The molecular regulation of horn growth in ruminants is still poorly understood. To investigate this process, we collected 1019 hornless (polled) animals from different cattle breeds. High-density SNP genotyping confirmed the presence of two different polled associated haplotypes in Simmental and Holstein cattle co-localized on BTA 1. We refined the critical region of the Simmental polled mutat...

ABSTARCT The objective of this study was to analyze the effects of factors affecting reproductive traits in the Holstein population of the Isfahan dairy farms for subsequent compilation of the model for genetic evaluation as well as for herd management practice. A data set containing 99012 records were analyzed by a linear model with fixed effects of year , herd ,season, parity of dam, calving ...

Two experiments were conducted to evaluate seasonal variation in oocyte competence in Holstein cows and to test whether oocyte quality in summer is affected by the magnitude of heat stress. In the first experiment, ovaries of Holstein cows were collected from a slaughterhouse and used to harvest oocytes over 1 yr (n = 18 replicates). After in vitro maturation, fertilization, and culture, propor...

The aim of this study was to determine the prevalence bacteria Dichelobacter nodosus (D. nodosus) and Fusobacterium necrophorum (F. necrophorum) in non-lame dairy cows on eight Slovak herds. In total, 1,631 Holstein Friesian were included study. Information collected from on-farm software cow ID, lactation number (heifer/cow), year milk yield (kg), DIM collection date. PCR method detected D. F....

The transition period for a dairy cow is from 3 to 2 wk prepartum until 2 to 3 wk postpartum. The term transition is to underscore the important physiological, metabolic, and nutritional changes occurring in this time frame. It constitutes a turning point in the productive cycle of the cow from one lactation to the next. The manner in which these changes occur and how they are managed are of gr...

The final goal of all dairy cow raising systems in the world is to use the available capacities and the cooperation of other sectors in order to solve the problems and issues, such as the limitations in time, man power and financial resources, for providing a complete answer. Therefore, the need for optimization of cow raising systems by prioritization of measures and plans is the most obvious ...

A high rate of on-farm cow mortality (i.e. unassisted death and euthanasia) is both a financial concern and an important animal welfare issue. The overall aim of this thesis was to evaluate the development of mortality in Swedish dairy herds and to identify characteristics associated with on-farm mortality at cow and herd levels. In paper I, two analyses were performed using data from the cattl...

This study estimated the fermentation characteristics and nutrient value of corn-lablab bean mixture silages relative to corn silages. The effects of feeding corn-lablab bean mixture silages on nutrient apparent digestibility and milk production of dairy cows in northern China were also investigated. Three ruminally cannulated Holstein cows were used to determine the ruminal digestion kinetics ...

The objective of this field study was to compare the udder health status as well as the clinical mastitis rate during the first 100 d of lactation in cows that received long-acting dry cow antibiotic alone (group AB) or in combination with an internal teat sealant (group AB + OS). The study was conducted during a 9-month period and included 136 Holstein cows from 12 dairy farms in Hessia, Germa...

Drying-off, calving, and start of lactation are critical transition events for a dairy cow. As consequence, most animal health issues occur during these periods. By extending the voluntary waiting period first insemination after calving interval (CInt) can be extended, with possible positive effects fertility health. Some cows might better suited an extended CInt than others, due to differences...