Effects of total mixed ration particle size on sorting behavior and milk production in lactating cow
2004
Satoh, S.(Aichi-ken. Agricultural Research Center, Nagakute (Japan)) | Asada, N. | Ishii, K.
The effects of sorting behavior of lactating cow on total mixed ration (TMR) remained on the feed bunk were investigated. Various TMRs were fed to cows ad libitum and degree of sorting were evaluated using Penn State Forage Particle Separator (PSPS). TMRs using two forage sources were compared. The ratio of particles on each sieve of PSPS from TMR containing grass silage were changed by sorting. TMR containing corn silage didn't change its ratio throughout a day. Three TMRs different in moisture content (30%, 45% or 60%) were compared. Addition of water didn't affect the ratio on each sieve of PSPS. In the use of PSPS, TMR containing up to 45% of moisture could be separated correctly, but TMR containing 60% of water may have risk not to be separated as the wet condition. Timothy hay cut at different theoretical length (2cm or 10cm) were used in TMRs as only source of forage and the effect of sorting was observed. The percentage of particles on the upper sieve of PSPS at the end of feeding was increased in TMR with long-cut hay. TMRs mixed in short time (15 min) or long time (90 min) were fed to the cow, then feeding characteristics, milk production, and rumen fermentability were compared. The TMR mixed quickly led to sorting and total volatile fatty acid concentration in the rumen fluid of cows fed TMR mixed in long time was higher than that mixed in short time, but no significant effects were observed in feed intake and milk production. These results suggest that forage cut properly in the TMR would reduce sorting behavior of cow. And in this study, it was allowable if sorting was happened in cows milked less than 30kg daily and fed sufficient fiber.
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