OMD
Osteomodulin precursor (Keratan sulfate proteoglycan osteomodulin) (KSPG osteomodulin) (Osteoadherin) (OSAD) [SLRR2C] [UNQ190/PRO216]
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Body weight (BW) at different ages are of increasing importance in dairy cattle breeding schemes, because of their strong correlation with energy efficiency traits, and their impact on cow health, longevity and farm economy. In total, 15,921 dairy cattle from 56 large-scale test-herds with BW records were genotyped for 45,613 single nucleotide polymorphisms (SNPs). This dataset was used for genome-wide association studies (GWAS), in order to localize potential candidate genes for direct and maternal genetic effects on BW recorded at birth (BW0), at 2 to 3 months of age (BW23), and at 13 to 14 months of age (BW1314). The first 20 principal components (PC) of the genomic relationship matrix ([Formula: see text]) grouped the genotyped cattle into three clusters. In the statistical models used for GWAS, correction for population structure was done by including polygenic effects with various genetic similarity matrices, such as the pedigree-based relationship matrix ([Formula: see text]), the [Formula: see text]-matrix, the reduced [Formula: see text]-matrix LOCO (i.e. exclusion of the chromosome on which the candidate SNP is located), and LOCO plus chromosome-wide PC. Inflation factors for direct genetic effects using [Formula: see text] and LOCO were larger than 1.17. For [Formula: see text] and LOCO plus chromosome-wide PC, inflation factors were very close to 1.0. According to Bonferroni correction, ten, two and seven significant SNPs were detected for the direct genetic effect on BW0, BW23, and BW1314, respectively. Seventy-six candidate genes contributed to direct genetic effects on BW with four involved in growth and developmental processes: FGF6, FGF23, TNNT3, and OMD. For maternal genetic effects on BW0, only three significant SNPs (according to Bonferroni correction), and four potential candidate genes, were identified. The most significant SNP on chromosome 19 explained only 0.14% of the maternal de-regressed proof variance for BW0. For correction of population structure in GWAS, we suggest a statistical model that considers LOCO plus chromosome-wide PC. Regarding direct genetic effects, several SNPs had a significant effect on BW at different ages, and only two SNPs on chromosome 5 had a significant effect on all three BW traits. Thus, different potential candidate genes regulate BW at different ages. Maternal genetic effects followed an infinitesimal model.
MeSH Terms
- Aging
- Animals
- Body Weight
- Cattle
- Extracellular Matrix Proteins
- Female
- Fibroblast Growth Factors
- Genome-Wide Association Study
- Male
- Polymorphism, Single Nucleotide
- Proteoglycans
- Quantitative Trait Loci
- Troponin T
The ability of young and mature horses to digest DM, OM, and NDF was compared using 6 weanling colts and 6 mature (13.2 ± 3.0 yr) geldings. Each colt was paired with a gelding, and the pair was adapted to a diet containing 67% alfalfa cubes and 33% concentrate for 21 d. During the adaptation period, horses were accustomed to housing and all handling procedures. The adaptation period was also used to adjust the amount of feed offered to minimize orts and to maintain similar rates of intake within a pair. After the adaptation period, a 5-d fecal collection period using fecal collection harnesses ensued. The average age of the weanling colts at the start of the 5-d collection period was 181.8 ± 2.9 d. On the morning of the first collection day, Co-EDTA (9 mg Co/kg BW(0.75)) and ytterbium-labeled hay fiber (9 mg Yb/kg BW(0.75)) were added to the concentrate portion of the diet, and horses were closely observed for complete consumption of the markers before additional feed was offered. The fecal collection bags were emptied every 1 to 2 h, and each collection was weighed and subsampled for later measurement of Co and Yb concentrations, which were used to determine the mean retention time (MRT) of the fluid and particulate phases of digesta, respectively. The remaining feces for each horse were composited each day and then subsampled for measurement of DM digestibility (DMD), NDF digestibility (NDFD), and OM digestibility (OMD). During the fecal collection period, DMI was similar between colts and geldings (91.4 and 91.2 g/kg BW(0.75), respectively). There were no differences between colts and mature geldings for DMD, OMD, or NDFD. Across both ages, the MRT of the particulate phase was 24.9 h compared with 21.8 h for the fluid phase (P = 0.002). However, MRT for the particulate phase was not different between colts and mature geldings (24.7 and 25.2 h, respectively). There was no difference in the MRT for the fluid phase between colts and mature geldings (21.5 and 22.0 h, respectively). The results indicated that the digestibility of DM, OM, and NDF in a diet consisting of good-quality cubed forage and concentrate is similar for weanling colts and mature geldings.
MeSH Terms
- Aging
- Animal Feed
- Animal Nutritional Physiological Phenomena
- Animals
- Diet
- Dietary Fiber
- Dietary Supplements
- Digestion
- Feces
- Horses
- Male
- Spectrophotometry, Atomic