Phenotypic relationships between meat quality parameters and residual feed intake in Japanese black Wagyu cattle.

Japanese black Wagyu cattle are renowned for producing some of the world's most highly valued and recognized beef with exceptional marbling. Therefore, the primary focus of genetic selection for Wagyu cattle has historically been on meat quality, particularly achieving high marbling levels. However, even when the price of the final product is high, production costs also remain high, especially considering that most of the feed has to be imported.

Verification of Candidate SNP Effects Reveals Two QTLs on BTA7 for Beef Marbling in Two Japanese Black Cattle Populations.

In our previous study, we used genome resequencing to detect all candidate polymorphisms within a quantitative trait loci (QTL) region for beef marbling reported previously at 10-30 Mbp on bovine chromosome 7, and we selected 6044 polymorphisms as candidate quantitative trait nucleotides (QTNs). In the present study, we aimed to identify quantitative trait genes (QTGs) and QTNs in this QTL region by verifying the effect of SNPs on beef marbling in two Japanese Black cattle populations using a Dynamic Array integrated fluidic circuit. In total, 96 selected SNPs were genotyped in 441 and 529 animals in Hyogo and Miyazaki cattle populations, respectively.

Estimation of genetic parameters for carcass grading traits, image analysis traits, and monounsaturated fatty acids in Japanese Black cattle from Hyogo Prefecture.

Genetic parameters for carcass grading traits, image analysis traits, and monounsaturated fatty acid (MUFA) percentages were estimated in 29,942 Japanese Black cattle from Hyogo Prefecture. The analyzed traits included five carcass grading traits, two image analysis traits, fat area ratio and fineness index, and two MUFA traits, one measured in intermuscular fat using near-infrared spectroscopy (NIRS) and the other in intramuscular fat using gas chromatography (GC). The heritability estimates of image analysis traits and MUFA were moderate to high, ranging from 0.

Detection of candidate polymorphisms around the QTL for fat area ratio to rib eye area on BTA7 using whole-genome resequencing in Japanese Black cattle.

In our previous study, we performed genome-wide association study (GWAS) to identify the genomic region associated with Fat area ratio to rib eye area (FAR) and detected a candidate in BTA7 at 10-30 Mbp. The present study aims to comprehensively detect all polymorphisms in the candidate region using whole-genome resequencing data. Based on whole-genome resequencing of eight animals, we detected 127,090 polymorphisms within the region.

LH and testosterone secretions in response to GnRH challenge in pubertal Japanese Black beef bulls with normal and abnormal semen.

Plasma luteinizing hormone (LH) and testosterone concentrations were examined in Japanese Black beef bulls with normal and abnormal semen in response to gonadotropin releasing hormone (GnRH) challenge at the start (10 months) and completion (20 months) of puberty. Bulls with normal semen had higher testosterone concentrations after GnRH treatment at 20 months than they did at 10 months, while LH concentrations did not differ between the two age groups. LH and testosterone concentrations were not different between bulls with normal and abnormal semen at 20 months.

Relationships of plasma insulin-like peptide 3, testosterone, inhibin, and insulin-like growth factor-I concentrations with scrotal circumference and testicular weight in Japanese Black beef bull calves.

This study was conducted to clarify the relationships of plasma concentrations of insulin-like peptide 3 (INSL3), testosterone, inhibin, and insulin-like growth factor-I (IGF-I) with scrotal circumference and testicular weight in Japanese Black beef bull calves (n = 20), from birth to pre-puberty. Monthly blood sampling (0 to 7 months) and scrotal circumference measurements (0 to 7 months) were performed. Testicular weight was recorded immediately after castration at 7 months.

Pool-based genome-wide association study identified novel candidate regions on BTA9 and 14 for oleic acid percentage in Japanese Black cattle.

Fatty acid composition is an important indicator of beef quality. The objective of this study was to search the potential candidate region for fatty acid composition. We performed pool-based genome-wide association studies (GWAS) for oleic acid percentage (C18:1) in a Japanese Black cattle population from the Hyogo prefecture.

A genome-wide association study for fat-related traits computed by image analysis in Japanese Black cattle.

The objective of this study was to identify genomic regions associated with fat-related traits using a Japanese Black cattle population in Hyogo. From 1836 animals, those with high or low values were selected on the basis of corrected phenotype and then pooled into high and low groups (n = 100 each), respectively. DNA pool-based genome-wide association study (GWAS) was performed using Illumina BovineSNP50 BeadChip v2 with three replicate assays for each pooled sample.

Effects of acrosomal conditions of frozen-thawed spermatozoa on the results of artificial insemination in Japanese Black cattle.

The purposes of this study were to examine the relationship between male artificial insemination (AI) fertility and sperm acrosomal conditions assessed by new and conventional staining techniques and to identify possible reproductive dysfunctions causing low conception rates in AI using frozen-thawed spermatozoa with poor acrosomal conditions in Japanese Black bulls. We investigated individual differences among bulls in the results concerning (1) acrosomal conditions of frozen-thawed spermatozoa as assessed by not merely peanut agglutinin-lectin staining (a conventional staining technique) but also immunostaining of acrosomal tyrosine-phosphorylated proteins (a new staining technique), (2) routine AI using frozen-thawed spermatozoa as assessed by pregnancy diagnosis, (3) in vivo fertilization of frozen-thawed spermatozoa and early development of fertilized eggs as assessed by superovulation/AI-embryo collection tests and (4) in vitro fertilization of frozen-thawed spermatozoa with oocytes. The percentages of frozen-thawed spermatozoa with normal acrosomal conditions assessed by the abovementioned staining techniques were significantly correlated with the conception rates of routine AI, rates of transferable embryos in superovulation/AI-embryo collection tests and in vitro fertilization rates.

A novel mutation of the bovine EDA gene associated with anhidrotic ectodermal dysplasia in Holstein cattle.

Anhidrotic ectodermal dysplasia (EDA) is a genetic disease characterized by the absence or hypoplasia of hair, teeth and eccrine sweat glands that has been reported in humans, the tabby mouse mutants, cattle and dogs. The EDA gene on the X chromosome encodes a protein, ectodysplasin-A (EDA), which is responsible for EDA. Here we describe a novel mutation of the EDA gene in which a 19 bp deletion in exon 1 in male Holstein calves demonstrated the phenotypic features of EDA.