Genetic correlations among and between wool, growth and reproduction traits in Merino sheep

Accurate estimates of adjustment factors for systematic environmental effects are required for genetic evaluation systems. This study combined data from 7 research resource flocks across Australia to estimate genetic parameters and investigate the significance of various environmental factors for production traits in Australian Merino sheep. The flocks were maintained for several generations and represented contemporary Australian Merino fine, medium, and broad wool bloodlines over the past 30 years. Over 110 000 records were available for analysis for each of the major wool traits, with over 2700 sires and 25 000 dams. Univariate linear mixed animal models were used to analyse 6 wool, 4 growth, and 4 reproduction traits. This first paper outlines the data structure and the non-genetic effects of age of the animal, age of dam, birth-rearing type, sex, flock, bloodline, and year, which were significant with few exceptions for all production traits. Age of dam was not significant for reproduction traits and fleece yield. Generally, wool, growth, and reproduction traits need to be adjusted for age, birth-rearing type, and age of dam before the estimation of breeding values for pragmatic and operational reasons. Adjustment for animal age in wool traits needs to be applied for clean fleece weight (CFW), greasy fleece weight (GFW), and fibre diameter (FD) with inclusion of 2 age groups (2 years old and >2 years old), but for reproduction traits, inclusion of all age groups is more appropriate. For GFW, CFW, and hogget weight (HWT), adjustment for only 2 dam age groups of maiden and mature ewes seems sufficient, whereas for birth (BWT), weaning (WWT), and yearling (YWT) weights, adjustments need to be applied for all dam age groups. Adjustment for birth-rearing type (single-single, multiple-single, multiple-multiple) is appropriate for wool, growth, and reproduction traits. The implications of adjustment for non-genetic effects are discussed.

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Genetic and phenotypic parameters for reproduction, production and bodyweight traits in Australian fine-wool Merino sheep

Animal Production Science ◽

10.1071/an15738 ◽

2018 ◽

Vol 58 (2) ◽

pp. 207 ◽

Cited By ~ 3

Author(s):

S. Dominik ◽

A. A. Swan

Keyword(s):

Genetic Relationships ◽

Genetic Correlations ◽

Fibre Diameter ◽

Careful Consideration ◽

Production Traits ◽

Merino Sheep ◽

Wool Production ◽

Phenotypic Correlations ◽

Reproduction Traits ◽

Definition Of

The present study estimated phenotypic and genetic relationships between wool production, reproduction and bodyweight traits in Australian fine-wool Merino sheep. The data for the study originated from the CSIRO Fine Wool Project, Armidale, Australia. Data on wool characteristics, measured at ~10 and 22 months of age, bodyweight and several reproduction traits across consecutive lambing opportunities were analysed. The genetic correlations were moderately negative between fibre diameter measured as yearling and adult, and lamb survival (rg = –0.34 ± 0.15 and rg = –0.28 ± 0.14 respectively) and total number of lambs weaned (rg = –0.32 ± 0.21 and rg = –0.40 ± 0.21 respectively). The genetic correlations of yearling and adult greasy and clean fleece weights with number of lambs weaned and fecundity showed moderately to highly negative relationships and a moderately negative correlation with the number of fetuses at pregnancy scanning. Phenotypic correlations between reproduction and wool production traits were estimated to be zero, with the exception of bodyweight showing low to moderate positive phenotypic correlations with total number of lambs born and weaned. Genetic variances were generally low for the reproduction traits and resulted in low heritability estimates (from h2 = 0.03 ± 0.01 to h2 = 0.12 ± 0.13), with the exception of total number of lambs born (h2 = 0.25 ± 0.03). The study indicated that parameter estimation and trait definition of lifetime reproduction records require careful consideration and more work in this area is required.

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Genetic importance of fat and eye muscle depth in Merino breeding programs

Animal Production Science ◽

10.1071/an14645 ◽

2016 ◽

Vol 56 (4) ◽

pp. 690 ◽

Cited By ~ 15

Author(s):

D. J. Brown ◽

A. A. Swan

Keyword(s):

Carcass Traits ◽

Genetic Correlations ◽

Fibre Diameter ◽

Economic Index ◽

Parasite Resistance ◽

Eye Muscle ◽

Breeding Programs ◽

Dual Purpose ◽

Internal Parasite ◽

Reproduction Traits

Australian Merino breeders have traditionally selected animals for breeding predominately on the basis of wool characteristics. Over recent decades, an increasing proportion of Merino breeders are interested in producing a ewe that can be used for prime-lamb production, but that also performs well for wool characteristics. Correlations between ultrasound carcass traits and other traits such as wool, internal parasite resistance and reproduction traits, are not very well known. The aims of this study were three-fold: (1) to estimate the genetic relationships between ultrasound carcass traits and wool, internal parasite resistance and reproduction traits, (2) to determine the value of recording ultrasound carcass traits in Merino breeding programs, and (3) to evaluate the impact of improving ewe genetic merit for fatness on their reproduction performance. Ultrasound fat and eye muscle depth had small to moderate genetic correlations with most traits, with positive correlations observed for bodyweight, fibre diameter, fibre curvature and reproduction, and negative correlations observed for fleece weight, fibre diameter coefficient of variation, worm egg count and breech wrinkle. As expected on the basis of these genetic correlations, estimated breeding values for fat depth of ewes had a positive association with their observed reproduction performance, but the effect explained only minimal variation in reproductive performance, and was extremely variable among flocks and years. A range of measurement scenarios was investigated for three standard MERINOSELECT indexes. Measuring fat and eye muscle depth resulted in 3%, 4% and 21% additional economic index gain for the fine, medium and dual purpose indexes, respectively, whereas measuring reproduction traits directly resulted in 17%, 27% and 45% additional gain in the economic index. Dual purpose index gains benefited more from measuring ultrasound carcass traits as it is the only index with a direct economic value placed on carcass traits. Measuring fat and eye muscle depth also resulted in a greater reduction in worm egg count. The results indicated that desirable genetic progress can be made in wool, ultrasound carcass, internal parasite resistance and number of lambs born and weaned simultaneously using multiple trait selection to account for the mix of favourable and unfavourable correlations between these traits. These results also demonstrated that the best method to maximise economic gain is to measure as many traits (or closely correlated traits) in the breeding objective as possible.

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Ectopic expression of FGF5s induces wool growth in Chinese merino sheep

Gene ◽

10.1016/j.gene.2017.06.037 ◽

2017 ◽

Vol 627 ◽

pp. 477-483 ◽

Cited By ~ 5

Author(s):

Wen-Rong Li ◽

San-Gang He ◽

Chen-Xi Liu ◽

Xue-Mei Zhang ◽

Li-Qin Wang ◽

...

Keyword(s):

Ectopic Expression ◽

Merino Sheep ◽

Wool Growth

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Effects of Growth Hormone Administration on Wool Growth in Merino Sheep

Australian Journal of Biological Sciences ◽

10.1071/bi9880177 ◽

1988 ◽

Vol 41 (2) ◽

pp. 177 ◽

Cited By ~ 12

Author(s):

PC Wynn ◽

ALC Wallace ◽

AC Kirby ◽

EF Annison

Keyword(s):

Amino Acids ◽

Growth Hormone ◽

Energy Intake ◽

Nitrogen Balance ◽

Daily Administration ◽

Maintenance Energy ◽

Merino Sheep ◽

Growth Hormone Administration ◽

Hormone Administration ◽

Wool Growth

The effects of daily administration of 10 mg of highly purified ovine growth hormone (GH) for a period of 4 weeks on wool growth have been measured in 12 Merino ewes fed either a calculated maintenance energy intake or 1�6 times this amount (six on each ration). Concentrations of hormones, glucose, urea, a-amino N and amino acids in the blood were monitored and faeces and urine collected for measurement of nitrogen balance.

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Genetic parameters of production and reproduetive traits in on a farm tested Danish Large White and Landrace swine in Greece

Archives Animal Breeding ◽

10.5194/aab-43-287-2000 ◽

2000 ◽

Vol 43 (3) ◽

pp. 287-298

Author(s):

J. Bizelis ◽

A. Kominakis ◽

E. Rogdakis ◽

F. Georgadopoulou

Keyword(s):

Maximum Likelihood ◽

Genetic Correlation ◽

Genetic Parameters ◽

Genetic Correlations ◽

Production Traits ◽

Likelihood Methods ◽

Large White ◽

Reproduction Traits ◽

Maximum Likelihood Methods ◽

Genetic And Phenotypic Correlations

Abstract. Production and reproduetive traits in Danish Landrace (LD) and Large White (LW) swine were analysed by restricted maximum likelihood methods to obtain heritabilities as well as genetic and phenotypic correlations. Production traits were: age, backfat thickness (BT), muscle depth (MD) and the ratio BT/MD, adjusted to Standard bodyweight of 85 kg. Reproduction traits were: number of pigs born (NB) and number of pigs weaned (NW) per sow and parity. Heritabilities for age, BT, MD and BT/MD were 0.60, 0.44, 0.51 and 0.42 for LD and 0.36, 0.44, 0.37 and 0.45 for LW, respectively. Genetic correlations between age and BT were −0.22 in LD and – 0.44 in LW. The genetic correlation between age and MD was close to zero in both breeds. Genetic correlation between BT and MD were −0.36 and −0.25 in LD and LW, respectively. Heritabilities for NB were 0.25 in LD and 0.13 in LW while heritabilities for NW were close to zero in both breeds. Genetic correlation between NB and NW was 0.46 and 0.70 in LD and LW, respectively.

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Growth and reproduction traits of white improved pigs housed in three types of pen technology

Biotechnology in Animal Husbandry ◽

10.2298/bah0502109m ◽

2005 ◽

Vol 21 (5-6-2) ◽

pp. 109-113

Author(s):

Marcel Matta ◽

Pavel Flak ◽

Ivan Paska ◽

Maros Vano

Keyword(s):

Reproduction Traits ◽

Growth And Reproduction

nema

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Fusarium head blight of small grains in Pennsylvania: unravelling species diversity, toxin types, growth and triazole sensitivity

Phytopathology ◽

10.1094/phyto-02-21-0070-r ◽

2021 ◽

Author(s):

Maira R. Duffeck ◽

Ananda Y. Bandara ◽

Dilooshi K. Weerasooriya ◽

Alyssa Collins ◽

Philip J. Jensen ◽

...

Keyword(s):

Fusarium Head Blight ◽

Management Practices ◽

Crop Residues ◽

Head Blight ◽

The North ◽

Reproduction Traits ◽

Small Grains ◽

Ascospore Production ◽

Growth And Reproduction

Fusarium graminearum is the main causal species of Fusarium head blight (FHB) globally. Recent changes in the trichothecene (toxin) types in the North American FHB pathogens support the need for continued surveillance. In this study, 461 isolates were obtained from symptomatic spikes of wheat, spelt, barley, and rye crops during 2018 and 2019. These were all identified to species and toxin types using molecular-based approaches. An additional set of 77 F. graminearum isolates obtained from overwintering crop residues during Winter 2012 were molecularly identified to toxin types. A subset of 31 F. graminearum isolates (15 15ADON and 16 3ADON) were assessed for mycelial growth, macroconidia, perithecia, and ascospore production, and sensitivity to two triazole fungicides. Ninety percent of isolates obtained from symptomatic spikes (n = 418) belonged to F. graminearum, with another four species found at a lower frequency (n = 39). F. graminearum isolates from symptomatic spikes were mainly of the 15ADON (95%), followed by 3ADON (4%), NIV (0.7%), and NX-2 (0.3%) toxin types. All F. graminearum isolates obtained from overwintering residue were of the 15ADON type. Toxin types could not be differentiated based on multivariate analysis of growth and reproduction traits. All isolates were sensitive to tebuconazole and metconazole fungicides in vitro. This study confirms the dominance of F. graminearum and suggests ecological and environmental factors that lead to similar composition of toxin types in Northern U.S. Our results are useful to assess the sustainability of FHB management practices and provide a baseline for future FHB surveys.

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Genetic and phenotypic trends and parameters in reproduction, greasy fleece weight and liveweight in Merino lines divergently selected for multiple rearing ability

Australian Journal of Experimental Agriculture ◽

10.1071/ea02225 ◽

2004 ◽

Vol 44 (8) ◽

pp. 745 ◽

Cited By ~ 36

Author(s):

S. W. P. Cloete ◽

A. R. Gilmour ◽

J. J. Olivier ◽

J. B. van Wyk

Keyword(s):

Genetic Correlations ◽

Annual Production ◽

Production Traits ◽

Genetic Progress ◽

Additive Variance ◽

Genetic Changes ◽

Environmental Correlations ◽

Breeding Values ◽

Reproduction Traits ◽

Fleece Weight

Genetic and phenotypic trends and parameters were estimated for reproduction, fleece weight and liveweight in a South African Merino population, divergently selected from 1986, either for (H line) or against (L line) maternal multiple rearing ability. Annual reproduction, ewe greasy fleece weight and pre-joining liveweight data were recorded on 809 Merino ewes, from 1986 to 2002. Phenotypic trends indicated divergence in reproduction traits between the H and L lines. The direct additive variance ratio (h2 ± s.e.) for day of lambing was 0.08 ± 0.02. Estimates of h2 for reproduction traits were: 0.10 ± 0.02 for number of lambs born per ewe; 0.04 ± 0.02 for number of lambs weaned per ewe; and 0.04 ± 0.02 for weight of lamb weaned per ewe, corrected for the gender of the lamb. Corresponding h2 estimates for annual production were 0.57 ± 0.06 for greasy fleece weight and 0.48 ± 0.06 for ewe liveweight at joining. Service sire only exerted a significant (P<0.05) effect on day of lambing, but it accounted for merely 2% of the overall phenotypic variation. Ewe permanent environment variance ratios (c2ewe) for the reproduction traits were: 0.07 ± 0.03 for number of lambs born per ewe; 0.11 ± 0.03 for number of lambs weaned per ewe; and 0.11 ± 0.03 for total weight of lamb weaned per ewe. Corresponding c2ewe estimates for annual production traits were 0.14 ± 0.05 for greasy fleece weight and 0.27 ± 0.06 for ewe joining weight. Genetic and ewe permanent environmental correlations between measures of reproduction exceeded 0.7. Genetic correlations of reproduction traits with greasy fleece weight were low and variable in sign. Genetic correlations of reproduction traits with ewe joining weight were positive and particularly high for weight of lamb weaned. Permanent environmental correlations of reproduction traits with greasy fleece weight and joining weight were generally low to moderate. Genetic trends for the H and L lines (derived from averaged direct breeding values within birth years) were divergent (P<0.01) for all reproduction traits. Expressed as percentage of the overall least squares means of the respective traits, breeding values in the H line increased annually, with 1.3% for lambs born per ewe, 1.5% for lambs weaned per ewe and by 1.8% for weight of lamb weaned per ewe. Corresponding trends in the L line were, respectively, –0.6%, –1.0% and –1.2% per year. Substantial genetic progress in annual lamb output was attainable, despite relatively small h2 estimates. This response was achieved without unfavourable genetic changes in wool and liveweight.

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RELATIONSHIPS OF REPRODUCTION TRAITS, BODY WEIGHT AND MILK YIELD IN DAIRY CATTLE

Canadian Journal of Animal Science ◽

10.4141/cjas86-007 ◽

1986 ◽

Vol 66 (1) ◽

pp. 53-65 ◽

Cited By ~ 11

Author(s):

T. R. BATRA ◽

A. J. LEE ◽

A. J. McALLISTER

Keyword(s):

Body Weight ◽

Dairy Cattle ◽

Milk Yield ◽

Fixed Effects ◽

Genetic Correlations ◽

Calving Interval ◽

Phenotypic Correlations ◽

Reproduction Traits ◽

Heritability Estimates ◽

National Cooperative

The relationships between reproduction traits, body weight and milk yield were investigated using data from 1611 heifers and 733 cows from two lines of the National Cooperative Dairy Cattle Breeding Project. The data were analyzed separately for heifers and cows within lines using a mixed linear model containing fixed effects for station, year of birth, season of birth and random effect of sires. Heritability estimates and genetic correlations were estimated by a paternal half-sib analysis. Heritability estimates for heifer and cow reproduction traits ranged between 0 and 26% while those of body weights at calving and 112 d postpartum and milk yield ranged from 24 to 43%. Heifers with difficult calving had a higher incidence of retained placenta than those with normal calving. Phenotypic correlations between heifer reproduction traits and milk yield during first lactation were small. High milk production in cows was associated with longer calving interval. Phenotypic correlations between heifer's and cow's reproduction traits were small. Difficult calving in heifers impairs reproductive performance after calving resulting in greater number of days from calving to first and last breeding and leading to a longer calving interval. Key words: Reproduction traits, heifers, cows, milk yield, dairy cattle

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