Effects of Annual and Perennial Forage Systems on Forage Biomass and Quality, Grazing Animal Performance and Enteric Emissions, and System Economics

Two experiments were conducted to evaluate annual and perennial forage systems with respect to forage yield and quality, grazing animal performance, rumen fermentation, enteric methane production, and system economics. Forage systems included (1) CDC Austenson barley (Hordeum vulgare L.) + 4010 pea (Pisum sativum L.) + Winfred forage brassica (Brassica oleracea L.× Brassica rapa L.) + Gorilla forage brassica (Brassica napus L.) (BRPEBRS), (2) AC Hazlet fall rye (Secale cereale L.) + Frosty berseem clover (Trifolium alexandrinum L.) (FRCLOV), (3) AC Success hybrid bromegrass (Bromus riparius Rehm. × Bromus inermis Leyss.) + PS3006 alfalfa (Medicago sativa L.) (HBGALF), and (4) AC Armada meadow bromegrass (Bromus riparius Rehm.) + AAC Mountainview sainfoin (Onobrychis viciifolia Scop.) (MBGSF). Experiment 1 was conducted over a 2-yr period (2020 and 2021). Each yr, Bos taurus crossbred steers (n = 156, initial body weight = 364 ± 17 kg) were randomly allocated to 1 of 4 forage systems (n = 3 replicates/treatment) for 54 ± 21 d grazing period each year. Dry matter yield (DMY) of HBGALF was greater (P < 0.01; 3046 kg ha-1) than all other treatments. Annual forage systems had greater (P < 0.01) total digestible nutrients (64.8 vs. 58.6% TDN), greater (P < 0.01) crude protein (13.7 vs. 10.2% CP), less (P < 0.01) neutral detergent fibre (46.9 vs. 59.5% NDF) and greater (P < 0.01) digestibility (74.9 vs. 61.85% NDFD30hr) than perennial forage systems. Steers grazing FRCLOV had greater (P < 0.01) DMI than all other treatments. Total beef production was greatest (P = 0.03) for HBGALF (124 kg ha-1). Enteric methane results were not conclusive. Economic net returns were also greatest (P < 0.01) for HBGALF. In Experiment 2, the in vitro ruminal fermentation of the forage treatments were investigated using the rumen simulation technique (RUSITEC). Annual forage systems had the greatest (P < 0.01) nutrient disappearance, greatest (P < 0.01) total volatile fatty acid (VFA) production (99 vs. 92 mmol d-1), and greatest (P< 0.01) ammonia-nitrogen (NH3-N) production (48.5 vs. 33.8 mg d-1). These fermentation parameters support improved growth performance in ruminants grazing annual forage systems however, DMY of perennial forage systems had a larger impact on total beef production and profitability.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Animal Science

Grantor

University of Saskatchewan

Year dc:date.issued

2024

Author dc:creator

• Wasden, Megan Irene

Advisor dc:contributor.advisor

• Lardner, Herbert A

Committee members dc:contributor.committeemember

• Ribeiro, Gabriel O
• Biligetu, Bill
• Larson, Kathy
• Coulman, Bruce E
• Penner, Gregory B

• forage
• annual
• perennial
• grazing
• methane

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10388/15579

OAI identifier oai:identifier

oai:harvest.usask.ca:10388/15579