Abstract
Background:
Assaf sheep are a major source of meat and milk in the northern West Bank, Palestine, yet limited information exists regarding their phenotypic and morphometric characteristics under local management conditions. Understanding these traits is essential for improving productivity, reproductive performance, and breeding strategies.

Aim:
This study aimed to investigate the morphology, productive traits, and reproductive performance of Assaf sheep raised in four governorates of the northern West Bank.

Methods:
A total of 580 adult sheep (520 ewes and 60 rams) were evaluated for both qualitative and quantitative traits across Jenin, Tulkarm, Nablus, and Jericho. Morphometric measurements, live weights, milk yield, prolificacy, lamb birth weight, and udder dimensions were recorded. Multivariate analysis was used to assess variability within the population and identify traits associated with productivity improvement.

Results:
Pronounced sexual dimorphism was observed, with males exhibiting higher average live weights (113.0 kg) and body lengths (116.9 cm) than females (72.7 kg and 85.5 cm, respectively). Productive traits varied by region and management practices, with the highest milk yield in Tulkarm (407 ± 19 kg/lactation) and the lowest in Jericho (255 ± 17 kg/lactation). Prolificacy increased with parity, averaging 1.15 lambs in the first parity and 1.61 lambs in the third. Lamb birth weights reflected regional differences, with Tulkarm lambs reaching the highest average (4.69 ± 0.07 kg), and singletons (4.72 kg) were heavier than multiples (4.30 kg). Morphometric traits associated with productivity were evident in udder measurements, with average udder length and depth of 21.4 and 15.1 cm, respectively.

Conclusion:
The study highlights significant variability in Assaf sheep phenotypic and productive traits across regions. These findings provide essential information for breeding programs and management strategies aimed at improving sheep productivity and reproductive performance in the northern West Bank.

Key words: Assaf sheep; Sexual dimorphism; Morphometric traits; Milk production; Reproductive performance.