| Popis: |
Egyptian Nubian (Zaraibi) goats, known to be a progenitor of the standard Anglo-Nubian, are raised as household dairy animal in North-East of Nile Delta and known for its high prolificacy. In 1990, sires of the present herd were selected based on their dam milk yield. From 2000, selection indices were applied on both males and females including body weights and milk yield of their dams at 1st parity. In all cases single-born goats were not allowed to breed. A total of 7298 E. Nubian does and 10,374 kids records were used to estimate annual genetic, phenotypic and environmental changes in milk yield, prolificacy, and growth traits. Total milk yield (TMY) averaged 253.1 ± 1.5 kg in 251.3 ± 0.8 days of lactation (including 90 days suckling). Seventeen percent of the does produced more than 350 kg of milk/lactation. Litter size averaged 2.1 ± .01 kids at birth and 1.6 ± .01 kids at weaning. Annual genetic changes were estimated based on the predicted breeding values over year of birth. It was positive and highly significant for TMY, (0.72 kg/yr, P P |
Full Text from ScienceDirect