May 4, 2000 - Aug. 6, 2000
Evaluation of 2X-2-2-5 PLUS Yeast in Cattle Feedlot Diets

Dr. John Carlson, Principal Investigator Agriculture Department 310 Knoblauch Western Illinois University Macomb, IL 61455 309/298-1611

Trial Protocol

Forty-eight steers were purchased from a commercial feedlot cattle marketer and transported to the research facility at the Western Illinois University farm.  The cattle were weighed upon arrival and equipped with a neckchain mounted radio transponder.  They were then divided into four groups so that the average weight of each group was approximately equal.  Each group was then randomly assigned to one of four pens, each of the same width and length for a seven day adjustment period.  Each pen was equipped with a self-feeding stall capable that allowed one steer to eat at a time and was capable of recording individual feed consumption by detecting the identification of the steer from the radio transponder unique to each steer. The weights of the four groups were:

            During the adjustment period, all animals were fed the same basal ration comprised mainly of corn, soybean hulls and soybean meal, as would be used in a common commercial cattle feeding operation.

            At the completion of the adjustment period, all steers were re-weighed to establish their beginning weight for the trial on May 4.  These weights were then evaluated to assure a beginning test weight approximately the same for each pen.  This involved switching a steer from one pen with a steer from another pen.  Only one such switch was needed.  All pen averages were within 0.5% of the overall mean of 844.5 pounds.  The beginning test weights for each pen were:

            While pens 1 and 2 continued to be fed the initial ration, pens 3 and 4 were fed a similar-type ration except that five pounds of 2X-2-2-5 PLUS Yeast was substituted for five pounds of corn. These rations were fed to each pen, respectively, until completion of the trial, which consisted of 94 days, ending on August 6.  During the trial, one steer was diagnosed with urinary calculi and required surgery to correct the condition. While this animal recovered and was able to complete the trial, the data on this animal was not included in the data analysis due to the abnormal situation it encountered during the trial.  Data on two additional animals was also not included in the analysis as their average daily gain and feed efficiency performances was more than two standard deviations from the overall mean.  Thus they are statiscally considered to be “outliers” and not representative of the group.  These three animals consisted of two animals from the control-fed group, and one from the group receiving 2X-2-2-5 PLUS Yeast in the ration.

            The data was analyzed using SPSS software on an IBM-compatible personal computer.  Average daily gain, average daily feed consumption and feed efficiency, measured as pounds of feed required per pound of gain, were analyzed using the overall mean, treatment(control feed versus the yeast addition ration), and pen within treatment as the model components.

            Average daily gain was not significantly different between the two treatment group.  The control pens averaged 3.645 pounds per day growth(standard error = .117), while the yeast treatment group averaged 3.731 pounds per day(standard error = .115).  While the yeast treatment mean is higher than the control mean, the significance level for this difference is only 0.603 and thus not considered statistically significant.  Pens within treatment was a significant factor, with pen 3 gaining significantly faster than pen 4.  There was no significant difference between pens 1 and 2.

            There were no significant differences between the control and yeast-fed cattle for daily feed consumption.  The control-ration cattle consumed an average of 28.6 pounds of feed per head per day (standard error = 0.601), while the cattle on the yeast-based ration consumed an average of 28.1 pounds per head per day (standard error = 0.614). 

            Feed efficiency was also not significantly different between the control and yeast-fed groups, but followed the previously noted trend of better performance for the yeast-fed animals, albeit not a statistically significant difference.  The control-ration cattle required 8.079 (standard error = 0.259) pounds of feed to gain a pound of body weight, while the yeast-fed cattle required 7.685(standard error = 0.253).  This difference had a statistical significance level of 0.283.  Thus while the yeast-fed steers appeared to be slightly more efficient, this difference was not statistically significant.  Pen was again a significant factor, as the steers in Pen 1 were significantly more efficient than the steers in Pen 2, and the steers in Pen 4 were significantly more efficient than were Pen 3 steers. 

            While the differences between the two groups were not significant for average daily gain, average daily feed consumption and feed efficiency, the trends appear favorable toward the yeast-based diet.  Based on these trends, it is interesting to speculate that perhaps the level of 2X-2-2-5 PLUS Yeast, only five pounds per ton, was not high enough to generate a response.  While there would be some benefit in conducting another trial similar to the one just concluded, it might be of more interest to conduct a similar trial but with the level of 2X-2-2-5 PLUS Yeast at ten pounds per ton to see if that would generate some statistical differences.

................................................................
  Home | Products | Cultures | Benefits | Tests | About Us | Contact Us |  Search