Fecal degradation and nutrient loss of manure from cattle offered four bermudagrass cultivars

Abstract

Abstract Bermudagrass ( Cynodon spp.) is one of the most common warm‐season perennial grasses utilized in the southeastern United States for pasture or stored forage. However, there is a paucity of data evaluating the fecal nutrient losses overtime by cattle grazing different bermudagrass cultivars. Therefore, the objective of this study was to assess the rate of fecal degradation and nutrient loss over time from cattle offered four different bermudagrass cultivars: Coastal, Russell, Tifton 44, or Tifton 85. Manure was collected from four ruminally fistulated heifers offered the bermudagrass cultivars previously mentioned in a 4 × 4 Latin square design. Manure was applied as surface pats into small plots arranged in a randomized complete block design with three replicates. Soil parameters were evaluated by bermudagrass cultivar, days after manure application (0, 28, 56, 84, and 112 days), and soil depth (0–5 cm and 5–10 cm). Concentrations of neutral and acid detergent fibers were greatest in the Coastal bermudagrass diet compared to other cultivars ( p ≤ 0.01). A greater dry matter (DM) loss was observed in manure from the Tifton 85 diet compared to other cultivars ( p = 0.02). Despite differences in manure fiber characteristics and DM disappearance, manure‐derived nitrogen (N), phosphorus (P), and potassium (K) concentrations did not differ among cultivars. Soil pH, carbon, and N were unaffected by cultivar, while temporal patterns in soil N, P, and K were driven by days after application rather than manure source. These results indicate that bermudagrass cultivar influences manure degradation rates but does not substantially alter short‐term soil nutrient availability.