Technical note: Evaluation of procedures for analyzing ration sorting and rumen digesta particle size in dairy cows

Effect of Total Mixed Ration Particle Size on Rumen pH, Chewing Activity and Performance in Dairy Cows

Two experiments were conducted to determine effects of particle size in total mixed ration (TMR) on performance of lactating cows. Three rumen cannulated Holstein cows were used in a 3×3 Latin square design for the metabolic experiment. The particle size of the diets was determined using the Penn State Particle Size Separator (PSPSS) and weighing the proportion of sample remaining on the top sc...

Technical note: use of laser diffraction for particle size distribution measurements in duodenal digesta.

Duodenal samples from three lactating cows were used to measure the particle size distribution by wet sieving and by laser diffraction (LD). The median particle size was calculated in the size range where the methods overlapped, and the median particle size was not different between the methods (P = 0.98). The particle size data were also fitted to a log normal distribution function. The logari...

Evaluation of n-alkanes as digesta markers in dairy cows.

Recovery of hentriacontane (C31 alkane) in feces as influenced by amount consumed and level of dietary fat was examined in a 2 x 2 factorial study in a 4 x 4 Latin square. Treatments were 1) alfalfa hay:concentrate (70:30; AH); 2) AH + calcium soap (500 g/d); 3) grass hay:concentrate (70:30, GH); and 4) GH + calcium soap. Fat did not influence C31 recovery in feces. Fecal recovery (grams/day) d...

Modeling of Rumen Particle Dynamics in Dairy Cows Fed Sugarcane

Effect of forage particle length on rumen fermentation, sorting and chewing activity of late-lactation and non-lactating dairy cows.

The objective of this study was to determine the effects of varying forage particle length on chewing activity, sorting behavior, rumen pH and rumen fill in late lactation and dry dairy cattle, fed rations with similar physically effective NDF but different mean particle length. Treatments consisted of three diets differing only in geometric mean length of forage: hay (5.40, 8.96 and 77.90 mm, ...