Data from 44 bulls of the genetic groups Selection Nellore (NeS), Control Nellore (NeC) and Caracu (Ca) herds born in 1999 were used to evaluate the effects of selection for post weaning weight on carcass traits and meat cuts yields at 378 days of age (P 378). The animals were randomly distributed into two experimental classes: restricted feeding (AR) and ad libitum feeding (AL) including 8 animals from the NeS and Ca groups and 6 animals from the NeC group. […]

Blood samples were collected from Pantaneiro Horses in five regions of Mato Grosso do Sul and Mato Grosso States. Arabian, Mangalarga Marchador and Thoroughbred were also included to estimate genetic distances and the existing variability among and within these breeds by RAPD-PCR (Random Amplified Polymorphic DNA – Polymerase Chain Reaction) molecular markers. From 146 primers, 13 were chosen for amplification and 44 polymorphic bands were generated. The analysis of molecular variance (AMOVA) indicated that the greatest portion of detected variability […]

The objective of this study was to estimate heritability and genetic correlations for body weight at birth (BW), weaning (WW), twelve (W12) and eighteen (W18) months of age, weight gains from birth to weaning (DGBW) and from birth to eighteen months of age (DGB18), days to 175 kg from birth to weaning (D175 = 175/DGBW), days to 450 kg from birth to slaughter (D450 = 450/DGB18) and female mature body weight (ABW) using data from a herd of Canchim (5/8 […]

The objective of this study was to estimate heritability of scrotal circumference at 12 months of age (SC12), age (AFC) and weight (WFC) at first calving and genetic correlations between each of these traits and the following growth traits: weight at birth (BW), weaning (WW), twelve (W12) and eighteen (W18) months of age, weight gain from birth to weaning (DGBW) and from birth to eighteen (DGB18) months of age, days to 175 kg from birth to weaning (D175 = 175/DGBW) […]

Nine populations, with five replications each, were simulated for average daily gain (GMD1) assuming normal distribution, average 100, and different group sizes as well as standard deviations. Each replication was divided into three different sets of contemporary (CG) and progeny groups. The first set (I) was formed by 1,000 contemporary groups, 100 observations each and 10 progenies/sire. The second set (II) included 2,500 CG, 40 observations and 4 progenies/sire. The third set (III) consisted of 5,000 CG, 20 observations and […]

Finite mixture models are helpful for uncovering heterogeneity due to hidden structure; for example, unknown major genes. The first part of this article gives examples and reviews quantitative genetics issues of continuous characters having a finite mixture of Gaussian components. The partition of variance in a mixture, the covariance between relatives under the supposition of an additive genetic model and the offspring-parent regression are derived. Formulae for assessing the effect of mass selection operating on a mixture are given. Expressions […]

The market demands, since the end of the 1920s the market demands a technology for spermatozoa sexing that can be inserted in the industry to production of frozen semen and that has the following features: a) does not change sperm viability; b) it be compatible with freezing of spermatozoa after treatment for sexing; c) it allows the spermatozoa sexing after their thawing; d) it allows the production of various doses of sexed frozen semen per day at a compatible cost […]

Genetical genomics experiments combine information on phenotypic traits, molecular markers and gene expression to study the genetic mechanisms governing variation in complex traits. Such studies can be used, for example, to estimate heritabilities of mRNA transcript abundances, to map expression quantitative trait loci (eQTL), and to infer regulatory gene networks. Microarray experiments, however, can be extremely costly and time consuming, which may limit sample sizes and statistical power. Thus it is crucial to optimize experimental designs by carefully choosing the […]

The development of in vitro embryo production (IVP) methodology to maximize genetic gain and animal production at lower cost is a challenge of the research and it has been studied for many years. The possibility to produce, in commercial scale, embryos from ovum pick up methodology may increase the benefits of the use of artificial insemination (AI) for its decisive role to maximize the genetic progress between generations, according to the requirements of each genetic improvement program and livestock capacity. […]

Microarray technology allows monitoring thousands of genes simultaneously in a specific tissue of an organism, in different developmental stages or environmental conditions. Microarrays are very common in functional genomics experiments with both animals and plant species, and they have been increasingly used also in different areas of livestock research, such as growth and metabolism, reproduction, immune response to diseases and parasites, response to non-infectious stress factors (such as dietary restriction, exposure to toxic elements and other unfavorable environmental conditions) as […]