The aim of this study was to evaluate the difference in birth weight and gestation length between Japanese Black calves obtained from transfer of bovine embryos produced in vitro (IVP) and those developed in vivo (IVD). An additional objective was to clarify the sire effect on birth weight and gestation length and to examine the birth rate of heavier calves. Two Japanese Black bulls breed at ou...

Bull fertility may be defined as the process by which spermatozoa fertilize and activate the ovum and then support embryonic development. Bull fertility is a complex trait having relatively low heritability and plays a vital role for efficient production and reproduction of bovine. Various mechanisms involved in regulating bull fertility associated phenotype and reliable biomarkers are poorly d...

High-fertility (control cows) and low-fertility (cows and heifers not pregnant after two consecutive breeding seasons -twice-open) cyclic bovine females were treated with a single injection of 1000 IU of human chorionic qonadotropin (HCG)orlOO ng of gonadotropin releasing hormone (GnRH) to enhance and/or hasten corpus luteum formation and progesterone secretion, and improve conception rate in t...

—The management and recovery of populations of bull trout Salvelinus confluentus requires a comprehensive understanding of habitat use across different systems, life stages, and life history forms. To address these needs, we collected microhabitat use and availability data in three fluvial populations of bull trout in eastern Oregon. We evaluated diel differences in microhabitat use, the consis...

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...

Commercial cow-calf producers commonly use the term “percent calf crop,” but what does it mean? Does percent calf crop represent the number of calves born relative to the number of cows bred, or perhaps it is the number of calves born relative to the number of cows exposed to a bull? Some might calculate percent calf crop as the number of calves weaned compared to the number of calves born, or ...

mation of cow/calf operations running between 200-500 head reveals an investment of over $2000.00 being made for each breeding cow in land, equipment, facilities and animal unit price.1 When herd bulls are used at 1:25 to 1:40 ratios, this represents an investment of $50,000 to $80,000 which is annually dependent upon the satisfactory reproductive potential of each breeding age bull, regardless...