Infectious and non-infectious factors affecting somatic cells count and new diagnostic approaches of intramammary infections in dairy goats: A review
Background: Intramammary infections constitute a major animal health and economic problem in commercial dairy goat farms, being responsible for decreases in milk yield, for alter milk composition, and lower milk quality. Objectives: This paper reviews the published literature during last three decades, highlighting the multiplicity of non-infectious and infectious factors that influence somatic cells count (SCC). Besides that, it intends to contributes to understand the conventional diagnostic methods and its limitations, and supports the implementation of new technologies for an efficient mastitis control, including the use of infrared thermography and ultrasonography. Methods: A search on Medline, ScienceDirect and University Institutional Repositories databases was performed using “goats AND mastitis OR intramammary infections OR somatic cells count” for publications from 1990 to present (2020). Results: A total of 144 publications were selected. The SCC is the most important criteria to evaluate the inflammatory status of the mammary glands in goats, but several non-infectious factors (e.g., phenotypic, reproductive, lactational factors) should be taken in consideration for it interpretation. Bacteria and fungi as well lentivirus are commonly responsive for intramammary infections. Intermittent secretion or environmental contamination of milk pathogens, costs and time delay pose challenges using conventional diagnosis methods. Ultrasonographic and thermographic techniques applied to the udder seems to be diagnostic value in acute and chronic mastitis. Conclusions: Unlike other ruminants species, non-infectious factors have a major impact on SCC which should be taken in account for mastitis diagnosis, and according to milk pathogens detection. Further research in imagological techniques is need to accurately contributes to implant new mastitis control strategies.