The computational complexity of the Vertex Coloring problem is known for all hereditary classes of graphs defined by forbidding two connected five-vertex induced subgraphs, except for seven cases. We prove the polynomial-time solvability of four of these problems: for (P5, dart)-free graphs, (P5, banner)-free graphs, (P5, bull)-free graphs, and (fork, bull)-free graphs.

The effects of potassium, sodium, chloride and calcium on the percentage progressive motility of samples of chimpanzee and bull spermatozoa were investigated. Inhibitors and stimulatory of motility were identified. Three parameters of chimpanzee sperm motility, velocity, frequency and amplitude, were measured. There was no consistent change related to ion concentration. The ionic constituents o...

Lethal recessive genes that cause early embryo loss are difficult to detect. Nonreturn rate at 70 d after first insemination (NR) was evaluated as a trait of the embryo using 1,739,055 first-service records from 1,251 Holstein bulls represented as both service sires and sires of cows. Effects modeled included herd-year-season, parity of cow, sire of cow, service bull, interaction of service bul...

A DNA polymerase was isolated from bull spermatozoa by differential centrifugation, ultrafiltration and gel filtration. Its apparent molecular weight and synthetic template utilization resemble that of DNA polymerase gamma. Chemical and enzymic fractionation of bull spermatozoa indicate that the enzyme is most probably located in the nucleus.

A deterministic model based on the gene flow method, considering the features of Iranian Holstein cattle population, was implemented in this study to evaluate the effect of altering the number of age-classes in the dams of future sire (DS) path and the number of dams required for breeding a young bull (YB), to be evaluated as future sire, on genetic gain and resultant economic efficiency of a g...

Lyman J . Bratzler was born September 24, 1905, at Barrington, IL, where he obtained his elementary and high school education. He was reared on a dairy farm, from which he developed his interest in agriculture. He entered the University of Illinois in 1926 and was a member of the Meats Judging Team in 1929. He received inspiration from some great teachers: Dean Mumford, Sleeter Bull, R. R. Snap...

If genetic evaluations are calculated with a single-trait repeatability model, evaluation changes may be attributed in part to bulls that have daughters that deviate considerably from the typical response to aging. Differences in maturity rate of bull daughters were examined to determine whether they influence change in bull evaluations. Standardized milk records for Holsteins that first calved...

The aim of this study was to investigate the comparison between some seminal plasma parameters and age of the bull. Concentrations of various biochemical parameters like fructose, glucose, total proteins, albumin and inorganic ions including Na, K and Cl ions of seminal plasma of breeding Sahiwal bulls of different ageswere assessed. Methods: 40Sahiwal bullsdivided into 4 age groups.Semen (2ml ...

Starch (SS) and fermented fiber (FFS), as energy sources were included in Holstein bull calf diets to evaluate their growth performance, rumen fermentation pattern and concentration of insulin and selected blood metabolites. Fourteen Holstein bull calves (BW=94.5±2.1 kg; age 87±9 d) were allocated to treatments (n=7 calves per treatment) and the study lasted 10 weeks. The diets were based on ba...