# Assessment of Milk Quality in Skopelos Goats Under Low- and High-Input Farming Systems
## 2 Materials and Methods  
### Farms and Animals  
This study was conducted from February 2022 to August 2023 on two goat farms in Greece: one extensive on the island of Skopelos (latitude 39.09\({}^{\circ}\), longitude 23.73\({}^{\circ}\)) and one intensive in the Attica region (latitude 37.95\({}^{\circ}\), longitude 23.95\({}^{\circ}\)). The environmental conditions on Skopelos island ranged from 2 \({}^{\circ}\)C to 42 \({}^{\circ}\)C in temperature and 55% to 74% in relative humidity, while the Attica region experienced temperatures ranging from \(-\)3 \({}^{\circ}\)C to 44 \({}^{\circ}\)C and humidity levels from 61% to 71%. The farms were classified as 'extensive' or 'intensive' based on the differences in input utilization, including farm characteristics, management practices, labor force, and infrastructure. A total of 237 goats were randomly selected for the study, including 132 from an extensive farming system and 105 from an intensive farming system. The sample sizes were designed to ensure the follow-up of at least 100 animals per system throughout the prospective study. All goats were in either their second or third lactation, with equal representation of lactation stages between farming systems to ensure balanced comparisons. This grouping reflects standard practices on commercial farms for managing feeding and milking. Additionally, goats were balanced by body weight (BW) and had similar parturition dates to minimize variability due to differences in lactation onset. The goats belonged to the Skopelos breed, an indigenous Greek breed known for its adaptation to dry and hot climates. The annual milk yield for the Skopelos breed ranges from 250 to 450 kg per 210-day lactation, with prolificacy ranging from 1.2 to 1.6 kids per doe. Genetic relatedness existed between the animals on both farms, as all goats in the intensive farming system originated from the Skopelos farm, having been purchased three years prior to the start of the study. Extensively reared goats were kept indoors at night in permanent sheds with ventilation openings, adequate floor space per animal, and floors that can absorb humidity and rainwater. Milking was performed by hand without prior udder preparation or teat disinfection. The goats grazed on natural grasslands and shrublands, and fed on typical endemic plants for the northwestern Aegean islands [31] and cultivated oat pastures. During the winter period, when pasture quality declined, the goats were supplemented with 0.5 to 1.0 kg/day of concentrated feed pellets (barley, corn, soybean meal, and a vitamin/mineral premix). In addition, 0.0 to 0.5 kg/day of alfalfa hay was offered depending on the condition and availability of natural forage. The goats continued to graze throughout the year; however, supplementary feeding was necessary in winter to compensate for the reduced nutritional value of the pasture. As pasture conditions improved in the spring and early summer, supplementation was gradually reduced, with concentrate offered at approximately 0.5 kg per day, while roughage needs were primarily met through grazing. In contrast, the intensively reared goats had no access to grazing and were kept in a permanent, well-ventilated barn with a controlled temperature and humidity, and straw bedding on the floor. These goats were fed 1.0 to 1.2 kg per day of commercial concentrated feed mixtures (including vitamin and mineral feed supplements) formulated specifically for dairy goats and 0.9 to 1.8 kg per day of alfalfa hay. The intensive farm was equipped with a 2 \(\times\) 24 parallel milking parlor and ample feed storage facilities. The parlor was regularly cleaned and well maintained to ensure hygienic conditions. Standard milking hygiene protocols were followed, including udder preparation using a wet towel followed by a dried towel before milking.