scholarly journals The inheritance of fibre traits in a crossbred population of cashmere goats

1996 ◽  
Vol 63 (3) ◽  
pp. 429-436 ◽  
Author(s):  
S. C. Bishop ◽  
A. J. F. Russel
Keyword(s):  
Standard Deviation ◽  
Genetic Parameters ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Live Weight ◽  
Correlated Responses ◽  
Genetic Origin ◽  
Functional Relationships ◽  
Cashmere Goats ◽  
Fibre Traits

AbstractGenetic parameters were calculated for fibre traits measured on patch samples taken at 5 months of age on a crossbred population of cashmere goats, comprising goats of Scottish feral, Icelandic, Tasmanian, New Zealand and Siberian origin. Within-strain heritabilities, fitting genetic origin as a covariable, were: live weight, 0·71 (s.e. 0·08), fibre diameter, 0·63 (0·07), diameter standard deviation 0·43 (0·08), logipatch cashmere weight), 0·60 (0·06), log(estimated annual cashmere production), 0·51 (0·07), and fibre length, 0·49 (0·15). Including between strain information increased these values to 0·74, 0·68, 0·45, 0·73, 0·67 and 0·57, respectively. Maternal effects for all fibre traits were negligible. Expressions were derived to relate cashmere weight to fibre diameter and length, using functional relationships between these traits. Logarithmic regressions showed cashmere weight to be proportional to diameter2'7, indicating that selection to reducefibre diameter will have a disproportionate effect on cashmere weight. Analyses of subsets of the data confirmed this and showed that correlated responses to selection can be accurately predicted by considering thefunctionally relatedfibre traits on the log scale.

Production and quality of cashmere grown by adult wether goats fed low quality forage with supplements of either whole barley or lupin grain.

2000 ◽  
Vol 40 (6) ◽  
pp. 795 ◽  
Author(s):  
B. A. McGregor ◽  
M. Z. Umar
Keyword(s):  
Fibre Diameter ◽  
Fibre Length ◽  
Late Summer ◽  
Experimental Period ◽  
Barley Grain ◽  
Practical Application ◽  
Whole Grain ◽  
Summer Pasture ◽  
Cashmere Goats

The effects of the provision of cereal (barley) and legume (lupin) grain supplements when 50 adult wether cashmere goats were individually penned and fed on senescent temperate summer pasture (DDM 46.9%, N 0.67%, ME 6.2 MJ/kg DM) were investigated using a factorial experiment. The goats grazed senescent temperate pasture during summer before pen feeding for 9 weeks and were then grazed on germinating autumn pastures for 3 months until shorn in mid June. The production and quality of cashmere was affected by: (i) provision of whole grain supplements, (ii) type of supplementary grain fed, and (iii) level of feeding of supplementary grain. Unsupplemented goats grew 95 g cashmere with mean fibre diameter 17.01 m and mean cashmere fibre length 52 mm. During the period of pen feeding unsupplemented goats lost 95 g liveweight/day. Provision of whole grain supplements significantly increased total yearly cashmere growth to 179 g (+88%) which was 26 mm longer (50%) and 2.12 m coarser (26%) than cashmere grown by unsupplemented goats. Increasing the level of supplementary grain resulted in linear increases in feed intake, cashmere growth, fibre diameter and length. For each 100 g/day of lupin or barley grain fed during the pen-feeding period the regression coefficients indicated an extra 33 g of cashmere was grown, which was 0.6 m coarser and for barley 10 mm longer and for lupins 17 mm longer. Cashmere (fibre length/fibre diameter2) ratio was increased by supplementary feeding, increased feed level and liveweight gain during the experimental period. Relatively longer cashmere was produced as the level of nutrition increased. It is clear that a base diet of senescent temperate pasture that is low in digestible nutrients and low in nitrogen results in suppressed cashmere growth. Strategic grain supplementation for at least 9 weeks during late summer and autumn has the potential to significantly increase cashmere production and cashmere fibre length when adult cashmere goats are grazing pastures deficient in digestible energy and nitrogen. However feeding high levels of lupin and barley grain to adult goats is contra indicated as cashmere mean fibre diameter may exceed market limits. The practical application of the results is discussed in light of previous research.

The effects of breed, crossbreeding and other factors on variation in fleece and skin traits

1980 ◽  
Vol 30 (3) ◽  
pp. 417-429 ◽  
Author(s):  
J. A. Woolliams ◽  
G. Wiener
Keyword(s):  
Unit Area ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Live Weight ◽  
Strong Relationship ◽  
Average Fibre Diameter ◽  
Wide Range ◽  
Average Fibre ◽  
Fleece Weight ◽  
The Relationship

ABSTRACTBreed and crossbreeding significantly affected variation in 10 fleece, follicle density and fibre diameter traits in 12-week-old lambs. The breeds involved were the Scottish Blackface, South Country Cheviot, Welsh Mountain, Lincoln Longwool, Southdown and Tasmanian Merino, but the last only by rams.The Southdown came closest to the Merino in affecting density and diameter traits although the Merino crosses remained clearly distinguishable by their high follicle density. The Lincoln and Blackface crosses were notable for their long fibres and the Blackface crosses also had the least dense follicle and coarsest primary fibres. The coarsest secondary fibres were from Lincoln and Cheviot crosses. Heterosis estimates were obtained for crosses involving the Blackface, Cheviot, Welsh and Lincoln breeds. Significant heterosis was present in a wide range of traits but was not apparent in all crosses. Maternal differences were evident for many of the traits but with density these differences were apparently related to maternal effects on live weight of the lamb. The sex of the lamb, its birth type and rearing and its 12-week live weight significantly affected many of the traits.Among breeds and crosses a strong relationship was found between fibre density and average fibre diameter. The relationship suggested that breed variation in total fibre area per unit area of skin was small compared with the breed variation in its components. Fleece weight per unit area was most closely related to mean fibre length.

scholarly journals Genetic parameters for wool traits in Finnsheep lambs

2008 ◽  
Vol 16 (2) ◽  
pp. 124 ◽  
Author(s):  
M-L. PUNTILA ◽  
K. MÄKI ◽  
A. NYLANDER
Keyword(s):  
Genetic Correlation ◽  
Variance Components ◽  
Genetic Parameters ◽  
Fibre Diameter ◽  
Live Weight ◽  
Bivariate Analysis ◽  
Component Estimation ◽  
Selection For ◽  
Fleece Weight ◽  
Staple Length

Genetic parameters were estimated for wool characteristics of white and coloured Finnsheep. The data consisted of 5 309 lambs from ordinary production flocks, the Finnsheep nucleus flock and a breeding flock. The variance component estimation was done applying REML analyses. Wool traits included fleece uniformity, density, staple formation, lustre, crimp frequency, fineness grade and staple length. There was a smaller dataset that contained also lamb live weight, greasy fleece weight and additional fleece characteristics including fibre diameter measured with the OFDA method. The variance components for direct and maternal effects were estimated using bivariate analysis for 42-day, 120-day weight and greasy fleece weight. Heritability for visually assessed wool characteristics varied from 0.23 to 0.43 and for measured traits from 0.45 to 0.62. Staple length had a high negative genetic correlation with crimp frequency and fineness grade. Heritability of greasy fleece weight was high (0.55) and that of fibre diameter 0.62. The genetic correlation between crimp frequency and fibre diameter was negative (- 0.56). The results imply that the assessed traits are useful indicators for fleece quality and those of major importance can be introduced into the breeding programme. The results suggest that there is no antagonism in selection for both growth capacity and wool quantity.;

Heritabilities and genetic correlations for live weight and fibre traits in New Zealand Cashmere goats

1993 ◽  
Vol 33 (1-2) ◽  
pp. 91-104 ◽  
Author(s):  
M.L. Bigham ◽  
C.A. Morris ◽  
B.R. Southey ◽  
R.L. Baker
Keyword(s):  
New Zealand ◽  
Genetic Correlations ◽  
Live Weight ◽  
Cashmere Goats ◽  
Fibre Traits

Measurement of cashmere yield and mean fibre diameter using the optical fibre diameter analyser

1996 ◽  
Vol 36 (4) ◽  
pp. 429 ◽  
Author(s):  
AD Peterson ◽  
SG Gherardi
Keyword(s):  
Standard Deviation ◽  
Optical Fibre ◽  
Low Cost ◽  
Fibre Diameter ◽  
Diameter Distribution ◽  
Poor Agreement ◽  
Standard Samples ◽  
Cashmere Goats ◽  
A New Technique ◽  
Good Agreement

A new technique was developed to measure the yield and mean fibre diameter of cashmere. The fibre diameter distribution of 2-mm snippets measured by the Optical Fibre Diameter Analyser (OFDA) was used to calculate cashmere yield of a goat fleece without dehairing. The total volume of fibres <35 and >35 �m was then calculated from the diameter distribution, and from this it was possible to predict the cashmere yield of 6 standards ranging from 10 to 60% yield (r2 = 0.98, n = 30). In addition, the Shirley Analyser was compared with the OFDA technique for measuring cashmere yield (r2 = 0.59, n = 110). OFDA estimates of cashmere yield were on average 10% higher (standard deviation � 7%) than those of the Shirley Analyser, indicating poor agreement between the 2 techniques. This is likely to be due to the Shirley Analyser and OFDA estimates of cashmere yield being affected by different fibre properties of the fleeces. There was good agreement between the Fibre Diameter Analyser (FDA) and the OFDA for measuring mean fibre diameter (MFD) of dehaired cashmere samples (r2 = 0.97, n = 108). There was also a good agreement in estimates of cashmere MFD between whole fleece and dehaired cashmere samples measured by the OFDA (r2 = 0.97, n = 77). Calculation of cashmere yield and down MFD by the OFDA has shown it to be accurate for measuring standard samples, and as precise as the Shirley Analyser. Therefore, the use of the OFDA is a potential low cost alternative to rank the value of cashmere goats for breeding.

The effect of breed type and inbreeding on characteristics of the fleece and skin of 12-week-old lambs

1981 ◽  
Vol 32 (1) ◽  
pp. 9-22 ◽  
Author(s):  
J. A. Woolliams ◽  
G. Wiener
Keyword(s):  
Density Ratio ◽  
Fibre Diameter ◽  
Fibre Length ◽  
Live Weight ◽  
Primary Follicle ◽  
Secondary Follicle ◽  
Clear Cut ◽  
Breed Type ◽  
Mean And Variance ◽  
Secondary Fibre

ABSTRACTSheep of three pure breeds, the Scottish Blackface, South Country Cheviot and Welsh Mountain, and the crosses among these breeds, were inbred mostly by younger-parent offspring matings for three generations. Observations on lambs at 12 weeks of age were weight of fleece per unit area of skin, mean and variance of fibre length, both primary and secondary follicle density, and fibre diameter. The observations were analysed for the effects of inbreeding of the lamb and its dam, breed type, parity, and the sex and birth type of the lamb. Variation in the traits was also analysed for their relationship to lamb's live weight.Secondary follicle density and the density ratio (Ns/Np) decreased with inbreeding of the lamb. Primary follicle density increased whilst secondary fibre diameter and mean fibre length decreased with inbreeding of the dam. The effects of inbreeding on the density ratio and on secondary fibre diameter were correlated with inbreeding effects on the lamb's 12-week live weight. For other traits inbreeding did not have a clear-cut effect. Heterosis observed in F2 lambs was in general greater than that previously recorded for F1. For mean fibre length and mean fibre diameter the comparison of the crossbred deviations from mid-parent of the F2 and inbred lambs suggested epistatic interactions were involved. The effect of inbreeding crossbreds and inbreeding purebreds was different for secondary follicle density and primary fibre diameter, the two traits most clearly exhibiting heterosis in the F2. Lambs from first parity ewes had finer primary fibres and lighter fleece samples than had lambs from later parities.

Selection for rate and efficiency of lean gain in Hereford cattle 1. Selection pressure applied and direct responses

1990 ◽  
Vol 51 (1) ◽  
pp. 23-34 ◽  
Author(s):  
R. A. Mrode ◽  
C. Smith ◽  
R. Thompson
Keyword(s):  
Genetic Parameters ◽  
Control Line ◽  
Correlated Responses ◽  
Direct Response ◽  
Lean Growth ◽  
Hereford Cattle ◽  
Frozen Semen ◽  
Phenotypic Standard Deviation ◽  
Selection For ◽  
Selection Of

ABSTRACTSelection of bulls for rate and efficiency of lean gain was studied in a herd of Hereford cattle. There were two selection lines, one selected for lean growth rate (LGR) from birth to 400 days and the other for lean food conversion ratio (LFCR) from 200 to 400 days of age, for a period of 8 years. A control line bred by frozen semen from foundation bulls was also maintained. Generation interval was about 2·4 years and average male selection differentials, per generation were 1·2 and — 1·1 phenotypic standard deviation units for LGR and LFCR respectively.Genetic parameters and responses to selection were estimated from the deviation of the selected lines from a control line and by restricted maximum likelihood (REML) techniques on the same material. Realized heritabilities were 0·40 (s.e. 0·12) for LGR and 0·40 (s.e. 0·13) for LFCR using the control line. Corresponding estimates from REML were 0·42 (s.e. 0·10) and 0·37 (s.e. 0·14). The estimate of the genetic correlation between LGR and LFCR was about — 0·69 (s.e. 0·12) using REML.The estimates of direct annual genetic change using deviations from the control were 3·6 (s.e. 1·3) g/day for LGR and — 0·14 (s.e. 0·07) kg food per kg lean gain for LFCR. Corrsponding estimates from REML were similar but more precisely estimated. The correlated responses for LFCR in the LGR line was higher than the direct response for LFCR.

scholarly journals GENETIC PARAMETERS IN FIBRE TRAITS FROM A FULL DIALLEL OF EUCALYPTUS UROPHYLLA IN SOUTHERN CHINA

2019 ◽  
Vol 31 (3) ◽  
pp. 343-352
Author(s):  
SJ Wu ◽  
JM Xu ◽  
ZH Lu ◽  
WZ Guo ◽  
L Zhou ◽  
...  
Keyword(s):  
Genetic Parameters ◽  
Southern China ◽  
Eucalyptus Urophylla ◽  
Fibre Traits

Genetic parameters for daily live-weight gain, live fleshiness and bone thinness in station-tested Piemontese young bulls

2001 ◽  
Vol 72 (3) ◽  
pp. 449-456 ◽  
Author(s):  
A. Albera ◽  
R. Mantovani ◽  
G. Bittante ◽  
A. F. Groen ◽  
P. Carnier
Keyword(s):  
Weight Gain ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Live Weight ◽  
Adaptation Period ◽  
Production Traits ◽  
Multiple Trait ◽  
Live Weight Gain ◽  
Total Gain

AbstractEstimates of genetic parameters for beef production traits were obtained for Piemontese cattle. Data were from 988 young bulls station-tested from 1989 till 1998. Bulls entered the station at 6 to 8 weeks of age and, after an adaptation period of 3 months, were tested for growth, live fleshiness and bone thinness. Length of test was 196 days. Growth traits considered were gain at farm, gain during the adaptation period, gain on test and total gain at the station. Six different fleshiness traits and bone thinness were scored on live animals at the end of the test using a linear system. Live evaluations of fleshiness were adjusted for the weight at scoring in order to provide an assessment of conformation independent of body size. Genetic parameters were estimated using animal models. Heritability of live-weight gain ranged from 0·20 in the adaptation period to 0·60 for total gain at the station. Genetic correlations between gains at station in different periods were high (from 0·63 to 0·97). Residual correlation between gain during the adaptation period and gain during test was negative, probably due to the occurrence of compensatory growth of the animals.Live fleshiness traits and bone thinness were of moderate to high heritability (from 0·34 to 0·55) and highly correlated indicating that heavy muscled bulls also have thin bones. Accuracy of breeding values and therefore response to selection were improved by multiple trait analysis of the live fleshiness traits and bone thinness. Overall weight gain at the station had a moderate negative genetic correlation with all live fleshiness traits and bone thinness (from –0·11 to –0·39).

scholarly journals Some observations on asymmetrical correlated responses to selection

1966 ◽  
Vol 7 (1) ◽  
pp. 44-57 ◽  
Author(s):  
B. B. Bohren ◽  
W. G. Hill ◽  
A. Robertson
Keyword(s):  
Model Selection ◽  
Gene Frequency ◽  
Genetic Parameters ◽  
Correlated Response ◽  
Correlated Responses ◽  
Gene Frequencies ◽  
Genetic Covariance ◽  
Gene Effects ◽  
Selection Experiments ◽  
Relative Change

The pattern of changes of the genetic covariance between two characters on selection was examined in an effort to explain the asymmetry of correlated responses in two traits, or of the same trait in two environments, frequently observed in experimental results.The algebraic conclusions were further examined by model selection experiments using a computer. The computer was programmed to calculate the change in gene frequency from generation to generation and to calculate from it the expected changes in genetic variances and covariance as selection proceeded. This procedure was carried out with several models of gene effects and gene frequencies.Asymmetry of the genetic covariance, and consequently of the correlated responses, resulted when the relative change in gene frequency at the loci contributing positively and negatively to the covariance depended on the trait selected. The conditions necessary for the development of asymmetry were examined and the results suggest that any symmetry found in an experiment is perhaps more surprising than asymmetry. Probably the most frequent contribution to asymmetry in practice will be from loci contributing negatively to the covariance and having frequencies other than 0·5.Accurate prediction of correlated response over many generations is therefore not possible without prior knowledge of the composition of the genetic covariance, as well as its magnitude. The validity of existing theory for the prediction of correlated responses is likely to be much poorer than for the prediction of direct responses. Predictions would then have to be based on the genetic parameters estimated in each generation.

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