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This study armed to estimate of non-genetic and genetic parameters that affecting Study traits including lactation length (LL), total milk yield (TMY), and 305 day milk yield (305d-MY). The number of records used were 1630 lactation records over a period of 10 years of pure Friesian cows raised at the commercial station in northern Egypt. Analysis was performed using SAS (To estimate non-genetic factors ) In addition to the animal model (estimate genetic parameters). The most important results of the study that have been reached are summarized as follows: All non-genetic factors were significant for all the study traits. The overall mean for (LL), (TMY) and (305d-MY) was 358.3 days; 8675.3 and 7387.7 kg, respectively. Heritability values for were 0.13 ± 0.027, 0.28 ± 0.031, and 0.35 ± 0.030 for trait) f (LL), (TMY), and 305d-MY) respectively. Present results recommended the productive performance of Friesian cows can be improved through the adoption of appropriate management, nutrition, and breeding programs achieved through the selection program. |
