economic data and performance records from 10 iranian holstein dairy cattle herds, as well as milk production and fertility records from iranian center of animal breeding and animal production improvment were used to estimate the effect of calving difficulty on milk production, fertility and as well on the economic aspects of maternal and direct calving difficulty. calving difficulty could be d...

mastitis in cattle is a serious problem which causes considerable economic losses in the dairy cattle herds. the aim of this survey was to identify mycoflorain milk of healthy, clinical and subclinical mastitis of lactating holstein dairy cows. milk samples of 154 holstein dairy cows were collected from 10 dairy cattle herds in suburb of mashhad-iran. the treatment groups included 104 lactating...

Bovine Viral Diarrhea Virus (BVDV) is a Pestivirus of the Flaviviviridaefamily that infects cattle, and its widespread distribution can cause substantial economic losses worldwide. The aims of this study were: (1) to estimate the prevalence of animals persistently infected (PI) with BVDV in industrial dairy cattle herds in suburb of Mashhad- Iran; and (2) to compare the occurrence of persistent...

Objective- Locomotor disorders are prevalent health problems in dairy herds that negatively affect milk production, reproduction performance and animal welfare. The ultimate cost of locomotor disorders in dairy cattle is substantially greater than treatment costs alone. As limited information is available on incidence of feet and leg disorders in Iran, the objective of this study was to determi...

This experiment was aimed to study the association between the DGAT1 K232A polymorphism and milk production traits and somatic cell score (SCS) in Iranian Holstein dairy cows. The records of 408 animals from five dairy herds were randomly identified and then genomic DNA was extracted from blood using the modified-salting method described by Miller. RFLP-PCR was performed to obtain all the polym...

This experiment was aimed to study the association between the DGAT1 K232A polymorphism and milk production traits and somatic cell score (SCS) in Iranian Holstein dairy cows. The records of 408 animals from five dairy herds were randomly identified and then genomic DNA was extracted from blood using the modified-salting method described by Miller. RFLP-PCR was performed to obtain all the polym...

bovine viral diarrhea virus (bvdv) is a pestivirus of the flaviviviridaefamily that infects cattle, and its widespread distribution can cause substantial economic losses worldwide. the aims of this study were: (1) to estimate the prevalence of animals persistently infected (pi) with bvdv in industrial dairy cattle herds in suburb of mashhad- iran; and (2) to compare the occurrence of persistent...

birth weight (bw) is the first trait recorded fllowing birth. it can influence the performance of thecow and as well impact the performance of the calf it,s duringits maturity. to investigate the effect ofa calf,s bw on the performance of holstein dairy cattle in iran, the records gathered between 1967 and2010 were obtained from the iranian animal breeding center. the data were then used to mod...

26 herds with 71 586 individual records were used. We tested a hypothesis that milk efficiency was influenced by the elevation of the farm, housing system, breed, area of altitude, and by the cooling of dairy cows. There were 20 herds from lowlands and 6 herds from mountains, 20 herds from free-stall housing, 6 herds from tie-stall housing. 8 herds consisted of Slovakian Pied cattle, 4 herds of...

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...