Estimation of the genetic and environmental trends for milk traits of Holstein herd | ||
| Egyptian Journal of Agricultural Research | ||
| Article 1, Volume 98, Issue 3 - Serial Number 1, September 2020, Pages 397-409 PDF (1.35 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/ejar.2020.128985 | ||
| Authors | ||
| Safaa Sanad* ; Gharib M. Gharib | ||
| Animal Production Research Institute (APRI), Agriculture Research Center (ARC), Egypt | ||
| Abstract | ||
| The study is to evaluate the performance of the herd and assess the different effects (genetic and non-genetic) on the production of this herd. Also, to improve the accuracy of genetic prediction of the traits affecting milk production as well as to determine the effect of different non-genetic factors (environmental trend). The total number of records used in this study was 2651 productive records in Holstein Friesian (HF) over 10 years in a commercial farm located in the northern part of Nile Delta, Egypt. Milk production for 305 days (305d-MY, kg), Peak yield (PY), and Persistency (PER). Records were analyzed Animal Models using WOMBAT software to estimate heritability (additive h2a and maternal h2m), breeding values of sires, dams and cows (SBV, DBV and CBV), and Environmental trend (EVT) and Epigenetic trend (EPT) for all studies traits of (HF) cattle. Average for (305d-MY, kg), (PY) and (PER).were 4227kg, 22.8kg and 64.5%, respectively, additive (h2a) estimates for (305d-MY, kg), (PY) and (PER) were: 0.43±0.05, 0.28±0.05 and 0.08±0.03, respectively, while low (h2m) were estimated as 0.057±0.033, 0.017±0.028 and 0.024±0.023, respectively. Permanent environmental impact (Pe), where 0.044±0.031, 0.0 and 0.0 respectively. The average (SBV) were 1687, 10.3 kg and 14.3% for 305d-MY, kg, PY and PER; while the average (DBV) for the same traits were 1514.3, 9.3 kg and 15.9%.Whereas, the average (CBV) were 1747.4, 9.4 kg and 18.8%, respectively. The estimates of the (h2a) in this study indicated that the genetic and environmental variability of PER is low, while the moderate value of h2a for 305d-MY and PY indicates the possibility of selection for these traits as this leads to the possibility of improving productivity in future generations for cows under Egyptian conditions. These results suggest that selection based on the selection of higher cows in (CBV). Also, genetic trends indicate that herd's productive performance is influenced by environmental changes; Epigenetic trend was generally positive in the cold climate seasons (winter and spring), while it was negative in the hot climate (summer and autumn) for both (305d-MY, kg) and (PY). Therefore, adequate care and nutrition are necessary as it helps in the emergence of full genetic potential by improving environmental conditions. | ||
| Keywords | ||
| Holstein Friesian; Milk traits; environmental and genetic parameters; Epigenetics trend | ||
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