Since domestication, population bottlenecks, breed formation, and selective breeding have radically shaped the genealogy and genetics of Bos taurus. In turn, characterization of population structure among globally diverse bull genomes enables detailed assessment of genetic resources and origins. By analyzing 432 unrelated bull genomes from 13 breeds and 16 countries, we demonstrate genetic dive...

Blood samples were taken from 19 double-muscled (DM) and 20 normal (N) bull calves at the ages of 1.5, 2, 2.5, 3, 3.5, 4, 5.5, 6.5 and 9 mo to compare the plasma concentrations of growth hormone and insulin in DM with those in N bull calves and to relate these to differences in growth rate between the two breed groups. Double-muscled bull calves were lighter (P less than .0001) than N calves at...

1. Ram and bull spermatozoa suspended in a glucose-sodium chloride solution rapidly lose motility at relatively high dilutions. The substitution of chloride-free diluents does not alter the phenomenon. 2. The rapid immobilization of ram and bull spermatozoa due to high dilution may be partially prevented by the addition of supernatants of either ram or bull semen, although motility is not maint...

We give a polynomial-time algorithm that computes the chromatic number of any graph that contains no path on five vertices and no bull as an induced subgraph (where the bull is the graph with five vertices a, b, c, d, e and edges ab, bc, cd, be, ce).

The aim of the study was to evaluate the effect of the addition of 20% bull seminal plasma to semen extenders on post-thaw sperm motility, morphology, and fertility. Two Merino rams at 3-5 years of age, 43 ewes, and one Holstein bull were used. Fourteen ejaculates were collected by the use of an artificial vagina, twice a day, at 60 min interval. Six semen ejaculates were extended with Tris-egg...

The ties and relationships within the Ayrshire and Jersey bull populations from the United States and Canada were investigated. Twenty-two percent of genes in the United States Ayrshire bull population were of Canadian origin, whereas 22% of genes in the Canadian Jersey bull population were of United States origin. Average genetic relationships among bulls between countries were comparable with...

Thermotaxis that sperm migrate to higher temperature area has been confirmed in rabbit and human. In this study, we examined the migration ability of bull sperm in a temperature gradient to confirm thermotaxis and elucidate the involvement of calcium in such thermotaxis, as well as the relation between sperm capacitation and bull fertility. Thermotaxis was evaluated in a temperature gradient of...

Bull trout (Salvelinus confluentus) were recently listed as threatened in the United States under the federal Endangered Species Act. Present and historical habitat of this species includes waterways that have been impacted by metals released from mining and mineral processing activities. We conducted paired bioassays with bull trout and rainbow trout (Oncorhynchus mykiss) to examine the relati...

This study evaluated night and day semen collection regimes in Holstein and Brahman bulls (four bulls of each breed) that were collected weekly, each during a morning and a night collection. Ejaculates (n=64) were obtained via artificial vagina over 4 weeks. The first collection of each week alternated between night and day. Two collection teams were employed. Bull behavior parameters included ...

OBJECTIVE To determine prevalence of infection with tritrichomonas fetus in a bull population; assess influence of age, breed, and grouping; assess effects on measures of cow performance (pregnancy rate, weaning percentage, weaning weight); and estimate test sensitivity. DESIGN Epidemiologic study. ANIMALS 1,383 bulls and records for 28,471 cows bred by these bulls in the immediate past bre...