Tim Wilson, UF/IFAS Extension St. Johns County, St. Augustine, FL, Matt Hersom, UF/IFAS Department of Animal Sciences, Gainesville, FL, Mark Warren, UF/IFAS Extension Flagler County, Bunnell, FL, Gary England, UF/IFAS Extension, Hastings Agricultural Extension Center, Hastings, FL, David Baggett, UF/IFAS Extension, Hastings Agricultural Extension Center, Hastings, FL
Situation: A proof of concept demonstration was designed to evaluate the use of cull, chip potatoes to upcycle low to marginal quality bahiagrass hay as an alternative feed resource for beef cattle producers. Methods: Two treatments were utilized; treatment one (Trt1) was a combination of 3.31 kg of hay (25%) and 9.99 kg of potatoes (75%; as-fed basis); treatment two (Trt2) was a combination of 2.5 kg of hay (20%) and 9.99 kg of potatoes (80%; as-fed basis). Two 208-L and one 132-L plastic barrels with lids were utilized for each treatment. Hay was peeled from the bale and potatoes were rough chopped through a wood chipper. Hay and potatoes (DM = 93.5 and 70.5%, TDN = 61 and 85%, CP = 8 and 10%) were alternately layered into a barrel and compressed. After the sixth layer, barrels were sealed and fitted with a check-valve and a vacuum was applied to remove air. Barrels were opened, and silage samples were taken after 72 d. Two cores from each barrel were collected for analysis. Data was analyzed using Mixed procedures of SAS and LSMeans were reported. Results: Dry matter content did not differ (P = 0.96, 32 ± 1.4%) between treatments and were 50% below the goal of a 60-65% DM product. Energy values did not differ (P ≥ 0.17) on a DM basis, but were below expectation (TDN = 62.1 ± 2.04%, NEm = 0.26 ± 0.016 mcal/kg, NEg = 0.15 ± 0.015 mcal/kg) based on the proportions used. Crude protein was not different (P = 0.47, 10.1 ± 0.49%) and greater than or equal to predicted. A nearly 50% greater (P = 0.11) amount of starch in Trt2 compared to Trt1 indicated that fermentation of starch was limited. Limited fermentation is indicated by the similar (P = 0.92) lactic acid, but nearly 50% decrease (P = 0.06) in total acid production in Trt2 compared to Trt1. Dry matter intake potential, predicted from NDF, was similar (P = 0.27, 13.5 ± 1.28 kg). Conclusion: Proof of concept was successful with this demonstration; however, caution must be made as no measure of digestibility or intake was established. Upscaling to a small-scale, on-farm demonstration would seem necessary to validate this conclusion.