## 1 Introduction  
Sheep milk stands out as a distinctive dairy product compared to cow and goat milk, primarily due to its higher concentration of butterfat and its lower levels of saturated fat. These characteristics make sheep milk an ideal source of medium-chain triglycerides, which are known for their cholesterol-lowering effects. Sheep milk is also recognized for its nutritional richness, containing higher concentrations of calcium, zinc, magnesium, and phosphorus compared to other milk varieties. Additionally, sheep milk is an excellent source of fat-soluble vitamins A, D, and E, as well as water-soluble vitamins like B2, B3, and folic acid (B9). Its protein content is significantly higher than that of cow and goat milk, which further boosts its nutritional value [1]. The composition of sheep milk per 100 g reveals an impressive nutritional profile, including total solids at 17.32 g, total protein at 5.86 g, and fat content at 7.28 g. These higher total solids contents, coupled with a rich profile of vitamins and minerals, make sheep milk particularly beneficial for producing dairy products such as yogurt and cheese. The presence of higher solids in sheep milk compared to cow milk is one of the key factors that makes it more suitable for manufacturing a range of value-added dairy products. Sheep milk's superior nutritional attributes, especially in terms of water-soluble vitamins and minerals, contribute significantly to the quality of dairy products made from it [2]. Yogurt, derived from the fermentation of milk, has become an essential part of many people's diets due to its well-established reputation as a nutritious food. It is a rich source of protein and calcium and offers a variety of health benefits. Many commercial yogurts are fortified with vitamin D or supplemented with probiotics, further enhancing their nutritional value and health-promoting properties. Regular consumption of yogurt has been linked to several health benefits, such as enhancing immunity, improving gut microbiota, and helping manage blood cholesterol levels [3]. Yogurt contains both casein and whey proteins, which offer numerous health benefits, including anti-inflammatory, antioxidant, and antitumor properties. The presence of essential micronutrients such as vitamins A, D, and E, along with a high concentration of calcium, makes yogurt an important contributor to human health. The fermentation process of yogurt enhances the bioavailability of these minerals, improving calcium absorption in the body [4]. The role of probiotics in yogurt is of great importance. Probiotic bacteria, which are living microorganisms, have been shown to provide various health benefits when consumed in adequate amounts. They are particularly known for their ability to promote gut health, alleviate lactose intolerance, and improve immune function. Probiotics also offer therapeutic benefits such as helping to restore the intestinal microbiota after antibiotic use, reducing the risk of diarrhea, and potentially assisting in the management of conditions like inflammatory bowel disease and irritable bowel syndrome. Probiotic strains such as _Lactobacillus rhamnos GG_ are especially valuable due to their ability to survive in the gastrointestinal tract, adhere to intestinal cells, and provide prolonged health benefits. _Lactobacillus rhamnus_ strains have been shown to remain in the colon up to 100 times longer than other probiotics, making them more effective for promoting long-term health [5]. When selecting probiotic strains for yogurt production, the compatibility between the probiotic bacteria and the starter cultures, such as _Lactobacillus bulgaricus_ and _Streptococcus thermophilus_, is crucial for ensuring the product's effectiveness. Furthermore, the survival of probiotics during storage and their stability during the fermentation process are essential factors that influence the quality of the final yogurt product.