Story in Brief Seasonal differences and growth rates were studied on 60 Hereford and Angus bulls born in the spring and fall calving seasons at Oklahoma State University. Hip height, scrotal circumference and weight measurements were taken over the two IO-month experiments. Season of birth had no influence on scrotal circumference for either Hereford or Angus bulls. Season of birth in Angus bul...

In order to determine the incidence of buffaloes on enteric CH4 emissions, information about animal production and farm management was analyzed and the CH4 emission factor estimated using the IPCC Tier 2 model. CH4 emission factor for the category of buffalo cattle and buffalo bulls was estimated for the period 2000-2007, in Italy, Europe and worldwide. During 2007, the CH4 emission factor for ...

The purpose of this study was to describe maturation-related changes in the sexual and aggressive behaviors of Hereford bulls. Two groups of 13 and 14 bulls, respectively, were tested for sexual and aggressive behaviors every 3 mo from 3 to 24 mo of age. At 3 and 6 mo of age, the bulls were exposed, as groups, to two estrous females, whereas at 9, 12, 15, 18, 21, and 24 mo these bulls were test...

Fertility Associated Antigen in Peripubertal Beef Bulls as an Indicator of Potential Fertility. (August 2005) Joanna Lynn Gallino, B.S., California State Polytechnic University Co-Chairs of Advisory Committee: Dr. L. R. Sprott Dr. D. W. Forrest Ejaculates from peripubertal Angus (n=106), Brahman (n=156) and Brangus (n=212) bulls were evaluated for the presence of a 31 kDa protein known as ferti...

Random samples of cryopreserved, milk-extended semen, collected from 20 Holstein bulls at about 14 mo of age (young) and again at about 4 yr of age (mature), were evaluated at thawing and during 3-h incubation to compare semen quality of young versus mature bulls. Evaluation by differential interference contrast microscopy showed greater proportions of cytoplasmic droplets in semen from young v...

Objectives were to determine if supplemental trace mineral levels and/or forms (sulfate and metal amino acid complexes) influence age at puberty, semen quality, endocrine status, and scrotal circumference in peripubertal bulls. Fifty peripubertal bulls were blocked by age and scrotal circumference and assigned to one of five treatments: (1) 1x sulfate form (1S); (2) 1x complexed form (1C); (3) ...

Canadian and United States evaluations of Holstein bulls were compared for longevity and somatic cell score. A total of 13 236 bulls was evaluated for longevity with 462 bulls having evaluations in both countries, and 10 945 bulls evaluated for somatic cell score with 564 bulls having evaluations in both countries. Multiple across country evaluation procedures were used to estimate the genetic ...

Aggressive behaviour and musth are constant problems in captive and sometimes in free-ranging African elephant bulls. Aggressive bulls are difficult and musth bulls almost impossible to manage without severely restricting their movement either by leg-chaining or using tranquillisers. This study investigated the relationship between faecal androgen metabolites (FAM) and faecal cortisol metabolit...

Controlling spatial positioning of cattle through use of electronic collars could provide new ways to farm under extensive conditions. This study examined the potential for bulls to be controlled during mating using mild electric shocks delivered through radio-controlled collars. Eighteen Belmont Red bulls were fitted with collars containing the Global Positioning System and that were able to e...

Twelve serologically negative bulls were used, six were vaccinated with a modified live LSD vaccine and six unvaccinated. All were then experimentally infected with a virulent field strain of LSDV. No clinical abnormality was detected following vaccination, and mild clinical signs were seen in four vaccinated bulls following challenge. Virus was not found in semen of vaccinated bulls. Two of th...