birth weight (bw) is the first trait recorded fllowing birth. it can influence the performance of thecow and as well impact the performance of the calf it,s duringits maturity. to investigate the effect ofa calf,s bw on the performance of holstein dairy cattle in iran, the records gathered between 1967 and2010 were obtained from the iranian animal breeding center. the data were then used to mod...

The purpose of this review is to define possible breeding objectives for Southern African beef cattle farmers and to review different means of expressing genetic reproductive merit. The breeding objective considered was to maximize the number of calves born or weaned for a given number of cows in a herd under prevailing environmental and management conditions. This is a complex trait that has m...

in this study 495 smallholder dairy farms in 52 villages of different township in southwestern province of iran (chaharmohal and bakhtiari province) included 1321 lactating cows and 2811 total mature cows (lactating and dry) during winter 2009 to summer 2010 were used to estimate economic opportunities insmallholder dairy farms. questionnaire survey was used to collect data from last year infor...

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....

In modern high-yielding dairy herds fertility is of major economic importance. In order to gain maximum profit, calving intervals should not exceed 365 days. The achievement of a 365-day calving interval requires an early resumption of ovarian activity, an excellent oestrus detection, and a high first-service conception rate. Especially the inability to detect oestrus and to mate the cows by 60...

The data pertaining to variable production and reproduction traits of Murrah buffaloes (1980 lactation records of 698 Murrah buffaloes) were collected from the Central Cattle Breeding Farm, Alamadhi, Tamil Nadu, India. The overall leastsquares means (± SE) for peak yield, days to attain peak yield, 305-day milk yield, lactation length, lactation milk yield, service period, calving interval and ...

The objective of this study was to evaluate postpartum resumption of ovulatory cycles among primiparous, suckled beef cows that were exposed continuously to mature bulls beginning at various intervals after calving. We sought to determine whether cumulative distributions of proportions of cows resuming ovarian cycles and interval from the start of bull exposure to resumption of ovarian cycling ...

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...