Department - Author 1

Dairy Science Department

Degree Name - Author 1

BS in Dairy Science



Primary Advisor

Bruce Golden


The objective of this trial was to determine if there was an increase in milk production or a decrease in feed consumption by dairy cattle when fed an exogenous rumen-resistant amylase, named RumiStar. High feed prices have caused dairymen to look for new ways to be more efficient. Commercial feed additives have been proposed as opportunities to improve efficiency. In our study a minimum of eighty multiparous Holstein cows were assigned to each of two pens, with a minimum of forty cows in each. Cows that completed their lactation during the study period were replaced with fresh cows to keep the number of cows in each string at or above 40. The experimental design used was a double-crossover. Ronozyme RumiStar with an amylase activity level of 600 kilo novo units (KNU)/g) was used as the treatment. The targeted dosage of 300KNU/kg of TMR %DM was fed. One pen was designated as the control string, where the cows received the additive carrier, wheat mill run, but no RumiStar at a rate of once per day during a four week period. The second pen was designated and marked as the treatment string and received the carrier, wheat mill run, and the additive RumiStar at a rate of once per day. After a seven day transition, the cows received the treatment and control diets for a minimum of four weeks. After four weeks strings’ diets were switched. Then, about thirty days later the treatment and control strings were switched a second time, and again a third time. Feed allowed and feed refusal was periodically weighed, calculated and recorded throughout the trial. Milk yield was weighed and recorded randomly throughout the trial. In doing so, this allowed for differences to be statically analyzed for milk production, feed consumption, TMR contents, amylase activity level, starch degradation, and manure starch and sugar levels. Statistical analysis was performed using the SAS mixed procedure for lbs of milk production and the SAS GLM procedure for feed consumption in SAS. The results showed that there was no statistically significant difference in the milk production or feed consumption of dairy cattle that received the treatment rations containing RumiStar. However, further research should be conducted because there was a trend for milk production to have numerical differences in older age cows that were favorable, and there was a corresponding numerical difference of feed consumption of those same cows that was favorable.

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Dairy Science Commons