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 (...

At calving, purebred animals of the Belgian Blue (BB) breed are compromised by the incompatibility in size and shape of the dam and her calf, resulting in a very high incidence of dystocia problems. To clarify which body parts of the calf are of decisive importance to allow natural delivery and to investigate both the mean value as well as the variation among these body sizes within this breed ...

Field records supplied by the American Simmental Association from 2-yr-old dams were used to study maternal grandsire • region of the U.S. and maternal grandsire • herd within region (herd/region) interactions. Regions were 1) Montana, North Dakota and South Dakota, 2) Kansas and Nebraska, 3) Texas and Oklahoma and 4) Alabama, Florida, Georgia, Louisiana and Mississippi. Analyses were conducted...

There is considerable concern about the consequences on fitness-related traits of using narrow breeding objectives for production traits. The aim of this study was to assess the potential consequences of selection for growth in French beef cattle breeds by estimating genetic correlations between growth, reproduction, calving and suckling traits of Charolais, Limousin and Blonde d’Aquitaine heif...

Retrospective data from Sebele Dairy Farm were analysed for reproductive performance of Friesian/Holstein cows. Three hundred records from 1989 to 1995 were used. The herd was zero grazed and the data was analysed for age at first calving (AFC), calf birth weights (BW), calving interval (CI), days open (DO), calving rate (CR), reproductive wastage (RW) and calving difficulty (CD); dystocia, aft...

This investigation aimed to determine the effects of some environmental factors on fertility traits and economic losses caused by deviations from ideal levels these parameters. The records 126 Holstein Simmental first-calf heifers three dairy cattle enterprises in Afyonkarahisar during period 2010 – 2016 were examined. technique ANOVA used detect different related calculated. ages at first calv...

The hypothesis of a continuous variation in the expression of muscular hypertrophy has been tested using field data. A modification of NEUVY and VISSAC's cularity index method (Culard Index) was assayed. Expression of muscular hypertrophy showed a broad phenotypical variability. Environmental factors affecting expression of muscular hypertrophy characterised by Culard Index were calving season,...

A method used to approximate reliabilities for animal models was modified to estimate reliabilities for sire-maternal grandsire (MGS) models. Accuracy of the approximation was tested on a calving-ease data set for 2,968 bulls for which the inverse of the coefficient matrix could be obtained. Correlations between estimated and true reliabilities ranged from 0.984 to 0.998 for first- and later-pa...

producers. This loss is estimated at $750 million annually nationwide. Calving difficulty increases calf death loss, cow mortality, labor and veterinary costs; it delays the return of cows to estrus and reduces conception rates. It also lowers calf weaning weight and market value, which results from breeding of young heifers and cows to easy calving bulls to reduce calving difficulty. Studies s...