- Blackberry pomace (BBP), a byproduct from juice processing, is often disposed of in landfills. We propose BBP as an antioxidant-rich feed supplement for transition dairy cows. To explore the effects of BBP on antioxidant status, 24 multiparous dairy cows (5 Holstein and 19 Jersey) were assigned randomly to one of three treatment groups, receiving 0, 56.7, or 113.4 g dried BBP/day as topdressing to feed (0, 1,844, or 3,688 μM Trolox equivalents Ferric Reducing Antioxidant Power, respectively). Supplementation started 28 days before expected parturition and ended 28 days after. Blood samples were collected once a week during supplementation and every other day in the weeks before and after parturition. Plasma Ferric Reducing Antioxidant Power (FRAP) was used to indicate antioxidant status. PROC MIXED in SAS version 9.4 was used for data analysis; fixed effects being breed, supplementation, time, and the interaction between supplementation and time. Repeated measures within the same cow were modeled using heterogeneous compound symmetry. Overall, BBP supplementation did not alter plasma FRAP concentrations (p = 0.99). Plasma FRAP concentrations did not change around calving (p = 0.40). Holsteins had higher plasma FRAP concentrations than Jerseys (540 ± 34 µM vs. 443 ± 16 µM; p = 0.01).
Key Words: Blackberry pomace, transition dairy cows, antioxidant status.