BREEDING INDEX MODELING FOR AIRSHIRE DAIRY CATTLE WITH APPLICATION OF EXTERIOR PARAMETRES

The article presents results of selection efficiency of potential parents in Ayrshire breed using IAYR multiple-factor selection index, which includes productivity traits such as milk yield, fat and protein yield and integrated exterior parametres: UDC udder index and FLC leg index. As an original data array, a sample was generated with parameters for milk productivity and exterior characteristics of 574 Ayrshire first-calf heifers, which are daughters of 21 bulls from the leading breeding farm of Leningrad region. Calculation of phenotypic and genetic correlations was carried out in the course of the study, which revealed the greatest paratypical relationship between milk yield and fat yield rp = 0.912 at p <0.001, and the highest genetic relationship was noted between milk yield and protein yield rg = 0.960 at p <0.001. A high value of heritability coefficient for milk yield was established, which amounted to h2 = 0.506, which is connected with usage of imported servicing bulls with high genetic potential for herd reproduction. To determine the values of index weight coefficients, the variance and covariance components of variability of the studied parametres were calculated. Economic components of the parametres included in the developed equation are formed. As a result of selection modeling with an intensity of 10% according to the constructed equation of the productive-exterior index IAYR, a significant and reliable advantage in milk production by 1899 kg of milk was established in comparison with other animals, in terms of fat yield - by 64.7 kg and protein yield - by 51.7 kg.

Genetic variance and covariance components for carbon dioxide production and postweaning traits in Angus cattle

This experiment investigated phenotypic and genetic relationships between carbon dioxide production, methane emission, feed intake, and postweaning traits in Angus cattle. Respiration chamber data on 1096 young bulls and heifers from 2 performance recording research herds of Angus cattle were analyzed to provide phenotypic and genetic parameters for carbon dioxide production rate (CPR; n = 425, mean 3,010 ± SD 589 g/d) and methane production rate (MPR; n = 1,096, mean 132.8 ± SD 25.2 g/d) and their relationships with dry matter intake (DMI; n = 1,096, mean 6.15 ± SD 1.33 kg/d), body weight (BW) and body composition traits. Heritability estimates were moderate to high for CPR (0.53 [SE 0.17]), MPR (0.31 [SE 0.07]), DMI (0.49 [SE 0.08]), yearling BW (0.46 [SE 0.08]), and scanned rib fat depth (0.42 [SE 0.07]). There was a strong phenotypic (0.83 [SE 0.02]) and genetic (0.75 [SE 0.10]) correlation between CPR and MPR. The correlations obtained for DMI with CPR and with MPR were high, both phenotypically (rp) and genetically (rg) (rp: 0.85 [SE 0.01] and 0.71 [SE 0.02]; rg (0.95 [SE 0.03] and 0.83 [SE 0.05], respectively). Yearling BW was strongly correlated phenotypically (rp ≥ 0.60) and genetically (rg &gt; 0.80) with CPR, MPR, and DMI, whereas scanned rib fat was weakly correlated phenotypically (rp &lt; 0.20) and genetically (rg ≤ 0.20) with CPR, MPR, and DMI. The strong correlation between both CPR and MPR with DMI confirms their potential use as proxies for DMI in situations where direct DMI recording is not possible such as on pasture.

GIBBSTHUR: Software for Estimating Variance Components and Predicting Breeding Values for Ranking Traits Based on a Thurstonian Model

(1) Background: Ranking traits are used commonly for breeding purposes in several equine populations; however, implementation is complex, because the position of a horse in a competition event is discontinuous and is influenced by the performance of its competitors. One approach to overcoming these limitations is to assume an underlying Gaussian liability that represents a horse’s performance and dictates the observed classification in a competition event. That approach can be implemented using Montecarlo Markov Chain (McMC) techniques with a procedure known as the Thurstonian model. (2) Methods: We have developed software (GIBBSTHUR) that analyses ranking traits along with other continuous or threshold traits. The software implements a Gibbs Sampler scheme with a data-augmentation step for the liability of the ranking traits and provides estimates of the variance and covariance components and predictions of the breeding values and the average performance of the competitors in competition events. (3) Results: The results of a simple example are presented, in which it is shown that the procedure can recover the simulated variance and covariance components. In addition, the correlation between the simulated and predicted breeding values and between the estimates of the event effects and the average additive genetic effect of the competitors demonstrates the ability of the software to produce useful predictions for breeding purposes. (4) Conclusions: the GIBBSTHUR software provides a useful tool for the breeding evaluation of ranking traits in horses and is freely available in a public repository (https://github.com/lvaronaunizar/Gibbsthur).

Maternal effect on sports performance traits in horses

The aim of the study was to estimate the direct additive genetic effect and the additive maternal effect on the level of traits estimated during the Polish Jumping Championships for Young Horses. The investigations involved 541 stallions and 353 mares, which in total started in the Championships 1232 times. Variance and covariance components were estimated using the Gibbs sampling method. Heritability (h²) and repeatability (r²) coefficients as well as maternal effects (m²) were calculated for 7 sports performance traits. There was an additive maternal effect, ranging from 0.11 to 0.39, on the level of traits assessed based on achieved scores. The effect was particularly high in the case of traits the level of which was determined by the animal organism performance and stress resistance. It was also noted that the value of the maternal effect in some traits was similar or higher than the coefficient of heritability, which may indicate a high effect of the mare’s specific environment in determining sport predispositions in the offspring. There is a need to analyse the cause of trait variability in other equestrian disciplines.

Variance components due to direct and maternal effects for birth weight of Brown Swiss cattle

This study was conducted to estimate variance components and genetic parameters for birth weights of Brown Swiss calves. Experimental data were gathered from the records of a State Farm of Turkey (Konuklar) covering the years between 1995 and 2005. Random effects considered in this study included direct and maternal additive genetic effects, maternal permanent environmental effects with direct-maternal genetic covariance and random residual effects. AI-REML algorithm of WOMBAT software was used to estimate variance and covariance components, genetic parameters and breeding values. The general mean for birth weights of all calves was calculated as 38.12±0.006 kg. The least square for mean birth weights was calculated as 38.99±0.007 kg for male calves and as 37.26±0.008 for female calves. Direct heritability (hD2), maternal heritability (hM2), total heritability (hT2), rAM and cAM estimates were respectively calculated as 0.15, 0.10, 0.39, 0.96 and 0.13

Estimates of genetic parameters for growth traits of local Hamra breed threatened with extinction in southwestern arid rangeland of Algeria

The data base for body weights and growths of 411 Hamra lambs were used to estimate genetic parameters. These lambs were obtained from 31 rams and 493 ewes between 2012 and 2017. Traits analysed were weights at birth (BW), 30 days (W30), 90 days (W90) of age, and average daily gains from 10 to 30 (ADG10-30) and30-90 (ADG30-90) days. REML estimates of variance and covariance components were obtained assuming animal models that included the fixed effects for year-type of birth (2012 single, 2012 twin, . ., 2017 single, 2017 twin), sex (male, female), and ewes age at lambing (< 18, 18-30, 30-42, 42-54, >54 months). Heritabilities were 0.12, 0.06 and 0.11 respectively for BW, W3Oand W90and the average daily gains were 0.05 and 0.17 for ADG0-30and ADG30-90. The estimates of genetic correlations showed no genetic antagonisms among the growth traits. The genetic correlations estimated were positive and medium to high, except those between ADG30-90 and ADG0-30 and between ADG30-90 and W30 which were slightly negative. Phenotypic correlations were positive and ranged from 0.12 to 0.85. They were high between adjacent weights and between ADG and their corresponding weights.

Evaluation of growth traits of Aceh cattle at the breeding station in Indrapuri District of Indonesia

The present study was conducted using records on four breeding bulls maintained at the Indrapuri’s Breeding and Forages Center (IBFC) of Aceh Cattle, Indrapuri district, Indonesia and 52 of their progeny born from 2010 to 2014 through natural mating. Family selection was practiced in this breeding station. Traits included in this study were birth weight at 0 day (BWc), weaning weight at 205 days of age (WWc), yearling weight at 365 days of age (YWc) and final weight at 550 days of age (FWc) of their progeny. The variance and covariance components were estimated by the Paternal Half-sib Correlation method with the Excel sheets of Microsoft office computer program. The mean body weights of the animals were BWc (13.25+1.18 kg), WWc (47.80+10.00 kg), YWc (73.97+16.79 kg) and FWc (101.87+23.91 kg). Estimated heritability (h2) for BWC was low (h2 < 0.10) and the other traits were high (h2>0.30). Higher standard error (SE) value than h2 caused by less number of calves observation. Research showed that best relative accuracy value (RA>1.00) reached in BWC. but its trait was not effective as selection criterion because of lower h2 value. It was concluded that WWC could be used as selection criterion for breeding bulls based on the similar estimated breeding value (EBV) rank and high h2 value. The EBV of WWC from breeding bull ID: 0752 was calculated and ranked accordingly. The EBVs of three top bulls ID were 100412 (10.32 kg), 100520 (9.38 kg) and 100317 (6.75 kg) and three top heifers were 100526 (9.65 kg), 100408 (7.04 kg) and 100807 (5.20 kg). It can be concluded that these top ranking three bulls and heifers can be selected and used in the breeding programs.Bang. J. Anim. Sci. 2015. 44(2): 85-91

Estimates for Genetic Variance Components in Reciprocal Recurrent Selection in Populations Derived from Maize Single-Cross Hybrids

This study was carried out to obtain the estimates of genetic variance and covariance components related to intra- and interpopulation in the original populations (C0) and in the third cycle (C3) of reciprocal recurrent selection (RRS) which allows breeders to define the best breeding strategy. For that purpose, the half-sib progenies of intrapopulation (P11and P22) and interpopulation (P12and P21) from populations 1 and 2 derived from single-cross hybrids in the 0 and 3 cycles of the reciprocal recurrent selection program were used. The intra- and interpopulation progenies were evaluated in a10×10triple lattice design in two separate locations. The data for unhusked ear weight (ear weight without husk) and plant height were collected. All genetic variance and covariance components were estimated from the expected mean squares. The breakdown of additive variance into intrapopulation and interpopulation additive deviations (στ2) and the covariance between these and their intrapopulation additive effects (CovAτ) found predominance of the dominance effect for unhusked ear weight. Plant height for these components shows that the intrapopulation additive effect explains most of the variation. Estimates for intrapopulation and interpopulation additive genetic variances confirm that populations derived from single-cross hybrids have potential for recurrent selection programs.