Association of CSSM066 and ILSTS011 microsatellite markers and thyroglobulin gene SNP with backfat in Canchim cattle

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

QTL affecting body weight in a candidate region of cattle chromosome 5

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Association of GH and IGF-1 polymorphisms with growth traits in a synthetic beef cattle breed

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

GENETIC-RELATIONSHIP, INBREEDING AND GENERATION INTERVAL IN REGISTERED GIR CATTLE IN BRAZIL

Two-hundred random pedigrees of cows and fifty of sires born in 1987 from the Gir herdbook of the Brazilian Association of Zebu Breeders were analized. The bull Chave de Ouro DGR no. 2851 was the most influential animal with a 7 % direct relationship to the breed. Total average inbreeding was 3.62 and 3.25 for the female and male sample, respectively. The subdivision of total inbreeding into current and non-current components resulted in values of 1.62, 1.25, 2.00 and 2.00 for the female and male sample, respectively. Long-term inbreeding was the principal component of non-current inbreeding, with values of 1.52 % and 1.26 %, respectively. Inbreeding due to strain formation strain due formation was less important (0.48 % and 0.74 %, respectively). The average generation interval was 8.02 years. The breed appears not yet to be subdivided into strains but this process may be starting. The average generation interval for the pedigree population was very high. Culling of old bulls could decrease this interval.

Association between IGF2 and CYP21 gene polymorphisms and characteristics of economic interest in Nellore cattle

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Crescimento pré-natal do corpo e de alguns órgãos de Zebu mestiço coletados em matadouros de São Paulo

A total of 196 fetuses of crossbred Zebu between 106 to 246mm in length collected from a slaughterhouse in São Paulo, Brazil, and divided into groups of 10mm size differences intervals into 15 classes were measured and weighed. Liver, heart and lungs were also removed and weighed. In order to select the method of evaluation of growth several mathematical functions were applied. Among significant equations the monologarithmic function was selected. Furthermore, the fetuses in similar conditions of length and weight were compared with racially pure fetuses.

Estimates of covariance functions for growth from birth to 630 days of age in Nelore cattle

Weight records of Brazilian Nelore cattle, from birth to 630 d of age, recorded every 3 mo, were analyzed using random regression models. Independent variables were Legendre polynomials of age at recording. The model of analysis included contemporary groups as fixed effects and age of dam as a linear and quadratic covariable. Mean trends were modeled through a cubic regression on orthogonal polynomials of age. Up to four sets of random regression coefficients were fitted for animals' direct and maternal, additive genetic, and permanent environmental effects. Changes in measurement error variances with age were modeled through a variance function. Orders of polyno-mial fit from three to six were considered, resulting in up to 77 parameters to be estimated. Models fitting random regressions modeled the pattern of variances in the data adequately, with estimates similar to those from corresponding univariate analysis. Direct heritability estimates decreased after birth and tended to be lowest at ages at which maternal effect estimates tended to be highest. Maternal heritability estimates increased after birth to a peak around 110 to 120 d of age and decreased thereafter. Additive genetic direct correlation estimates between weights at standard ages (birth, weaning, yearling, and final weight) were moderate to high and maternal genetic and environmental correlations were consistently high. © 2001 American Society of Animal Science. All rights reserved.

Effects of CSN3 and LGB gene polymorphisms on production traits in beef cattle

The objective of the present study was to estimate the allele and genotype frequencies of the CSN3/Hinfl and LGB/HaeIII gene polymorphisms in beef cattle belonging to different genetic groups, and to determine the effects of these polymorphisms on growth and carcass traits in these animals, which are submitted to an intensive production model. Genotyping was performed on 79 Nelore, 30 Canchim (5/8 Charolais + 3/8 Zebu) and 275 crossbred cattle originating from the crosses of Simmental (n = 30) and Angus (n = 245) sires with Nelore females. Body weight, weight gain, dressing percentage, longissimus dorsi area and backfat thickness were fitted using the GLM procedure, and least square means of the genotypes were compared by the F test. The results showed that the CSN3/Hinfl and LGB/HaeIII polymorphisms did not have any effect on growth or carcass traits (p > 0.05). Copyright by the Brazilian Society of genetics.

Effect of superstimulatory treatments on the expression of genes related to ovulatory capacity, oocyte competence and embryo development in cattle.

Multiple ovulation (superovulation) and embryo transfer has been used extensively in cattle. In the past decade, superstimulatory treatment protocols that synchronise follicle growth and ovulation, allowing for improved donor management and fixed-time AI (FTAI), have been developed for zebu (Bos indicus) and European (Bos taurus) breeds of cattle. There is evidence that additional stimulus with LH (through the administration of exogenous LH or equine chorionic gonadotrophin (eCG)) on the last day of the superstimulatory treatment protocol, called the 'P-36 protocol' for FTAI, can increase embryo yield compared with conventional protocols that are based on the detection of oestrus. However, inconsistent results with the use of hormones that stimulate LH receptors (LHR) have prompted further studies on the roles of LH and its receptors in ovulatory capacity (acquisition of LHR in granulosa cells), oocyte competence and embryo quality in superstimulated cattle. Recent experiments have shown that superstimulation with FSH increases mRNA expression of LHR and angiotensin AT(2) receptors in granulosa cells of follicles >8 mm in diameter. In addition, FSH decreases mRNA expression of growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) in oocytes, but increases the expression of both in cumulus cells, without diminishing the capacity of cumulus-oocyte complexes to generate blastocysts. Although these results indicate that superstimulation with FSH is not detrimental to oocyte competence, supplementary studies are warranted to investigate the effects of superstimulation on embryo quality and viability. In addition, experiments comparing the cellular and/or molecular effects of adding eCG to the P-36 treatment protocol are being conducted to elucidate the effects of superstimulatory protocols on the yield of viable embryos.

Seasonal effects on semen and testosterone in zebu and taurine bulls

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Genetic relationship between reproductive traits in Nellore cattle

Pós-graduação em Genética e Melhoramento Animal - FCAV

Genome-Wide Association for Growth Traits in Canchim Beef Cattle

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)