Fernández Novo, AitorFargas, OctaviLoste, Juan ManuelSebastián, FranciscoPérez Villalobos, NatividadPesantez Pacheco, José LuisPatrón Collantes, RaquelAstiz Blanco, Susana2021-10-192021-10-192020Fernández-Novo, A., Fargas, O., Loste, J. M., Sebastián, F., Pérez-Villalobos, N., Pesantez-Pacheco, J. L., Patrón-Collantes, R., & Astiz, S. (2020). Pregnancy loss (28–110 days of pregnancy) in holstein cows: A retrospective study. Animals, 10(6), 925. https://doi.org/10.3390/ani100609252076-2615http://hdl.handle.net/11268/10417The objective of this retrospective study was to investigate the prevalence of pregnancy loss (PL; between 28–110 pregnancy days) and its relationship with factors: farm, year (2015–2018), season, artificial insemination (AI)-rank, parity, AI-type (fixed-time vs. oestrus-AI), previous PL, days in milk (DIM), fixed-time-AI protocol, AI-technician, bull, and semen-type (sexed vs. conventional). Data of 19,437 Holstein cattle AIs from eight Spanish farms were studied. Overall conception rate was 34.3% (6696/19,437) and PL 12.3% (822/6696). The PL was more likely to occur in primiparous (10.8%, odds ratio (OR) = 1.35; p = 0.04) and multiparous (15.3%; OR = 2.02, p < 0.01) than in heifers (PL = 6.9%, reference). Pregnancies achieved with AI after observed oestrus and natural breedings were associated with less PL than pregnancies after fixed-time-AI (12.7 vs. 11.9%; OR = 0.12, p = 0.01). First AIs related to higher PL than ≥2nd AIs (PL = 13.8% vs. 11.2; OR = 0.73, p < 0.01). The factors season, fixed-time-AI protocol, DIM, bull, AI-technician, or type of semen were not significantly associated with PL. Therefore, farmers and consultants should adapt their preventive strategies relating to PL, particularly, to the parity of the cattle.engAttribution-NonCommercial-NoDerivatives 4.0 Internacionalhttp://creativecommons.org/licenses/by-nc-nd/4.0/journal article10.3390/ani10060925open accessGanado vacunoEmbarazoVeterinaria