This study was undertaken to estimate the genetic parameters for some reproduction traits in Sistani beef cattle. The data set consisted of 1489 records of number of insemination, calving, and insemination dates in different calving was used. Reproduction traits including calving interval (CI), gestation length (GL), days open (DO), calving to first service (CTFS), first service to conception (...

A recent study evaluating whether reproductive data could be used for syndromic surveillance found an increased frequency of early calving (calving occurring a few days earlier than expected) in areas exposed to the Bluetongue virus serotype 8 (BTV-8) in northern Europe. A high proportion of herds infected during the 2006-2009 European outbreak were not reported through the surveillance system....

Data from insemination and calving events of Italian Holstein cows and heifers collected from January 1996 until December 2002 were used to estimate phenotypic and genetic parameter for some fertility traits. A validation procedure of the data based on gestation length and information on service sire was used. According to these procedure, in Italy 75.9 % of the calvings are associated to servi...

The objective of this study was to investigate the effect of birth weight (BW) on future milk production and reproductive performance in Iranian Holstein cattle. Records of Holstein cows between 1967 and 2010 were obtained from the Animal Breeding Center of Iran. Birth weights within each herd were grouped into five categories based on the standard normal distribution curves (z ≤-0.8416, -0.841...

The objectives of the study were to compare the ovarian activity of Holstein-Friesian (CH HF), Fleckvieh (CH FV) and Brown Swiss (CH BS) dairy cows of Swiss origin with that of Holstein-Friesian (NZ HF) dairy cows of New Zealand origin, the latter being used as a reference for reproductive performance in pasture-based seasonal calving systems. Fifty, second-lactation NZ HF cows were each paired...

The objectives of this work were to compare reproduction and parturition traits of the Criollo breed Romosinuano as straightbred and crossbred cows with Angus and Brahman, to estimate heterosis and direct and maternal genetic breed effects, and to describe calf loss, cow removals from the project, the occurrence of calving difficulty, inadequate calf vigor at birth, and udder problems by cow br...

Whether to select for longer life in the herd or shorter calving interval depends on the genetic and phenotypic relationships among herd life, amount of milk in first lactation, and calving interval. Herd life and average calving intmwal are essentially phenotypically uncorrelated. The phenotypic and genetic correlations of herd life and milk in first lactation ranged from .19 to .25 and from ....

The objective was to quantify the strength of the relationship between body condition score (BCS) and live weight (LW) in pasture-based Holstein-Friesian dairy cattle, and to determine the kg LW per unit BCS. A total of 26021 test-day records with information on both BCS (1-10 scale, where 1 is emaciated and 10 is obese) and LW across 1110 lactations from one research farm were used in the anal...