The effects of reference population size and the availability of information from genotyped ancestors on the accuracy of imputation of single nucleotide polymorphisms (SNP) were investigated for Mexican Holstein cattle. Three scenarios for reference population size were examined: (1) a local population of 2,011 genotyped Mexican Holsteins, (2) animals in scenario 1 plus 866 Holsteins in the US ...

Heterosis and breed differences were estimated for milk yield traits, somatic cell score (SCS), and productive life (PL), a measure of longevity. Yield trait data were from 10,442 crossbreds and 140,421 purebreds born since 1990 in 572 herds. Productive life data were from 41,131 crossbred cows and 726,344 purebreds born from 1960 through 1991. The model for test-day yields and SCS included eff...

Reproductive information since 1995 from the USDA national dairy database was used to calculate yearly Holstein and Jersey means for days to first breeding after calving (DFB), 70-d nonreturn rate, conception rate (CR), number of breedings per lactation (NB), interval between first and last breedings during the lactation, days to last breeding after calving (DLB), pregnancy rate (PR), calving i...

Calving records from the Animal Breeding Center of Iran collected from January 1990 to December 2007 and comprising 207 106 first calving events of Holsteins from 2 506 herds were analysed using linear sire models to estimate genetic trends for age at first calving (AFC) and milk traits. Genetic trends were obtained by regressing yearly mean estimates of breeding values on year of birth. In gen...

The intensive selection programs for milk made possible by mass artificial insemination increased the similarity among the genomes of North American (NA) Holsteins tremendously since the 1960s. This migration of elite alleles has caused certain regions of the genome to have runs of homozygosity (ROH) occasionally spanning millions of continuous base pairs at a specific locus. In this study, gen...

A Pseudomonas aeruginosa strain (UCBPP-PA14) is infectious both in an Arabidopsis thaliana leaf infiltration model and in a mouse full-thickness skin burn model. UCBPP-PA14 exhibits ecotype specificity for Arabidopsis, causing a range of symptoms from none to severe in four different ecotypes. In the mouse model, UCBPP-PA14 is as lethal as other well-studied P. aeruginosa strains. Mutations in ...