Selection response in fecal worm egg counts in the Rylington Merino parasite resistant flock

2006 ◽  
Vol 46 (7) ◽  
pp. 809 ◽  
Author(s):  
L. J. E. Karlsson ◽  
J. C. Greeff
Keyword(s):  
Genetic Gain ◽  
Genetic Correlations ◽  
Time Frame ◽  
Selection Response ◽  
Breeding Value ◽  
Selection Line ◽  
Production Traits ◽  
Parasite Resistance ◽  
Component Trait ◽  
Parasite Challenge

The Rylington Merino internal parasite resistant selection line was initiated in 1987 from a wide genetic base of 100 ewe flocks. Selection for parasite resistance was based on selecting animals with a low worm egg count in a natural parasite challenge environment. The realised annual genetic gain for estimated breeding value of worm egg count is 2.7%. The genetic gain in parasite resistance has been achieved without any adverse genetic correlations with the other economically important production traits. There is an unfavourable genetic correlation between worm egg count and scouring traits. The recommendation to industry is to select for both low worm egg count and reduced diarrhoea and combine these traits with other economically important production traits. The relative weighting applied to each component trait will vary according to the local parasite challenge situation and the time frame available to achieve sustainable parasite control.

scholarly journals Corrigendum to: Consequences of genetic selection for environmental impact traits on economically important traits in dairy cows

2018 ◽  
Vol 58 (10) ◽  
pp. 1966
Author(s):  
Purna Kandel ◽  
Sylvie Vanderick ◽  
Marie-Laure Vanrobays ◽  
Hélène Soyeurt ◽  
Nicolas Gengler
Keyword(s):  
Dairy Cows ◽  
Body Condition Score ◽  
Genetic Correlations ◽  
Genetic Selection ◽  
Selection Response ◽  
Direct Selection ◽  
Correlated Response ◽  
Production Traits ◽  
Ch4 Emissions ◽  
Natural Logarithm

Methane (CH4) emission is an important environmental trait in dairy cows. Breeding aiming to mitigate CH4 emissions require the estimation of genetic correlations with other economically important traits and the prediction of their selection response. In this study, test-day CH4 emissions were predicted from milk mid-infrared spectra of Holstein cows. Predicted CH4 emissions (PME) and log-transformed CH4 intensity (LMI) computed as the natural logarithm of PME divided by milk yield (MY). Genetic correlations of PME and LMI with traits used currently were approximated from correlations between estimated breeding values of sires. Values were for PME with MY 0.06, fat yield (FY) 0.09, protein yield (PY) 0.13, fertility 0.17; body condition score (BCS) –0.02; udder health (UDH) 0.22; and longevity 0.22. As expected by its definition, values were negative for LMI with production traits (MY –0.61; FY –0.15 and PY –0.40) and positive with fertility (0.36); BCS (0.20); UDH (0.08) and longevity (0.06). The genetic correlations of 33 type traits with PME ranged from –0.12 to 0.25 and for LMI ranged from –0.22 to 0.18. Without selecting PME and LMI (status quo) the relative genetic change through correlated responses of other traits were in PME by 2% and in LMI by –15%, but only due to the correlated response to MY. Results showed for PME that direct selection of this environmental trait would reduce milk carbon foot print but would also affect negatively fertility. Therefore, more profound changes in current indexes will be required than simply adding environmental traits as these traits also affect the expected progress of other traits.

Genetic analysis of docility score of Australian Angus and Limousin cattle

2018 ◽  
Vol 58 (2) ◽  
pp. 213 ◽  
Author(s):  
S. F. Walkom ◽  
M. G. Jeyaruban ◽  
B. Tier ◽  
D. J. Johnston
Keyword(s):  
Adverse Effect ◽  
Animal Model ◽  
Genetic Analysis ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Production Costs ◽  
Breeding Value ◽  
Maternal Behaviour ◽  
Production Traits ◽  
Subjective Score

The temperament of cattle is believed to affect the profitability of the herd through impacting production costs, meat quality, reproduction, maternal behaviour and the welfare of the animals and their handlers. As part of the national beef cattle genetic evaluation in Australia by BREEDPLAN, 50 935 Angus and 50 930 Limousin calves were scored by seedstock producers for temperament using docility score. Docility score is a subjective score of the animal’s response to being restrained and isolated within a crush, at weaning, and is scored on a scale from 1 to 5 with 1 representing the quiet and 5 the extremely nervous or anxious calves. Genetic parameters for docility score were estimated using a threshold animal model with four thresholds (five categories) from a Bayesian analysis carried out using Gibbs sampling in THRGIBBS1F90 with post-Gibbs analysis in POSTGIBBSF90. The heritability of docility score on the observed scale was 0.21 and 0.39 in Angus and Limousin, respectively. Since the release of the docility breeding value to the Australian Limousin population there has been a favourable trend within the national herd towards more docile cattle. Weak but favourable genetic correlations between docility score and the production traits indicates that docility score is largely independent of these traits and that selection to improve temperament can occur without having an adverse effect on growth, fat, muscle and reproduction.

scholarly journals The effectiveness of genomic selection for milk production traits of Holstein dairy cattle

2020 ◽  
Vol 33 (3) ◽  
pp. 382-389 ◽  
Author(s):  
Yun-Mi Lee ◽  
Chang-Gwon Dang ◽  
Mohammad Z. Alam ◽  
You-Sam Kim ◽  
Kwang-Hyeon Cho ◽  
...  
Keyword(s):  
Genomic Selection ◽  
Milk Production ◽  
Genetic Gain ◽  
Milk Fat ◽  
Breeding Value ◽  
Production Traits ◽  
Milk Production Traits ◽  
Data Set ◽  
Selection For ◽  
Estimated Breeding Value

Objective: This study was conducted to test the efficiency of genomic selection for milk production traits in a Korean Holstein cattle population.Methods: A total of 506,481 milk production records from 293,855 animals (2,090 heads with single nucleotide polymorphism information) were used to estimate breeding value by single step best linear unbiased prediction.Results: The heritability estimates for milk, fat, and protein yields in the first parity were 0.28, 0.26, and 0.23, respectively. As the parity increased, the heritability decreased for all milk production traits. The estimated generation intervals of sire for the production of bulls (L<sub>SB</sub>) and that for the production of cows (L<sub>SC</sub>) were 7.9 and 8.1 years, respectively, and the estimated generation intervals of dams for the production of bulls (L<sub>DB</sub>) and cows (L<sub>DC</sub>) were 4.9 and 4.2 years, respectively. In the overall data set, the reliability of genomic estimated breeding value (GEBV) increased by 9% on average over that of estimated breeding value (EBV), and increased by 7% in cows with test records, about 4% in bulls with progeny records, and 13% in heifers without test records. The difference in the reliability between GEBV and EBV was especially significant for the data from young bulls, i.e. 17% on average for milk (39% vs 22%), fat (39% vs 22%), and protein (37% vs 22%) yields, respectively. When selected for the milk yield using GEBV, the genetic gain increased about 7.1% over the gain with the EBV in the cows with test records, and by 2.9% in bulls with progeny records, while the genetic gain increased by about 24.2% in heifers without test records and by 35% in young bulls without progeny records.Conclusion: More genetic gains can be expected through the use of GEBV than EBV, and genomic selection was more effective in the selection of young bulls and heifers without test records.

scholarly journals Consequences of genetic selection for environmental impact traits on economically important traits in dairy cows

2018 ◽  
Vol 58 (10) ◽  
pp. 1779
Author(s):  
Purna Kandel ◽  
Sylvie Vanderick ◽  
Marie-Laure Vanrobays ◽  
Hélène Soyeurt ◽  
Nicolas Gengler
Keyword(s):  
Dairy Cows ◽  
Body Condition Score ◽  
Genetic Correlations ◽  
Genetic Selection ◽  
Selection Response ◽  
Direct Selection ◽  
Correlated Response ◽  
Production Traits ◽  
Ch4 Emissions ◽  
Natural Logarithm

Methane (CH4) emission is an important environmental trait in dairy cows. Breeding aiming to mitigate CH4 emissions require the estimation of genetic correlations with other economically important traits and the prediction of their selection response. In this study, test-day CH4 emissions were predicted from milk mid-infrared spectra of Holstein cows. Predicted CH4 emissions (PME) and log-transformed CH4 intensity (LMI) computed as the natural logarithm of PME divided by milk yield (MY). Genetic correlations of PME and LMI with traits used currently were approximated from correlations between estimated breeding values of sires. Values were for PME with MY 0.06, fat yield (FY) 0.09, protein yield (PY) 0.13, fertility 0.17; body condition score (BCS) –0.02; udder health (UDH) 0.22; and longevity 0.22. As expected by its definition, values were negative for LMI with production traits (MY –0.61; FY –0.15 and PY –0.40) and positive with fertility (0.36); BCS (0.20); UDH (0.08) and longevity (0.06). The genetic correlations of 33 type traits with PME ranged from –0.12 to 0.25 and for LMI ranged from –0.22 to 0.18. Without selecting PME and LMI (status quo) the relative genetic change through correlated responses of other traits were in PME by 2% and in LMI by –15%, but only due to the correlated response to MY. Results showed for PME that direct selection of this environmental trait would reduce milk carbon foot print but would also affect negatively fertility. Therefore, more profound changes in current indexes will be required than simply adding environmental traits as these traits also affect the expected progress of other traits.

Genetic relationships between internal parasite resistance and production traits in Merino sheep

2017 ◽  
Vol 57 (2) ◽  
pp. 209 ◽  
Author(s):  
D. J. Brown ◽  
N. M. Fogarty
Keyword(s):  
Genetic Parameters ◽  
Genetic Correlations ◽  
Production Traits ◽  
Parasite Resistance ◽  
Breeding Programs ◽  
Sheep Breeding ◽  
Breeding Values ◽  
Merino Sheep ◽  
Internal Parasite ◽  
Australian Sheep

Breeding Merino sheep that are resistant to internal parasites alleviates the high costs associated with treatment of worm infestation and loss of production, as well as mitigating the development of anthelmintic resistance among the major worm species. Faecal worm egg count ((cube root transformation), wec) can be used in sheep as a measure of internal parasite resistance. Accurate estimates of genetic parameters for wec are required for calculation of Australian Sheep Breeding Values and inclusion of worm resistance in sheep breeding programs. This study provides updated estimates of heritability for wec and its genetic correlations with production traits. Data were analysed from a wide range of Australian and New Zealand Merino sheep in the MERINOSELECT database, which included 141 flocks with 801 flock years and up to 217 137 animals with wec recorded in at least one of four ages (W = weaning, P = post weaning, Y = yearling, H = hogget). The heritability estimates ranged from 0.16 ± 0.01 for Ywec to 0.29 ± 0.01 for Wwec, with generally high genetic correlations between the ages. Bivariate analyses estimated genetic correlations between wec at the various ages and growth, carcass quality, reproduction and wool production traits at various ages. These genetic correlations were generally small or close to zero, albeit with some significantly different from zero. The moderate heritability for wec (0.2–0.3) and its high phenotypic variation (coefficient of variation >30%) shows that relatively rapid selection response for worm resistance could be achieved. Inclusion of wec in sheep breeding programs to increase worm resistance would be expected to have little if any impact on other important production traits. These genetic parameters have been incorporated into MERINOSELECT by Sheep Genetics to provide Australian Sheep Breeding Values for wec and appropriate indices for wool and meat production. There is evidence that genotype × environment interactions may be important in some environments by reducing the accuracy of Australian Sheep Breeding Values for wec. Hence it may be prudent for breeders to implement strategies that manage the risk of any impact of genotype × environment on their breeding program.

scholarly journals Genetic parameters for egg production traits in crosses between local and exotic chickens estimated by Bayesian inference

2021 ◽  
Vol 44 (3) ◽  
pp. 1-8
Author(s):  
I. Udeh ◽  
S. I. Omeje
Keyword(s):  
Egg Production ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Breeding Value ◽  
Appreciable Amount ◽  
Production Traits ◽  
Base Population ◽  
Egg Weight ◽  
Highest Posterior Density ◽  
Selection Of

Estimates of genetic parameters for economic traits are important to enable the breeder estimate the breeding value of individuals available for selection. Thus, this study was carried out to estimate genetic parameters namely heritability and genetic correlations among egg production traits in two strain crosses using bivariate animal model in Bayesian (MCMC) method. The egg production data were obtained from four generations which comprised the base population of two commercial egg strains and the local chicken, the inbred population derived from the base population, the F1 crossbred population obtained from the crossing of the local and exotic inbred chickens and the backcross population obtained from the backcrossing of the crossbred to their parents. A total number of 1,138 daughters of 62 sires and 620 dams were used for the study. The autocorrelations among samples in the MCMC chain were less than 0.1 for all lag values indicating that all samples of the posterior distribution were independent. The estimated heritability for age at first egg, body weight at first egg, hen day egg number, weight of first egg, egg weight at thirty week and egg weight at forty week were 0.62, 0.48, 0.47, 0.53, 0.54 and 0.56 for strain 1 crosses and 0.43, 0.48, 0.49, 0.52, 0.52 and 0.53 for strain 2 crosses. The corresponding highest posterior density interval ranged from 0.22 to 0.91 for strain 1 crosses and 0.07 to 0.83 for strain 2 crosses. The genetic correlations among egg production traits ranged from 0.06 to 1.97 in strain 1 and 0.06 to 2.59 in strain 2 crosses. The estimates were within the range reported in literature for egg production traits in chicken and imply that appreciable amount of additive genes exist in the strain crosses which could be used for the selection of superior birds. The magnitude of genetic correlations implies that selection of one trait could lead to correlated response to the other traits.

scholarly journals Analysis of (co) variance components and estimation of breeding value of growth and production traits in Dahlem Red chicken using pedigree relationship in an animal model

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247779
Author(s):  
U. Rajkumar ◽  
L. Leslie Leo Prince ◽  
K. S. Rajaravindra ◽  
S. Haunshi ◽  
M. Niranjan ◽  
...  
Keyword(s):  
Animal Model ◽  
Maternal Effects ◽  
Variance Components ◽  
Egg Production ◽  
Genetic Correlations ◽  
The Body ◽  
Breeding Value ◽  
Egg Mass ◽  
Residual Variance ◽  
Production Traits

Variance and covariance components of growth and production traits were analyzed employing REML animal model to assess the Dahlem Red (PD-3) chicken population for direct additive genetic, maternal effects and to estimate the estimated breeding value (EBV), genetic parameters, genetic trends and rate of inbreeding (ΔF) utilizing seven generation’s data. The generation and hatch had significant (P≤0.01) effect on the body weight at 0 day (BW0), 2 (BW2), 4 (BW4) and 6 weeks (BW6) and shank length at six weeks of age (SL6). The average least squares means (LSM) for BW6 and SL6 were 273.93±0.62 g and 53.97±0.05 mm, respectively. All the production traits were significantly (P≤0.01) influenced by generation and hatch. The average LSM for age at sexual maturity (ASM), egg production up to 40 weeks (EP40) and egg mass up to 40 weeks (EM40) were 168.82±0.25 d, 72.60±0.41 eggs and 4.21±0.07 kg, respectively. Model 5 with additive direct, maternal genetic, maternal permanent environmental and residual variance components was the best for BW0, BW2 and BW4 based on the AIC values obtained in WOMBAT. Model 4 was the best model for BW6, SL6, ASM, EP40 and EM40 with additive direct, maternal permanent environmental and residual variance components. Maternal effects were higher during early age, decreased with age, and remained present until 20 weeks of age. The heritability (h2) estimates were low to moderate in magnitude for all the growth traits and ranged from 0.02±0.03 to 0.19±0.03. The maternal heritability was high at hatch (0.35±0.06), decreased gradually until 4th week (0.02±0.01) and ceased afterwards. The heritabilities of EP40 (0.11±0.03) and EM40 (0.12±0.04) were low. The direct additive genetic correlations (ra) between BW2, BW4, BW6 and SL6 were high and positive (P≤ 0.05). The additive genetic and maternal permanent environmental correlation between EP40 and EM40 were high and positive (P≤ 0.05). The EBV of EM40 was significant (P≤ 0.05) with 0.48 kg/generation in PD-3 chicken at the end of the seventh generation. The EBV of EP40 showed an increasing trend with a genetic gain of 1.87 eggs per generation. The average inbreeding coefficient of the population was 0.019 and average ΔF was 0.007 over the last seven generations of selection. The EBV trends for primary and associated traits showed linear trends in the desired direction and negligible inbreeding.

Genetic relationships between live animal scan traits and carcass traits of Australian Angus bulls and heifers

2013 ◽  
Vol 53 (10) ◽  
pp. 1075
Author(s):  
Vinzent Börner ◽  
David J. Johnston ◽  
Hans-Ulrich Graser
Keyword(s):  
Genetic Gain ◽  
Genetic Parameters ◽  
Genetic Relationships ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Age Effect ◽  
Breeding Value ◽  
Muscle Area ◽  
Live Animal ◽  
Eye Muscle

Genetic parameters of four ultrasound live-scan traits and five carcass traits of Australian Angus cattle were examined with regard to sex and age of the scanned individuals. Live-scans were subdivided according to whether the observation was obtained from a bull or a heifer. In addition, two age subset (‘young’ and ‘old’) within sex were formed by k-means clustering around two centres within sex according to the age at scanning. REML estimates for heritabilities, genetic, residual and phenotypic correlations for each trait and trait combination were derived from a series of uni-, bi- and tri-variate analysis. Statistically significant age effects could be found for heritablities of scan intra-muscular fat content in heifers and scan fat depth at P8 site and scan rib fat depth in bulls, and for genetic correlations between the scan traits fat depth at P8 site, rib fat depth and eye muscle area. However, differences in heritablities between age sets within sex did not exceed 0.05, and genetic correlations between scan traits of ‘young’ and ‘old’ animals were at least 0.9. Differences between genetic correlations of abattoir carcass traits and ‘young’ and ‘old’ live-scan traits, respectively, were not significant due to high standard errors but up to 0.44. The larger of these differences were found for combinations of scan-traits and non-target carcass traits and not for combination of scan-traits and their actual carcass target traits. Thus, although some results suggest an age effect on the genetic parameters of scan traits, the extent of this effect is of limited impact on breeding value accuracy and genetic gain of scan traits. Furthermore, a possible age effect on correlations to economically important carcass traits need to be underpinned by more carcass traits observations in order to get unambiguous results allowing to draw consequences of scanning younger individuals for accuracy of breeding values and genetic gain in carcass traits.

Selection of dairy sheep in Greece for parasitic nematode resistance: defining the aggregate genotype and evaluating selection schemes

1999 ◽  
Vol 69 (3) ◽  
pp. 535-542 ◽  
Author(s):  
A. Kominakis ◽  
G. Theodoropoulos
Keyword(s):  
Genetic Gain ◽  
Milk Fat ◽  
Genetic Correlations ◽  
Selection Procedure ◽  
Nematode Resistance ◽  
Repeated Measurements ◽  
Production Traits ◽  
Dairy Sheep ◽  
Wide Range ◽  
Selection Of

AbstractThe effects on genetic and economic responses of adding faecal egg count (FEC) in the aggregate genotype of dairy sheep in Greece were investigated. The extra responses obtained in the full aggregate genotype were expressed as a percentage change of the responses in terms of genetic gain, profit and selection response of single traits before adding the trait. The initial aggregate genotype included the traits milk fat yield (FY) and number of lambs weaned per ewe per year (NLW). Inclusion of FEC in the aggregate genotype resulted always in increased genetic gain and profit. The extra responses from adding the FEC in the index selection were variable and often very large, depending on the parameters varied i.e. the economic weight of FEC and the genetic correlation of FEC with the other production traits. For a wide range in the size of the genetic correlations between FEC and other traits, gains of FEC and no appreciable losses of responses for FY and NLW were predicted when FEC accounted proportionately for 0·10 to 0·20 of the total monetary genetic deviation. While FEC showed a wide range of change, selection responses of FY and NLW remained remarkably insensitive under various weightings of FEC and different genetic correlations of FEC with the production traits. The genetic and economic efficiency of alternative selection schemes were also evaluated. A two-stage selection procedure involving preliminary selection of rams on dam’s FEC, FY, NLW and on their own FEC and final culling on progeny’s FEC, FY and NLW was predicted to be the most efficient in both genetic and economic terms. Female replacements should be selected on dam’s FEC, FY and NLW (first stage) and their own FEC, FY and NLW (second stage). When repeated measurements of FEC are taken, the recommended number of FEC measurements was found to be 4.

scholarly journals Investigations on breeding plans for organic dairy cattle

2004 ◽  
Vol 47 (2) ◽  
pp. 129-139 ◽  
Author(s):  
B. Harder ◽  
W. Junge ◽  
J. Bennewitz ◽  
E. Kalm
Keyword(s):  
Natural Selection ◽  
Population Size ◽  
Artificial Insemination ◽  
Genetic Gain ◽  
Selection Response ◽  
Breeding Program ◽  
Production Traits ◽  
Cattle Breeding ◽  
Economic Weights ◽  
The Impact

Abstract. facilities in Germany, different alternative breeding plans for organic cattle breeding were developed using the computer program ZPLAN. First the impact of the population size on the parameters of success was analysed. A conventional cattle breeding program was compared with an organic breeding program. The results indicate that the selection response increased with increasing population size due to improved selection of bull sires. The EU Regulations on organic farming say that the proportion of artificial insemination has to be reduced as much as possible. According to this, the influence of different proportions of artificial insemination on the monetary genetic gain was investigated. The reduction of artificial insemination below 50% led to high losses in the discounted profit. The influence of higher economic weights for functional traits on the natural selection response was investigated. An increase of the economic weights by 50% led to tolerable decreases in the natural selection response of production traits with regard to a more ecological orientated breeding goal. The effect of the variation of the test capacity and the number of test bulls on the monetary genetic gain was analysed. The optimum for the monetary genetic gain was located at a test capacity of 50%, 30 test bulls and 99 daughters per test bull.

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