The primary aim of this research was to assess the impact of supplementing fish oil into the diet of pregnant Awassi ewes on various aspects of the dam’s productive performance, offspring birth weight, colostrum yield and quality, milk production and composition, postpartum offspring performance, and the composition of fatty acids in milk. In this study, two different fat sources, namely palm oil (PO) and fish oil (FO), were utilized, with both being included at a rate of 2.4% of dietary dry matter (DM) during the initial 65 days of gestation (early gestation stage), and then at 2.1% DM from day 65 of gestation until lambing (late gestation stage). The study subjects were Awassi ewes with a body weight (BW) averaging 57 ± 1.5 kg and an age of 3.5 ± 1.2 years. These ewes were randomly assigned to one of four dietary treatments: (i) a diet containing only palm oil from day 0 to day 150 of pregnancy (PO, n = 15); (ii) a diet containing palm oil from day 0 to day 65 of pregnancy, followed by a diet containing fish oil from day 66 to day 150 of pregnancy (POFO, n = 16); (iii) a diet containing fish oil from day 0 to day 65 of pregnancy, followed by a diet containing palm oil from day 66 to day 150 of pregnancy (FOPO, n = 16); (iv) a diet containing only fish oil from day 0 to day 150 of pregnancy (FO, n = 16). Within each treatment, ewes were housed in three replicates, with each replicate further divided into three subgroups. The first two subgroups each contained eight ewes, while the third subgroup contained nine ewes. In addition, each treatment contained 10 primiparous and 15 multiparous ewes. The results indicated that the POFO treatment led to significant increases (p < 0.05) in birth weight, gestation length, and colostrum IgG concentration. However, it also resulted in a decrease (p < 0.001) in colostrum production and a reduction (p < 0.001) in the percentage of milk fat and milk protein. Furthermore, the milk from the POFO treatment exhibited higher levels of polyunsaturated fatty acids (PUFAs) (p < 0.001) compared to the PO and FOPO treatments, while the milk saturated fatty acids (SFA) were lower (p < 0.001). In conclusion, the addition of fish oil at a rate of 2.1% DM during the late pregnancy period showed promise for enhancing birth weight, colostrum IgG concentration, and the PUFA content in the milk.

This research provides an in-depth analysis of the effectiveness of sheep farming, with a particular focus on the Awassi breed in the harsh environments of the Middle East. Investigations were conducted at the Fjaj sheep station in Jordan, with emphasis on how various factors, including lambing type, lamb sex, parity, age at lambing, and the ram affect the weight characteristics of 2,263 records. Advanced statistical models, both fixed and mixed were employed to estimate genetic and breeding values, particularly in relation to the number of lambs per ram. The findings underscore the crucial role that both genetic and environmental factors play towards improving weigh traits and overall flock performance. Similar strategies may be effective in other breeds and in other regions with diverse environmental conditions. The study concludes that when farmers prioritize selective breeding and environmental management they can significantly enhance weight traits, boost profitability, and achieve sustainable economic success in sheep farming.

Sheep farming thrives in diverse climates, with the Awassi breed well-suited for arid environments, though it faces challenges that necessitate selective breeding and innovative management to improve productivity and weight performance. This study, conducted in 2023 at Al-Fjaj Station in Jordan, analyzed the weights of Awassi sheep managed under a semi-intensive system, examining 2,263 records to evaluate the environmental and genetic factors influencing growth and utilizing statistical models to estimate heritability and breeding values. Variance analysis revealed that birth type, lamb sex, parity, and ewe age at lambing significantly influence birth, weaning, 6-month, and annual weights, with single-born lambs generally heavier than twins, males surpassing females, and younger ewes producing lighter lambs at birth that catch up in weight later. Lamb weights are correlated positively across various stages, especially between weaning, six-month, and yearling weights, while the influence of birth weight on later weights is comparatively weaker. Analysis of Variance (Type 3) indicates that rams have the greatest influence on lamb weights at all ages, while ewes primarily affect early weight, and genetic factors play a moderate role in weight variation, with maternal effects being more significant than paternal influences. There are significant positive genetic correlations among lamb weight traits, indicating that improvement in one trait can benefit others, while mean breeding values decrease with age due to increasing environmental influences, suggesting the use of index selection to enhance multiple traits in breeding programs. High correlation coefficients between breeding values and mean weights of Awassi sheep indicate that higher breeding values for specific weight traits are associated with greater actual weights, demonstrating that selection based on breeding values can effectively enhance genetic potential and predict future performance. The genetic performance and growth traits of rams' progeny indicate that selecting rams with higher breeding values can enhance weight gain in future generations, while mean weights serve as performance benchmarks to help breeders improve flock genetics and profitability. In conclusion, this study identifies key factors influencing lamb weights, such as birth type, lamb sex, ewe parity, and ewe age, emphasizing the importance of single lambs and males in achieving higher growth, while suggesting that an index selection approach combining genetic merit with environmental factors is vital for optimizing sustainable lamb production in arid environments.