Raising dairy heifers from birth to calving has been found to comprise the second largest expense on the dairy farm towards the production of milk, while deriving no revenue until the onset of lactation (Heinrichs, 1993). Therefore, many experiments involving dairy heifers have focused on ways to minimize the costs associated with the growth period or decreasing the unproductive period of the a...

In this paper the genetic relationships between major reproductive traits in beef cattle (Calving Date, Calving Interval and Age at First Calving) and type traits have been estimated to evaluate the usefulness of type classification in predicting reproductive performance in beef cattle. We estimated favourable genetic correlations between Calving Interval and type traits ranging from 2 0.027 to...

The present investigation was undertaken to access age at first calving, actual lifetime milk yield per day of productive life, herd life and total life. non-genetic factors such as period birth, season AFC group farms on these traits were studied by least-squares analysis the means compared using Duncan's multiple range test. for estimated 1668.3±16.6 days, 1.878±0.04 litres/day, 1.735±0.05 li...

This experiment was conducted to determine the association between several risk factors which may affect culling of the Iranian Holstein cows. The data consisted of 329,772 lactation records collected by the Animal Breeding Center of Iran (2003 to 2012).The logistic regression was applied to investigate the associations between the response variable, the risk of culling, and predictor variables...

The present study aimed to examine the productive and reproductive performance of Indigenous buffaloes in Mymensingh district Bangladesh. Buffalo husbandry plays a crucial role livelihoods numerous farmers across various upazilas Mymensingh. A total 100 indigenous were selected for study, representing four upazilas: Trishal, Haluaghat, Muktagachha, Sadar upazilla district. findings this reveale...

The effect of growth rate from birth through 30 months of age on the reproductive performance of Polled Hereford heifers calving as 2-year-olds was examined. Heifers with high gains during the first winter as weanlings had higher breeding efficiency when bred as yearlings, had larger pelvic areas as 2-year-olds, gave birth to larger calves, had less calving difficulty at first parturition and h...

in this study which was carried out in 1974 in isphahan, 3,000 married women between the ages of 15 to 44 who were the residents of the city of isphahan and a similar group of women who were residents of the villages surrounding the city were interviewed. results indicate that the average and the median of age at the first marriage had been increasing steadily since 1959 for the city women and ...

the objective of this study was to estimate genetic parameters coupled with genetic and phonotypic trends for age at first calving (afc), open days(od) and milk yield(my) of first lactation in iranian holstein cows. records of reproduction and production for genetic evaluation from 1984 to 2005 for afc, od and my were 71736, 20126 and 20126, respectively. single and two-variable animal models w...