introduction: lactation yield and persistency are two economic important traits in dairy cow. the production level of a dairy cow is determined by a joint effect of genetic and environmental factors.the main factors determining the total amount of milk production are milk yield at the peak of lactation and persistency as well as length of lactation period. persistency are defined as a extent to...

Intensive selection of sires is possible by using artificial insemination; coupled with accurate measurement of a potential sire’s genetic value, this has markedly improved genetics for easily measured traits like milk production and type traits. Increased milk production has in turn increased gross feed efficiency through dilution of maintenance. Additional genetic gains in feed efficiency wou...

in the research the genetic investigation productive and reproductive traits and changes trend the traits in years, seasons and different lactation periods and genetic evaluation cows and bulls of 785 records for milk and 665 records for fat yield and reproductive information during years 1998 to 2003 of 207 dairy cows ghezlagh farm aboureyhan campus (university of tehran) studied. the least sq...

The aim of this study was to investigate the effect of bacterial inoculation on the fermentation and aerobic stability of corn silage and on the dry matter degradability and milk composition when fed to sheep or cows. Four male sheep were selected to measure dry matter degradability of uninoculated (UCS) and inoculated (ICS) corn silage. Milk composition was measured for 22 Holstein cows, separ...

background: the public health importance of human fascioliasis has increased during last few decades due to the appearance of new emerging and re-emerging foci in many countries. iran, as the most important focus of human disease in asia, has been included among six countries known to have a serious problem with fascio­liasis by who. various aspects of the disease in iran are discussed in this ...

The intensive selection programs for milk made possible by mass artificial insemination increased the similarity among the genomes of North American (NA) Holsteins tremendously since the 1960s. This migration of elite alleles has caused certain regions of the genome to have runs of homozygosity (ROH) occasionally spanning millions of continuous base pairs at a specific locus. In this study, gen...