GENETIC EVALUATION OF MILK PRODUCTION AND REPRODUCTION TRAITS IN HOLSTEIN FRIESIAN RAISED IN HUNGARY USING SINGLE—AND MULTI-TRAIT ANIMAL MODEL ANALYSES | ||||
| Journal of Animal and Poultry Production | ||||
| Article 5, Volume 31, Issue 10, October 2006, Page 6217-6231 PDF (194.82 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jappmu.2006.235630 | ||||
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| Author | ||||
| M. A. Mostafa, | ||||
| Animal Production Department, Faculty of Agriculture. Mansoura University, El-Mansoura, Egypt. | ||||
| Abstract | ||||
| A total of 3165 normal first lactation records of Holstein-Friesian cows Kept at Mezoheges State Farm, Hungary collected during the period from 1982 to 1990 were used. The number of sires and the average number of daughters per sire were 281 and 11.3, respectively. The data were used to evaluate genetic parameters and breeding values for milk production and reproduction traits by using single-trait and multi-trait animal model. Each of reproduction trait, as well as persistency of milk yield was joined with milk yield. Spearman rank correlation based on EBVs of all animals (sires) for trait studied from single trait and tw0-trait analyses with milk yield were estimated. Production Traits studied were: 305 — day milk yield (305-d My), 305-day fat yield (305—d Fy), maximum daily milk yield (MdMY): days in milk (DIM) age at first calving (AFC), days open (DO), number of services per conception (NSC) and persistency of milk yield (Per My). Unadjusted means of AFC, DO, NSC, DIM, Per My, MdMy, 305-d My and 305- d Fy were 24.4 month, 133.6 day 2.1, 334.9 day, 76.7%, 27.3 Kg, 6568 Kg and 243.9 Kg, respectively. Estimates of heritability (hz) of AFC, DO, NSC were 0.06, 0.11 and 0.07, respectively; while for DIM, Per My, MdMy, 305-d My and 305-d Fy were 0.05, 0.08, 0.29, 0.26 and 0.29, respectively. The standard errors (SE) of h"2 ranged from 0.02 to 0.04 for all traits studied, using single-trait analyses. Minor differences were observed in h2 from single-trait versus two-trait genetic analyses. Estimates of genetic and phenotypic correlations between productive traits and reproductive traits were positive and medium to high; between Per My and each of D0 and NSC were negative and low; between production traits and AFC were positive and moderate. The genetic and phenotypic correlation between AFC and Per My were positive and medium. The results indicated higher breeding values (EBVs) for two—trait than single- trait analyses for all animals (sires). Low rank correlations between single-trait and two-trait analyses with milk yield of all animal or only sires (0.56 — 0.99 and 0.71 — 0.99, respectively) for sires indicated that re—ranking of sires would be considered between the Mo methods. The present results indicate the antagonistic relationship < /p> of production with reproduction traits. Therefore, evaluation of the sire role as well cow on reproduction must be taken into consideration and subsequently incorporated into a muIti-trait selection index. | ||||
| Keywords | ||||
| Holst-2m; rnrm production; reproduction; persistency; Dr-céifig vii-"res. genetrc parameters; single-and muiii-irait animal model; Hungary | ||||
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