The objective was to compare the relative response between rams and bulls in characteristics of LH, FSH and testosterone (T) secretion, during and after long-term treatment with GnRH analogs. Animals were treated with GnRH agonist, GnRH antagonist, or vehicle (Control) for 28 days. Serial blood samples were collected on day 21 of treatment, and at several intervals after treatment. Injections o...

Transcriptome analyses of bovine muscle tissue differing in intramuscular fat (IMF) content identified agouti signaling protein (ASIP) as a promising candidate gene for fat deposition. The protein is secreted from adipocytes and may serve as a signaling molecule in cross-talk between adipocytes and muscle fibers or other cells. Known receptors for ASIP are the melanocortin receptors (e.g., MC4R...

The objective of the study was to characterize body growth, testicular development, and puberty from 8 to 14 mo of age in bulls (n = 120) produced by mating sires from Hereford, Angus, Norwegian Red, Swedish Red and White, Friesian, and Wagyu breeds to MARC III ((1/4) Hereford, (1/4) Angus, (1/4) Red Poll, and (1/4) Pinzgauer) cows. Traits evaluated were birth weight, weaning weight (at 215 d),...

To explore the potential of cattle to produce both milk and beef, the genetic aspects of beef production among Holstein‐Friesian bulls pedigree selected for milk were studied. The data included growth records of 504 bulls (DPT) by 120 sires (SPT) pedigree selected for progeny testing by American Breeders Service, 1964 to 1971. DPT bulls with proofs had an average predicted difference for milk (...

Th e aim of the study was to compare carcass traits between Cika and Brown cattle of all slaughter categories. Th e data used were collected in Slovenian slaughterhouses from 2007 to 2010. Aft er the slaughter carcass weight was recorded and carcass conformation and fatness were scored according to the EUROP system. Net daily gain was calculated. Data were analysed by GLM procedure of statistic...

Energy and protein retained in 50, 38, and 54 nonimplanted Holstein and Angus heifers, steers, and bulls, respectively, 17 pens (237 cattle) of beef breed implanted heifers, and 65 pens (535 cattle) of beef breed implanted steers were compared to values predicted by the 1984 National Research Council (NRC), Cornell Net Carbohydrate and Protein System (CNCPS), and the model of Oltjen et al. (OLT...

Different semen assays were employed to determine the post -thaw fitness of buffalo and Sahiwal bull spermatozoa. Semen (two ejaculates) was collected from buffalo and Sahiwal bulls (six each) once a week for three consecutive weeks. Semen was diluted in lactose-fructose-egg yolk glycerol extender, equilibrated at 4 ac for 4 hr and frozen in liquid nitrogen vapors. A highly significant differen...

Sperm DNA damage affects the conception rate resulting from human assisted reproduction technology. The objective of this study was to adapt the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay to provide a quality parameter for bull semen based on the detection of sperm DNA damage. Fresh semen was collected from two Japanese Black bulls (A, B) several times o...

Three methods of copper supplementation were compared in 9to 15-month-old Friesian bulls on a farm with a history of copper deficiency. A group of 60 bulls grazed 19 ha which had been topdressed in May with 120 kg copper sulphate (6.3 kg/ha). Five of the bulls were identified for repeated sample collection. A second group of 60 bulls grazed an untreated area and five of these were each given a ...

Onset of puberty was observed in 12 bison bulls by the collection of semen at monthly intervals for 12 months beginning at 13 months of age. Onset of puberty was defined as the time in development when an ejaculate contained a minimum of 50x10 sperm showing at least 10% progressive motility. At each collection, data were recorded on body weight, semen quality, fecal testosterone concentration, ...