GENETIC AND PHENOTYPIC PARAMETERS FOR DAILY GAIN AND BODY WEIGHTS IN SUFFOLK LAMBS

1985 ◽  
Vol 65 (3) ◽  
pp. 575-582 ◽  
Author(s):  
J. N. B. SHRESTHA ◽  
J. A. VESELY ◽  
J. P. CHESNAIS
Keyword(s):  
Genetic Correlations ◽  
Performance Testing ◽  
Genetic Response ◽  
Testing Program ◽  
Body Weights ◽  
Genetic And Phenotypic Correlations ◽  
Selection Indexes ◽  
Selection For ◽  
The Stability ◽  
Daily Gain

Body weights of 19 400 Suffolk lambs from the Federal-Provincial Canadian Record of Performance program were studied. The paternal half-sib estimate of heritability for daily gain from 50 to 100 days of age was 0.47 ± 0.04. The corresponding estimates for lamb weights at 50 and 100 days of age were 0.46 ± 0.04 and 0.43 ± 0.04, respectively. The moderate levels of heritability and the intermediate (16–25%) coefficient of variation in the Suffolk breed confirm that selection for daily gain and body weights would result in genetic response. Estimates of genetic and phenotypic correlations among daily gain from 50 to 100 days of age and 100-day lamb weight were 0.80 ± 0.02 and 0.73, respectively. Corresponding correlations among lamb weights at 50 and 100 days were 0.89 ± 0.02 and 0.76. Selection for daily gain from 50 to 100 days of age does not offer any advantage over selection based on lamb weight at 100 days when lamb weight at that age is the response criterion. Similarity in the estimates of genetic and phenotypic parameters from 1980 to 1983 indicates the stability of the estimates and their usefulness in selection indexes and predicting breeding values for sheep in the Canadian performance testing program. Key words: Suffolk, lamb weights, heritabilities, genetic correlations

Predicted and realized responses to selection for an index of bone length and body weight in Scottish Blackface sheep 2. Correlated responses in lifetime productivity

1986 ◽  
Vol 43 (3) ◽  
pp. 437-445 ◽  
Author(s):  
K. D. Atkins ◽  
R. Thompson
Keyword(s):  
Body Weight ◽  
Population Genetic ◽  
Genetic Correlations ◽  
Reproduction Rate ◽  
Base Population ◽  
Correlated Responses ◽  
Genetic Response ◽  
Bone Length ◽  
Body Weights ◽  
Selection For

ABSTRACTA selection experiment with Scottish Blackface sheep was used to compare predicted and realized correlated responses to selection. Three lines were maintained between 1956 and 1974 in which selection was either at random or for high and low values of an index of cannon-bone length at 8 weeks of age adjusted for body weight at the same age.There was no evidence of asymmetrical responses in any trait. Selection for increased cannon-bone length, adjusted for body weight, resulted in (i) increased body weights at all ages between birth and maturity, (ii) increased reproduction rate, principally from increased litter size but also from small responses in ewe fertility and lamb survival and (iii) decreased survival of adult ewes. The realized genetic correlations were relatively small (up to 0·3) but mostly significantly different from zero, whereas base population genetic correlation estimates were very imprecise. The realized responses in reproduction rate were probably a consequence of the genetic response in body weight.

scholarly journals Selection indexes for genetic improvement of yearling weight in Egyptian buffaloes

2010 ◽  
Vol 53 (4) ◽  
pp. 436-446
Author(s):  
K. A. Shahin ◽  
O. Y. Abdallah ◽  
T. A. Fooda ◽  
K. A. Mourad
Keyword(s):  
Body Weight ◽  
Genetic Improvement ◽  
Average Daily Gain ◽  
Breeding Value ◽  
Direct Selection ◽  
Body Weights ◽  
Practical Standpoint ◽  
Selection Indexes ◽  
Selection For ◽  
Daily Gain

Abstract. Estimates of genetic and phenotypic parameters for body weight at birth, 3, 6, 9, and 12 months of age, and for preweaning and postweaning average daily gain were computed and used to construct 14 selection indexes to improve the 12-month weight in Egyptian buffaloes. The full index incorporating body weight at birth, 3, 6, 9 and 12 months of age had the highest correlation with aggregate breeding value (rTI=0.63). The correlation fell to 0.62 when body weight at birth and 3 months were omitted from the index. Selection for body weight at 12 months of age alone is expected to be 76.2 % as efficient as selection for the full index. The maximum expected genetic gain in 12-month body weight was 8.85 kg/generation when all five body weights were included in the index; this decreased to 8.09 kg/generation when body weights at birth, 3 and 6 months were excluded and further decreased to 6.94 kg/ generation when selection based on yearling weight only. From the practical standpoint, selection on I5 involving body weight at 9 month of age can be considered as the best for improving body weight at 12 month since its application is earlier, less expensive, higher accuracy than any index excluding body weight at 12 month and giving reasonable amount (+5.39 kg) improvement in yearling weight as compared to direct selection (+6.94 kg).

scholarly journals Genetic parameters and predicted response to selection for lean growth in an Australian commercial nucleus pig herd

2000 ◽  
Vol 51 (7) ◽  
pp. 833 ◽  
Author(s):  
Nguyen Hong Nguyen ◽  
Cam P. McPhee ◽  
Claire M. Wade ◽  
Brian G. Luxford
Keyword(s):  
Growth Rate ◽  
Genetic Parameters ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Genetic Response ◽  
Lean Growth ◽  
Derivative Free ◽  
Total Data ◽  
Selection For ◽  
Daily Gain

Genetic parameters for performance traits in a pig population were estimated using a multi-trait derivative-free REML algorithm. The 2590 total data included 922 restrictively fed male and 1668 ad libitum fed female records. Estimates of heritability (standard error in parentheses) were 0.25 (0.03), 0.15 (0.03), and 0.30 (0.05) for lifetime daily gain, test daily gain, and P2-fat depth in males, respectively; and 0.27 (0.04) and 0.38 (0.05) for average daily gain and P2-fat depth in females, respectively. The genetic correlation between P2-fat depth and test daily gain in males was –0.17 (0.06) and between P2-fat and lifetime average daily gain in females 0.44 (0.09). Genetic correlations between sexes were 0.71 (0.11) for average daily gain and –0.30 (0.10) for P2-fat depth. Genetic response per standard deviation of selection on an index combining all traits was predicted at $AU120 per sow per year. Responses in daily gain and backfat were expected to be higher when using only male selection than when using only female selection. Selection for growth rate in males will improve growth rate and carcass leanness simultaneously.

Genetic parameters of Barki sheep raised under semi-arid conditions

1969 ◽  
Vol 11 (3) ◽  
pp. 361-367 ◽  
Author(s):  
M. H. Fahmy ◽  
E. Salah E. Galal ◽  
Y. S. Ghanem ◽  
S. S. Khishin
Keyword(s):  
Genetic Parameters ◽  
Genetic Correlations ◽  
Research Station ◽  
Phenotypic Correlations ◽  
Arid Conditions ◽  
Body Weights ◽  
Genetic And Phenotypic Correlations ◽  
Fleece Weight ◽  
Semi Arid ◽  
Desert Research

SUMMARYRecords on 695 lambs were collected over a period of 5 years from 1961/62 to 1965/66, at Ras El-Hekma Desert Research Station, 230 km west of Alexandria. The characters studied were birth, weaning and yearling body weights, pre- and post-weaning daily gains and greasy fleece weight.Birth, 120-day and 365-day body weights were 3·4, 18·2 and 33·4 kg respectively. Greasy fleece weight at 16 months of age was 3·29 kg. Heritability estimates of birth, weaning, yearling weights, pre- and post-weaning daily gains and greasy fleece weight were 0·22, 0·45, 0·41,0·45 and 0·29 respectively. Genetic and phenotypic correlations between birth, weaning and yearling weights were all positive and significant. Genetic correlations between fleece weight and body characteristics were negative and low.

scholarly journals The Impact of Selection using Residual Average Daily Gain and Marbling EPDs on Growth Performance and Carcass Traits in Angus Steers

2019 ◽  
Vol 3 (2) ◽  
Author(s):  
T. R. Krause ◽  
E. R. Moore ◽  
J. Duggin ◽  
J. R. Segers ◽  
T. D. Pringle
Keyword(s):  
Growth Performance ◽  
Feed Efficiency ◽  
Average Daily Gain ◽  
Backfat Thickness ◽  
Feeding Trial ◽  
Body Weights ◽  
Selection For ◽  
Carcass Merit ◽  
The Impact ◽  
Daily Gain

ObjectivesProfitability in the beef industry has narrow margins regulated by revenue from output traits like growth and carcass merit, but profitability is also largely impacted by input expenses like feed costs. Selecting for improvements in feed efficiency during the finishing phase, one of the most feed intensive segments of the industry, can help to mitigate those input costs. This study compared growth performance, feed efficiency, body composition, and carcass characteristics in Angus steers (n = 321) from bulls divergently selected for feed efficiency and marbling.Materials and MethodsAngus sires were selected based on high (10th percentile or better) and low (85th percentile or worse) residual average daily gain (RADG) EPD as well as high (fifth percentile or better) and average (near 50th percentile) marbling (MARB) EPD. These criteria resulted in a 2 × 2 factorial design with four breeding lines: high RADG/high MARB, high RADG/average MARB, low RADG/high MARB, low RADG/average MARB. Data were analyzed using MIXED procedures of SAS with RADG and MARB as main effects. Significance was set at α = 0.05. Generation was also analyzed, where generation one (GEN1) steers were from a selected sire while generation two (GEN2) steers were from a selected sire and a selected dam.ResultsUltrasound and carcass data revealed no differences (P ≥ 0.12) in 12th rib backfat thickness from weaning through slaughter for the RADG EPD groups. Yield grade and dressing percent did not differ (P ≥ 0.56) across RADG or MARB groups. At the beginning and end of the feeding trial, the high RADG (P ≤ 0.02) group had larger ultrasound ribeye area (REA) than the low RADG group. Carcass REA tended (P = 0.08) to be larger in the high versus low RADG steers. During the feedlot trial and through slaughter, body weight was heavier (P ≤ 0.006) for the high versus low RADG steers but did not differ (P ≥ 0.44) across MARB EPD. Feed efficiency measures did not differ (P ≥ 0.32) across RADG or MARB groups apart from the tendency (P = 0.08) for residual feed intake to be lower in the high versus low RADG steers. Marbling scores differed (P ≤ 0.04) across RADG and MARB groups with the low RADG steers and the high MARB steers having improved marbling. The quality grade distribution across MARB EPD revealed that the average MARB steers graded 73% Choice and 25% Prime while the high MARB steers graded 56% and 42%, respectively. Slice shear force did not differ (P ≥ 0.32) across RADG or MARB EPD. Body weights tended (P = 0.06) to be heavier at the start of the feeding trial for GEN1 versus GEN2 steers. Total gain, average daily gain, and feed to gain (F:G) differed by generation (P ≤ 0.007) with increased rates of gain and reduced F:G in the GEN2 versus GEN1 steers. Body weights did not differ (P = 0.72) across GEN at the end of the feeding trial. Backfat thickness at the start and end of the feedlot phase was less (P ≤ 0.03) and marbling score was improved (P = 0.02) in the GEN2 versus GEN1 steers, respectively.ConclusionThese results suggest that selection using RADG EPD has negligible impacts on meat quality; and that progress in selection for efficiency can be achieved while advancing carcass quality and value. Furthermore, continued divergent selection for feed efficiency and marbling has the potential to improve feed efficiency through advancements in the rate of gain, while enhancing carcass merit through marbling.

Estimates of genetic parameters for pre-weaning and post-weaning growth traits of Chios lambs

1980 ◽  
Vol 30 (2) ◽  
pp. 271-276 ◽  
Author(s):  
A. P. Mavrogenis ◽  
A. Louca ◽  
O. W. Robison
Keyword(s):  
Body Weight ◽  
Birth Weight ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Heritability Estimate ◽  
Weaning Weight ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Daily Gain

ABSTRACTData on 792 Chios lambs born during the 1972/73 and 1973/74 lambing seasons were used to estimate genetic and phenotypic parameters for birth weight, weaning weight, age at weaning, pre-weaning daily gain, body weight at 5, 10, 15 and 20 weeks of age, and postweaning daily gain. Body weight at 15 weeks of age had the highest heritability estimate (0·73 ± 0·17) and that of post-weaning daily gain was also high (0·56 ± 0·15). Selection for either weight at 15 weeks or post-weaning daily gain would be expected to yield a greater response than selection for pre-weaning daily gain or weaning weight. Genetic correlations among weights and/or gains were positive (approximately 0·20). Phenotypic correlations among weights and gains were generally higher than genetic correlations. However, the correlation between pre— and post-weaning daily gain was small (0·08). Likewise, post-weaning daily gain had low correlations with all weights before 10 weeks. Age at weaning had moderate negative associations with all weights but a very low positive correlation with post-weaning daily gain.

ESTIMATES OF GENETIC CORRELATIONS AMONG CERTAIN CARCASS AND PERFORMANCE TRAITS IN SWINE

1968 ◽  
Vol 48 (1) ◽  
pp. 1-6 ◽  
Author(s):  
G. L. Roy ◽  
W. J. Boylan ◽  
M. E. Seale
Keyword(s):  
Birth Weight ◽  
Genetic Correlation ◽  
Genetic Relationships ◽  
Carcass Traits ◽  
Genetic Correlations ◽  
Development Project ◽  
Carcass Trait ◽  
Selection For ◽  
And Performance ◽  
Daily Gain

Data from a swine breed development project provided estimates of the genetic correlation among six performance and carcass traits. The data from the new breed, called Managra, were obtained over a 7-year period. Most genetic relationships examined were such that selection for improvement of one trait would yield a favorable improvement in another. Both carcass backfat and live backfat probe were found to be negatively correlated with area of loin eye and length of carcass. A positive genetic correlation was found between post-weaning daily gain and loin eye area. A high positive genetic correlation was found between birth weight and loin eye area. An unfavorable association involved a positive genetic correlation between birth weight and backfat.Correction factors for effect of carcass weight on the magnitude of carcass trait measurements and differences in means between sexes were obtained.Heritability of the traits was estimated by paternal half-sib correlation. The estimates for carcass traits were moderately high and agree well with most other estimates reported in the literature.

scholarly journals EFFECT OF FIXED FACTORS AND ESTIMATION OF GENETIC PARAMETERS OF GROWTH TRAITS FOR MOUNTAIN KIDS

2019 ◽  
Vol 50 (6) ◽  
Author(s):  
Hermiz & Baper
Keyword(s):  
Variance Components ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Maximum Likelihood Method ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Likelihood Method ◽  
Phenotypic Correlations ◽  
Body Weights ◽  
Genetic And Phenotypic Correlations

Body weights at birth (469), weaning (394) and at six month of age (358) for kids utilized in this study were raised at private project in Duhok governorate, Iraq during two kidding season (2016-2017) and (2017-2018). GLM within SAS programme was used to analyze the data which include the fixed effects (age of doe, year and season of kidding, sex of kid and type of birth, regression on doe weight at kidding, and the regression of later weights of kids on earlier weights) influencing the studied traits. Restricted Maximum Likelihood Method was used to estimate repeatability, heritability, genetic and phenotypic correlations after adjusting the records for fixed effects. Variance components of random effects were tested for positive definite. Overall mean of weights at birth (BWT), weaning (WWT) and 6 month of age (WT6M) were 2.92, 15.32 and 24.45 kg, respectively. Differences among groups of age of doe in all studied traits were not significant, while year of kidding and sex of kid affect all traits significantly (p<0.01). Season of kidding affect BWT and WWT significantly (P<0.01). Single born kids were heavier (P<0.01) than twins in BWT only. Regression of BWT on doe weight at kidding (0.033 kg/kg) was significant (P<0.01), while the regressions of WWT and WT6M were not significant. The regression coefficients of WWT on BWT (1.906 kg/kg) and of WT6M on WWT (0.835 kg/kg) were highly significant (P<0.01). Repeatability estimates for BWT, WWT and WT6M were 0.47, 0.45 and 0.35, respectively; on the same order the estimates of heritability were 0.41, 0.61 and 0.79. Genetic correlations between BWT with each of WWT (0.45) and WT6M (0.55), and between WWT and WT6M (0.68) were highly significant. All phenotypic correlations between each pair of body weights were higher than genetic correlations and ranged between 0.48 and 0.73.

scholarly journals Genetic and non genetic effects for lactation curve traits in Holstein-Friesian cows

2012 ◽  
Vol 55 (5) ◽  
pp. 450-457 ◽  
Author(s):  
I. Boujenane ◽  
B. Hilal
Keyword(s):  
Milk Yield ◽  
Genetic Correlations ◽  
Genetic Effects ◽  
Peak Time ◽  
Holstein Friesian ◽  
Lactation Curve ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
Calving Season ◽  
Friesian Cows

Abstract. The objective of this study was to determine the genetic and non genetic effects on lactation curve traits determined by the incomplete gamma function of Wood (1967) for Holstein-Friesian cows in Morocco. Data analysed included 49262 monthly records of the test-day milk yield from 4888 lactations of 3932 cows at their 1st, 2nd or 3rd parity collected during 1990 and 1999 in 232 herds enrolled in the official milk recording. In general, lactation curve traits (A, B, C, peak time [Tmax], peak milk yield [Ymax], persistency and 305 day milk yield [MY305]) were affected by herd, parity, age at calving, season of calving and year of calving. Heritability estimates were low and varied from 0.01 for parameter A to 0.10 for Ymax. Genetic and phenotypic correlations among traits varied from −0.79 to 1.00 and from −0.80 to 0.96, respectively. Genetic correlations between MY305 and parameter C were negative, but those between MY305 and all the other lactation curve traits were positive. It was concluded that selection for high peak milk yield and persistency will result in higher 305 day milk yield.

scholarly journals The performance testing of boars II. Phenotypic and genetic correlations

1971 ◽  
Vol 43 (2) ◽  
pp. 103-110
Author(s):  
Elsi Ettala
Keyword(s):  
Growth Rate ◽  
Total Variation ◽  
Feed Efficiency ◽  
Genetic Correlations ◽  
Performance Testing ◽  
Stepwise Multiple Regression ◽  
Daily Growth ◽  
Fat Thickness ◽  
Selection For ◽  
Different Characteristics

In this study the interrelationships between the various characteristics for the boar material described in the first part were analysed. For this purpose the phenotypic, genetic and intra-sire correlation matrix as well as stepwise multiple regression analyses were calculated by computer for the material of 138 boars. The results showed that there was a very strong correlation between fat thickness and testing score (rG = —0.95***, rP = —0.88***). Of the total variation in the testing score 85.2 % was accounted for by the variation in fat thickness. Although the testing score is made up of the points for fat thickness and growth, the latter accounted for only 9.2 % of the variation in the score. Daily growth was positively associated with the testing score and negatively with the amount of feed units required per growth kilogram, but significantly so only for the intra-sire correlations; the genetic correlations being even, contrary to expectation. The association between growth rate and fat thickness was positive (rG = 0.47***). Of the total variation in feed efficiency the testing score accounted for 35.6 %. A high testing score was associated with a favourable feed efficiency (rg = —0.63***). By correlation studies attempts were also made to find out whether it would be possible to shorten the testing period without decreasing the accuracy. The correlations show that the growth rate can be predicted with an appreciable degree of accuracy already from the weight at the 8th testing week. The correlations between the above weight and growth rates were; rG = 0.84***, rP = 0.82***. From the associations between different characteristics one can decide on the suitability of testing and the consequences of selection for particular traits.

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