stillbirth is defined as a calf death just prior to, during, or within 24 to 48 h of parturition. the exact cause of calf death in dairy cows in this period of time is unknown. the objective of this study was to investigate about the effective factors on stillbirth and also to estimate some of the genetic parameters in iranian dairy holsteins. data in the first and second lactation that have be...

Data from Hereford, 25% Simmental-75% Hereford, 50% Simmental-50% Hereford, and 75% Simmental-25% Hereford dams were used to estimate maternal heterosis and level of agreement with the dominance model. Cows were located at the Northern Agricultural Research Center near Havre, MT and were managed consistent with practices for western range environments. Sample halves of dam breed groups were bre...

calving records of iranian buffaloes from april 1991 to june 2010 comprising 1,151 herds with 34,911 calving events were used to evaluate reported secondary sex ratio, stillbirth, and calf birth weight. logistic regression models were applied to analyze stillbirth and calf sex at birth, and statistical analysis of calf birth weight was performed using a linear mixed model. overall, the ratio of...

Birth traits of 68 Angus and 49 Charolais x Angus calves sired by four Angus and seven Charolais bulls, respectively, were studied. Timed intervals during the calving process were compared between breed of sire groups. The Charolais sired calves required an average of 3.7 rain longer from the first appearance of the water bag until the feet were first visible; 8.1 rain longer (P<.01) from the t...

In the current study, principal component (PC) analysis was used to reduce the number of predictors in the estimation of direct genomic breeding values (DGV) for meat traits in a sample of 479 Italian Simmental bulls. Single nucleotide polymorphism marker genotypes were determined with the 54K Illumina beadchip. After edits, 457 bulls and 40,179 SNP were retained. Principal component extraction...

the purpose of this study was to investigate the effect of maternal inbreeding on incidence of twinning,dystocia and stillbirth in holstein cows of iran. calving records from march 2000 to april 2009 comprisingof 365,021 calvings on 153,802 cows from 86 dairy herds were used. the mean level of inbreeding was0.7%, less than 37% of all animals were inbred, and a small proportion (3.45%) of inbree...

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...

Twoand 3-year-old beef bulls were exposed to 25 or 40 beef cows on pasture during a 90-day breeding period. Reproductive performance of bulls by age of bull and size of cow group was evaluated in terms of percentage calf crop. Results indicated that reproductive performance of 2-year-old bulls was higher, but not significantly different (P>.05), than that of 3-year-old bulls. The percentage cal...

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 national sample of cow-calf producers was contacted to participate in a study to describe selected calving management practices on operations throughout the United States. Information was gathered on calving season, frequency of dystocia, frequency of observation, timing of assistance, and calving facilities. Regional and herd size differences existed in all parameters evaluated. Most calves ...