Dairy Comparison

By Jim Halbeisen, Growers Director of Research

In February, 2001, a respected dairy operation in eastern Pennsylvania agreed to split their 40 cow milking herd, using the Growers Mineral Solutions (GMS)  as a mineral supplement on one half and continuing with their commercial mineral on the other half.  The comparison was done only on the milking cows with the dry cow feed the same for both herds. We felt this would be a particularly good trial since this operation had not previously used Growers in the field or in the barn. We were also hopeful the results would be of interest to other dairy farmers not acquainted with Growers especially since we implemented the feeding trial in a typical actual working farm environment.

We realize many institutions will find fault with our results because they did not come from a perfectly designed statistical setting.  Our feeling, however, is that a statistically pure setting does not always reflect the results to be found in a real world dairy. Although the conclusions could be the subject for debate, we do not intend it to be the focus of this comparison.  Rather, our purpose here is to present the data we collected over a 9 month period and let the men and women who make a living milking cows decide for themselves what the information really has to say to them about the GMS feeding recommendations.

We initiated this comparison mainly to show Growers customers and prospective customers that feeding GMS can have very important positive effects on lowering manure phosphorus levels.  New Manure Management Regulations in most states are, or will be, using both manure phosphorus and soil phosphorus level readings to set permitted manure application rates. Reducing phosphorus levels in manure will surely allow more manure on fields. Several operations, after monitoring, have found using GMS as their feed phosphorus source lowers phosphorus levels in the manure. The Growers Solution Spring 2000 Volume 15 Issue 2 discusses in detail the science behind the success of GMS being able to lower manure phosphorus levels.

Besides examining the manure for phosphorus content we also had the producer monitor the manure quantities produced. Using the total amount produced and the phosphorus concentrations, we calculated the amount of phosphorus actually spread out into the environment. (Tables I and II)

Table I  Manure Analysis Report
Pounds of Phosphorus/1000 Gallons of Manure

Table II  Per Cow Comparison of Manure Phosphorus
From 24 hour collection periods

This study was also meant to answer some of the objections and questions raised by dairy nutritionists, and to see if, indeed, using GMS negatively influences other aspects of dairy production as claimed by some.  Even if the producer's numbers were gathered crudely, as many would contend, they were consistently developed the same way for both sets of cows.  The data shows the herd using GMS had much lower manure phosphorus levels, and it was achieved while holding same or higher levels of phosphorus in the blood stream which is where it is needed. In fact all of the important nutrients' levels in the blood were maintained by the herd using GMS, which is contrary to the idea that the GMS program merely uses up and depletes the mineral reserves in the animals' bodies.  Many long term Growers customers continue seeing at least adequate mineral blood serum levels after feeding GMS over a period of several years. Even though our data contradicts what some of the experts have been predicting, we are all the more convinced the blood serum levels confirm the effectiveness of GMS. (Table III)

Table III   Comparison of Blood Serum Analyses for Two Programs started 2/01
(figures shown are in ppm)

*Pennsylvania Animal Diagnostic Laboratory System, University of Pennsylvania, Kennett Square, PA

Finally, we have included data taken from the farm's DHIA record sheets (Table IV) during the comparison trial which dairymen can use to evaluate cow response to the two different feed programs. Using the data from the comparison trial, along with the brief summary of the feed rations (Table V), dairy farmers can plug in their local feed and component cost numbers to predict potential profits for their own dairies.

Table IV  Herd Study
Comparison of GMS Mineral Program and Other Mineral Program

Table V  Sample Rations *

(as fed per head per day)

 Cows over 80# top dress

*These are typical rations or the comparison trial. The ration recommendations changed during the comparison to match feeds dictated by environment or philosophy.