The complexity of livestock production systems implies the interrelation of physical, technical, social, environmental, and animal factors. This study aimed (i) to classify and characterize farms in representative typologies and (ii) to point out the main factors responsible for the differences between the sheep farm typologies in Brazilian semiarid region. A structured questionnaire with 29 variables related to social, physical, livestock, technological, herd management, and productive indicators was applied to 65 sheep farmers. The farms typology was classified, characterized, and differentiated using several techniques of multivariate analysis. Three sheep production systems were identified: Emerging (16 farms): young adults farmers, medium farms and herds, intensive management, intermediate technological level, and high meat production; Conventional (40 farms): adult farmers, smallholder farms, small herds, low technological level, and low meat production; and traditional (09 farms): mature farmers, large farms and herds, extensive management, low technological level, and high meat production. Social, physical, livestock, herd management, technological, and productive factors showed discriminatory power (P < 0.05) to differentiate typologies. The family-based productive system still represents the primary sheep production system. Sheep farming in the Brazilian semiarid region is characterized as extensive, heavily dependent on natural resources, and susceptible to seasonal variations. Some common characteristics among the farms studied were the use of family labour and the predominance of extensive breeding with low stocking density. The emerging system is expanding and may represent the future of sheep farms. It is believed that the traditional system can intensify its management and migrate to the emerging system in the future. It is recommended to direct public policies that encourage the efficient succession of workers in sheep farming, adoption of technologies, and training of know-how professionals. The insertion of young farmers was considered a determining factor in the future of the sheep production system in the Brazilian semiarid region.

Studies on ruminant nutrition have been notable in recent years for the efficiency of the results and for providing useful information about maintaining or increasing the maximum growth rate and productive and reproductive performance of the animals. The association of several research lines can generate useful information. For the ruminants, the rumination process is a complex and occurs stimulated by the physical presence of food, which is the basis of any ruminant animal’s diet, and which above all generates endogenous heat from ruminal movements and metabolic processes that occur simultaneously. This amount of heat is associated with the absorption of heat from the external environment and can cause effects on animal performance. Thus, there is a need to study the factors and how they will directly or indirectly affect animal production, aiming at maximizing livestock production in the tropics. The objective of this review is to discuss nutritional influences in relation to thermoregulatory responses of ruminants, in addition to providing useful information from the different cases cited in the literature.