Abstract #T143
Section: Ruminant Nutrition (posters)
Session: Ruminant Nutrition: Digestion and Metabolism
Format: Poster
Day/Time: Tuesday 7:30 AM–9:30 AM
Location: Exhibit Hall A
Session: Ruminant Nutrition: Digestion and Metabolism
Format: Poster
Day/Time: Tuesday 7:30 AM–9:30 AM
Location: Exhibit Hall A
# T143
Switchgrass (Panicum virgatum) as a replacement for wheat straw in lactating dairy cow rations.
B. R. Lemay*1, R. L. Nagle1, J. C. DeBruyn2, A. Heeg3, M. Thimmanagari2, A. J. Carpenter4, 1Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada, 2Ontario Ministry of Food, Agriculture, and Rural Affairs, Guelph, ON, Canada, 3Ontario Ministry of Food, Agriculture, and Rural Affairs, Woodstock, ON, Canada, 4Department of Animal Biosciences, University of Guelph, Ridgetown, ON, Canada.
Key Words: switchgrass, milk production, DMI
Switchgrass (Panicum virgatum) as a replacement for wheat straw in lactating dairy cow rations.
B. R. Lemay*1, R. L. Nagle1, J. C. DeBruyn2, A. Heeg3, M. Thimmanagari2, A. J. Carpenter4, 1Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada, 2Ontario Ministry of Food, Agriculture, and Rural Affairs, Guelph, ON, Canada, 3Ontario Ministry of Food, Agriculture, and Rural Affairs, Woodstock, ON, Canada, 4Department of Animal Biosciences, University of Guelph, Ridgetown, ON, Canada.
Switchgrass (Panicum virgatum) is a native tall grass which has been researched as a novel species in the biomass industry, but also as a promising crop in the area of livestock feed. This study aimed to determine if switchgrass can be used as a replacement for wheat straw in lactating dairy cow rations in a crossover design. Holstein cows (n = 24, DIM = 129 ± 16.0) were randomly assigned a TMR containing equal amounts of either wheat straw (CON) or switchgrass (SGR) over 2 periods consisting of 17 d of adaptation and 4 d of sampling, where milk, blood, and feed samples were collected. Statistical analysis was conducted by a repeated measures analysis using PROC GLIMMIX of SAS with the fixed effect of treatment, day, and treatment × day, and the random effect of cow in the model for milk production, components and blood metabolites. DMI was consistent between groups (SGR = 25.1 ± 0.74, CON = 24.2 ± 0.74 kg/d; P = 0.17), but cows on the CON diet tended to produce greater daily milk yield (SGR = 34.2 ± 1.25, CON = 36.3 ± 1.24 kg/d; P = 0.07). Milk yield (kg) per kg of DMI was not significant between treatments but tended to be better for cows given the CON diet (SGR = 1.4 ± 0.12, CON = 1.6 ± 0.12; P = 0.09). Blood sample analysis for glucose, BHBA, and NEFA showed no differences between diets (P ≥ 0.32). Fat yield between diets was consistent (SGR = 1.46 ± 0.064, CON = 1.54 ± 0.064 kg/d; P ≤ 0.01), while protein was different (SGR = 1.09 ± 0.045, CON = 1.19 ± 0.045 kg/d; P = 0.03). Analysis of feed samples indicated no significant differences between the 2 diets in terms of NDF or NEl (SGR = 33.5 ± 0.74, CON = 34.8 ± 0.74; P = 0.26; and SGR = 1.6 ± 0.01, CON = 1.6 ± 0.01% diet DM, P = 0.29, respectively); however, CP tended to be different between the diets (SGR = 7.5 ± 0.31, CON = 6.6 ± 0.31% diet DM; P = 0.06). The switchgrass crop used in this trial was infected with head smut; however, these results suggest that replacement of wheat straw with switchgrass at an inclusion of 0.5 kg DM/d does not affect the metabolic health or fat production of Holstein dairy cows. Future trials should be repeated with different switchgrass crops to determine the effect of uninfected switchgrass under similar conditions.
Key Words: switchgrass, milk production, DMI
