ESTIMATION OF GENETIC AND PHENOTYPIC PARAMETERS OF MILK PRODUCTION TRAITS IN EGYPTIAN BUFFALOES USING TEST-DAY MODEL
Heba Ahmed Mohamed Mostafa;
Abstract
A total number of 3007 test-day milk records for 401 Egyptian buffaloes, daughters of 54 bulls covered the period from 1991 to 2002 were used in this study. Data were collected from Mahllet Mousa and EI-Nattaf EI-Kadeem farms in Kafr El-Sheikh. The two farms belong to Animal Production Research Institute, Ministry of Agriculture and Land Reclamation, Egypt. Genetic parameters and breeding values were estimated for :(I) total milk yield, (2)test-day milk yield, (3) monthly milk yield, and (4) cumulative milk yield. Statistical analyses were performed using SAS (2002), PLS (XLSTAT,
2010) analysis and DFREML (Meyer, 1998).
Averages of total milk yield (TMY), test-day and monthly milk was
1429kg. 7.3kg and 215kg, respectively.
Heritability estimates of individual test-day records ranged from 0.02 to
0.12, the heritability estimates of monthly and cumulative monthly milk yield ranged from 0.04 to 0.17 and from 0.01 to 0.20, respectively, and heritability estimates for total milk yield was 0.28.
Correlations between test-day (TD) measurements and total milk yield in the middle lactation (TD3, 1D4) were higher than at the beginning and the end of lactation for milk yield.
The regression of TMY on year of calving showed a positive trend (+67
kg per year of calving). Also, genetic trend was positive (+12.55kg per year of birth). In conclusion, although the trend in the estimated breeding values was positive, it still did not lead to adequate change required in the average milk production due, probably, to inadequate feeding and/or impaired management of the herds.
The results obtained suggest that test-day model could be used in genetic
evaluation of Egyptian buffalo. Also, from Variable Importance for Projection (VIP) plot we note that accurately predict total milk yield from second to fifth test-day can be effective.
Keywords: Heritability, genetic and phenotypic trend, test-day, total milk yield, Egyptian buffalo, Correlations.
2010) analysis and DFREML (Meyer, 1998).
Averages of total milk yield (TMY), test-day and monthly milk was
1429kg. 7.3kg and 215kg, respectively.
Heritability estimates of individual test-day records ranged from 0.02 to
0.12, the heritability estimates of monthly and cumulative monthly milk yield ranged from 0.04 to 0.17 and from 0.01 to 0.20, respectively, and heritability estimates for total milk yield was 0.28.
Correlations between test-day (TD) measurements and total milk yield in the middle lactation (TD3, 1D4) were higher than at the beginning and the end of lactation for milk yield.
The regression of TMY on year of calving showed a positive trend (+67
kg per year of calving). Also, genetic trend was positive (+12.55kg per year of birth). In conclusion, although the trend in the estimated breeding values was positive, it still did not lead to adequate change required in the average milk production due, probably, to inadequate feeding and/or impaired management of the herds.
The results obtained suggest that test-day model could be used in genetic
evaluation of Egyptian buffalo. Also, from Variable Importance for Projection (VIP) plot we note that accurately predict total milk yield from second to fifth test-day can be effective.
Keywords: Heritability, genetic and phenotypic trend, test-day, total milk yield, Egyptian buffalo, Correlations.
Other data
| Title | ESTIMATION OF GENETIC AND PHENOTYPIC PARAMETERS OF MILK PRODUCTION TRAITS IN EGYPTIAN BUFFALOES USING TEST-DAY MODEL | Other Titles | تقدير المقاييس الوراثية والمظهرية لصفات انتاج اللبن في الجاموس المصري باستخدام نموذج يوم الاختبار | Authors | Heba Ahmed Mohamed Mostafa | Issue Date | 2011 |
Attached Files
| File | Size | Format | |
|---|---|---|---|
| B16653.pdf | 1.25 MB | Adobe PDF | View/Open |
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