American Journal of Animal and Veterinary Sciences

The Association between Total Mixed Ration Particle Size and Fecal Scores in Holstein Lactating Dairy Cows from Florida, USA

Pedro Melendez and Elizabeth Roy

DOI : 10.3844/ajavsp.2016.33.40

American Journal of Animal and Veterinary Sciences

Volume 11, Issue 1

Pages 33-40


The objective of this study was to determine the association between the proportion of particles greater than 19 mm in a total mixed ration fed to dairy cattle and their fecal score. Over a 22 day period, random feed samples were collected twice a day from a one-side barn and assessed for particle size using the Pennsylvania State Particle Separator. In addition, at each feeding sampling, the same barn was inspected and fresh feces were scored on a four point scale. Multiple regression models were developed to associate the proportion of particles >19 mm with fecal scores at one, two and three days after that specific particle evaluation. Results of this observational study showed a significant relationship between particle size and fecal scores two days later. The results demonstrated a cubic polynomial effect: Fecal scores improved with increasing of the proportion of particle size >19 mm at a low proportion of large particles, then it was maintained constant at intermediate proportion (10-15%) of large particles and finally increased again with a high proportion (up to 17%) of particle >19 mm.


© 2016 Pedro Melendez and Elizabeth Roy. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.