Mammary gland development represents a complex and highly regulated biological process that is critical for mammalian reproductive success. This review provides a comprehensive analysis of the molecular, cellular, and hormonal mechanisms governing mammary gland development across distinct developmental stages: embryonic, pubertal, pregnancy, lactation, and involution. Mammary organogenesis is orchestrated by multiple factors, including conserved genetic pathways, endocrine signaling cascades, and environmental stimuli. Drawing primarily from studies in rodents and dairy ruminants, recent advances in molecular biology have elucidated key signaling pathways, including Wnt, Notch, and TGF-β, which provide fundamental insights into mammary epithelial growth and differentiation. Furthermore, we examine the effects of external factors, including thermal stress, photoperiodic variation, and dry period duration on mammary function and lactational performance. The dry period, in particular, serves a critical role in tissue remodeling and preparation for subsequent lactation cycles. Through systematic review of physiological and molecular dynamics across developmental stages, this article identifies key genetic regulators and cellular mechanisms, offering valuable insights for optimizing milk production and composition in agricultural systems.

Equines play a crucial role in global food security, economic development, and recreation, particularly in regions such as Central Asia, parts of Africa, and South America. However, parasitic infections significantly impact their health, productivity, and reproductive performance, leading to economic losses and reduced animal welfare. This review synthesizes the effects of parasitic infections, including protozoan, helminthic, and ectoparasitic species, on equines. These infections cause hematological alterations like anemia, leukocytosis, leukopenia, and thrombocytopenia, compromising overall health and resilience. Protozoan parasites, such as Trypanosoma spp., Theileria equi, and Babesia caballi, directly affect semen quality and fertility by causing testicular lesions, orchitis, and hormonal disruptions. Helminths like Cyathostomins and Strongyles reduce nutrient absorption, impairing productivity, while some protozoan species can cause abortion through transplacental transmission. Zoonotic parasites, including Sarcocystis spp. and Toxoplasma gondii, pose a human health risk through contaminated meat and milk consumption. Despite the effectiveness of conventional anthelmintics, emerging biological control methods like Duddingtonia flagrans (BioWorma^® and Bioverm^®) show promise. However, the development of standardized herbal anthelmintics and vaccines is hindered by limited efficacy validation, complex parasite biology, and inadequate funding. The need for better diagnostic tools and sustainable treatments remains critical for the long-term sustainability of the equine industry.

Stem cells (SCs), distinguished by their capacity for self-renewal and multipotent differentiation, represent a cornerstone of regenerative medicine. These cells, which can be categorized according to their differentiation potential and developmental origin, have emerged as pivotal elements in both biomedical research and veterinary science. In herbivorous species, stem cell applications have yielded particularly promising advances across multiple domains, including reproductive biotechnology, tissue engineering and regeneration, therapeutic interventions, and immunomodulation. This review synthesizes contemporary research on stem cell biology in five economically significant herbivorous species: bovine, ovine, deer, equine, and camelid. Special emphasis is placed on stem cell isolation methodologies, culture optimization techniques, and the molecular mechanisms governing key signaling pathways. The discussion encompasses both the technical impediments facing stem cell research and the ethical framework necessary for responsible scientific advancement, with particular attention to animal welfare considerations in the development and implementation of stem cell-based technologies.