Comparison of estimates of repeatability and heritability for some production traits in Merino rams and ewes. I. Repeatability

1960 ◽  
Vol 11 (2) ◽  
pp. 257 ◽  
Author(s):  
SSY Young ◽  
Turner H Newton ◽  
CHS Dolling
Keyword(s):  
Body Weight ◽  
Sex Differences ◽  
Population Density ◽  
Fibre Diameter ◽  
Early Selection ◽  
Production Traits ◽  
General Body ◽  
Lifetime Performance ◽  
High Repeatability ◽  
Selection Of

Repeatabilities of 10 traits, namely, greasy wool weight, clean scoured yield, clean wool weight, body weight, wrinkle score, face cover score, fibre population density, fibre diameter, staple length, and crimps per inch, were estimated in ewes and rams. Estimates ranged from 0.4 to 0.7 for the 10 traits in both sexes. In general, body weight was the most repeatable trait and face cover the least. There is no evidence of sex differences in repeatability of the traits studied. Correlations between pairs of records obtained at different ages were high in both rams and ewes. This finding, together with the high repeatability values for all the traits, suggests that selection of sheep based on a single record is probably sufficiently accurate for lifetime performance of these 10 traits in Merinos. The correlations between yearling records and subsequent records in ram were found to be in agreement with correlations between records taken at older ages. Early selection of rams for lifetime performance therefore is probably almost as efficient as selection at a later age, and it is suggested that this finding might also be found to apply to ewes.

Comparison of estimates of repeatability and heritability for some production traits in Merino rams and ewes. 2. Heritability

1960 ◽  
Vol 11 (4) ◽  
pp. 604 ◽  
Author(s):  
SSY Young ◽  
Turner H Newton ◽  
CHS Dolling
Keyword(s):  
Body Weight ◽  
Population Density ◽  
Sex Difference ◽  
Fibre Diameter ◽  
Production Traits ◽  
Merino Sheep ◽  
Lower Figure ◽  
Selection Of ◽  
Australian Merino ◽  
Staple Length

Heritability estimates were calculated for 10 traits in rams and ewes of a medium-woolled strain of Australian Merino sheep. The traits were greasy wool weight, clean scoured yield, clean wool weight, body weight, wrinkle score, face cover score, fibre population density, fibre diameter, staple length, and crimps per inch. Estimates were made by dam-offspring correlations, measurement on the dams being at 15-16 months, on daughters at 15-16 months, and on sons at both 10-12 and 15-16 months. All estimates for both sexes lay between 0.3 and 0.6, except for fibre population density (0.24) and fibre diameter (0.12) in rams at 15-16 months and for clean wool weight (0.29) and face cover score (0.29) in rams at 10-12 months. The only significant sex difference lay in the lower figure for fibre diameter in rams at 15-16 months, but this is of doubtful importance as the corresponding figure for rams at 10-12 months (0.37) did not differ significantly from the ewe figure. All traits may be considered highly heritable, and the high values for the yearling rams indicate that consideration might be given to the selection of rams for production traits at an earlier age than the traditional one of 18 months or older.

Genetic studies of South Australian Merino sheep. 3. Heritabilities of various wool and body traits

1982 ◽  
Vol 33 (2) ◽  
pp. 355 ◽  
Author(s):  
IP Gregory
Keyword(s):  
Body Weight ◽  
Fibre Diameter ◽  
Skin Thickness ◽  
Production Traits ◽  
Primary Follicle ◽  
Merino Sheep ◽  
Main Production ◽  
Fleece Weight ◽  
Australian Merino ◽  
Staple Length

Heritabilities have been estimated for a large number of quantitative and qualitative wool and body traits recorded on two flocks of South Australian Merino sheep over a 12-year period. Data were unadjusted for fixed environmental effects and so the estimates are applicable to the heterogeneous populations found in most practical situations. Dam-offspring heritabilities of quantitative traits ranged from 0.15 for primary follicle number to 0.63 for body weight. Greasy and clean fleece weights, percentage clean yield, staple length, crimps per inch, fibre diameter, secondary and total follicle number, skin thickness, coefficient of variation of fibre diameter and secondary/primary follicle ratio had moderate to high heritabilities. Dam-offspring heritabilities of qualitative traits ranged from 0.12 for weather damage of the fleece to 0.75 for birthcoat. Total folds, face cover and hocks had high heritabilities, and wool character, type of staple formation and wool quality had moderate heritabilities. The main production traits (body weight, greasy fleece weight, yield, clean fleece weight, staple length, fibre diameter and total follicle number) were corrected for variation due to type of birth and age of dam and their heritabilities re-estimated. No change occurred in the half-sib heritabilities; dam-offspring heritabilities increased by an average of 0.05.

Vital statistics for an experimental flock of Merino sheep. V. The effects pf age of ram, maternal handicap, and year of measurement on 10 wool and body characteristics for unselected rams

1968 ◽  
Vol 19 (5) ◽  
pp. 825 ◽  
Author(s):  
GH Brown ◽  
HN Turner ◽  
CHS Dollling
Keyword(s):  
Body Weight ◽  
Population Density ◽  
Similar Pattern ◽  
Fibre Diameter ◽  
Vital Statistics ◽  
Mean Difference ◽  
Body Area ◽  
Merino Sheep ◽  
Twin Birth ◽  
Staple Length

Estimates were made of the effects of the following factors on 10 fleece and body characteristics measured on rams aged 1½ to 5½ years in a randomly bred control flock, for rams born 1953 to 1957 inclusive: age of ram, single or twin birth, age of dam, and the year in which measurements were made. Changes with age were present in all characteristics and the ranges of the age deviations from the overall mean were larger in magnitude than the corresponding figures for ewes. Greasy and clean wool weights showed a similar pattern of change with age as ewes. For greasy wool weight the age deviation increased from –2.4 lb at 1½ years to 1.1 lb at 3½ years and then declined to 0.5 lb at 5½ years of age. The corresponding figures for clean wool weight were –0.7 to 0.5 lb. falling to –0.2 lb at 5½ years of age. Other characteristics showed different patterns of change with age from the corresponding figures for ewes. Staple length, crimps per inch, yield, and fibre population density decreased with age over the range available, whilst face cover, body weight, fibre diameter, and wrinkle score increased. The fitted mean difference in clean wool weight between rams and ewes was 33%, largely attributed to differences in body area (25%) with a smaller contribution from staple length (7%). Twin-born rams cut 0.28 lb of clean wool weight per year less than single-born rams over the five shearings, whilst the progeny of 2-year-old dams did not differ significantly from the progeny of adults. Large between-year differences occurred for most characteristics. For clean wool weight the range was from –1.52 to 1.44 lb, fibre volunme being the most important component, while for body weight the range was –18.6 to 19.7 lb.

ESTIMASI NILAI HERITABILITAS BOBOT IKAN MAS VARIETAS PUNTEN DALAM PROGRAM SELEKSI INDIVIDU

2016 ◽  
Vol 11 (3) ◽  
pp. 217
Author(s):  
Estu Nugroho ◽  
Budi Setyono ◽  
Mochammad Su’eb ◽  
Tri Heru Prihadi
Keyword(s):  
Body Weight ◽  
Selection Response ◽  
Base Population ◽  
Breeding Programs ◽  
Male And Female ◽  
Body Weight Trait ◽  
Population Selection ◽  
Selection For ◽  
Weight Trait ◽  
Selection Of

Program pemuliaan ikan mas varietas Punten dilakukan dengan seleksi individu terhadap karakter bobot ikan. Pembentukan populasi dasar untuk kegiatan seleksi dilakukan dengan memijahkan secara massal induk ikan mas yang terdiri atas 20 induk betina dan 21 induk jantan yang dikoleksi dari daerah Punten, Kepanjen (delapan betina dan enam jantan), Kediri (tujuh betina dan 12 jantan), Sragen (27 betina dan 10 jantan), dan Blitar (15 betina dan 11 jantan). Larva umur 10 hari dipelihara selama empat bulan. Selanjutnya dilakukan penjarangan sebesar 50% dan benih dipelihara selama 14 bulan untuk dilakukan seleksi dengan panduan hasil sampling 250 ekor individu setiap populasi. Seleksi terhadap calon induk dilakukan saat umur 18 bulan pada populasi jantan dan betina secara terpisah dengan memilih berdasarkan 10% bobot ikan yang terbaik. Calon induk yang terseleksi kemudian dipelihara hingga matang gonad, kemudian dipilih sebanyak 150 pasang dan dipijahkan secara massal. Didapatkan respons positif dari hasil seleksi berdasarkan bobot ikan, yaitu 49,89 g atau 3,66% (populasi ikan jantan) dan 168,47 g atau 11,43% (populasi ikan betina). Nilai heritabilitas untuk bobot ikan adalah 0,238 (jantan) dan 0,505 (betina).Punten carp breeding programs were carried out by individual selection for body weight trait. The base population for selection activities were conducted by mass breeding of parent consisted of 20 female and 21 male collected from area Punten, eight female and six male (Kepanjen), seven female and 12 male (Kediri), 27 female and 10 male (Sragen), 15 female and 11 male (Blitar). Larvae 10 days old reared for four moths. Then after spacing out 50% of total harvest, the offspring reared for 14 months for selection activity based on the sampling of 250 individual each population. Selection of broodstock candidates performed since 18 months age on male and female populations separately by selecting based on 10% of fish with best body weight. Candidates selected broodstocks were then maintained until mature. In oder to produce the next generation 150 pairs were sets and held for mass spawning. The results revealed that selection response were positive, 49.89 g (3.66%) for male and 168.47 (11.43%) for female. Heritability for body weight is 0.238 (male) and 0.505 (female).

Mapping and validation of Anthocyanin1 pigmentation gene for its effectiveness in early selection of shrunken2 gene governing kernel sweetness in maize

2019 ◽  
Vol 87 ◽  
pp. 258-265 ◽  
Author(s):  
Rashmi Chhabra ◽  
Firoz Hossain ◽  
Vignesh Muthusamy ◽  
Aanchal Baveja ◽  
Brijesh Mehta ◽  
...  
Keyword(s):  
Early Selection ◽  
Pigmentation Gene ◽  
Selection Of

scholarly journals BREED AND SEX EFFECTS ON THE RELATIONSHIP BETWEEN WEIGHT AND FATNESS IN LACOMBE AND YORKSHIRE SWINE AND THEIR RECIPROCAL CROSSES

1965 ◽  
Vol 45 (1) ◽  
pp. 33-36
Author(s):  
G. W. Rahnefeld
Keyword(s):  
Body Weight ◽  
Sex Differences ◽  
Regression Coefficients ◽  
Average Depth ◽  
Constant Weight ◽  
Reciprocal Crosses ◽  
Sex Effects ◽  
Female Mating ◽  
The Mean ◽  
The Relationship

The relationship between thickness of fat measured at the shoulder, last rib, and loin of live pigs and market weight (86.2 to 95.2 kg) was studied in 1596 pigs from the Lacombe and Yorkshire breeds and their reciprocal crosses. No significant breed or sex differences were found in the proportion of fat at the three sites. Breed and sex differences were evident in the average depth of fat. The regression coefficients for the mean of three fat measurements on market weight were.016 ±.003,.019 ±.007, and.017 ±.004 for Lacombe males, barrows, and females respectively;.039 ±.002,.036 ±.005, and.041 ±.001 for Yorkshire males, barrows and females respectively;.027 ±.005 and.029 ±.004 for barrows and females from the Lacombe male × Yorkshire female mating; and.023 ±.007 and.021 ±.009 for barrows and females from the Yorkshire male × Lacombe female mating. Comparisons between animals measured at a relatively constant weight should be made after the fat measurement is adjusted for variations in body weight. The results of this study indicate that separate corrections should be applied for each breed. Separate corrections for sexes within breeds do not appear warranted.

Genetic evaluation of production traits between and within flocks of Merino sheep. I. Hogget fleece weights, body weight and wool quality

1989 ◽  
Vol 40 (2) ◽  
pp. 433 ◽  
Author(s):  
SI Mortimer ◽  
KD Atkins
Keyword(s):  
Body Weight ◽  
Environmental Effects ◽  
Genetic Variance ◽  
Research Centre ◽  
Production Traits ◽  
Merino Sheep ◽  
Wool Production ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Fleece Weight

Wool production traits were measured on Merino hogget ewes in an unselected multiple-bloodline flock over a 7-year period at Trangie Agricultural Research Centre, N.S.W. The traits measured were greasy fleece weight (GFW), skirted fleece weight (SKFW), yield (Y), clean fleece weight (CFW), fibre diameter (FD), body weight (BWT) and staple length (SL). These measurements were used to examine genetic differences between and within flocks of Merino sheep, and to estimate heritability of and genetic and phenotypic correlations among these traits. Significant strain, flock within strain and flock effects were present for all traits. Interactions between these effects and year were non-significant. Within-flock genetic variance was always larger than between-flock within strain genetic variance for each trait. The influence of environmental effects on these traits was also examined. The environmental effects of birth-rearing type, age at observation and age of dam together accounted for about 7-10% of the total within-flock variation in fleece weights and body weight.After adjusting for significant environmental effects, paternal half-sib heritability estimates were 0.29 �. 0.06 for GFW, 0.22 � 0.05 for SKFW, 0.35 � 0.05 for Y, 0.30 �0.06 for CFW, 0.48 �0.07 for FD, 0.34 �. 0.06 for BWT and 0.44 �0.07 for SL. Estimates for genetic and phenotypic correlations were in agreement with published estimates except for the genetic correlation between CFW and FD (0.40 �. 0.11), and the genetic correlations involving BWT, which were essentially zero. The implications of the results of this study for the genetic improvement of Merino sheep for wool production are discussed.

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