Estimation of Genetic Parameters a nd Non Genetic Factors for Milk Yield and Litter Size at Birth of Awassi Sheep in Drylands

Al-Najjar, K.; Al-Momani, A.; Al-Yacoub, A.; Elnahas, A. Elnahas4,; Elsaid, Reda

doi:10.21608/ejsgs.2022.266898

Estimation of Genetic Parameters a nd Non Genetic Factors for Milk Yield and Litter Size at Birth of Awassi Sheep in Drylands

Document Type : Original Article

Authors

¹ General Commission for Scientific Agricultural Research (GCSAR), Damascus, SYRIA.

² Animal Production and Protection Department, Faculty of Agriculture, Jerash University, JORDAN.

³ Biology Department, Faculty of Applied Science, Umm Al-Qura University, Makkah, SAUDI ARABIA.

⁴ Animal Production Department, Faculty of Agriculture, Sohag University, EGYPT.

⁵ Sustainable Development Department, Environmental Studies and Research Institute (ESRI), University of Sadat City, Menofyia, EGYPT.

10.21608/ejsgs.2022.266898

Abstract

The present study utilized 1195 records from 702 ewes of Awassi sheep progenies of 111 sires and 451 dams bred in the drylands at Al-Fjaj station, Jordan. The aim of this study was to estimate genetic parameters as well as to investigate non-genetic factors affecting milk yield (MK) and litter size at birth (LZB) using SAS and MTDFREML programs. Average of MK and LZB were 92.84 (kg) and 1.16, respectively. MK was high significantly (P<0.01) affected by parity, age of ewe, year of lambing, and lactation period, while only the year of lambing had a significant (P<0.05) effect on LZB. The heritability and repeatability were 0.07 and 0.10 for MK, while they were 0.05 and 0.25 for LZB. Genetic and phenotypic correlations between MK and LZB were 0.17 and 0.02, respectively. The research concluded that the herd is genetically homozygous and therefore there are a need to increase genetic variance by introducing improved rams and selected females.

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