Intake and diet preference of dairy heifers grazing mixed or alternating rows of birdsfoot trefoil and cool-season grasses

Authors: Peel, Michael; Waldron, Blair; BRISCOE, JACOB - Utah State University; ROSE, MARCUS - Utah State University; ISOM, S.CLAY - Utah State University; THORNTON, KARA - Utah State University; HADFIELD, JACOB - Utah State University; ROOD, KERRY - Utah State University; CREECH, J.EARL - Utah State University

Submitted to: Cool Season Grasses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/13/2024
Publication Date: 9/18/2024
Citation: Peel, M., Waldron, B.L., Briscoe, J.T., Rose, M.F., Isom, S., Thornton, K.J., Hadfield, J.A., Rood, K.A., Creech, J. 2024. Intake and diet preference of dairy heifers grazing mixed or alternating rows of birdsfoot trefoil and cool-season grasses. Cool Season Grasses. 3(3):219-229. http://dx.doi.org/10.1002/glr2.12094.
DOI: https://doi.org/10.1002/glr2.12094

Interpretive Summary: Mixtures of birdsfoot trefoil (BFT) with cool-season grasses increase the amount of forage that grazing dairy cattle consume. We hypothesized that spatially separated BFT would further increase preferential grazing of BFT and overall animal intake. Birdsfoot trefoil was planted in mixtures with orchardgrass, meadow bromegrass, tall fescue and perennial ryegrass in alternating rows and in mixed rows in separate pastures. These four mixtures were grazed by Jersey cows for three seasons, and forage production, animal forage intake, and animal grazing preference were measured. Planting BFT in alternating rows with grass did not change available forage, overall animal intake, nor animal preference of BFT compared to mixed rows. Birdsfoot trefoil comprised the same proportion of consumed forage in both alternating and mixed rows and showed a partial preference for BFT over grasses. The largest preferential grazing was in TF and OG mixtures, but was less than commonly reported for legumes, suggesting a larger separation between the legume and grass plants may increase BFT preference and consumption. Since the mixed versus alternating rows did not change what the animals consumed alternating rows can be used to achieve better BFT establishment and with competitive and less palatable grasses.

Technical Abstract: Mixtures of birdsfoot trefoil (BFT, Lotus corniculatus L.) and cool-season grasses increase dry-matter intake (DMI) in grazing dairy cattle. We hypothesized that spatially separated BFT would further increase preferential grazing of BFT and overall DMI. Binary mixtures of BFT were established with orchardgrass (OG, Dactylis glomerata L.), meadow bromegrass (Bromus biebersteinii Roem. & Schult.), tall fescue [TF, Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.] and perennial ryegrass (Lolium perenne L.) in alternating rows and in mixed rows. Pastures were rotationally stocked with Jersey heifers for three grazing seasons, and herbage mass, DMI, and preferential grazing measured. Planting BFT in alternating rows did not affect available herbage, overall DMI, nor BFT preference compared to mixed rows. Regardless of BFT spatial arrangement, pastures produced on average 4116 kg ha-1 per rotation of which 32% was BFT. Birdsfoot trefoil comprised the same proportion (39%) of DMI in both alternating and mixed rows, which was 7% greater (p=0.001) than that offered, indicating partial preference for BFT. The greatest preferential grazing was in TF and OG mixtures, but was less than commonly reported for legumes, suggesting greater spatial separation may increase BFT preference and DMI. Nevertheless, the lack of an effect of spatial arrangement on herbage, DMI, and diet preference indicates that alternating rows can be used to achieve better BFT establishment and persistence in mixtures with competitive and less palatable grasses.