Abstract :
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 < .0001) and litter size at weaning
(0.001 kid/yr, P < 0.001), which indicates positive response to the applied selection program.
Annual phenotypic changes were negative for milk yield and growth traits, indicating
unfavorable environmental conditions and the need for better management of the herd to
explore its genetic potentiality. Genetic parameters were moderate for TMY and low for
prolificacy traits, while their genetic correlation was moderate. It is recommended to apply
more intensive selection program under favorable managerial conditions to explore the E.
Nubian genetic potentiality as a subtropical dairy prolific breed.
