# Assessment of Milk Quality in Skopelos Goats Under Low- and High-Input Farming Systems
## 4 Discussion  
This study evaluated the combined effects of farming systems (intensive vs. extensive) and LS across two lactation periods on the chemical and physical characteristics and SCC of Skopelos goat milk derived from two commercial farms. To the best of our knowledge, there are no previous studies comparing these effects in commercial dairy goat farms with the same genetic background under different farming systems. This study demonstrated that milk yields are consistently higher in the intensive farming system. These results are in agreement with those reported in other breeds, including Italian local goat breeds [40] and Baladi goats [41], indicating that a controlled environment, as is often the case in intensive farming systems, improves productivity in dairy goats. In addition to the farming system, the LS significantly affects milk yields. Milk output gradually declines from the beginning to the end of lactation with a relatively fast reduction towards the end. As lactation progresses, the decline in mammary gland synthesis efficiency leads to a reduction in milk yield. As observed in our study, am_MY decreases by 30% and 36% in the third and fourth LSs, respectively, compared with the first stage. The farming system in this study did not influence the fat content of the milk. These results are in agreement with [PERSON] et al. [42] who reported that grazing-based systems do not significantly affect fat content and [PERSON] et al. [43] who noted that in goats with moderate to low milk production potential, such as the Skopelos breed, farming systems have a relatively minor influence on fat content. Regardless of the farming system, LS significantly affects the fat content of milk with the higher values occurring during mid-lactation. This peak coincides with the spring season, where goats in the extensive farming system have access to fresh, high-quality pasture, while those in the intensive system benefit from the higher availability and lower prices of alfalfa [44]. Protein content was significantly higher in the extensive system compared with the intensive system. This suggests that grazing may enhance the nutritional profile of milk, and particularly its protein fraction, as observed in another study [45]. This supports the idea that while intensive farming maximizes milk volume, extensive systems may enhance milk protein content, which is particularly valuable for cheese production and dairy product formulation, as demonstrated in [PERSON] goat milk by [PERSON] et al. [46]. Lactation stage also influences the protein content of milk, with lower values during mid-lactation. Similar findings have also been reported with higher productivity breeds such as the Alpine and Nubian breeds [47]. Caseins are the predominant proteins in milk, accounting for approximately 80% of total milk proteins [48]. Caseins play a crucial role in calcium transport and absorption and they are a precursor for bioactive peptides, which have various potential health benefits [49]. Additionally, caseins are fundamental in cheese manufacturing, affecting both cheese yield and texture. They are the major proteins involved in coagulation during renting [46]. In this study, the Cas content was similarly affected by farming system and LS as total protein level. Goats in the extensive system produced milk with higher Cas levels (2.72%) than those from the intensive system (2.57%). These findings are consistent with the results of [PERSON] et al. [50] who studied Norwegian dairy goats under grazing. Cas content was also affected by LS with higher levels in early and mid-lactation compared with later stages. These findings are in agreement with previous studies [51], suggesting that early lactation supports higher casein synthesis, which gradually decreases as lactation progresses due to metabolic shiftsprioritizing energy and lipid production over protein synthesis. The lactose content of milk is not affected by farming systems but significantly and consistently declines during lactation.