Evaluation of Perennial Ryegrass Straw as a Forage Source for Ruminants M. J. Fisher, D. W. Bohnert, C. J. Ackerman, C. S. Schauer, T. DelCurto, A. M. Craig, E. S. Vanzant, D. L. Harmon, and F. N. Schrick

Perennial Ryegrass Internationally  International markets increase the value of perennial ryegrass straw  Large demand for straw in the Pacific Rim  286+ thousand tons of Oregon’s Perennial Ryegrass straw shipped to Japan, Korea, & Taiwan from July 2000 thru June 2001 (Young, 2001)  Accounted for 52% Oregon’s total straw exports

Perennial Ryegrass Domestically  Potential economic impact of using straw as a feedstuff  Local & national use as a low-cost, winter forage source (Oregon State University – Crop & Soil Sciences Department)

Alkaloid Threshold Levels SpeciesErgovaline (ppb)Lolitrem B (ppb) Cattle ,800 – 2,000 Sheep ,800 – 2,000 Horses not determined Adapted from Hovermale & Craig (2001)

Objective Document safe feeding levels of lolitrem B in perennial ryegrass straw

Experiment 1: Digestion/Physiology

Materials & Methods  Protocol approved by OSU Animal Care and Use Committee  16 ruminally cannulated steers (509 ± 1 lb BW)  Randomized Complete Block  25-day period  Straw provided at 120% of the previous 5 d average; SBM at 0.24% BW (DM Basis)

Materials & Methods  Treatments: graded levels of a low and high lolitrem B straw  L = <100 ppb; H = 1550 ppb  100L:0H; 67L:33H; 33L:67H; 0L:100H  Orthogonal Contrasts  Linear  Quadratic

Feedstuff Nutrient Content (DM Basis) ItemLow a StrawHigh a StrawSBM CP5646 NDF Lolitrem B< 100 ppb1550 ppbN/A Ergovaline< 10 ppb160 ppbN/A a = Indication of lolitrem B level in perennial ryegrass straw

Effect of Increasing Lolitrem B on OM Intake < 100 ppb578 ppb1072 ppb1550 ppb OM Intake, % BW

Effect of Increasing Lolitrem B on OM Digestibility < 100 ppb 578 ppb1072 ppb1550 ppb OM Digestibility, %

Effect of Increasing Lolitrem B on Total Volatile Fatty Acids < 100 ppb 578 ppb1072 ppb1550 ppb Total VFA, mM

Effect of Increasing Lolitrem B on Serum Prolactin < 100 ppb 578 ppb1072 ppb1550 ppb

Effect of Increasing Lolitrem B on Steer Respiration Rate Q: P = 0.03 < 100 ppb 578 ppb1072 ppb1550 ppb

Effect of Increasing Lolitrem B on Steer Temperature < 100 ppb 578 ppb1072 ppb1550 ppb Temperature, ºF Q: P = 0.03

Experiment 2: Cow Performance/Production

Materials & Methods  Protocol approved by OSU Animal Care and Use Committee  72 cows (1188 ± 11 lb BW; BCS 5.4 ± 0.03)  Randomized Complete Block  Straw provided ad libitum; SBM at 0.18% BW (DM Basis)

Materials & Methods  Treatments: graded levels of a low and high lolitrem B straw  L = 467 ppb; H = 2017 ppb  100L:0H; 50L:50H; 0L:100H  Orthogonal Contrasts  Linear  Quadratic

Feedstuff Nutrient Content (DM Basis) ItemLow a Straw High a Straw SBMMeadow Hay CP, % N/A NDF, % Lolitrem B, ppb N/A Ergovaline, ppb40200N/A a = Indication of lolitrem B level in perennial ryegrass straw

Perennial Ryegrass Clinical Sign Evaluation Scale a Score Clinical Signs 0 No clinical signs 1 No resting tremors or incoordination; Low-intensity tremor and incoordination with handling 2 No resting tremors or incoordination; Moderate-intensity tremors and incoordination with handling 3 b Spontaneous low-intensity tremors and incoordination at rest; Moderate to severe tremors and incoordination with handling 4 Pronounced resting tremors and incoordination; Convulsive tremors and severe incoordination with handling 5 Severe spontaneous tremors and incoordination at rest usually accompanied by convulsive episodes. a Adapted from Galey et al., b Removal from study with a scale reading of 3.

13 of 24 (54%) of cows consuming ppb lolitrem B were removed from this experiment after receiving “clinical signs” score of 3 or greater

Effect of Increasing Lolitrem B on DMI 467 ppb 1242 ppb2017 ppb Dry Matter Intake, % BW

Effect of Increasing Lolitrem B on BCS at Calving Initial BCS 5.4 ± ppb 1242 ppb2017 ppb BCS Change

Effect of Increasing Lolitrem B on Milk Production L: P = ppb1242 ppb2017 ppb 24 hour milk production, lbs

Summary  No clinical symptoms of toxicosis observed up to 1550 ppb lolitrem B  54% of cows consuming ppb lolitrem B were removed from experiment after receiving a “clinical signs” score of 3 or greater  Increasing lolitrem B consumption had no affect on nutrient intake or performance of steers or cows

Implications  Feeding straw with a lolitrem B levels ≥ 2000 ppb can cause clinical symptoms of ryegrass staggers  Blending straws with low or high lolitrem B concentrations can be a successful management tool  These data provide the grass-seed industry and livestock producers with information concerning safe feeding practices of perennial ryegrass straw

Questions?