To prevent distribution of recessive alleles in dairy herds all bulls used for AI (Artificial Insemination) haveto be tested. In this study 26 blood and 4 semen samples were supplied from Iranian Holstein bulls used forAI. Genomic DNA was extracted from 100 μl of blood and 200 μl of semen. Samples were tested by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR...

The development of breeding tools, such as genomic selection and sexed semen, has progressed rapidly in dairy cattle during the past decades. In combination with beef these tools are adopted increasingly at herd level. Dairy crossbreeding is emerging, but economic genetic consequences combining it other relatively unknown. We investigated 5 different semen schemes where 0, 50, 90% heifers; 50% ...

This experiment was designed to test the hypothesis that delayed insemination of nonestrous cows would increase pregnancy rates when using sex-sorted semen in conjunction with fixed-time artificial insemination (FTAI). Estrus was synchronized for 656 suckled beef cows with the 7-d CO-Synch + controlled internal drug release (CIDR) protocol (100 μg GnRH + CIDR [1.38 g progesterone] on d 0, 25 mg...

A study based on bulk tank milk samples from 120 randomly selected dairy cattle herds was conducted to estimate the prevalence of Coxiella burnetii seropositive dairy herds, to describe the geographical distribution, and to identify risk factors. Using the CHEKIT Q-fever Antibody ELISA Test Kit (IDEXX), the study revealed a prevalence of 79.2% seropositive herds, 18.3% seronegative herds, and 2...

bovine venereal campylobacteriosis, caused by campylobacter fetus subsp. venerealis (cfv), is regarded as one of the major threats to the cattle industry around the world. abortion and infertility are two important reproductive problems in cows infected with c. fetus subsp. venerealis. reports on the presence of cfv are scarce in the cattle, in iran. therefore, the present study was designed to...

Johne's disease ('paratuberculosis') is a chronic, infectious, wasting disease that affects dairy cattle. Estimation of its impact on herd productivity and corresponding economic loss on US dairy operations was part of the USDA National Animal Health Monitoring System's (NAHMS) 1996 national dairy study. Johne's-positive herds experience an economic loss of almost US$ 100 per cow when compared ...