An inter- and transgenerational study on the effect of calving month of ancestors on dairy performances of Mediterranean buffalo

In this work intergenerational and transgenerational effects of calving months on dairy performances of Italian Mediterranean river buffaloes were investigated. The EBVs for milk, fat, and protein yields, as well as fat and protein contents of 112,625 females (F3) born between 1985 and 2022 were analyzed with a linear model that included the fixed effects of the calving month of their dams (F2, 63,442 cows), granddams (F1, 44,015 cows), and great-granddams (F0, 33,452), the covariable of F0 calving date, and the covariable of the F1 EBV. For a subset of 53,706 F3 buffaloes, further analyses were run including in the model the number of days with a temperature-humidity index larger than 70 during the last 100 d of their F0 pregnancy. All the 5 considered traits were affected by the ancestor month of calving. The effect tended to decrease as the distance between generations increased. Buffaloes whose greatgranddams calved in September showed the lowest LSM of EBV for dairy traits, whereas the largest values were exhibited by buffaloes whose F0 had calvings in December. Similar pattern was observed for the F1 calving month effect. An exception was found for the effect of F2 calving month. The F3 cows whose dams calved in December showed the largest average EBV for yield traits. This result seems to indicate that for adjacent generations, environmental conditions in the periconceptional period may be more important than in late pregnancy. Results of the present work confirmed previous reports of inter- and transgenerational effects of calving months of female ancestors in dairy cattle, suggesting the existence also for buffalo of mechanisms of epigenetic inheritance related to environmental conditions during pregnancy. A deeper understanding of the role of transgenerational and intergenerational epigenetic inheritance in the expression of phenotypes of economic interest would provide useful insights for the management and the breeding of river buffaloes