Genetic parameters for faecal worm egg count at different ages in Australian sheep under natural challenge

2019 ◽  
Vol 59 (7) ◽  
pp. 1201 ◽  
Author(s):  
L. Li ◽  
D. J. Brown ◽  
A. A. Swan ◽  
J. H. J. van der Werf
Keyword(s):  
Genetic Correlations ◽  
Random Regression ◽  
Research Centre ◽  
Steady Increase ◽  
Cooperative Research ◽  
Multiple Trait ◽  
Full Data ◽  
Different Ages ◽  
Australian Sheep ◽  
Univariate Analyses

The data used in the present study consisted of 24535 worm egg count records on sheep observed from 63 to 560 days of age under conditions of the natural challenge of trichostrongylid species. Records were extracted from the Information Nucleus Flock database of the Australia Sheep Cooperative Research Centre program from 2007 to 2011. Records were observed at various ages and subdivided into weaning (W, ~3 months), post-weaning (P, ~4 months), yearling (Y, ~12 months) and hogget (H, ~18 months) age stages and were used to investigate genetic variation at different age stages in univariate analyses and estimate genetic correlations between age stages in multi-trait analyses. The full data were also analysed by random regression models to study how heritability and genetic correlations varied with age. Heritability estimates from univariate analyses were 0.20 ± 0.05, 0.15 ± 0.02, 0.36 ± 0.09, 0.22 ± 0.06 for W, P, Y and H age stages respectively. A similar trend of heritability over ages was found from random regression analyses, which decreased from 0.16 at 90 days to 0.09 at 120 days, following a steady increase to 0.32 at ~410 days, and then decreased afterwards to 0.24 at 520 days. Strong genetic correlations (>0.8) were found between W and P age stages, along with Y and H age stages. Sire by flock interaction effects were significant, and accounted for the reduced estimates of heritability and increased genetic correlations between age stages. The results indicated that a multiple-trait approach is required for genetic evaluation of worm egg count when measurements are at different ages, and the accuracy of evaluations would benefit from recording at least two separate age stages.

Genetic parameters for lamb autopsy traits

2014 ◽  
Vol 54 (6) ◽  
pp. 736 ◽  
Author(s):  
D. J. Brown ◽  
R. M. Jones ◽  
G. N. Hinch
Keyword(s):  
Genetic Correlations ◽  
Selection Criterion ◽  
Research Centre ◽  
Cooperative Research ◽  
Crown Rump Length ◽  
Australian Sheep ◽  
Lamb Survival ◽  
Fleece Weight ◽  
Indicator Traits ◽  
Overall Mortality

Heritabilities and genetic correlations were estimated between individual and composite autopsy traits for lambs autopsied in the Australian Sheep Cooperative Research Centre information nucleus flocks between 2008 and 2011 (n = 3224). Correlations were also estimated between autopsy categories and the production parameters Yearling greasy-fleece weight and Yearling weight, and the potential survival indicator traits: Lamb ease, Thorax circumference and Crown–rump length. All autopsy trait heritability estimates were low (range 0.01–0.04). For all traits, a higher proportion of the variance was partitioned into the maternal permanent environment than the direct effects (range 0.01–0.12), suggesting that selection based on lamb autopsy results would impart little advantage over the lamb survival trait itself in improving lamb survival. Genetic correlations between Lamb ease and all autopsy traits were positive, indicating that birth trauma is related to all causes of lamb deaths and that Lamb ease may be a useful selection criterion in seedstock flocks to reduce overall mortality. There were also positive genetic correlations between Thorax circumference after adjusting for birthweight and two classes of dystocia, as well as a positive correlation between Thorax circumference and incidences of Starvation mismothering, implying that Thorax circumference may be a useful indirect field measurement to reduce death from these causes. Of concern were the antagonistic genetic correlations estimated between Yearling greasy-fleece weight and a composite trait of All Dystocia classes plus Starvation mismothering (0.27 ± 0.15), implying that selection for increased fleece weight could be having a detrimental effect on overall lamb survival.

A review of genetic and non-genetic opportunities for manipulation of marbling

2004 ◽  
Vol 44 (7) ◽  
pp. 687 ◽  
Author(s):  
B. M. Bindon
Keyword(s):  
Vitamin A Deficiency ◽  
Genetic Correlations ◽  
Consumer Preference ◽  
High Energy ◽  
Water Soluble ◽  
Research Centre ◽  
Chemical Extraction ◽  
Eating Quality ◽  
Gene Marker ◽  
Cooperative Research

The biology of marbling is a considerable issue for the Australian beef industry. Measurement of the trait is still a concern: subjective assessment based on the degree of visual fat deposition and its distribution is the 'industry standard' and the basis for payment of marbling grades. Yet this measurement may be subject to operator error and is influenced by chiller temperature. Chemical extraction gives an unequivocal measure of all fat in the muscle (intramuscular fat percentage: IMF%) and has higher heritability and genetic variation than marble score; but does this mirror exactly what the trade regards as 'marbling'?Progeny test results from the Cooperative Research Centre (CRC) for Cattle and Beef Quality breeding projects provide improved understanding of breed and genetic effects on IMF% and marble score. Estimated breeding values (EBVs) for IMF% have been released to the industry for 7 breeds. Heritability estimates confirm that genetic progress will be faster when selection is based on IMF% rather than marble score. Genetic correlations of IMF% with growth, retail beef yield (RBY%), P8 fat, residual feed intake (RFI) and tenderness are now available to underpin selection indices. A favourable allele for marbling (TG5) on chromosome 14 has been identified by CSIRO/MLA as a direct gene marker for the trait. This is now being marketed as GeneSTAR marbling. Other favourable chromosomal regions are under investigation by the CRC.Nutritional manipulation of marbling remains problematic. It is accepted that high-energy grain diets achieve higher marbling than pasture diets. Within grain-based feedlot diets higher marbling is achieved with maize than barley, while barley diets in turn are better than sorghum. Steam flaking produces higher marbling than dry rolled grain and this effect is more marked with sorghum than maize. Beyond these establishments there are many uncertainties: experiments have examined the effects of diets with high protein; low protein; protected lipid; protected protein; added oil with and without calcium; vitamin A deficiency. None of these manipulations gave consistent improvement in marble score or IMF%. Commercial feedlots supplying Japanese B3/B4 markets may have successful dietary manipulations to enhance marbling but because of its proprietary nature the information is not normally available for scientific scrutiny.Japan is the only market for Australian beef where marbling is an important component of the market specification. There can be no doubt that marbling meets a special consumer preference in that niche market. In other markets scientific evidence for a link between marbling and beef tenderness or eating quality has been difficult to define (marbling is a key component of the USA grading scheme for primal cuts but Australia is not a big supplier to that market). In the domestic Meat Standards Australia market there is a trend for marbling to become more important as a consumer issue in 5-star products where higher order sensory attributes of beef come into play. Early meat science investigations concluded that beef flavour elements were water-soluble. This would exclude marbling fat as having a notable influence on flavour.Marbling remains the major determinant of carcass value in Australia's most valuable beef market. Research should continue to assist Australian producers to meet the specifications of that market with increased precision and reduced costs.

Preliminary estimates of genetic parameters for carcass and meat quality traits in Australian sheep

2010 ◽  
Vol 50 (12) ◽  
pp. 1135 ◽  
Author(s):  
S. I. Mortimer ◽  
J. H. J. van der Werf ◽  
R. H. Jacob ◽  
D. W. Pethick ◽  
K. L. Pearce ◽  
...  
Keyword(s):  
Meat Quality ◽  
Nutritional Value ◽  
Genetic Correlations ◽  
Research Centre ◽  
Quality Traits ◽  
Live Animal ◽  
Sheep Industry ◽  
Meat Quality Traits ◽  
Australian Sheep ◽  
Meat Colour

Using performance from progeny born in 2007 and 2008 generated by the Information Nucleus program of the Cooperative Research Centre for Sheep Industry Innovation, preliminary estimates of heritability were obtained for a range of novel carcass and meat attributes of lamb relevant to consumers, including carcass characteristics, meat quality and nutritional value of lamb. Phenotypic and genetic correlations of live animal traits with carcass composition and meat quality traits were also estimated. The data were from progeny located at eight sites, sired by 183 rams from Merino, maternal and terminal meat breeds and were representative of the Merino, Border Leicester × Merino, Terminal × Merino and Terminal × Border Leicester-Merino production types of the Australian sheep industry. Data were available from 7176 lambs for weaning weight, 6771 lambs for ultrasound scanning and 4110 lambs for slaughter traits. For the novel meat quality traits, generally moderate to high heritability estimates were obtained for meat quality measures of shear force (0.27 aged 1 day, 0.38 aged 5 days), intramuscular fat (0.39), retail meat colour (range of 0.09 to 0.44) and myoglobin content (0.22). The nutritional value traits of omega-3 fatty acids and iron and zinc contents tended to have low to moderate heritabilities (0.11–0.37), although these were based on fewer records. Fresh meat colour traits were of low to moderate heritability (0.06–0.21) whereas measures of meat pH were of low heritability (~0.10). For the carcass traits, estimates of heritability were moderate to high for the various measures of carcass fat (0.18–0.50), muscle weight (0.22–0.35), meat yield (0.24–0.35), carcass muscle dimensions (0.25–0.34) and bone weight (0.27). Results indicate that for most lamb carcass and meat quality traits there is sufficient genetic variation for selection to alter successfully these characteristics. Additionally, most genetic correlations of live animal assessments of bodyweight, muscle and subcutaneous fat with the carcass and meat quality traits were favourable. Appropriate definition of breeding objectives and design of selection indexes should be able to account for the small unfavourable relationships that exist and achieve the desired outcomes from breeding programs.

scholarly journals Unraveling the genetic variability of host resilience to endo and ectoparasites under natural infestation, in Nellore cattle

2021 ◽  
Author(s):  
Gabriela Canabrava Gouveia ◽  
Virgínia Mara Pereira Ribeiro ◽  
Marina Rufino Salinas Fortes ◽  
Fernanda Santos Silva Raidan ◽  
Antonio Reverter-Gomez ◽  
...  
Keyword(s):  
Association Studies ◽  
Genetic Correlations ◽  
Parasite Burden ◽  
Random Regression ◽  
Economic Losses ◽  
Control Analysis ◽  
Genome Wide Association Studies ◽  
Multiple Trait ◽  
Eimeria Spp ◽  
Natural Infestation

Abstract Background: Host resilience (HR) to parasites can affect growth in pastured raised cattle. This study is a detailed investigation of the genetic mechanisms of HR to ticks (TICK), gastrointestinal nematodes (GIN), and Eimeria spp. (EIM) under natural infestation. HR was defined as the slope coefficient of random regression models of body weight (BW) when TICK, GIN, and EIM burdens were used as environmental gradients. The BW was evaluated in five measurement events (ME): when animals were 331, 385, 443, 498, and 555 days old on average. 7307 BW records were available from 1712 animals weighted at least in one ME. Out of those, 1075 animals had valid genotypic information after quality control analysis that were used in genome-wide association studies (GWAS) and GWAS meta-analyses to identify genomic regions associated with HR. Results: Both the genetic correlations between intercept and HR to each parasite, and the genetic correlations between BW measured in animals submitted to different parasite burden indicated that there was genotype x parasite burden interaction for BW, and selection for BW under environment with controlled parasite burden might be an efficient strategy to improve both, BW and HR. Furthermore, there was no impact of age of measurement on genetic variance estimates for HR to different parasites. However, genetic correlation between HR to the same parasite measured in different ages ranged from low to moderate in magnitude, with a posteriori means (high posterior density interval with 90% of samples) varying from 0.13 (-0.05; 0.35) to 0.40 (0.15; 0.63) for TICK, from 0.11 (-0.06; 0.29) to 0.52 (0.37; 0.67) for GIN and from 0.25 (0.07; 0.43) to 0.56 (0.34; 0.77) for EIM. These results indicate the importance of age of measurement in studies on HR. Conclusions: HR to GIN and EIM can be used as a complementary tool to parasitic control management, and a multiple trait selection method that combine BW and HR to parasites should be used in parasitic endemic areas to avoid economic losses due parasitic diseases.

Designing complex research projects to estimate genetic parameters plus treatment and other effects - optimising the experimental design

2008 ◽  
Vol 48 (8) ◽  
pp. 1110 ◽  
Author(s):  
D. L. Robinson
Keyword(s):  
Experimental Design ◽  
Genetic Parameters ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Research Centre ◽  
Parameter Estimates ◽  
Cooperative Research ◽  
Number Of Factors ◽  
Integrated Research ◽  
One Year

There is an increasing trend towards integrated research, in which several individuals or institutions pool their expertise and make use of common resources, collaborating towards a common set of scientific goals. Integrated research enables a larger number of factors to be investigated, and the most influential or important ones identified, providing information on how the different factors interact or fit together. Good experimental design is, however, required to ensure the aims can be achieved and resources spent wisely. Issues involved in the experimental design of the Australian Beef Cattle Cooperative Research Centre for Meat Quality are discussed. Theoretical results and simulation studies were used to determine optimal numbers of progeny per sire for estimating genetic parameters. For heritabilities of 0.2 and 0.5, the optima are respectively 21 and 9 progeny with recorded measurements. The curves surrounding the optima are quite flat, so aiming for 10–15 progeny with measurements per trait should provide reasonable accuracy in many situations. Estimates of heritabilities, genetic correlations and phenotypic variances have lower sampling correlations than genetic variances and covariances, suggesting that when results are pooled over different breeds or trials, it is better to pool estimates of heritabilities and genetic correlations than (co)variances. Using sires in more than one year increases the robustness of estimated sire effects and increases the accuracy of genetic parameter estimates for hard-to-measure traits (e.g. feed efficiency) that are not recorded on all animals. Unless sires can be chosen as a true random sample of the population, arrangements of link sires (and other effects such as treatments) should be chosen to provide accurate estimates when all terms in the model are fitted as fixed.

scholarly journals Using Random Regression Models to Genetically Evaluate Functional Longevity Traits in North American Angus Cattle

Animals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2410
Author(s):  
Hinayah R. Oliveira ◽  
Luiz F. Brito ◽  
Stephen P. Miller ◽  
Flavio S. Schenkel
Keyword(s):  
North American ◽  
Regression Models ◽  
Genetic Correlations ◽  
Genetic Selection ◽  
Random Regression ◽  
Pedigree Information ◽  
Residual Variance ◽  
Multiple Trait ◽  
Structural Problems ◽  
Angus Cattle

This study aimed to propose novel longevity indicators by comparing genetic parameters for traditional (TL; i.e., the cow’s lifespan after the first calving) and functional (FL; i.e., how long the cow stayed in the herd while also calving; assuming no missing (FLa) or missing (FLb) records for unknown calving) longevity, considering different culling reasons (natural death, structural problems, disease, fertility, performance, and miscellaneous). Longevity definitions were evaluated from 2 to 15 years of age, using single- and multiple-trait Bayesian random regression models (RRM). The RRM fitting heterogenous residual variance and fourth order Legendre polynomials were considered as the optimal models for the majority of longevity indicators. The average heritability estimates over ages for FLb (from 0.08 to 0.25) were always higher than those for FLa (from 0.07 to 0.19), and higher or equal to the ones estimated for TL (from 0.07 to 0.23), considering the different culling reasons. The average genetic correlations estimated between ages were low to moderate (~0.40), for all longevity definitions and culling reasons. However, removing the extreme ages (i.e., 2 and >12 years) increased the average correlation between ages (from ~0.40 to >0.70). The genetic correlations estimated between culling reasons were low (0.12 and 0.20 on average, considering all ages and ages between 3 and 12 years old, respectively), indicating that longevity based on different culling reasons should be considered as different traits in the genetic evaluations. Higher average genetic correlations (estimated from 3 to 12 years old) were observed between TL and FLb (0.73) in comparison to TL and FLa (0.64), or FLa and FLb (0.65). Consequently, a higher average proportion of commonly-selected sires, for the top 1% sires, was also observed between TL and FLb (91.74%), compared to TL and FLa (59.68%), or FLa and FLb (61.01%). Higher prediction accuracies for the expected daughter performances (calculated based on the pedigree information) were obtained for FLb in comparison to TL and FLa. Our findings indicate that FLb is preferred for the genetic evaluation of longevity. In addition, it is recommended including multiple longevity traits based on different groups of culling reasons in a selection sub-index, as they are genetically-different traits. Genetic selection based on breeding values at the age of four years is expected to result in greater selection responses for increased longevity in North American Angus cattle.

Design and role of an information nucleus in sheep breeding programs

2010 ◽  
Vol 50 (12) ◽  
pp. 998 ◽  
Author(s):  
J. H. J. van der Werf ◽  
B. P. Kinghorn ◽  
R. G. Banks
Keyword(s):  
Large Scale ◽  
Research Centre ◽  
Cooperative Research ◽  
Breeding Programs ◽  
Sheep Breeding ◽  
Genome Association ◽  
Current Design ◽  
Australian Sheep ◽  
Whole Genome Association ◽  
Design Factors

The Australian sheep Cooperative Research Centre has initiated an information nucleus with the aim to estimate genetic parameters for new traits, to undertake a large-scale whole-genome association study and to enhance the breeding values of breeding animals in commercial studs. This paper presents the rationale behind the current design factors to meet the main objectives. It then discusses the potential design of an information nucleus if it were a sustainable part of commercial sheep-breeding programs in the long term. Advantages of such an information nucleus are summarised and quantified where possible.

scholarly journals Estimation of genetic parameters for daily milk yields of primiparous Iranian Holstein cows

2013 ◽  
Vol 56 (1) ◽  
pp. 455-466
Author(s):  
K. Kheirabadi ◽  
S. Alijani ◽  
L. Zavadilová ◽  
S. A. Rafat ◽  
G. Moghaddam
Keyword(s):  
Milk Fat ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
National Level ◽  
Genetic Correlations ◽  
Protein Yield ◽  
Random Regression ◽  
Production Traits ◽  
Multiple Traits ◽  
Multiple Trait

Abstract. Applying a multiple trait random regression (MT-RR) in national level and for whole test day records of a country is a great advance in animal breeding context. Having reliable (co) variance components is a critical step in applying multiple traits genetic evaluation especially in developing countries. Genetic parameters of milk, fat and protein yields were estimated for Iranian Holstein dairy cows. Data included 276 692 test day (TD) production traits records collected of 30 705 primiparous cows belonging to 619 sires. An animal multi-trait random regression model was employed in the analyses using the restricted maximum likelihood (REML) method. The model included herd-test-date, age-season of calving (by applying a fixed regression for each subclass of this effect) and year of calving as fixed effects and random regression (RR) coefficients for additive genetic (AG) and permanent environmental (PE) effects. Obtained results showed that daily heritabilities ranged from 0.10 to 0.21 for milk, from 0.05 to 0.08 for fat and from 0.08 to 0.18 for protein yield. Estimated heritability for 305-d milk, fat and protein yields were 0.25, 0.20 and 0.25, respectively. Correlations between individual test day records within traits were high for adjacent tests (nearly 1) and decreased as the interval between tests increased. Correlations between yields of milk, fat and protein on a given test day are also high and greater during late lactation than during early or mid-lactation. Genetic correlations between 305-d yield traits ranged from 0.75 to 0.92. The largest genetic correlation, as well as permanent environmental correlation, was observed between milk and protein yield.

A strategy for achieving innovation through Sheep Cooperative Research Centre research and development

2010 ◽  
Vol 50 (12) ◽  
pp. 1145 ◽  
Author(s):  
Graham Truscott ◽  
Philip Thomas
Keyword(s):  
Product Development ◽  
New Product Development ◽  
Product Development Process ◽  
Research Centre ◽  
Cooperative Research ◽  
Sheep Industry ◽  
Development Framework ◽  
Sheep Meat ◽  
Adoption Research ◽  
Australian Sheep

The Sheep Cooperative Research Centre’s role to facilitate the transformation of the Australian sheep industry is complicated by the extensive nature of the industry across some 31 000 small to medium farming enterprises, linking to both sheep meat and wool supply chains. Close integration of the market with research and adoption through a product development focus is enabling a staged product development process while providing the management flexibility needed for development of each product type within target markets. This paper presents the basis of the New Product Development Framework and the adoption strategies used across the Sheep Cooperative Research Centre programs to accelerate utilisation of products developed out of research. These strategies include: communication; training coordination; network engagement and use of key influencers; supply chain engagement and the use of specific adoption research tools.

scholarly journals Unraveling the genetic variability of host resilience to endo and ectoparasites under natural infestation, in Nellore cattle

2021 ◽  
Author(s):  
Gabriela Canabrava Gouveia ◽  
Virgínia Mara Pereira Ribeiro ◽  
Marina Rufino Salinas Fortes ◽  
Fernanda Santos Silva Raidan ◽  
Antonio Reverter ◽  
...  
Keyword(s):  
Association Studies ◽  
Genetic Correlations ◽  
Parasite Burden ◽  
Random Regression ◽  
Economic Losses ◽  
Control Analysis ◽  
Genome Wide Association Studies ◽  
Multiple Trait ◽  
Eimeria Spp ◽  
Natural Infestation

Abstract Background: Host resilience (HR) to parasites can affect growth in pastured raised cattle. This study is a detailed investigation of the genetic mechanisms of HR to ticks (TICK), gastrointestinal nematodes (GIN), and Eimeria spp. (EIM) under natural infestation. HR was defined as the slope coefficient of random regression models of body weight (BW) when TICK, GIN, and EIM burdens were used as environmental gradients. The BW was evaluated in five measurement events (ME): when animals were 331, 385, 443, 498, and 555 days old on average. 7307 BW records were available from 1712 animals weighted at least in one ME. Out of those, 1075 animals had valid genotypic information after quality control analysis that were used in genome-wide association studies (GWAS) and GWAS meta-analyses to identify genomic regions associated with HR. Results: Both the genetic correlations between intercept and HR to each parasite, and the genetic correlations between BW measured in animals submitted to different parasite burden indicated that there was genotype x parasite burden interaction for BW, and selection for BW under environment with controlled parasite burden might be an efficient strategy to improve both, BW and HR. Furthermore, there was no impact of age of measurement on genetic variance estimates for HR to different parasites. However, genetic correlation between HR to the same parasite measured in different ages ranged from low to moderate in magnitude, with a posteriori means (high posterior density interval with 90% of samples) varying from 0.13 (-0.05; 0.35) to 0.40 (0.15; 0.63) for TICK, from 0.11 (-0.06; 0.29) to 0.52 (0.37; 0.67) for GIN and from 0.25 (0.07; 0.43) to 0.56 (0.34; 0.77) for EIM. Conclusions: These results indicate the importance of age of measurement in studies on HR. HR to GIN and EIM can be used as a complementary tool to parasitic control management, and a multiple trait selection method that combine BW and HR to parasites should be used in parasitic endemic areas to avoid economic losses due parasitic diseases.

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