Telomeres cap the ends of linear chromosomes and shorten with age in many organisms. In humans short telomeres have been linked to morbidity and mortality. With the accumulation of longitudinal datasets the focus shifts from investigating telomere length (TL) to exploring TL change within individuals over time. Some studies indicate that the speed of telomere attrition is predictive of future d...

Our initial genome-wide association study (GWAS) demonstrated that two SNPs (ARS-BFGL-NGS-33248, UA-IFASA-9288) within the protein tyrosine kinase 2 (PTK2) gene were significantly associated with milk production traits in Chinese Holstein dairy cattle. To further validate if the statistical evidence provided in GWAS were true-positive findings, a replication study was performed herein through g...

genetic trend for production traits were estimated in iranian holstein cattle using the first lactation data recorded by cattle breeding and dairy product improvement center of the state from 1991 to 2006. effect of some factors on genetic trend was investigated using data from 18 large herds. (co) variance components and genetic parameters were estimated, using five trait animal model and em-a...

Breed differences in adult animals are determined during fetal development. If interventions are to be developed that influence growth of muscle and fat, it is important to know at which time during gestation breed differences appear and are fixed. The objective of this study was to characterize fetal development in cattle of different breeds. Pregnant cows of 4 cattle breeds with different gro...

a deterministic model was employed to simulate various progeny testing programs compatible with the conditions of holstein dairy cattle population in iran. in simulated programs, the selection intensity of bulls was increased by increasing the ratio of cow population in mate with young bulls. selection accuracy in the programs was fixed because of the fixed progeny group. economic efficiency (t...

Dominance may be an important source of non-additive genetic variance for many traits of dairy cattle. However, nearly all prediction models for dairy cattle have included only additive effects because of the limited number of cows with both genotypes and phenotypes. The role of dominance in the Holstein and Jersey breeds was investigated for eight traits: milk, fat, and protein yields; product...

The major histocompatibility complex (MHC) is a gene complex closely linked to the vertebrate immune system due to its importance in antigen recognition and immune response to pathogens. To improve our understanding of the MHC and disease resistance in dairy cattle, we gathered 5119 test day records of somatic cell count (SCC) and performance traits of 262 Holstein dairy cows to determine wheth...

To assess relationships between nucleotide polymorphisms of the prion protein (PRNP) gene and susceptibility to bovine spongiform encephalopathy (BSE), we investigated polymorphisms in the open reading frame (ORF) and 2 upper regions of the PRNP gene from 2 Japanese cattle breeds: 863 healthy Holstein cattle, 6 BSE-affected Holstein cattle, and 186 healthy Japanese Black (JB) cattle. In the ORF...

Left-sided displacement of the abomasum (LDA) is a common disease in many dairy cattle breeds. A genome-wide screen for QTL for LDA in German Holstein (GH) cows indicated motilin (MLN) as a candidate gene on bovine chromosome 23. Genomic DNA sequence analysis of MLN revealed a total of 32 polymorphisms. All informative polymorphisms used for association analyses in a random sample of 1,136 GH c...

Although dairy manure is widely applied to land, it is relatively understudied compared to other livestock as a potential source of antibiotic resistance genes (ARGs) to the environment and ultimately to human pathogens. Ceftiofur, the most widely used antibiotic used in U.S. dairy cows, is a 3rd generation cephalosporin, a critically important class of antibiotics to human health. The objectiv...