Abstract The aim of this study was to evaluate the heat stress influence on milk production from primiparous and multiparous Holstein-Friesian cows estimate economic losses associated with decrease in farm’s yield. selected for were middle phase 1st, 2nd, 3rd lactation characterized by similar daily production. Additionally, animals kept same conditions fed feeds throughout season. analysis cov...

The objective of this study was to assess the effects feeding gelatin capsules containing fish oil, treated with alcoholic solutions flavoring agents followed by drying, on lactation performance, rumen fatty acids content and milk enrichment acids. In Trial 1, four multiparous ruminally fistulated Holstein cows were randomly assigned one dietary treatments sequences in a 4 × Latin square design...

The objective of this study was to analyze the correlation between Holstein body conformation traits and milk production traits in the Shanghai region. In total, 871 Holstein cows were randomly chosen from 28 dairy farms in Shanghai at second stage of lactation as the object of our study. Five milk production traits, including 305-d milk yield, butter fat percentage, milk protein percentage, pe...

The molecular regulation of horn growth in ruminants is still poorly understood. To investigate this process, we collected 1019 hornless (polled) animals from different cattle breeds. High-density SNP genotyping confirmed the presence of two different polled associated haplotypes in Simmental and Holstein cattle co-localized on BTA 1. We refined the critical region of the Simmental polled mutat...

ABSTARCT The objective of this study was to analyze the effects of factors affecting reproductive traits in the Holstein population of the Isfahan dairy farms for subsequent compilation of the model for genetic evaluation as well as for herd management practice. A data set containing 99012 records were analyzed by a linear model with fixed effects of year , herd ,season, parity of dam, calving ...

Two experiments were conducted to evaluate seasonal variation in oocyte competence in Holstein cows and to test whether oocyte quality in summer is affected by the magnitude of heat stress. In the first experiment, ovaries of Holstein cows were collected from a slaughterhouse and used to harvest oocytes over 1 yr (n = 18 replicates). After in vitro maturation, fertilization, and culture, propor...