Esophageal Plug and Fasting Effects on Particle Size Distribution and Quality of Extrusa from Grass Pastures
- D. S. Fisher ,
- J. C. Burns and
- K. R. Pond
Diet selection and mastication by cattle (Bos taurus L.) can be examined using extrusa from esophageal fistulas. Experiments were conducted to investigate the use of an esophageal plug and the influence of a 16-h fast, prior to collection, on the particle size distribution and quality of masticated forage. Extrusa was freeze-dried and sieved into seven size-classes, and the weight of masticate in each class was determined. The proportions of large (>>1.7 mm), medium (0.5–1.7 mm), and small (<0.5 mm) particles and the mean and median particle sizes were analyzed. Neutral detergent fiber (NDF) and in vitro dry matter disappearance (IVDMD) were also determined. In both experiments, significant differences between single pastures of Coastal bermudagrass [Cynodon dactylon L. (Pers.)] with 3500 kg ha−1 and flaccidgrass (Pennisetum flaccidum Griseb.) with 2900 kg ha−1 available forage were found in particle size, NDF, and IVDMD. Averaged over experiments, the proportions of large, medium, and small particles found in bermudagrass were 20, 54, and 26%, respectively, and 35, 47, and 18%, respectively, for flaccidgrass. The NDF of bermudagrass and flaccidgrass averaged 550 and 505 g kg−1, respectively, and the IVDMD averaged 640 and 700 g kg−1, respectively. Neither the esophageal plug nor the fasting had an influence on the particle size distribution, NDF, or IVDMD.
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