG), weaning to yearling weight gain (YWG), weaning conformation (WC), weaning precocity (WP), weaning muscling (WM), yearling conformation (YC), yearling precocity (YP), yearling muscling (YM) and yearling scrotal circumference (SC). Direct and maternal heritability for weaning traits were 0.21±0.03 and 0.13±0.01 (BWG); 0.19±0.03 and 0.07±0.01 (WC); 0.22±0.03 and 0.07±0.01 (WP); 0.20±0.03 and 0.07±0.01 (WM), respectively. For yearling traits, direct heritability were 0.19±0.04 (YWG); 0.32±0.05 (YC); 0.37±0.05 (YP); 0.38±0.05 (YM) and 0.41±0.04 (SC). Positive and significant direct genetic changes (p < 0.05) were found for all traits, except for WC (p = 0.09), equal to 0.138 kg year-1 (BWG), 0.003 units year-1 (WC), 0.011 units year-1 (WP), 0.009 units year-1 (WM), 0.132 kg year-1 (YWG), 0.003 units year-1 (YC), 0.011 units year-1 (YP), 0.011 units year-1 (YM) and 0.020 cm year-1 (SC), indicating favorable genetic gains in the period. For weaning traits, we obtained negative and non-significant (p > 0.05) maternal genetic trends, with values of -0.084 kg year-1 (BWG), -0.004 units year-1 (WC), -0.004 units year-1 (WP) and -0.004 units year-1 (WM). Thus, greater emphasis should be given for maternal genetic merit of weaning traits in this population, if improvements in maternal ability were desirable. [ABSTRACT FROM AUTHOR]

The DMRT3 mutation has had a major effect on the diversification of the domestic horse, as the altered gait characteristics of a number of breeds, including this mutation. Doublesex and mab-3 related transcription factor 3 (DMRT3) gene shown that a mutation from cytosine (C) to adenine (A) has a major impact on harness racing performance of different breeds. The DMRT3 mutant allele (A) has been found in high frequency in gaited breeds and breeds bred for harness racing (trot or pace), while other horse breeds were homozygous for the wild-type allele (C). The heterozygous allele (CA) were found in horse breeds for harness racing and four- and fi ve-gaited breeds. Sequncing at SNP BIEC2-620109 resulted in detection of both heterozygous (CT) and homozygous genotypes (CC, TT). Mutation in DMRT3 has a major impact on gaitedness in horses and is presented at a high frequency in gaited breeds and in horses breed for harness racing. The aim of the study is to describe the effect of the DMRT3 gene mutation and higly linked SNP in different gaited and harness horse breeds. [ABSTRACT FROM AUTHOR]

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Advancing the age at which puberty and subsequent sexual maturation is attained in cattle is central to the reproductive and economic efficiency of both beef and dairy production systems worldwide. Onset of puberty in both male and female cattle is regulated by a complex network of biochemical processes and involves interaction among many key metabolic, neuroendocrine and reproductive tissues. Although our understanding of the biochemical interplay that conditions and eventually triggers the pubertal process has improved in recent years, much of the intricate mechanistic detail still eludes us. Environmental factors, such as nutritional management, as well as the genetic makeup of the animal undoubtedly affect the timing of puberty in cattle. In particular, there is now overwhelming evidence to support the importance of early life nutrition in regulating the timing of puberty in both bulls and heifers. For both genders, there is significant evidence that an improved metabolic status, early in calfhood, advances maturation of the hypothalamic- pituitary-gonadal axis, therefore facilitating earlier sexual development. Although advancing sexual maturation is a desirable goal, it is important that any strategy used does not impinge upon normal gametogenesis or postpubertal fertility potential. To this end, the aim of this review is to discuss the underlying biology of puberty in cattle with particular emphasis on the role of nutritional management during early calfhood in: (1) advancing the maturity of the hypothalamic- pituitary-gonadal axis; and (2) implications for the quality of gametes and subsequent fertility. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of the Indonesian Tropical Animal Agriculture is the property of Diponegoro University & Indonesian Society of Animal Agriculture, Faculty of Animal Agriculture and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Covariance components and genetic parameters were estimated for birth weight (BiW); adjusted weights at 4, 7, 12, and 18 mo; and ADG between 0 and 4 mo, between 4 and 7 mo, between 7 and 12 mo, and between 12 and 18 mo. Additionally, reproductive traits, calving interval, and age at first calving were analyzed, together with traits measured by ultrasound: loin eye area, deep fat mean, back fat, and rump fat. Analyses were performed using an animal model, considering the fixed effects of the farm (n = 37), year and month of birth, sex, calving number (1 to 7), season (dry and rainy seasons), region (North Coast, Andean Region, and Oriental Savannas), and conception (natural mating or AI), whereas the age of the cows at calving was considered a polynomial covariate with linear and quadratic effects. Three different models were used to find the one with the best fit for each trait: a single-trait model with an additive direct genetic effect, a single-trait model with additive direct and maternal genetic effects, and finally, a multitrait model with an additive direct genetic effect. For the growth traits, the heritability was between 0.24 and 0.47, with the lowest value for weight at 7 mo and the greatest value for BiW, and the maternal heritability was found to be between 0.15 and 0.21 but did not decrease later on. The correlation between direct and maternal effects was high and negative (-0.59 to -0.76). With ultrasound traits, a model with only direct effects was used. The heritability was between 0.13 and 0.28 for back fat and loin eye area, respectively. The heritabilities for deep fat mean and rump fat were similar, being 0.19 and 0.21, respectively. The reproductive traits showed high residual variance. In particular, the heritability of calving interval was low (0.06). The results showed that the growth traits have an important genetic component, which is a favorable indicator for obtaining improvement progress in the zebu Brahman breed for beef production in tropical regions of Colombia. The maternal effects influenced the weight performance from 4 to 18 mo and should be taken into account in genetic analyses. In general, the direct heritability of medium magnitude estimated for growth and traits measured by ultrasound suggests that individual selection for these traits will be effective. [ABSTRACT FROM AUTHOR]

The diacylglycerol acyltransferase 1 gene (DGAT1) was identified as a strong candidate gene affecting mutton quality traits in sheep. Single nucleotide polymorphism creates a single base mutation (C to T) in AGCT site of endonuclease AluI. DGAT1 is one of the candidate genes to improve carcass characteristics in feedlot animals. In order to study area T487C in exon 17 of the DGAT1 polymorphism, Iranian Moghani sheep breeds randomly slaughtered in the abattoir were recorded. DNA was extracted from 150 samples of Moghani sheep. Polymerase chain reaction to amplify 309 bp of exon 17 DGAT1 gene using a pair of specific primers was performed. Genotypes obtained from method PCR-RFLP and directly from agarose gel. Two alleles T and C with frequencies of 0.829 and 0.171 were observed respectively. Statistical analysis showed polymorphism in exon 17 region of the gene significantly correlated with carcass weight and dressing percentage (P<0.05). So that the CC genotypes of the significant mean carcass weight and dressing percentage heavier than had TT genotypes (P<0.05). Of polymorphism can be observed that improvement in breeding programs to improve carcass weight and dressing percentage through selection in favor of superior genotypes be used. [ABSTRACT FROM AUTHOR]

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Copyright of Revista Brasileira de Saúde e Produção Animal (RBSPA) is the property of Revista Brasileira de Saude e Producao Animal (RBSPA) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)