ABSTRACT This study aimed to estimate heritability, genetic, and residual correlations between reproductive traits such as age at first calving, calving interval, dry period, and first service period and linear type traits measured in Holstein cows born between the years 1990 and 2008 in Brazil. The (co)variance components were estimated by restricted maximum likelihood, using the MTDFREML software. The heritability for reproductive traits and linear-type traits ranged from 0.02 to 0.03 and from 0.07 to 0.40, respectively. Estimates of genetic […]

This work aimed to estimate genetic parameters for age at first calving, scrotal circumference, and seminal traits, and to evaluate genetic trend for age at first calving for dairy Gyr breed animals by analyzing data of 7,055 females and 97 males from several Brazilian herds. Covariance components were estimated by using the restricted maximum likelihood method under animal model in univariate analyses. The model for seminal traits included the company-year-season of semen collection fixed effects, age at the collection as […]

The objectives of this study were to evaluate reproductive traits (age at first calving and calving interval) and to obtain heritability estimates for birth weight in a crossbred (Murrah and Mediterranean breeds) Buffalo population in Rondonia State, Brazil. Data recorded between 1979 and 2001 were analyzed by SAS®. Variance components and heritability estimates were obtained by using the DFREML program. Age at first calving (1,291 ± 235 days) was significantly influenced by the contemporary group of dam. Calving interval (451 […]

Genetic parameters for scrotal circumference at 12 (SC12) and at 18 months of age (SC18) of males, and yearling weight (W365), weight at first calving (WFC), age at first calving (AFC), days to first calving (DC) and length of first gestation (GL) of females were estimated using records from 9,932 females and 14,521 males from 28 Nellore herds, located in the South and Southeast regions of Brazil. Covariance components were estimated by REML, fitting bivariate animal models. Heritability estimates were […]

The present study aimed to evaluate the effects of hair coat on age at first calving (IPP) and calving interval (IEP) of Holstein cows managed under free stall with fans and sprinklers and to estimate genetic and phenotypic parameters for these traits. Data were analyzed by the least-squares method using a model that included the effects of year; season; origin of sire; sire within origin; number of inseminations; age (only for calving interval); percentage of black meshes; hair coat thickness; […]

ABSTRACT This study aimed to evaluate the reproductive performance of Chianina cows born from 1977 to 2002. Data was used to calculate age at first calving (AFC), first calving interval (CI1) and average calving intervals (avgCIs) for the whole lifetime of cows. After editing data, the number of records used for AFC, CI1 and avgCIs analyses were respectively 31,023; 23,998 and 94,497 respectively. Statistical analyses were done using the SAS program (Statistical Analysis System) and variance components were estimated by […]

The objective of the present work was to investigate the effects of some genetic and environmental factors on production (weaning weight WW; eighteen month weight W18) and reproduction (scrotal perimeter at 18 months SP18; calving interval CI; age at first calving AFC; True fertility TF, calving date CD) traits in a Nellore cattle herd in the Mato Grosso do Sul State, Brazil. The observations were analysed using the least squares methodology, and the statistical models included the fixed effects: year […]

The objective of this study was to estimate the genetic correlations of female body weights at weaning (BWW), 12 (W12) and 18 (W18) months of age with age at first calving (AFC), body weight at first calving (WFC), adult body weight (ABW), and the parameters for mature weight (A) and maturation rate (k) obtained using the Von Bertalanffy model, in a Canchim herd. The restricted maximum likelihood method, with two-trait analyses, was used with models that included the fixed effects […]

The experiment evaluated the reproductive performance of primiparous beef heifers at two years old (‘one year system’). These heifers data were collected at Agropecuaria Guatambu, Dom Pedrito, RS, of 395 beef calves from three genetic groups, Hereford (H); 3/4 Hereford -1/4 Nellore (1/4 N); 5/8 Hereford- 3/8 Nellore (3/8 N). The heifers were submitted to three alternatives autumn-winter feeding systems a) continuous grazing on cultivated annual ryegrass (L. multiflorum Lam) (PAST); b) continuous grazing on natural pasture plus energy and […]

Productive and reproductive performance of a buffalo herd, located at Paracuru, west cost of Ceará State, were evaluated. Animals were raised in feedlot conditions, with two daily milking. Data from 87 Murrah dams breed, collected from 1984 to 1998 were analysed. The statistical analysis was carried out by GLM procedure (SAS, 1990), fitting a mixed linear model. The observed means for total milk yield, lactation length, milk yield at peak, age at first calving and calving interval, were: 2130.80+535.60kg, 301.41+49.30days, […]