Giovani da Costa Caetano

Estimação dos componentes de variância para as características de produção e de qualidade de ovos em matrizes de codorna de corte

Data from two genetic groups UFV1 and UFV2 of meat-type quail, with 629 animals the first file and 707 the second, were evaluated by technique main components. The following characteristics were considered for analyses: bird weight (P1, P2, P3 and P4), egg average weight (POM1, POM2, POM3 and POM4), shell average weight (PCM1, PCM2, PCM3 and PCM4), yolk average weight (PGM1, PGM2, PGM3 and PGM4), egg average specific gravity (DM1, DM2, DM3 and DM4), egg average width (LOM1, LOM2, LOM3 and LOM4), egg average length (COM1, COM2, COM3 and COM4), number of eggs (N1, N2, N3 and N4), and age at the first egg (IDPO). After data collecting were carried analyses of the main components out with the aim to select the most explanatory characteristics. Next the highest significant characteristics in total variance had their genetic parameters and genetic correlations estimated. For genetic group UFV1 were: P1, PCM1, PCM3, PGM1, PGM2, PGM4, DM4, LOM2, LOM3, COM1 and IDPO. For UFV2: P1, P2, PCM1, PCM4, DM3, LOM2 and LOM4. The high estimates of heritability capacity found indicate a high variability for the characteristics of egg quality. The genetic correlations indicate the possibility of correlation between body weight gains and the quality of eggs. Little response to selection for egg production can be expected for these genetic groups.

Heterogeneidade de variância residual em modelos de regressão aleatória na descrição do crescimento de codornas de corte

In order to compare the residual heterogeneity variance influence on the genetic parameters estimated for the growth curve of meat quail, data from 26835 and 27447 observations, from 3909 and 4040 meat quails of the UFV-1 and UFV-2 strains, respectively, were used. Body weight was evaluated, for the two strains, at 1, 7, 14, 21, 28, 35 and 42 days of age, through an animal model at random regression, considering residual variances in the age classes. Loge L showed increase, significant by the likelihood ratio test (LRT), with an increase in the number of heterogeneous classes. In the modeling, the following residual variances were considered in the age classes of: homogeneous: CL1 (one class): 1-42 days; and heterogeneous: CL2 (two classes): 1 and 7-42 days; CL3 (three classes): 1, 7 and 14-42 days; CL4 (four classes): 1, 7, 14 and 21-42 days; CL5 (five classes): 1, 7, 14, 21 and 28-42 days; CL6 (six classes): 1, 7, 14, 21, 28 and 35-42 days; CL7 (seven classes): 1, 7, 14, 21, 28, 35 and 42 days of age. The model that considered residual variance homogeneity showed unsuitable. Variance estimates, heritability and correlations were influenced by the modeling of the residual variance. The use of residual variance heterogeneity (CL7) to model the variances associated with the growth curve of meat quail is necessary.

Herdabilidade de características de produção e postura em matrizes de codornas de corte

The objective of this study to determine the heritability of characteristics of productive and reproductive performance of different genetic groups of arrays of meat quails, estimating genetic parameters using univariate analyzes. We evaluated two genetic groups (UFV1 and UFV2) in the period 2006 to 2009, being accompanied by five generations, totaling 2136 arrays. Quail were weighed at birth, 7, 14, 21, 28, 35, 42, 77, 112 and 147 days of age. We evaluated each quail eggs were collected for three consecutive days, during four periods of 35 days and measured the width and length of eggs, yolk weight, albumen and shell. We evaluated the specific gravity of eggs and measured the rate of overall posture and age at first egg. Univariate analyzes were performed to estimate the variance components, using the method of restricted maximum likelihood using the program and calculated the MTDFREML hedabilidades. For the quality of eggs heritability values were moderate to high (0.13 to 0.55), high values for growth (0.64 to 0.68) and moderate to high for egg shape (0.10 to 0.57). Heritability estimates for egg quality found indicate a high genetic variability for both genetic groups. As for the weights indicated that selection within the population could result in increases in weight by selection based on individual information. For the characteristics of an egg shape, the heritability values suggest the possibility of genetic groups that meet a standard shape.

Genetic evaluation for egg mass in partial periods and complete period in meat quails

The objective of this study was to obtain estimates of genetic and phenotypic parameters for egg mass of meat quails and also to propose an optimal age for selection of birds through the egg mass. The data used in this study came from 3,503 female meat quails (UFV1: 1.811 quails; UFV2: 1.692 quails) of the Poultry Breeding Program from Universidade Federal de Vicosa. The traits examined were egg mass in partial periods until 77, 112, 147 and 182 days, and egg mass in the total period of 407 days by the use of single and bi-trait animal models. For the genetic group UFV1, the heritability values for the periods were high: 0.58, 0.59, 0.57, 0.59 and 0.24 (until 77, 112, 147,182 and 407 days, respectively). The values of genetic correlations were medium, ranging from 0.51 (77 and 407 days) to 0.61 (112 and 407, 147 and 407 days). For the genetic group UFV2, the estimates of heritability were of low magnitude: 0.05, 0.03, 0.04, 0.05, and 0.11 (until 77, 112, 147, 182, and 407 days, respectively). The values for genetic correlation ranged from 0.61 (112 and 407 days) to 0.93 (77 and 407 days). For the genetic group UFV1, the second partial period (112 days) for selection of meat quails using the egg mass trait is recommended, due to a higher value of heritability and a higher value of genetic correlation with the total and relative efficiency close to the unity in this period. In the genetic group UFV2, the first partial period (77 days) is indicated, since it had a higher estimation of genetic correlation and a higher relative efficiency. The choice of these partial periods reduces the generation interval, increasing the intensity of selection and an increase in genetic gain per unit of time.

Modelos de regressão aleatória para avaliação da curva de crescimento em matrizes de codorna de corte

The objective was to compare different random regression models using Legendre polynomial functions of different orders, to evaluate what best fits the genetic study of the growth curve of meat quails. It was evaluated data from 2136 cut dies quail, of which 1026 belonged to genetic group UFV1 and 1110 the group UFV2. Quail were weighed at 10, 70, 140, 210, 280, 350, 420, 770, 1120 and 1470 days of age, and weights used for the analysis. It was tested two possible modeling of heterogeneous residual variance, which was grouped into three five age classes. After, it was studied the random regression mode, which is better applied to the growth curve quail. The comparison between models was made by the Akaike Information Criterion (AIC), Bayesian Information Criterion of Schwarz (BIC), logarithm of the likelihood function (Loge L) and the likelihood ratio test (LRT), at 1%. The model which considered the heterogeneity of residual variance CL3 was adequate to UFV1 lineage and the lineage model CL5 UFV2. A Legendre polynomial with order 5, for direct genetic effect and 5 for the permanent animal to UFV1 bloodline and order 3 for direct genetic effect and 5 for the permanent animal for UFV2 bloodline should be used in genetic evaluation of the growth curve of meat quails.

Características quantitativas em matrizes de codorna de corte através de análises multicaracterística

The aim of this paper to evaluate the productive and reproductive performance of different strains of meat-type quail hens, estimating the genetic parameters measured. Two groups were evaluated genetic and UFV2 UFV1 matrix quail cutting, with 1110 being the first animal and second with 1026. Multivariate analysis were conducted using the methodology of principal components to define the most important variables. Then, two-trait analysis to estimate covariances and genetic correlations of traits. The characteristics of the analysis were: weight of the bird (P0, P7, P14, P21, P28, P35, P42, P77, P112 and P147), average egg weight (POM1, POM2, and POM3 POM4), average weight of the shell ( PCM1, pcm2, and PCM3 PCM4), average weight of yolk (PGM1, PGM2, and PGM3 PGM4), weight of albumen (PAM1, PAM2, and PAM3 PAM4), average egg specific gravity (DM1, DM2, DM3 and DM4 ), average width of the egg (LOM1, LOM2, and LOM3 LOM4), average length of egg (COM1, COM2, COM3 and COM4), eggs (N1, N2, N3 and N4), total egg production (TXT) and age at first egg (IDPO). For the group of genetic UFV1, an increase in weight of birds may result in an early and that IDPO to select for increased body weight of birds does not result in significant losses in egg quality. As for UFV2, a selection made at 35 days can identify the most weight matrices throughout the production cycle, and do not generate large losses in total egg production.

A note on transgenerational epigenetics affecting egg quality traits in meat-type quail

ABSTRACT 1. The aim of the following experiment was to estimate transgenerational epigenetic variance for egg quality traits using genealogical and phenotypic information in meat-type quail. Measured traits included egg length (EL) and width (EWD), albumen weight (AW), shell weight (SW), yolk weight (YW) and egg weight (EW). 2. A total of 391 birds were evaluated for egg quality by collecting a sample of one egg per bird, during three consecutive days, starting on the 14th d of production. Analyses were performed using mixed models including the random epigenetic effect. Variance components were estimated by the restricted maximum likelihood method. A grid-search for values for the auto-recursive parameter (λ) was used in the variance components estimation. This parameter is directly related to the reset (v) and epigenetic transmissibility (1 − v) coefficients. 3. The epigenetic effect was not significant for any of the egg quality traits evaluated. Direct heritability estimates for egg quality traits ranged in magnitude from 0.06 to 0.33, whereby the higher estimates were found for AW and SW. Epigenetic heritability estimates were low and close to zero (ranging from 0.00 to 0.07) for all evaluated traits. 4. The current breeding strategies accounting for additive genetic effect seem to be suitable for egg quality traits in meat-type quail.

Modelling lactation curves of dairy goats by fitting random regression models using Legendre polynomials or B-splines

Abstract: A total of 17 356 test-day milk yield (TDMY) records from 642 first lactations of Alpine goats were used to model variations in lactation curve using random regression models (RRM). Orthogonal Legendre polynomials and B-splines were evaluated to obtain adequate and parsimonious models for the estimation of genetic parameters. The analysis was performed using a single-trait RRM, including the additive genetic, permanent environmental, and residual effects. We estimated the mean trend of milk yield, and the additive genetic and permanent environmental covariance functions through random regression using different orders of orthogonal Legendre polynomial (three to six) and B-spline functions (linear, quadratic, and cubic, with three to six knots). This study further evaluated different number of classes of residual variances. The covariance components and the genetic parameters were estimated using the restricted maximum likelihood method. Heritability estimates presented similar trends for both functions. The RRM with a higher number of parameters better described the genetic variation of TDMY throughout the lactation. The most suitable RRM for genetic evaluation of TDMY of Alpine goats is a quadratic B-spline function with six knots, for the mean trend, curves of additive genetic and permanent environmental effects, and five classes of residual variance.