Bulut, F. T. O.Dogan, H.Erdem, E.2024-10-292024-10-2920241516-635X1806-9061https://doi.org/10.1590/1806-9061-2023-1852https://hdl.handle.net/20.500.11776/14558This exploratory study aimed to investigate the effects of breed and body mass index (BMI) on arrested -laying (AL) associated with polycystic ovarian syndrome (AL-PCOS) in geese. Moreover, detailed pathological assessments in geese with AL were also performed. Mast geese and Large gray geese were reared under intensive feeding conditions. Observations during the laying season showed that all AL cases (n:8) (7.84%) were in Mast geese (n:102) fed with energy and protein -dense feeds. Necropsy revealed that all Mast geese with AL also had PCOS (8/8). In Mast geese, a significant difference was observed in body weight (BW) (p<0.0001) and BMI (p<0.0001) between the AL-PCOS group and the regular laying group. Follicle classifications detected by necropsy in AL-PCOS geese showed that among the Mast geese with AL-PCOS (n=8), two had atretic and cystic follicles (25%), four had type -1 and type -2 follicles (50%), and two had necrotic type -3 follicles (25%). The research data revealed that AL-PCOS might be correlated with breed and BMI, and that overfeeding and high BMI might increase AL- PCOS in breeds with high egg production, such as Mast geese. Therefore, it is crucial for farms raising high -yielding breeds such as Mast geese to strictly follow the laying periods and feeding regimes for high profitability. No previous reports had ever investigated AL-PCOS in geese, making this study the first of its kind. Moreover, the current study is also among the few presenting data on geese reproductive physiology and pathology.en10.1590/1806-9061-2023-1852info:eu-repo/semantics/openAccessArrested layingbody-mass indexgeesegenotypepolycystic ovarian syndromeArticle261N/AWOS:0011873587000022-s2.0-85188070765Q3