Histopathological examination of the heart, particularly the right atrium including the sinoatrial (SA) node, was carried out in 9 Holstein dairy cows with idiopathic atrial fibrillation (AF; AF group) and 12 healthy cows of the same breed (control group) in order to establish the correlation between idiopath

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...

Two studies were performed to evaluate the effects of dried distillers grains with solubles (DDGS) on the lactational performance of dairy cows. The intent of experiment 1 was to evaluate the effects of feeding increasing concentrations of DDGS on the feed intake and production of Holstein dairy cows. Twenty multiparous Holstein cows averaging 76 +/- 24 d in milk and 638 +/- 68 kg of body weigh...

Forty Holstein dairy cows in their first and second lactation were used in a lactation study from 4-week prepartum through 14-week postpartum to investigate the potential effect of feeding different levels of ruminally protected methionine and choline on milk yield persistency of Holstein dairy cows. Cows were randomly assigned to receive one of the following treatments: 18 g/d of rumen-protect...

The objective of the study was to determine the effect of puerperal metritis prevalence in high yielding Holstein cows on productive (305 days, actual milk yields), reproductive (days to first estrus, days open and services per conception) variables and culling rates. Throughout the study, 2885 dairy records were collected from high yielding private Holstein dairy farm (average milk yield was u...

Automatic milking systems (AMS) rely upon voluntary cow traffic (the voluntary movement of cattle around a farm) for milk harvesting and feed consumption. Previous research on conventional milking systems has shown differences between dairy cow breeds for intake and milk production, however, the ability to manipulate voluntary cow traffic and milking frequency on AMS farms through breed selecti...

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 study examined the use of PGF(2α) and estradiol benzoate (EB) either with or without GnRH to synchronize estrus in dairy cows for timed artificial insemination (TAI) under field conditions. First, Holstein dairy cows with a corpus luteum (CL) received 500 μg cloprostenol and were then randomly allocated to three groups: no further treatment (control, n=236); treatment with 1 mg EB 56 h aft...

The reproductive ability, milk-producing capacity, survival time and relationships of these parameters with telomere length were investigated in 4 groups of cows produced by somatic cell nuclear transfer (SCNT). Each group was produced using the same donor cells (6 Holstein (1H), 3 Holstein (2H), 4 Jersey (1J) and 5 Japanese Black (1B) cows). As controls, 47 Holstein cows produced by artificial...

Farm location is an important factor in dairy farms, as it is closely associated with temperature and humidity that are crucial factors of influencing the physiological conditions and productivity of cows especially during the lactation period. The purpose of this study was to determine the effect of farm location on the physiological conditions and productivity of cows. The study was involved ...