The aim of the current study was to evaluate the performance of experimental and commercial genotypes of chicken recommended for free-range rearing system submitted to two diet programs (conventional and alternative). The experimental design consisted of a randomized design applied until 28 days and a randomized factorial 8×2 design (eight genotypes: Paraíso Pedrês, Caipirão da ESALQ, 7 P, Embrapa 041, Label Rouge, Paraíso Pelado, Caipirinha da ESALQ and Carijó Barbada and two diet programs), using two replicates with 30 chickens/box […]

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 aims of this study were to estimate heritability coefficients and genetic trends for visual scores of conformation (C), finishing precocity (P) and musculature (M) in Nelore beef cattle. Variance components and heritability coefficients were estimated by restrict maximum likelihood and breeding values were predicted by an animal mixed model using data from 56,076 animals born between 1990 and 2002. Genetic trends for each trait were estimated by the regression of breeding values on animal birth year. Heritability estimates for […]

The aim of this study was to evaluate ovarian pre-stimulation using recombinant bovine somatotropin (rbST) or rbST associated to FSH on follicular population, oocyte retrieval and in vitro embryo production in Gir cows (Bos indicus). Estrous cycle of non-lactating cycling cows with similar body and reproductive conditions were synchronized with cloprostenol followed by norgestomet ear implants, replaced every fourteen days. The animals were randomly distributed in three treatments: TI or control (punctured without pre-stimulation), TII (injection of 160 mg of […]

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; […]

This study aimed to estimate genetic and phenotypic parameters and trends for adjusted 305 days milk yield of Murrah buffaloes, which were born from 1982 to 2003. Variance components, genetic parameters and breeding values were obtained using the MTDFREML program. Genetic trends were estimated by regression of breeding values on birth year of the animals by two methodologies: 1) linear regression and 2) articulated polynomial regression using a spline smoothing function. Heritability and repeatability estimates were 0.20 and 0.36, respectively. […]

The objective of this study was to evaluate the relationship between complementary (hiposmotic, thermo-resistance and acrosome reaction tests) and conventional evaluations (physical and morphologic aspects) of bovine frozen/thawed semen and conception rates. Average values for spermatic motility evaluated by thermo-resistance test were of 53.48% (post-thawed), 43.69% (60 minutes), 35.88% (120 minutes) and 33.04% (180 minutes). The percentage of reactive cells observed for the hiposmotic test was 37.89%. Average intensity was observed for post-thawing spermatic motility, positively correlated to hiposmotic test […]

During the reproductive season of 2001 and 2002, 43 recipient mares of the Mangalarga Marchador breed were treated randomly with intra-muscular application of 200mg/day of oily progesterone (P4). Another group of 41 mares of the same breed were treated randomly, via oral, with 0.044 mg/kg/day of Altrenogest. Both treatments were performed between D0 (ovulation day) and D5. The recipients were evaluated on D2 and those in adequate conditions were in ovulated. Two groups of 85 mares of the same breed […]

This study aimed to evaluate the inbreeding coefficient, alleles fixation and selection limit in a population selected during 20 generations. Selection was based on breeding values predicted by classical best linear unbiased prediction (BLUP), BLUP associated with molecular markers (BLUPM) and individual selection (IS) using different mating designs. The genetic similarity matrix used in BLUPM was obtained by simulating 100 micro satellite markers (simple sequence repeats) using a similarity coefficient corresponding to the mean Euclidean distance between quantitative data. The […]

The objective of this study was to estimate the genetic and phenotypic relationships between somatic cell count (SCC) and milk yield and to evaluate the possibility of using SCC as a selection criteria in breeding programs of dairy cattle. Somatic cell count records were transformed into somatic cell score (SCS) using a logarithmic scale. Genetic parameters for milk yield (305 days) and average somatic cell score (ASCS) were estimated. The overall means for 305-day milk yield (MY305) and ASCS were, […]