Publication Date
1993
Description
Changes in intake ,ate (IR), bite mass (BM), and biting rate (BR) and ingestive mastication of tall fescue (Festuca arundinacea Schrcb; TF), orchardgrass (Dactylis glomerata L; OG) and ryegrass (Lolium perenne L: RG) were studied over 3 grazings between early spring and early summer of 2 consecutive years. Defoliation by steers started at 100 mm canopy height (Tl) and terminated at 50 mm (T2). At Tl, and again at T2, ocsophageal-fistulated steers were used to estimate IR, BM and BR and to provide extrusa samples for determination of 1nasticatc particle size after dry sieving. At Tl there was no consistent trend of IR with date. Intake rate of RO increased from 31 to 37 g dry matter (DM)/min, whereas that of TF decreased from 42 to 33 g OM/ min with advancing season. At T2, mean IR was lower and declined linearly (P<0.05) with advancing season for each species, from 22 to 15 g DMlmin. This was based on a linear decline (P<0.05) in BM from 0.37 lo 0.27 g OM/bite from early spring lo late spring. Biting rate did not change significantly with advancing season at either TI or T2. Masticate mean particle size at TI was similar for each sampling date and averaged 3.11 mm. At T2 mean particle si.r:e was smaller than at Tl and showed a linear decrease (P<0.05) with sampling date from 2.55 mm in early spring to 1.93 mm in late spring. Canopy height at which grazing terminates, needs to be progressively increased during the season to maintain constant IR.
Citation
Cosgrove, G P.; Burns, J C.; Fisher, D S.; Pond, K R.; and Mueller, J P., "Variation in Intake Rate and Mastication by Grazing Steers in the Spring" (2024). IGC Proceedings (1993-2023). 9.
https://uknowledge.uky.edu/igc/1993/session18/9
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Variation in Intake Rate and Mastication by Grazing Steers in the Spring
Changes in intake ,ate (IR), bite mass (BM), and biting rate (BR) and ingestive mastication of tall fescue (Festuca arundinacea Schrcb; TF), orchardgrass (Dactylis glomerata L; OG) and ryegrass (Lolium perenne L: RG) were studied over 3 grazings between early spring and early summer of 2 consecutive years. Defoliation by steers started at 100 mm canopy height (Tl) and terminated at 50 mm (T2). At Tl, and again at T2, ocsophageal-fistulated steers were used to estimate IR, BM and BR and to provide extrusa samples for determination of 1nasticatc particle size after dry sieving. At Tl there was no consistent trend of IR with date. Intake rate of RO increased from 31 to 37 g dry matter (DM)/min, whereas that of TF decreased from 42 to 33 g OM/ min with advancing season. At T2, mean IR was lower and declined linearly (P<0.05) with advancing season for each species, from 22 to 15 g DMlmin. This was based on a linear decline (P<0.05) in BM from 0.37 lo 0.27 g OM/bite from early spring lo late spring. Biting rate did not change significantly with advancing season at either TI or T2. Masticate mean particle size at TI was similar for each sampling date and averaged 3.11 mm. At T2 mean particle si.r:e was smaller than at Tl and showed a linear decrease (P<0.05) with sampling date from 2.55 mm in early spring to 1.93 mm in late spring. Canopy height at which grazing terminates, needs to be progressively increased during the season to maintain constant IR.
