The Effect of Perennial Grass Species on Forage Growth and Quality, Etiolated Growth, Animal Performance and Economics
A series of experiments were conducted during 2005 and 2006 to evaluate five perennial grass species for forage yield and quality, steer performance and grazing capacity, animal intake, plant energy reserves and economic return under grazed conditions. In 1999, two 0.8 ha replicates each of Paddock meadow bromegrass (Bromus ripariusRehm.), Carlton smooth bromegrass (Bromus inermisLeyss.) and AC Knowles hybrid bromegrass (B. riparius x B. inermis) were seeded. In 2003, two 0.8 ha replicates each of AC Goliath crested wheatgrass (Agropyron cristatum (L.) Gaertn.), hybrid bromegrass, and Courtenay tall fescue (Festuca arundinacea Schreb.) were seeded. A long established stand of crested wheatgrass acted as the control pasture. For 2003 established pastures, AC Goliath crested wheatgrass (7515 kg ha-1) had greater (P<0.05) cumulative dry matter yield than hybrid bromegrass (3136 kg ha-1) during the 2005 grazing season. Average (2005-2006) crude protein (CP) was greatest (P<0.05) for hybrid and smooth bromegrass for 1999 established pastures at start and middle of period one. Control pastures had the greatest (P<0.05) neutral detergent fiber (NDF) mid-grazing period. Over 2 years, smooth bromegrass had greater acid detergent fiber (ADF) (P<0.05) than control pastures at the end of the grazing period one. Average (2005-2006) in vitro organic matter digestibility (IVOMD) was greatest for hybrid and meadow bromegrass (P<0.05) at the start of grazing period one. Control pastures (129 g kg-1) had lower CP levels at the start of the 2005-2006 (average) grazing period 1 (P<0.05) compared to species seeded in 2003. Control and hybrid bromegrass pastures had the greatest NDF and ADF levels at the start of grazing period 1 (2005-2006 average) while tall fescue pastures had the lowest (P<0.05) NDF and ADF levels. Over 2 years, control pastures had the lowest IVOMD at start of grazing (P<0.05). In 2006, hybrid and smooth bromegrass had greater etiolated re-growth than control pastures (P<0.05). In 2006, grazed plants seeded in 1999 had greater (P<0.05) etiolated re-growth than ungrazed plants. For 2003 seeded grasses, crested wheatgrass produced greater (P<0.05) etiolated re-growth than tall fescue and control pastures. Average daily gain was similar (P>0.05) for all 1999 and 2003 seeded grasses. Overall, bromegrasses seeded in 1999 produced greater animal grazing days (AGD) than control pastures (P<0.05). Total beef production (TBP) was greater (P<0.05) for hybrid and meadow bromegrass compared to the control. All species seeded in 2003 produced greater AGD (P<0.05) compared to the control. Crested wheatgrass produced greater (P<0.05) TBP than the control over both years of the study. The C33:C32 alkane ratio estimated greater DMI (P<0.05) for hybrid bromegrass (9.9 kg d-1) and control pastures (9.6 kg d-1) compared to crested wheatgrass (6.8 kg d-1) or tall fescue (6.8 kg d-1) during period 1 in 2006. Over 2 years, net return to labor, equity and personal draw was greater (P<0.05) for hybrid bromegrass ($91.24 ha-1) compared to the control (-$54.32 ha-1). For 2003 seeded pastures, all pastures generated positive returns over 2 years. Crested wheatgrass ($92.49 ha-1) had greater net return than control pastures (-$54.32 ha-1) (P<0.05). Finally, the results of this grazing study indicate beef producers can manage these grasses during the summer grazing season and maintain high levels of animal performance and pasture production. This study has demonstrated that bromegrasses, crested wheatgrass and tall fescue could work well in a complementary grazing system.
Advisor:Herbert A. Lardner
School:University of Saskatchewan
School Location:Canada - Saskatchewan
Source Type:Master's Thesis
Keywords:hybrid bromegrass tall fescue grazing energy reserves animal intake meadow smooth crested wheatgrass
Date of Publication:02/13/2009