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...

the aim of this study was to determine the factors affecting stillbirth and the consequences of stillbirth on longevity, production, and reproductive performance in holstein cows of iran. calving records from march 2000 to april 2009 comprising of 220,043 calvings on 102,199 cows in 33 herds were used. the results showed that 4.06% of the newborn calves died within 48 h of birth. the stillbirth...

milk samples from high and low milk producer holstein cows, were obtained during the morning and afternoon milking over a one week period. overall, 1064 samples were tested within 14 times sampling in urmia, iran. milk macro-mineral concentrations in the morning milking and in low producers were greater than in the afternoon and in high producers. the highest and lowest concentrations were obse...

In this study, the relationships and correlations between milk production and some blood metabolites related to energy and protein balance and their effects were investigated on returning to estrus after AI in lactating Holstein dairy cows. Blood and milk samples were collected from sixty lactating Holstein dairy cows based on their reproductive status in 13-17 d post AI. BUN, MUN, glucose, tri...

This field study aimed to investigate the relationships between the urinary zearalenone (ZEN) concentration, which reflects dietary ZEN intake, and the numbers of total and transferable embryos in superovulated cattle. A total of 38 cows (Japanese Black, n=16; Holstein, n=22) were superovulated for commercial embryo production. Urine samples were collected from all cows at the time of embryo fl...

The number of dermal mast cells in several European and Zebu cattle breeds was determined and correlated with the tick load. Breeds included European registered and non-registered Holstein, Brown-Swiss and Jersey cows, Zebu (Nelore and Gyr) and crossbred cows with either high or low tick infestations. Animals were naturally infested with Rhipicephalus (Boophilus) microplus and evaluated at regu...

The objective of this study was to estimate the genetic parameters of milk protein yields in Iranian Holstein dairy cattle. A total of 1,112,082 test-day milk protein yield records of 167,269 first lactation Holstein cows, calved from 1990 to 2010, were analyzed. Estimates of the variance components, heritability, and genetic correlations for milk protein yields were obtained using a random reg...

INTRODUCTION Bovine immunodeficiency virus (BIV) and bovine leukemia virus (BLV) have worldwide distributions, but their prevalences in Iran are unknown. We investigated the presence of infections in Iranian Holstein cattle and determined changes in hematological values for infected animals. METHODOLOGY Nested PCR was used on blood samples from 143 animals Holstein cattle to detect proviral B...

The traits particularly important for milk production include milk yield, protein percentage, fat percentage, and the somatic cell score. Alpha-lactalbumin (α-LA) is an important whey protein of cow milk, and is also present in the milk of many other mammalian species. In this study, we analyzed the genetic polymorphisms of the α-LA gene and their relationship to milk production traits (milk yi...

This study was conducted to investigate the effect of the interval between the onset of spontaneous estrus and artificial insemination (AI) on reproductive performance and calf sex ratio in repeat breeder Holstein cows. Two hundred eighty lactating Holstein cows were used in this study. The animals were artificially inseminated at different times (0–6, 7–12, 13–18, or 19–24 h) after the onset o...