dairy cattle breeding programs have been based in the selection for traits related to milk production. in this research a data set of 63 herds of east azerbaijan province holstein cattle, collected during 2002-2013 by the iranian animal breeding center was used to estimate the repeatability and heritability of three traits of economic importance. genetic parameters for first three lactations of...

Dairy products are a key source of valuable proteins and fats for many millions of people worldwide. Dairy cattle are highly susceptible to heat-stress induced decline in milk production, and as the frequency and duration of heat-stress events increases, the long term security of nutrition from dairy products is threatened. Identification of dairy cattle more tolerant of heat stress conditions ...

Dairy farms in some arid areas around the world have to use drinking water that contained elevated total dissolved solids (TDS); however, very limited data is available concerning water TDS effects on health status and blood mineral levels of cattle. The aim of this study was to compare 3 dairy cattle groups in several dairy farms with different drinking water TDS: High (HTDS; >4000 ppm), Mediu...

The European Community's (EC) Key, which is also called Bendixen's Key, is a well-established bovine leukemia virus (BLV) diagnostic method that classifies cattle according to the absolute lymphocyte count and age. The EC Key was originally designed for dairy cattle and is not necessarily suitable for Japanese Black (JB) beef cattle. This study revealed the lymphocyte counts in the BLV-free and...

bovine immunodeficiency virus is a lentivirus which can cause varieties of infectious complications and induce remarkable losses to dairy industry. considering to the probability of worldwide distribution of the biv infection, this study was conducted for the first time in iran to determine of the status of biv infection in the holstein cattle and evaluate the associated findings. according to ...

Dairy cattle in East Africa imported from the U.S. and Europe have been adapted to new environments. In small local farms, cattle have generally been maintained by crossbreeding that could increase survivability under a severe environment. Eventually, genomic ancestry of a specific breed will be nearly fixed in genomic regions of local breeds or crossbreds when it is advantageous for survival o...

The objective of this study was to determine the seroprevalence of paratuberculosis in dairy cattle in Burdur province located in southwest of Turkey. Blood samples were collected and tested by the enzyme linked immunosorbent assay (ELISA) from 465 dairy cattle older than 2 years randomly selected from 24 dairy cattle herds. Seroprevalence of paratuberculosis was found in 6.2% at the individual...

The study was carried out at Agarfa ATVET College dairy farm to evaluate the reproductive performance of Holstein Friesian× Arsi and Holstein Friesian ×Boran cattle. For the study, records compiled from 1983 to 2012 at the Agarfa dairy farm were used as original data. The effects of breed, bloodlines, season and parity on the reproductive traits were evaluated. Data were analyzed using the gene...

Liver abscesses are the primary liver abnormality of feedlot cattle at slaughter. The incidence of liver abscesses is highly variable, but generally ranges from 10% to 20%. The incidence of total and the proportion of severely abscessed livers (A+) are greater in Holsteins fed for beef production and culled dairy cows than in beef breeds. The reason for the greater incidence of liver abscesses ...

This study was conducted to investigate the blood serum and diet levels of copper, zinc and iron in Holstein dairy cattle kept under industrial farming in Isfahan province, Iran. A total of 240 blood serum samples and 24 diet samples were collected from industrial dairy cattle farms. The Cu, Fe and Zn contents were assessed in samples using atomic absorption spectrophotometer. In serum samples,...