Table 1.
Year effects on the forage mass (FM) and nutritive values (CP; NDF; ADF; and true in vitro dry matter digestibility, IVTD) for a cool-season grass mixture and percentages of tall fescue (Lolium arundinaceum, TF), Kentucky bluegrass (Poa pretense, KBG), and orchardgrass (Dactylis glomerata, OG) for grazing trials conducted in 2016 (13 May– 22 July) and 2017 (25 April– 30 June).
Fig 1.
Effect of dried distiller’s grains (DDG) with or without red clover hay (RC) compared with pasture-only control on average daily gain (mean ± SEM bars) of steers grazing a mixture of endophyte-free tall fescue (Lolium arundinaceum), Kentucky bluegrass (Poa pratensis), and orchardgrass (Dactylis glomerata) during the early season (2016: 13 May to 22 July, 71 d; 2017: 25 April to 30 June, 67 d).
Thirty-six cross-bred Angus steers were blocked by body weight (BW; 12 pastures, n = 3 steers pasture-1) for random assignment to 1 of 4 treatments: Pasture only control, DDG (pasture + 2.27 kg DDG steer-1), Low RC (pasture + 1.51 kg DDG steer-1 + 0.91 kg RC steer-1), or High RC (pasture + 0.75 kg DDG steer-1 + 1.81 kg RC steer-1). The steers were weighed on the initial and final days of each year’s grazing trial following a 12- to 14-h fast from water and feed. Steers were placed on the pasture approximately 1-wk prior to obtaining initial shrunk BW. Means lacking a common letter are different (P < 0.05); Year: P < 0.01, Treatment: P < 0.01, Year × Treatment: P = 0.54.
Table 2.
Effect of dried distiller’s grains (DDG) with or without red clover hay (RC) compared with a pasture-only control on rumen short chain fatty acids (SCFA) and pH.
Table 3.
Effect of dried distiller’s grains (DDG) with or without red clover hay (RC) compared with a pasture-only control on the viable number of rumen bacterial guilds.
Fig 2.
Effect of dried distiller’s grains (DDG) with or without red clover hay (RC) compared with a pasture-only control on the ex vivo dry matter digestibility of cellulose by predominant cellulolytic bacteria in the rumen of steers grazing a mixture of endophyte- free tall fescue (Lolium arundinaceum), Kentucky bluegrass (Poa pratensis), and orchardgrass (Dactylis glomerata) during the early season (9 June– 22 July, 2016; 18 May– 29 June, 2017).
Ruminally cannulated Holstein steers (n = 12) were assigned to 1 of 4 treatments: Pasture only control, DDG (pasture + 2.27 kg DDG steer-1), Low RC (pasture + 1.51 kg DDG steer-1 + 0.91 kg RC steer-1), or High RC (pasture + 0.75 kg DDG steer-1 + 1.81 kg RC steer-1). Rumen fluid samples were collected at 4 and 6 weeks of grazing for cellulolytic bacteria enumeration. After incubation, top dilutions were evaluated for ex vivo dry matter digestibility of cellulose. Means lacking a common letter are different (P < 0.05); Year: P < 0.01, Treatment: P < 0.01, Treatment × Year: P < 0.01; SEM: Year = 0.40, Treatment = 0.67, Treatment × Year = 0.80.
Table 4.
Effect of dried distiller’s grains (DDG) with or without red cover hay (RC) compared with a pasture-only control on ex vivo dry matter digestibility by rumen fluid (RF) or bacterial cell suspensions (CS) fermenting ground corn, hay, or DDG.
Table 5.
Effect of dried distiller’s grains (DDG) with or without red cover hay (RC) compared with a pasture-only control on pH decline and NH3 accumulation in ex vivo fermentations of ground corn, hay or DDG by rumen fluid (RF) or bacterial cell suspensions (CS).