Average Estimated Breeding Values Research Articles

Exploring definitions of daily enteric methane emission phenotypes for genetic evaluations using a population of indoor-fed multi-breed growing cattle with feed intake data.

Genetic selection has been identified as a promising approach for reducing enteric methane (CH4) emissions; a prerequisite for genetic evaluations; however, these are estimates of the necessary genetic parameters based on a population representative of where the genetic evaluations will be used. The objective of this study was, therefore, to derive genetic parameters for a series of definitions of CH4, carbon dioxide (CO2), and dry matter intake (DMI) as well as genetic correlations between CH4, CO2, and DMI in a bid to address the paucity of studies involving methane emissions measured in beef cattle using GreenFeed systems. Lastly, estimated breeding values (EBV) were generated for nine alternative definitions of CH4 using the derived genetic parameters; the EBV were validated against both phenotypic performance (adjusted for non-genetic effects) and the Legarra and Reverter method comparing EBV generated for a subset of the dataset compared to EBV generated from the entire dataset. Individual animal CH4 and CO2 records were available from a population of 1,508 multi-breed growing beef cattle using 10 GreenFeed Emission Monitoring systems. Nine trait definitions for CH4 and CO2 were derived: individual spot measures, the average of all spot measures within a 3-h, 6-h, 12-h, 1-d, 5-d, 10-d, and 15-d period and the average of all spot measures across the full test period (20 to 114 d on test). Heritability estimates from 1,155 animals, for CH4, increased as the length of the averaging period increased and ranged from 0.09 ± 0.03 for the individual spot measures trait to 0.43 ± 0.11 for the full test average trait; a similar trend existed for CO2 with the estimated heritability ranging from 0.17 ± 0.04 to 0.50 ± 0.11. Enteric CH4 was moderately to strongly genetically correlated with DMI with a genetic correlation of 0.72 ± 0.02 between the spot measures of CH4 and a 1-d average DMI. Correlations, adjusted for heritability, between the adjusted phenotype and (parental average) EBV ranged from 0.56 to 1.14 across CH4 definitions and the slope between the adjusted phenotype and EBV ranged from 0.92 to 1.16 (expectation = 1). Validation results from the Legarra and Reverter regression method revealed a level bias of between -0.81 and -0.45, a dispersion bias of between 0.93 and 1.17, and ratio accuracy (ratio of the partial evaluation accuracies on whole evaluation accuracies) from 0.28 to 0.38. While EBV validation results yielded no consensus, CH4 is a moderately heritable trait, and selection for reduced CH4 is achievable.

125 Implementing a Genetic Evaluation Program for Acute Hepatopancreatic Necrosis Disease Resistance in Penaeus Vannamei (Pacific White Shrimp)

Abstract This study aims to evaluate the feasibility of a genomic evaluation program for Acute hepatopancreatic necrosis disease (AHPND) resistance in a commercial population of Penaeus vannamei. AHPND is caused by a strain of Vibrio parahaemolyticus (VpAHPND) producing a binary toxin. It is a World Organization for Animal Health (WOAH, Paris, France)-listed bacterial disease that has caused severe economic losses to the shrimp industry worldwide in recent years. The working hypothesis of this study is that the genetic variation in a commercial P. vannamei population allows an efficient genetic and genomic selection program. To investigate the genetic parameters for AHPND resistance, a controlled challenge experiment was performed at the Shrimp Improvement System biosafety laboratory in Miami, Florida, following an immersion challenge protocol using 4.95 × 107 CFU/ mL bacteria and Specific Pathogen Free (SPF) P. vannamei post larvae (n = 2,400) representing 40 selected families. The bioassay was terminated at 3 days post-challenge. Each family consisted of 60 animals, with one-half of the families (n = 20) representing a fast-growth (FG) line and the remaining one-half (n = 20) representing a slow-growth (SG) line. Survival was recorded as a binary of dead or alive at the end of the three days challenge experiment. Variance components were estimated under an animal threshold binary model using a Gibbs sampler. Estimation of genetic parameters was done within lines and by combining all data records. The average hazard risk ratio (HRR) of survival was 80% greater for the FG line (average mortality 40%) than the SG line (average mortality 20%, P < 0.05) based on survival analysis with a 31% mortality rate combining all data records. The posterior mean estimates of heritabilities were 0.14 (± 0.06) for FG, 0.16 (± 0.07) for SG, and 0.38 (± 0.08), combining all records. Estimated breeding values (EBVs) based on the animal threshold binary model ranged from -0.76 to 1.01 on the liability scale. Spearmans’ rank correlation coefficient between the average EBV of parents and the average mortality rates of corresponding families was 0.98. The results suggest that a breeding program for AHPND resistance is feasible. Moreover, the heritabilities suggest that both lines will respond to mass selection due to the presence of additive genetic variation for APHND-survivability. The next step of this project is to genotype animals from every family and implement a genomic selection program. Additionally, high throughput laboratory results and histopathology scores will be introduced in the genetic evaluation as correlated traits.

The Relevance of the Expected Value of the Proportion of Arabian Genes in Genetic Evaluations for Eventing Competitions.

The Arabian horse is a generally reliable sport horse, and continues to be a remarkable endurance horse, so the relevance of the expected value of the proportion of Arabian genes (EV%AG) in horses participating in eventing could be a relevant factor. A total of 1089 horses participating in eventing (8866 records) were used. A GLM revealed that the EV%AG was significant in dressage, show jumping and cross-country. A BLUP genetic evaluation was computed with five genetic models (without the EV%AG (0) using as a covariate (A), as a fixed effect (B), with variance heterogeneity, and in genetic groups without (C) and with (D)). Dressage heritability ranged from 0.103 to 0.210, show jumping ranged from 0.117 to 0.203 and cross-country ranged from 0.070 to 0.099. The lowest DIC value was used as a criterion of fitness. The best fits (those which included variance heterogeneity) showed fewer than two points of difference in DIC values. The highest average estimated breeding value in dressage, show jumping and cross-country was found for horses with an expected value of the proportion of Arabian genes of 0%, ≥1% to <25%, and 100%, respectively. Therefore, the best way to model the EV%AG effect seems to be by considering the variance heterogeneity.

The association of immune response and colostral immunoglobulin G in Canadian and US Holstein-Friesian dairy cows

In cattle, maternal immunoglobulins are transferred through colostrum to provide passive immunity to the neonatal calf once they are absorbed into circulation. Cows can be assessed for antibody- and cell-mediated immune responses (AMIR and CMIR, respectively), and through estimated breeding values (EBV) and genomic parent averages (GPA), cows can be classified as having high, average, or low immune response (IR). The objective of this study was to identify associations of colostral IgG concentrations with IR in dairy cows. High IR dairy cows identified by GPA or EBV were hypothesized to produce higher colostral IgG concentrations than cows with average or low IR. Colostrum was collected from Holstein dairy cows from 3 large commercial herds (n = 590) in the United States and 1 research herd at the Ontario Dairy Research Centre (n = 275) in Canada. For the US herds, IR GPA were available through genotyping. For the Canadian herd, IR EBV were available through phenotyping and pedigree information. Colostral IgG concentrations were measured by radial immunodiffusion and analyzed using general linear models in SAS. Based on a prediction equation, cows in US herds with a CMIR GPA of 1 would have colostral IgG concentrations 6.3 g/L higher on average than cows with a CMIR GPA of 0. High CMIR cows produced statistically greater colostral IgG concentrations (least squares mean ± standard error of the mean, 107.5 ± 7.7 g/L) than low CMIR cows (91.4 ± 7.1 g/L), with intermediate values for average CMIR cows (105.1 ± 5.6 g/L). No differences were found among AMIR categories in US cows. The Canadian herd showed a trend for cows with high CMIR EBV (continuous variable) to produce greater colostral IgG. No differences were observed among high, average, and low AMIR EBV classifications in Canadian cows. The findings suggest that selective breeding of Holstein cows to enhance CMIR could contribute to higher-quality colostrum in succeeding generations.

Case Study on Increasing Breeding Value Estimation Reliability of Reproductive Traits in Serbian Highly Prolific Large White and Landrace Sows.

Simple SummaryIn the Republic of Serbia, pig selection in recent decades has been based on genetic improvement of growth and carcass quality traits. Genetic improvement of reproductive traits of pigs was based on the so-called phenotypic selection. The introduction of modern information systems and the availability larger dataset have opened the possibility to perform genetic estimation of reproductive traits within the main breeding programme of the Republic of Serbia. Using the methods of gene flow and connectedness evaluation, our study investigated the possibility of improving the reliability of estimating the breeding value of reproductive traits in highly productive sows. We believe that these methods could lead to a systematic improvement of the genetic value of reproductive traits in sows. Thus far, none of the methods for estimating the degree of connectedness between herds in pigs has been used in the preparation of the National Breeding Programme of the Republic of Serbia.This study investigated the influence of the degree of connectedness on the reliability of the estimated breeding values (EBVs). The focal trait in the study was the number of piglets born alive (NBA) from sows of the highly prolific Large White and Landrace sows. An analysis included total of 58,043 farrowing’s during the 2008–2020 period. BLUP procedure was used to estimate the breeding values for NBA for the three herds separately and after merging all three herds into one herd. The model for EBV estimation included the following fixed factors: parity, genotype, seasons, litter sire, herds, sow age at farrowing, weaning-conception interval, length of previous lactation, and the following random effects: common litter environment, permanent litter environment, and direct additive genetic effect of animal. Heritability values for NBA ranged from 0.048 to 0.097, depending on the data included in the analysis. The connectedness between herds was analysed using the connectedness rating (CR) and the gene flow (GF) methods. CR among the observed herds ranged from 0.245 to 0.994%, depending on the data included. The exchange of genetic material between all three herds was determined using GF method. The high degree of connectedness determined by the CR and GF method had a strong effect on EBV reliability. The average EBV reliability ranged from 0.520 to 0.867, depending on the data included. The increase in average reliability was observed in both cases when the data were added, both in the analysis of average reliability for purebred animals and when crossbreeds were added, where an increase in this value was also observed. The increase in average EBV reliability is a consequence of the greater amount of information included in the joint evaluation. In conclusion, we believe that our research will improve EBV reliability and help in further selection work in the Republic of Serbia.

Genetic improvement of Sahiwal cattle through associated herd progeny testing programme

The breed improvement programme of Sahiwal cattle is implemented under AICRP on Cattle through associated herd progeny testing aiming for their conservation and propagation, and improvement in milk production. The production of frozen semen doses of genetically superior young bulls are being done at germplasm (GP) unit located at NDRI, Karnal and frozen semen doses of the bulls are supplied to all Sahiwal data recording (DR) units for test mating. During the last 11 years, 35 bulls in four sets have been inducted under the programme for test mating. First set of eight Sahiwal bulls were evaluated on the basis of 123 first lactation 305-days records of their daughters born during the period between 2011 and 2013 using Best Linear Unbiased Prediction (BLUP) method. The BLUP model included the Herd-year-season effect as fixed factor and sires as random factor. The overall average estimated breeding value (EBV) was 1957.76 kg and the values of bulls ranged between –16.84 (–0.86) to +31.98 (+1.63) kg. It was also recommended to use the frozen semen doses of two top ranked Sahiwal bulls for nominated mating for producing young male calves for increasing the milk production in subsequent generations. The results also revealed that the performance of Sahiwal cattle has improved over the years due to the implementation of the project, and continuous and sincere efforts are essential to propagate this valuable germplasm.

Single-step genomic evaluation of milk production traits in Canadian Alpine and Saanen dairy goats

Genomic evaluations are routine in most plant and livestock breeding programs but are used infrequently in dairy goat breeding schemes. In this context, the purpose of this study was to investigate the use of the single-step genomic BLUP method for predicting genomic breeding values for milk production traits (milk, protein, and fat yields; protein and fat percentages) in Canadian Alpine and Saanen dairy goats. There were 6,409 and 12,236 Alpine records and 3,434 and 5,008 Saanen records for each trait in first and later lactations, respectively, and a total of 1,707 genotyped animals (833 Alpine and 874 Saanen). Two validation approaches were used, forward validation (i.e., animals born after 2013 with an average estimated breeding value accuracy from the full data set ≥0.50) and forward cross-validation (i.e., subsets of all animals included in the forward validation were used in successive replications). The forward cross-validation approach resulted in similar validation accuracies (0.55 to 0.66 versus 0.54 to 0.61) and biases (-0.01 to -0.07 versus -0.03 to 0.11) to the forward validation when averaged across traits. Additionally, both single and multiple-breed analyses were compared, and similar average accuracies and biases were observed across traits. However, there was a small gain in accuracy from the use of multiple-breed models for the Saanen breed. A small gain in validation accuracy for genomically enhanced estimated breeding values (GEBV) relative to pedigree-based estimated breeding values (EBV) was observed across traits for the Alpine breed, but not for the Saanen breed, possibly due to limitations in the validation design, heritability of the traits evaluated, and size of the training populations. Trait-specific gains in theoretical accuracy of GEBV relative to EBV for the validation animals ranged from 17 to 31% in Alpine and 35 to 55% in Saanen, using the cross-validation approach. The GEBV predicted from the full data set were 12 to 16% more accurate than EBV for genotyped animals, but no gains were observed for nongenotyped animals. The largest gains were found for does without lactation records (35-41%) and bucks without daughter records (46-54%), and consequently, the implementation of genomic selection in the Canadian dairy goat population would be expected to increase selection accuracy for young breeding candidates. Overall, this study represents the first step toward implementation of genomic selection in Canadian dairy goat populations.

Effect of Some Non-Genetic Factors on 305-day Milk Yield and Lactation Persistency in Holstein Friesian Cows

This study was performed on productive data collected from private farm of Holstein Friesian cows. The objective of this study was to evaluate the effect of days in milk (DIM), peak milk yield (PMY), dry period (DP), calving interval (CI), parity, and season of calving on 305-day milk yield (305-DMY). And the effect of 305- day milk yield (305-DMY), peak milk yield (PMY), days in milk (DIM), parity, and season of calving on lactation persistency. We found that DIM, parity, and PMY had significant effect on 305-DMY, the highest milk production was obtained when DIM more than 357 days and in the 1st lactation. Moreover, PMY, 305-DMY, and season of calving had significant effect on lactation persistency. In addition, average estimated breeding value (EBV) for 305-DMY, PMY and CI was higher in sire than in cow and dam. Also, Average estimated breeding values for lactation persistency, DP, and DIM were higher in dam than in cow and sire.

Genetic basis of thermotolerance in 2 local dairy sheep populations in the Iberian Peninsula

Sheep milk production in the Northern Mediterranean countries heavily relies on local breeds subject to selection schemes to improve milk production. Climate change may shift the range of thermal loads on the animals and challenge their adaptation to the new thermal gradient. The objective of this study was to characterize the genetic component of thermal tolerance of 2 local breeds from the Iberian Peninsula, Latxa and Manchega, belonging to different genetic types that have evolved under different climatic environments (Oceanic for Latxa and Continentalized Mediterranean for Manchega). A total of 79,243 and 2,388,853 test day monthly records of milk, fat and protein yields from 12,882 and 277,904 ewes of Latxa and Manchega breeds, respectively, along a 12-yr period, were matched with the value of the average temperature-humidity index (THI) on the day of milk recording of the closest weather station to the flocks. These data were used to fit individual reaction norms (Legendre polynomials) describing changes in yields along the THI gradient. Genetic values for thermal tolerance were obtained from the slopes of those reaction norms under cold or heat stress and variances and covariances between yield and thermal tolerance were derived from the (co)variance matrices of the polynomial random regression coefficients. Results showed differing patterns in the 2 breeds. The Latxa breed showed clearer signs of genotype by environment interaction than did Manchega. Estimated correlations between yields under extremes of cold and heat were always above 0.8 for Manchega and around 0.4 for Latxa for all traits. Estimates of correlations between comfort and thermal stress were again over 0.8 for Manchega and lower for the higher (hot end) values (down to 0.6) than for the lower (cold end) values (down to 0.84) of the THI gradient for Latxa, indicating greater thermal stress expected from high than from low temperatures in this breed. Substantial variability in thermal tolerance under the more extreme THI values was found in both breeds. Estimated genetic correlations between yield and thermal tolerance were close to 0 and 0.2 for Latxa and Manchega in the cold and down to -0.6 and -0.3 in the heat end, although small variation was observed for fat in Latxa. Estimated realized trends from the average estimated breeding value, by year of birth, showed a positive response for yields in both breeds [around 0.1 standard deviation (SD) unit], but a detrimental correlation for thermal tolerance (down to -0.03 SD units for heat tolerance in Latxa). These results can be used to design optimal selection strategies for sustainable improvement of productivity under a rising-temperature scenario associated with climate change.

Selection response and genetic parameters for growth in North African catfish, Clarias gariepinus (Burchell, 1822)

The North African catfish, Clarias gariepinus (Cga) is economically important and has been cultured worldwide. There had previously been no genetic improvement programs for this species, and thus its genetic potential had not been explored or utilized. A selection program to improve growth of Cga has now been established in Thailand and the response to one generation of selection and genetic parameters are presented in this study. The selection was performed by selecting the 17 families that had the highest average EBV (estimated breeding value) for body weight at harvest, while fish from 17 families with medium family EBV were kept as the control group. When they reached maturation, mating was done within groups following a partial factorial mating design which eventually resulted in 51 full-sib (14 paternal-, 13 maternal half-sib families) for the selected group, and 62 full-sib (16 families each of paternal- and maternal half-sibs) for the control group. The families were tagged by family at 100 DAH and communally reared in two 400 m2 earthen ponds. The dataset at 160 DAH (n = 6920) was used to estimate variance components using a multiple-traits animal model by an Average-Information Restricted Maximum Likelihood procedure. Heritability for body weight (BW), total length (TL) and standard length (SL) was low and almost equal (range of 0.128–0.129) and heritability for condition factor (K) was 0.155. Genetic correlations between growth traits ranged from 0.966 to 0.996 and between growth traits and K were 0.294–0.509. Selection response, measured as the difference between least squares mean of the selected and the control groups was 28.00 g (10.37%). Selection resulted in 3.65, 3.77, and − 0.95% correlated response for TL, SL and K, respectively. Despite of a desirable selection response, there is a concern that apparent reduction of heritability may result in low selection response in succeeding generations.

Development of optimal genetic evaluations for teat and udder structure in Canadian Angus cattle.

Despite their heritability and influence on female productivity, there are currently no genetic evaluations for teat and udder structure in Canadian Angus cattle. The objective of this study was to develop optimal genetic evaluations for these traits in the Canadian Angus population. Guidelines recommended by Beef Improvement Federation (BIF) were used to score teat and udder structure in 1,735 Canadian Angus cows from 10 representative herds. Cows scored ranged in parity from 1 to 13; however, >70% of cows were parity ≤4. Scores ranged from 1 (large, bottle shaped) to 9 (very small) for teats and from 1 (very pendulous) to 9 (very tight) for udders. Consistent with parity distribution, >70% of teat and udder scores were ≥6. Teat and udder scores (TS9 and US9, respectively) were modeled using a multiple trait animal model with random effects of contemporary group (herd-year-season) and additive genetic effect, and fixed effects of breed, parity group, and days between calving and scoring. To test good versus poor structure, a binary classification of 1 or 2 (TS2, US2) [comprised of scores 1 to 5 = 1 (poor structure) and scores 6 to 9 = 2 (good structure)] was created. Further, to assess the impact of grouping less frequently observed poor scores, a 1 to 7 scale (TS7, US7) was created by combining teat and udder scores 1 to 3. Analyses for teat and udder scores on scales TS9, US9, TS7, US7, and TS2, US2 were compared. In addition, both threshold and linear animal models were used to estimate variance components for the traits. Data treatment and models were evaluated based on correlation of resulting estimated breeding value (EBV) with corrected phenotypes, Spearman’s rank correlation coefficient, average EBV accuracies (r), and deviance information criteria (DIC). TS9, US9 scales for teat and udder scores and linear models performed best. Estimates of heritability (SE) for teat and udder score were 0.32 (0.06) and 0.15 (0.04), respectively, indicating these traits were moderately heritable and that genetic improvement for teat and udder scores was possible. Estimates of phenotypic and genotypic correlations for teat and udder score were 0.46 (0.02) and 0.71 (0.09), respectively. Estimates of genotypic correlations with birth weight (BW), weaning weight (WW), and yearling weight (YW), ranged from −0.04 (0.10) to −0.20 (0.12), verifying the importance of selecting for improved teat and udder score as individual traits, alongside performance traits.

PRODUCTIVITY AND ESTIMATED BREEDING VALUE OF THE DAIRY CATTLE GENE POOL IN THE REPUBLIC OF KAZAKHSTAN

With a linear estimation of the physique of first-calf heifers, it is established that in cows of domesticbreeds, the parameters correspond to the optimal points of the species and the indicators of the extremities, but theparameters of the udder differ sharply. All the data on productive and exteriors were entered into the program of theInformation and Analytical System (IAS), where the estimated breeding value of the studied cows was automaticallycalculated. The average estimated breeding value (EBV) for all breeds was 81.4. Among all breeds, the highest EBVlevel was determined in Holstein cows (84.3) of imported selection.The average milk yield of the studied herds per 1 cow was 5300± 30 kg of milk, with a mass fraction of fat of3.74±0.02%, the mass fraction of protein of 3.16±0.01%, with a content of 324.7±23.8 thous. of somatic cells. Themost productive were the cows of the Holstein breed, their productivity over the Alatau breed was 694 kg (P>0.99),over the black-and-motley breed it was1446 kg (P>0.999), over the Simmental breed it was 1982 kg (P>0.999), overthe red steppe - 2038 kg (P>0.999), no significant difference was found in the content of fat and protein of cow.Somatic cells were within normal limits. When studying the dynamics of milk yields according to lactation, it isestablished that the milk productivity of the Alatau breed is characterized by growth (4844... 5679... 5458 kg) by thesecond-third lactation and gradual decrease (4716... 4017 kg) by the fifth. On average, for all lactations, cows of thisbreed brought 5123±275.4 kg. The dairy productivity of Holstein cows is increased by the fifth lactation, withoutrecessions. On average, for cows of black and motley breed for all lactations, the milk yield was 4671±190 kg. Dynamics of milk yield of the Simmental breed increases from the first to the second lactation (3917... 4035 kg), in thethird it decreases (4035... 3334 kg), from the fourth to the sixth lactation the sequence increases.

A comprehensive comparison between single- and two-step GBLUP methods in a simulated beef cattle population

The statistical methods used in the genetic evaluations are a key component of the process and can be best compared by using simulated data. The latter is especially true in grazing beef cattle production systems, where the number of proven bulls with highly reliable estimated breeding values is limited to allow for a trustworthy validation of genomic predictions. Therefore, we simulated data for 4980 beef cattle aiming to compare single-step genomic best linear unbiased prediction (ssGBLUP), which simultaneously incorporates pedigree, phenotypic, and genomic data into genomic evaluations, and two-step GBLUP (tsGBLUP) procedures and genomic estimated breeding values (GEBVs) blending methods. The greatest increases in GEBV accuracies compared with the parents’ average estimated breeding values (EBVPA) were 0.364 and 0.341 for ssGBLUP and tsGBLUP, respectively. Direct genomic value and GEBV accuracies when using ssGBLUP and tsGBLUP procedures were similar, except for the GEBV accuracies using Hayes’ blending method in tsGBLUP. There was no significant or slight bias in genomic predictions from ssGBLUP or tsGBLUP (using VanRaden’s blending method), indicating that these predictions are on the same scale compared with the true breeding values. Overall, genetic evaluations including genomic information resulted in gains in accuracy &gt;100% compared with the EBVPA. In addition, there were no significant differences between the selected animals (10% males and 50% females) by using ssGBLUP or tsGBLUP.

Selection response and estimation of the genetic parameters for multidimensional measured breast meat yield related traits in a long-term breeding Pekin duck line.

ObjectiveThis study was conducted to estimate the genetic parameters and breeding values of breast meat related traits of Pekin ducks. Selection response was also determined by using ultrasound breast muscle thickness (BMT) measurements in combination with bosom breadth (BB) and keel length (KL) values.MethodsThe traits analyzed were breast meat weight (BMW), body weight (BW), breast meat percentage (BMP) and the three parameters of breast meat (BB, KL, and BMT). These measurements were derived from studying 15,781 Pekin ducks selected from 10 generations based on breast meat weight. Genetic parameters and breeding value were estimated for the analysis of the breeding process.ResultsEstimated heritability of BMW and BMP were moderate (0.23 and 0.16, respectively), and heritability of BW was high (0.48). Other traits such as BB, KL, and BMT indicated moderate heritability ranging between 0.11 and 0.28. Significant phenotypic correlations of BMW with BW and BMP were discovered (p<0.05), and genetic correlations of BMW with BW and BMP were positive and high (0.83 and 0.66, respectively). It was noted that BMW had positive correlations with all the other traits. Generational average estimated breeding values of all traits increased substantially over the course of selection, which demonstrated that the ducks responded efficiently to increased breast meat yield after 10 generations of breeding.ConclusionThe results indicated that duck BMW had the potential to be increased through genetic selection with positive effects on BW and BMP. The ultrasound BMT, in combination with the measurement of BB and KL, is shown to be essential and effective in the process of high breast meat yield duck breeding.

Economic and genetic performance of various combinations of in vitro-produced embryo transfers and artificial insemination in a dairy herd

The objective of this study was to find the optimal proportions of pregnancies from an in vitro-produced embryo transfer (IVP-ET) system and artificial insemination (AI) so that profitability is maximized over a range of prices for embryos and surplus dairy heifer calves. An existing stochastic, dynamic dairy model with genetic merits of 12 traits was adapted for scenarios where 0 to 100% of the eligible females in the herd were impregnated, in increments of 10%, using IVP-ET (ET0 to ET100, 11 scenarios). Oocytes were collected from the top donors selected for the trait lifetime net merit (NM$) and fertilized with sexed semen to produce IVP embryos. Due to their greater conception rates, first ranked were eligible heifer recipients based on lowest number of unsuccessful inseminations or embryo transfers, and then on age. Next, eligible cow recipients were ranked based on the greatest average estimated breeding values (EBV) of the traits cow conception rate and daughter pregnancy rate. Animals that were not recipients of IVP embryos received conventional semen through AI, except that the top 50% of heifers ranked for EBV of NM$ were inseminated with sexed semen for the first 2 AI. The economically optimal proportions of IVP-ET were determined using sensitivity analysis performed for 24 price sets involving 6 different selling prices of surplus dairy heifer calves at approximately 105 d of age and 4 different prices of IVP embryos. The model was run for 15 yr after the start of the IVP-ET program for each scenario. The mean ± standard error of true breeding values of NM$ of all cows in the herd in yr 15 was greater by $603 ± 2 per cow per year for ET100 when compared with ET0. The optimal proportion of IVP-ET ranged from ET100 (for surplus dairy heifer calves sold for ≥$300 along with an additional premium based on their EBV of NM$ and a ≤$100 embryo price) to as low as ET0 (surplus dairy heifer calves sold at $300 with a $200 embryo price). For the default assumptions, the profit/cow in yr 15 was greater by $337, $215, $116, and $69 compared with ET0 when embryo prices were $50, $100, $150, and $200. The optimal use of IVP-ET was 100, 100, 62, and 36% of all breedings for these embryo prices, respectively. At the input price of $165 for an IVP embryo, the difference in the net present value of yr 15 profit between ET40 (optimal scenario) and ET0 was $33 per cow. In conclusion, some use of IVP-ET was profitable for a wide range of IVP-ET prices and values of surplus dairy heifer calves.

Divergent breeding values for fatness or residual feed intake in Angus cattle. 6. Dam-line impacts on steer carcass compliance

The present study determined the impact of maternal genetics for estimated breeding values for rib fat (High-Fat, Low-Fat) or residual feed intake (RFI; High-RFI, Low-RFI) on the carcass compliance of Angus steer progeny when reared pre-weaning under High or Low-Nutrition and post-weaning under various finishing system (grazing versus short-term feedlot). The dams were joined to sires of similar genetic background (close to average estimated breeding values) and sires were rotated among all dam genotypes, with herds located at either Struan Research Centre, near Naracoorte in the south-east of South Australia, or Vasse Research Station, in the south-west of Western Australia. The breeding herd was part of the Beef CRC maternal productivity project and cows were managed under either High or Low-Nutrition, achieved by adjustments to stocking rate in rotational grazing systems and supplementary feeding, so as to maintain ~20% difference in cow liveweight. The steer progeny were weaned at ~7 months of age, with individuals from both pre-weaning nutritional treatments being treated the same from then on at each site. Steers from Struan Research Centre in South Australia born in 2008 and 2009 were sold and grown out on pasture on a local commercial property. Steer calves born in 2010 at Vasse remained on the station where they were backgrounded on hay, followed by a short period (111 days) total mixed ration containing 40% grain. In the first year, steers from Struan (n = 58) were slaughtered together at ~2 years of age, and in the second year (n = 85), consigned to six slaughter groups as their ultrasound-scanned subcutaneous P8 (rump) fat reached 7 mm and their liveweight exceeded 550 kg. Steers from Vasse (n = 101) were slaughtered at ~12 months of age, all on the same day. High-Fat-line dams produced steers with carcasses with greater P8 fat than did Low-Fat-line dams at both sites. At Struan, when the 2008-born steers were slaughtered together, more steers from Low-Fat dams failed to meet minimum fat specifications, than steers from High-Fat dams (28% vs 9% respectively). The steers born in 2009 at Struan all met processor fat specifications but steers from the Low-Fat dams took longer to reach the fat threshold, and so had greater carcass weight, but attracted more price penalties because of increased dentition. All steers from Vasse met minimum requirements for fat, with none penalised for dentition. Vasse steers from High- or Low-RFI dams performed in a manner similar to that from High- and Low-Fat dams, respectively, in that the High-RFI group produced fatter carcasses than did the Low-RFI group. Steers reared under low pre-weaning nutrition weighed less at weaning than did those on High-Nutrition, but had higher weight gains after weaning, although insufficient to result in the same carcass weight. The results showed that commercial cattle producers need to be aware of the balance and trade-off among fat breeding value, effect of pre-weaning nutrition and post-weaning growth required to ensure their cattle meet market specifications and to avoid price penalties.

Correlated response in litter size components in rabbits selected for litter size variability.

A divergent selection experiment for the environmental variability of litter size (Ve) over seven generations was carried out in rabbits at the University Miguel Hernández of Elche. The Ve was estimated as the phenotypic variance within the female, after correcting for year-season and parity-lactation status. The aim of this study was to analyse the correlated responses to selection in litter size components. The ovulation rate (OR) and number of implanted embryos (IE) in females were measured by laparoscopy at 12 day of the second gestation. At the end of the second gestation, the total number of kits born was measured (TB). Embryonic (ES), foetal (FS) and prenatal (PS) survival were computed as IE/OR, TB/IE and TB/OR, respectively. A total of 405 laparoscopies were performed. Data were analysed using Bayesian methodology. The correlated response to selection for litter size environmental variability in terms of the litter size components was estimated as either genetic trends, estimated by computing the average estimated breeding values for each generation and each line, or the phenotypic differences between lines. The OR was similar in both lines. However, after seven generations of selection, the homogenous line showed more IE (1.09 embryos for genetic means and 1.23 embryos for phenotypic means) and higher ES than the heterogeneous one (0.07 for genetic means and 0.08 for phenotypic means). The probability of the phenotypic differences between lines being higher than zero (p) was 1.00 and .99, respectively. A higher uterine overcrowding of embryos in the homogeneous line did not penalize FS; as a result, this line continued to show a greater TB (1.01 kits for genetic means and 1.30 kits for phenotypic means, p=.99, in the seventh generation). In conclusion, a decrease in litter size variability showed a favourable effect on ES and led to a higher litter size at birth.

Important genealogical bloodlines of Pinzgau cattle in Slovakia

Received: 2016-05-26 | Accepted: 2016-06-13 | Available online: 2017-03-31 http://dx.doi.org/10.15414/afz.2017.20.01.13-15 The aim of this paper was to analyze sire bloodlines within the Slovak Pinzgau cattle population. There were 13 genealogical bloodlines found together. The most widespread bloodline was Apollo. The average estimated breeding values according to sire bloodlines were predominately negative. The best milk production EBV were found in Benito line (-39.35 kg). The best growth ability according to EBV for weaning weight (210 days) was found in Karst bloodline (+3.39 kg). Significant influence of genealogical bloodline was found on EBV for weight in 365 days, protein production and weaning weight (210 days). References ANTALIK, P. and STRAPAK, P. (2010). The evaluation of milkability of Slovak Pinzgau cattle by lactocorder. Slovak J. Anim. Sci., vol. 43, no. 4, pp. 173–178. ERHARD L. and. SCHMID, D. O. (1965). Blood Group Studies on Pinzgau-Cattle. Matousek, J. (ed). Blood Groups of Animals. Proceedings of the 9th European Animal Blood Group Conference (First Conference Arranged by E.S.A.B.R.) held in Prague, August 18–22, 1964. doi:http://dx.doi.org/10.1007/978-94-017-6289-2_5 KADLECIK, O. et al. (2004) Development of dual-purpose Pinzgau cattle. Nitra: Slovak University of Agriculture in Nitra. 128 p. KASARDA, R. and KADLECIK, O. (2007) An economic impact of inbreeding in the purebred population of Pinzgau cattle in Slovakia on milk production traits. Czech Journal of Animal Science, vol. 15, no. 1, pp. 8–13. KASARDA, R. et al. (2014) Influence of mating systems and selection intensity on the extent of inbreeding and genetic gain in the Slovak Pinzgau cattle. Czech Journal of Animal Science, vol. 59, no. 5, pp. 219–226. PAVLIK, I. et al. (2014) Joint genealogical analysis as a tool for diversity evaluation in Pinzgau cattle populations. Archiv Tierzucht, vol. 57, no. 14, pp. 1–12. SAS. (2009) User´s Guide Version 9.2. SAS/STAT ® SAS Institute Inc. Cary, NC, USA. SIDLOVA, V. et al. (2014a) Microsatellite analysis of population structure in Slovak Pinzgau cattle. Acta Agraria Kaposvarienis, vol. 18, supplement 1, pp. 24–29. SIDLOVA, V. – KASARDA, R. – MORAVCIKOVA, N. (2014b). Genealogic structure of Slovak Pinzgau cattle population. MendelNet 2014: International Scientific Conference Proceedings, Brno, November 19–20, 2014. pp. 187–191.

Genomic prediction of survival time in a population of brown laying hens showing cannibalistic behavior.

BackgroundMortality due to cannibalism causes both economic and welfare problems in laying hens. To limit mortality due to cannibalism, laying hens are often beak-trimmed, which is undesirable for animal welfare reasons. Genetic selection is an alternative strategy to increase survival and is more efficient by taking heritable variation that originates from social interactions into account, which are modelled as the so-called indirect genetic effects (IGE). Despite the considerable heritable variation in survival time due to IGE, genetic improvement of survival time in laying hens is still challenging because the detected heritable variation of the trait with IGE is still limited, ranging from 0.06 to 0.26, and individuals that are still alive at the end of the recording period are censored. Furthermore, survival time records are available late in life and only on females. To cope with these challenges, we tested the hypothesis that genomic prediction increases the accuracy of estimated breeding values (EBV) compared to parental average EBV, and increases response to selection for survival time compared to a traditional breeding scheme. We tested this hypothesis in two lines of brown layers with intact beaks, which show cannibalism, and also the hypothesis that the rate of inbreeding per year is lower for genomic selection than for the traditional breeding scheme.Results and discussionThe standard deviation of genomic prediction EBV for survival time was around 22 days for both lines, indicating good prospects for selection against mortality in laying hens with intact beaks. Genomic prediction increased the accuracy of the EBV by 35 and 32 % compared to the parent average EBV for the two lines. At the current reference population size, predicted response to selection was 91 % higher when using genomic selection than with the traditional breeding scheme, as a result of a shorter generation interval in males and greater accuracy of selection in females. The predicted rate of inbreeding per generation with truncation selection was substantially lower for genomic selection than for the traditional breeding scheme for both lines.ConclusionsGenomic selection for socially affected traits is a promising tool for the improvement of survival time in laying hens with intact beaks.Electronic supplementary materialThe online version of this article (doi:10.1186/s12711-016-0247-4) contains supplementary material, which is available to authorized users.

Random Regression Models Are Suitable to Substitute the Traditional 305-Day Lactation Model in Genetic Evaluations of Holstein Cattle in Brazil.

The aim of this study was to compare two random regression models (RRM) fitted by fourth (RRM4) and fifth-order Legendre polynomials (RRM5) with a lactation model (LM) for evaluating Holstein cattle in Brazil. Two datasets with the same animals were prepared for this study. To apply test-day RRM and LMs, 262,426 test day records and 30,228 lactation records covering 305 days were prepared, respectively. The lowest values of Akaike’s information criterion, Bayesian information criterion, and estimates of the maximum of the likelihood function (−2LogL) were for RRM4. Heritability for 305-day milk yield (305MY) was 0.23 (RRM4), 0.24 (RRM5), and 0.21 (LM). Heritability, additive genetic and permanent environmental variances of test days on days in milk was from 0.16 to 0.27, from 3.76 to 6.88 and from 11.12 to 20.21, respectively. Additive genetic correlations between test days ranged from 0.20 to 0.99. Permanent environmental correlations between test days were between 0.07 and 0.99. Standard deviations of average estimated breeding values (EBVs) for 305MY from RRM4 and RRM5 were from 11% to 30% higher for bulls and around 28% higher for cows than that in LM. Rank correlations between RRM EBVs and LM EBVs were between 0.86 to 0.96 for bulls and 0.80 to 0.87 for cows. Average percentage of gain in reliability of EBVs for 305-day yield increased from 4% to 17% for bulls and from 23% to 24% for cows when reliability of EBVs from RRM models was compared to those from LM model. Random regression model fitted by fourth order Legendre polynomials is recommended for genetic evaluations of Brazilian Holstein cattle because of the higher reliability in the estimation of breeding values.