Data on 1440 Awassi (AW), 2114 Assaf (AF), 261 Crossbred (XB), and 439 Improved Awassi (IA) lamb genotypes from 689 AW, 1009 AF, 105 XB, and 195 IA dams, and 152 sires, obtained from three geographical districts in the West Bank and collected between 2010 and 2015, were analyzed to estimate (co)variance components and genetic parameters for pre-weaning growth traits, including birth weight (BW), weaning weight (WW), pre-weaning average daily gain (PADG), and Kleiber ratio (KR). Explanatory statistical analyses employed the least squares method of the following factors: lamb genotype, mating type (natural mating or artificial insemination), lamb sex, and birth type, on lamb pre-weaning growth traits. The estimation of genetic parameters was performed by an animal model in Restricted Maximum Likelihood (REML) The heritability estimates for lamb traits showed that AF lambs had the highest heritability for KR 0.62, while IA lambs had a relatively high heritability for PADG 0.42. In terms of genetic correlations, the correlation between birth weight and PADG was strongest in AW 0.80, and IA lambs had a negative genetic correlation between BW and WW −0.28. For maternal genetic correlations, AF lambs exhibited a high maternal correlation between BW and WW 0.78, and AW lambs had a strong maternal correlation between PADG and KR 0.57. Phenotypic correlations were particularly strong in XB lambs between BW and KR 0.79. It was concluded that IA lambs had higher BW, and AF lambs excelled in WW and PADG. These results indicated the potential for genetic improvement in feed efficiency among AF lambs, whereas AW lambs exhibited a stronger environmental influence on growth traits.

The objective of the present study was to evaluate the protective effects of nanoemulsion of thyme (Thymus vulgaris) essential oil (EO) during the liquid state preservation of ram semen. Storage media were prepared: one containing Thymus vulgaris essential oil (Th), another with its nanoemulsion form (NTh), and a control sample without essential oil (Dovx). The quality of the semen diluted in the prepared media after preservation at 4°C and 15°C was examined by measuring the two parameters indicative of semen quality: semen motility and progressivity refer to the ability of ram sperm cells to move actively and efficiently, which is crucial for successful fertilization. The results showed a decrease in the mobility and progressivity of the sperm in all the mediums, but the thyme EO and its nanoemulsion showed slight decreases compared to the control medium (p<0.05). On the other hand, the study identified a negative impact of thyme EO nanoemulsions on catalase concentrations, potentially leading to mobility inhibition (p<0.05). In addition, the nanoemulsion significantly (p<0,05) decreased the malondialdehyde concentration, increased the total protein and the glucose contents, the lactate dehydrogenase activity. A significant decrease in calcium content was observed (p < 0.05). The essential oil of Thymus vulgaris, combined with nanotechnology encapsulation as a delivery method (nanoemulsion), demonstrated a notable and effective role in enhancing the preservation of ovine semen.

The detrimental effects of hyperthermia on the testes and the protective effect of thyme essential oil against testicular damage induced by this stress in rams were studied. Twenty‐four rams of the Barbarine breed with an average weight of 62.5 ± 0.3 kg and an average age of 24 ± 0.6 months. The experiment consisted of inducing localized heat stress on the first group of rams by applying heat bags to both testicles of six rams (G s). The second group underwent the same heat stress on the testes but received orally 100 µL/day/animal of thyme essential oil (G s‐he). A positive control did not undergo stress but received thyme essential oil (G he) with the same doses as the (G s‐he) group, and the negative control did not undergo either stress or receive the essential oil of thyme (G c). One hundred twenty‐eight adult ewes of the same breed divided into four groups of 32 ewes were used to study the effect of different treatments on the in vivo ram's fertility. Ewes are synchronized and we have applied natural mating with oestrus control, the reproduction balance sheet is calculated after lambing. The results showed that tests of heat stress (HS) negatively affect semen quality but did not cause infertility. However, neither tests for heat stress nor treatment with thyme EO significantly affected the haematological profile. The study of the effect of heat stress on the testes on fertility in vivo showed a drop in the number of females who were fertilized at the first oestrus and consequently a drop in fertility. However, the rams that suffered the same stress but were treated with EO thymus recorded an improvement in these parameters.

This study aimed to investigate the effect of wormwood and rosemary supplementation on some reproductive traits of Barbarine rams. The experiment lasted 2 months. Twenty‐four adult rams were divided into four groups (n = 6) balanced for the weight (53.3 ± 1.2 kg body weight [BW] ± SD). All rams received 1200 g of straw and 600 g of barley. Control rams (C) without aromatic medicinal plant (AMP), while experimental rams received 20 g of fresh rosemary leaves (R), 20 g of fresh wormwood leaves (A), and 10 g of fresh rosemary leaves plus 10 g of fresh wormwood leaves (RA). The results revealed that the live weight of all rams increased (p < .05) in the RA group compared to the C, A, and R groups. Scrotal circumference increased in the R rams when compared to the controls rams (p < .05). For sperm parameters we showed that the A rams had higher sperm concentrations (p < .05). But, the sperm volume decreased in the R rams (p > .05). However, when the rams received rosemary plus wormwood, their sperm volume increased (p > .05). The sperm mass motility was higher for the A, R and AR rams in comparison to the C rams (p = .05). On the other hand, biochemical analysis of the seminal fluid showed no effect of diets on calcium and total proteins concentration. But the measurement of glucose and seminal insulin showed a decrease (p < .05) in these two biochemical markers in group A rams and a decrease (p < .05) in insulin without modification of the glucose concentration in R rams. Blood glucose and insulin decreased in the animals on AMP diet compared to the other groups (p < .05) while aspartate aminotransferase (AST) increased (p < .05). Rosemary leaves (R and RA groups) increased (p < .05) plasma cortisol compared to the other groups. It can be concluded that the addition ofRosmarinus officinalisand/orArtemisia herba albain ram diet can have a positive effect on the reproductive function by increasing the concentration and motility of sperm, plasma testosterone, and sexual behavior.

Background and Aim: Artificial insemination (AI) is a critical technique in sheep breeding programs, yet its success is influenced by factors such as semen quality, storage conditions, and insemination timing. This study examines the effects of different semen extenders, storage durations, and insemination schedules on semen motility and pregnancy rates in Palestinian Assaf sheep. The primary aim of this study was to assess and compare the efficacy of three semen extenders – Andromed, Indonesian, and Syrian – on the quality of stored semen and its subsequent effect on pregnancy rates following AI. In addition, the study investigated the impact of semen storage duration and the timing of insemination post-equine chorionic gonadotropin (eCG) injection on reproductive outcomes. Materials and Methods: Semen was collected from eight Assaf rams, diluted with one of three extenders, and stored at 4°C for up to 72 h. Sperm motility was analyzed using a computer-assisted sperm analysis system at different time intervals. AI was performed on 180 Assaf ewes across three farms in Palestine, with insemination conducted at either 48 h, 52 h, or both 48 and 52 h post-eCG injection. Pregnancy rates were determined through ultrasound 45 days post-insemination. Statistical analysis was conducted using the Statistical Package for the Social Sciences 22 (IBM® NY, USA), with p-values set at <0.05 for significance. Results: Semen motility decreased significantly over time, with total motility (TM) declining from 0.85 ± 0.01 (fresh) to 0.63 ± 0.02 after 3 days of storage. The Syrian extender exhibited superior fast motility (FM) (0.35 ± 0.01) compared to the others. Strong positive correlations were observed between TM and progressive motility (0.90, p ≤ 0.01). Pregnancy rates did not significantly differ among extenders (Andromed: 0.58 ± 0.06, Indonesian: 0.54 ± 0.07, Syrian: 0.56 ± 0.08). However, insemination performed at both 48 and 52 h post-eCG injection resulted in the highest pregnancy rate (0.62 ± 0.07), while the second ejaculation showed a tendency for improved fertility outcomes (0.61 ± 0.07). Conclusion: Prolonged semen storage negatively impacts motility, though the Syrian extender preserves FM better than the others. Pregnancy rates were not significantly influenced by the extender type but were optimized by insemination at both 48 and 52 h post-eCG injection. These findings highlight the importance of refining semen preservation techniques and timing AI procedures to enhance breeding success in Assaf sheep. Keywords: artificial insemination, breeding efficiency, Palestinian Assaf sheep, semen preservation.

As global demand for sheep products increases, improving reproductive efficiency and lamb growth performance has become a priority for sheep farmers. Artificial insemination (AI) offers several advantages over natural mating, including improved genetic selection and disease control. This study contributes to understanding the impact of different mating methods and semen preservation techniques on reproductive performance and growth traits in Palestinian Assaf sheep under local breeding conditions. The research included 123 adult Assaf ewes from two farms, which were hormonally synchronized and divided into three groups for different reproductive biotechnologies. Group 1 (G1) comprised 50 ewes inseminated with frozen semen straws, while Group 2 (G2) had 37 ewes inseminated with fresh semen from genetically superior rams. Both G1 and G2 used 0.5 mL straws containing 250 million sperm, with insemination occurring 48 h post sponge removal and eCG hormone injection. Group 3 (G3) consisted of 36 ewes that underwent natural mating at a ratio of 1 ram to 6 ewes. The study revealed that insemination methods significantly affected fertility rates (45.4, 61.1, and 71.9% for G1, G2, and G3, respectively; p < 0.05). Artificial insemination notably enhanced lamb performance indicators (p < 0.05), although it did not significantly influence prolific lambing (p > 0.05). Prolific lambing significantly impacted birth weight, weaning weight, and average daily gain at 60 days across all groups (p < 0.05), but not the average daily gain or final weight at 180 days (p > 0.05). The management system significantly affected birth and weaning weights at 60 days (p < 0.05), but not the final weight at 180 days or prolific lambing (p > 0.05). Lamb sex significantly influenced average daily gains at 60 and 180 days, as well as final weight at 180 days (p < 0.05). The findings suggest that, while artificial insemination with semen from elite rams may reduce fertility rates, it significantly improves lamb performance rates. In conclusion, our study demonstrates that, while natural mating offers higher fertility rates, AI with fresh semen can be a valuable tool for improving lamb growth performance in Palestinian Assaf sheep. These findings provide valuable insights for sheep farmers in the region to optimize reproductive strategies and enhance lamb production