An experiment was conducted to test whether the magnitude of effects of heat shock on spermatozoal function were less for thermotolerant breeds (Brahman and other breeds with Brahman influence) than for breeds that evolved in northern Europe (Angus and Holstein). Frozen spermatozoa were thawed, purified by Percoll gradient centrifugation and incubated at 38.5, 41, or 42 degrees C for 4 h. Sperm...

A study of chromosomal analysis for 200 breeding bulls of different breeds of cattle (Jersey, Holstein Friesian, Sahiwal and Cross-bred) and Nili-Ravi buffalo, maintained at Semen Production Unit, Qadirabad and Livestock Experiment Station, Bhunikey (Pattoki) was carried out. Micromethod was adopted for leukocyte culture and chromosomes were trapped at metaphase stage. The diploid number of chr...

Dissection and chemical analysis data from 197 bulls of 15 breedtypes were used to examine the distribution of total fat (TOTFAT) among carcass fat (CFAT), viscera fat (VIF), kidney plus pelvic fat (KPF) and blood fat (BLF). The bulls were obtained from a five-breed diallel involving Angus, Brahman, Hereford, Holstein and Jersey; reciprocal crosses were pooled. One or two bulls of each breedtyp...

The main objective of this study was to estimate the proportion of total genetic variance attributed to a quantitative trait locus (QTL) on Bos taurus autosome 6 (BTA6) for milk production traits in the German Holstein dairy cattle population. The analyzed chromosomal region on BTA6 spanned approximately 70 cM, and contained 6 microsatellite markers. Milk production data were obtained from rout...

Neosporosis is caused by the protozoan parasite, Neospora caninum which is major cause of fatal disease and abortion in cattle in Iran and in many countries. The economic impacts of neosporosis are lost milk, meat and abortions in cattle. The purpose of the present study was to evaluate the presence of N. caninum DNA in fresh and frozen semen samples of Iranian bulls that were used for artifici...

Genetic evaluations of Holstein bulls for February 1997 through May 1998 were examined to determine the value of more frequent evaluation for quicker identification of bulls with changing predicted transmitting abilities (PTA) and of new bulls of superior genetic merit. Changes in PTA between evaluations that were calculated quarterly rather than semiannually were reduced by 30%. About two-thir...

Used were 15 bulls and 15 heifers of the Black-and-White Polish Holstein-Friesian breed, semiintensively fattened, with the aim of evaluating the effect of sex on the selected traits of quality of beef. Bulls were slaughtered at the mean age of 536.2 days and 523.1 kg body weight, and heifers at 528.7 days and 459.7 kg body weight, respectively. After slaughter and post-slaughter treatment, the...

The first large-scale, international genetic evaluation of Holstein bulls computed by the International Bull Evaluation Service Centre in February 1995 was examined and compared with national evaluations from Canada, Denmark, Finland, France, Germany, Italy, Sweden, The Netherlands, and the US. Assumption of a genetic correlation of 0.995 between all countries and exclusion of bull daughters fr...

Genetic and phenotypic performance of U.S. Holstein embryo-split and nuclear-transfer clones was documented for yield and fitness traits. For cows, mean genetic superiority based on pedigree was 186 kg of milk, 9 kg of fat, and 7 kg of protein for embryo-split clones and 165, 10, and 8 kg, respectively, for nuclear-transfer clones compared with the population for the same birth year; pedigree a...

objective: the aim of this study was to select the best medium to maintain sperm motility during sperm-dna incubation and assess the dna uptake by spermatozoa of iranian holstein bulls and its effects on sperm motility. materials and methods: frozen sperms from an iranian holstein bull were thawed and centrifuged. motile sperms were separated through puresperm gradient (40/80%) followed by two ...