Bovine tuberculosis (BTB) is a significant veterinary and financial problem in many parts of the world. Associations between specific host genes and susceptibility to mycobacterial infections, such as tuberculosis, have been reported in several species. The objective of this study was to identify and evaluate the relationship of single-nucleotide polymorphisms (SNPs) in the CARD15 gene with sus...

Survival analysis in a Weibull proportional hazards model was used to evaluate the impact of somatic cell count (SCC) on the involuntary culling rate of US Holstein and Jersey cows with first calvings from 1990 to 2000. The full data set, consisting of records from 978,043 Holstein and 250,835 Jersey cows, was divided into subsets (5 for Holsteins and 3 for Jerseys) based on herd average lactat...

The objective of the current study was to evaluate the effect of bovine somatotropin (bST) on milk yield and composition of Holstein cows in early and very early lactations. Twenty-two lactating Holstein cows averaging 62 days in milk (DIM:25-115), 28.5 kg/d milk, a body condition score (BCS) of 2.87, and 648.2 kg of body weight (BW), were assigned to one of the four treatments in a completely ...

Cows with superior genetic merit, based on an economic index for milk, fat, and yields (milk-fat-protein dollars), have been designated as elite by USDA. Because of the concern that adjustment for heterogeneous variance may have resulted in inequitable state representation for elite cows, the percentages of US cows with elite status were compared by state using evaluations of registered Holstei...

The purpose of this study was to investigate the effect of maternal inbreeding on incidence of twinning,dystocia and stillbirth in Holstein cows of Iran. Calving records from March 2000 to April 2009 comprisingof 365,021 calvings on 153,802 cows from 86 dairy herds were used. The mean level of inbreeding was0.7%, less than 37% of all animals were inbred, and a small proportion (3.45%) of inbree...

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...