Endocrine, Metabolic, and Reproductive Responses to Bee Pollen Supplementation During Seasonal Anestrus in Goats in a Time-Dependent Manner

Goats in subtropical and temperate regions experience seasonal anestrus during long-day conditions. This study evaluated the effects of bee pollen (BP) supplementation on circulating metabolic and endocrine measures, plasma short-chain fatty acids (SCFAs), and reproductive outcomes. Thirty crossbred Spanish × Boer does were assigned to T-CTL (n = 15) or T-BP (n = 15). After a 7-day adaptation period, T-BP received 10 g/day BP for 42 days (approximately 0.31 g/kg initial body weight/day), while T-CTL received carrier feed alone. We measured plasma glucose, insulin, insulin-like growth factor 1 (IGF-1), progesterone (P4), and SCFAs. BP supplementation did not significantly (p > 0.05) alter plasma glucose, insulin, IGF-1, or overall P4 concentrations. Only five does became pregnant (T-BP, 2/15; T-CTL, 3/15); therefore, fertility, prolificacy, and reproductive rate were summarized descriptively. Most plasma SCFAs did not show a consistent treatment-dependent temporal response. Isovalerate showed a significant treatment × date interaction, whereas hexanoate differed overall between treatments without a significant treatment × date interaction. Under this single-dose protocol, BP did not consistently modify circulating metabolic–endocrine markers or improve reproductive performance during the suboptimal breeding season. Future studies should include dose-ranging, direct rumen measurements, and adequately powered reproductive endpoints.