A Prospective Study of the Prevalence and Predictive Risk Factors of Repeat Breeder Syndrome in Dairy Cattle in the North of Spain.

This study examined the prevalence and risk factors of repeat breeder syndrome (RB) in 2370 dairy cows in northern Spain. Data collected included the prevalence of postpartum pathologies, metabolic markers, and productive and reproductive parameters. The overall RB prevalence was 21.1%. In primiparous cows, the postpartum body condition loss (Odds Ratio (OR): 2.9-8.1, depending on severity), ketosis (OR: 3.5), lameness (OR: 3.4), clinical mastitis (OR: 4.2), dystocia (OR: 5.2), and endometritis (OR: 12.2) significantly increased the RB risk. Summer (OR: 0.4) or autumn (OR: 0.6) calvings reduced this likelihood compared to winter or spring calvings. In multiparous cows, risk factors included body condition loss (OR: 2.0), ketosis (OR: 4.3), lameness (OR: 2.5), clinical mastitis (OR: 4.2), dystocia (OR: 1.9), endometritis (OR: 6.2), metritis (OR: 1.38), and subclinical mastitis (OR: 1.9). A longer interval between calving and first postpartum insemination reduced the RB risk (OR: 0.99). Overall, metabolic and reproductive disorders were significant risk factors for RB across both cow groups, while seasonal calving and delayed insemination mitigated risk in primiparous and multiparous cows, respectively.