sixty eight holstein cows, 38 primiparous and 30 multiparous ones, were employed in a randomized complete block design, blocked to evaluate the effects of 2 diets in various ruminal fermentable carbohydrate sources (ground corn vs rolled wheat) on rumen fermentation and performance during preparturient period. primiparous and multiparous cows were blocked by parity. the cows were fed diets as t...

Delayed conception is defined as an interval of greater than 90 days postpartum before a cow becomes pregnant again. In this study, the risk factors for delayed conception in Korean dairy herds were determined by evaluating several reproductive factors in individual cows. The following data was recorded from 1,012 pregnancies in eight dairy herds (designated A-H) from July 2001 to June 2006: he...

Mortality in dairy cattle is not only relevant with regard to economic losses but also to animal health and welfare. Thus, the aim of this investigation was to explore the genetic background of postnatal mortality in calves and replacement heifers in different age groups until first calving in Danish Holsteins. Records of Danish Holstein heifer calves born in the years 1998 to 2007 were extract...

Inadequate dietary energy intake and poor body condition can negatively affect reproductive function. Supplemental lipids have been used to increase energy density of the diet and may also have direct positive effects on reproduction in beef cattle. Several fatty acid sources have been studied as they relate to reproductive function. Common sources include sunflower, safflower, cottonseed, rice...

Transfer of sufficient immunoglobulin G (IgG) to the neonatal calf via colostrum is vital to provide the calf with immunological protection and resistance against disease. The objective of the present study was to determine the factors associated with both colostral IgG concentration and colostral weight in Irish dairy cows. Fresh colostrum samples were collected from 704 dairy cows of varying ...

A national fertility evaluation was developed based on pregnancy rate, which measures the percentage of nonpregnant cows becoming pregnant within each 21-d opportunity period. Data for evaluation are days open, which are calculated as date pregnant minus previous calving date. Date pregnant is determined from last reported breeding or from subsequent calving minus expected gestation length. Suc...

The objective of this study was to estimate genetic parameters predicted N use efficiency (PNUE) and losses (PNL) as proxies loss for Holstein cows. Furthermore, we have assessed approximate correlations between PNUE, PNL, dairy production, health, longevity, conformation traits. These traits are considered important in many countries currently evaluated by the International Bull Evaluation Ser...

the objective of the present study was to determine factors affecting body condition score (bcs) and its association with productive and reproductive performances in holstein cows. mixed model analysis was performed on monthly records of bcs from april 2006 to july 2012 comprising 34666 records from 3134 dairy cows in a large commercial dairy herd under arid climatic conditions of isfahan in ir...

Five alternative models were applied for analysis of dystocia and stillbirth in first and second parities. Models 1 and 2 were included only to estimate the parameters required for model 4, and models 3 and 5 are included only as comparisons to the model 4 estimates. Variance components were estimated by multi-trait REML, including cows with valid calving records for both parities. For the effe...