| Titles |
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English :
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Genetic analysis of number or services per conception and days open as continuous and binary traits using Gibbs sampling and Reml in Holstein cows
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Arabic :
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تحليلات وراثية لصفتي عدد التلقيحات اللازمة للإخصاب و الفترة المفتوحة كصفات سلمية و مستمرة بإستخدام طريقتى جبس و التشاية العظمى المحددة لابقار الهولشتين
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| Abstract |
Variance components were estimated for a total of 3652 lactation records obtained from 1501 Holstein cows raised in a single commercial farm, using two procedure Multiple Trait Derivative Free- REML (MTDFREML) via restricted maximum likelihood and Gibbs Sampling via Baysian analysis with a multiple- trait repeatability animal model. The model included year-season of calving (18 groups) and parity (first three lactations) as fixes effects and additive genetic and permanent environmental as random effects.
Records were analyzed to compare estimates for variance components for number of service per conception (NS) and days open (DO) when measured once as continuous traits and another as binary traits through the two previous procedures.
When NS and DO were considered as continuos traits, hertability estimates were 0.010 and 0.030 through MTDREML and 0.034 ±0.023 and 0.054 ± 0.014 using GS, respectively. Repeatability estimates were 0.048 and 0.069 via MTDREML and 0.054 ±0.019 and 0.060± 0.022 through GS, respectively. Genetic and phenotypic coronations between the two traits were 0.680 and 0.770 using MTDEREML and 0.680 and 0.740 using Gibbs Sampling (GS), respectively.
When the two traits were considered as binary traits hertiability estimates were 0.003 and 0.030 through MTDREML and 0.067 ± 0.030 and 0.062± 0.030 using GS, respectively. Repeatability estimates were 0.047 and 0.035 via MTDREML and 0.175± 0.012 and 0.127 ±0.007 through GS, respectively. Genetic and phenotypic correlations between the two traits were 0.350 and 1.000, respectively, through MTDFREML and 0.990 and 0.310, respectively, via GS.
The optioned results revealed that differences in the estimates are due to the form considered for the traits( continuous or binary ) and the employed methodology. The size of the variance components plays an important role in determining these differences.
Keywords: Holstein- Friesian, genetic parameters, REML, Gibbs Sampling.
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| Publication year |
2001
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| Pages |
51-59
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| Availability location |
معهد بحوث الانتاج الحيوانى- شار ع نادى الصيد- الدقى - الجيزة
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| Availability number |
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| Organization Name |
Animal Production Research Institute (APRI)
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| serial title |
Egyptian Journal Animal Production
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| Author(s) from ARC |
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| External authors (outside ARC) |
محمد عبد العزيز محمد ابراهيم
جامعة القاهرة
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| Agris Categories |
Animal husbandry
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AGROVOC
TERMS |
Cows.
Genetic parameters.
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| Proposed Agrovoc |
Gibbs Sampling;REML;Holstein- Friesian;
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| Publication Type |
Journal
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