AbstractTwenty-four grade Holstein cows, which averaged not less than 30 pounds of milk daily during a 30-day preliminary period were subjected to either of two treatments: 1, The control treatment which consisted of grazing properly managed Pangolagrass supplemented with a commercial 20-percent crude protein concentrate mixture; and 2, the experimental treatment which consisted of confining the cows and feeding them ad libitum a 15.3-percent crude protein complete ration containing 22.5- percent ground sugarcane bagasse and 77.5 percent concentrates, minerals, and vitamin supplement. The average milk production of the control and experimental cows was 42.9 and 40.1 pounds, respectively, during the preliminary period. During the comparison period the corresponding figures were 43.8 and 42.0 pounds for the first 30 days (peak lactation), 35.3 and 31.6 pounds for the remaining 175 days (declining lactation), and 36.5 and 33.1 pounds for the entire 205 days. None of these differences between treatments was significant using covariance adjustment for milk production during the preliminary period. The experimental cows consumed an average of 36.1 pounds of complete ration daily and required 1.09 pounds of feed per pound of milk produced. The average protein content of the milk produced by the experimental cows during the comparison period was significantly (P < .01) higher than that of the control cows (3.55 vs. 3.18 g./100 ml.). The average milk-fat percentages were 3.07 and 3.28, and the average milk solids-not-fat percentages were 8.33 and 8.34 under the control and experimental treatments, respectively. The control and experimental cows gained live weight at the average rates of 0.52 and 0.56 pound per day, respectively. Based on costs of $3.58 and $4.41 per 100 pounds for the complete ration and commercial concentrate, respectively, $0.34 per head per grazing day, and $7.80 income per 100 pounds of milk produced, the following economic estimates were made under the control and experimental treatments, respectively: Total daily feed costs per cow, $1.16 and $1.29; gross income from milk produced, $2.85 and $2.58; income from milk above feed costs, $1.69 and $1.29; and feed costs per 100 pounds of milk produced, $3.18 and $3.90. With respect to the productive responses, no evidence was found contrary to the null-hypothesis that the treatment under evaluation was not better than the control. The mean figures for economic return were in favor of the control treatment, though no tests of statistical significance could be made with the data available. The results emphasize the indispensability of obtaining high average milk production (at least 40 pounds per cow daily) in order to make the complete ration economically competitive.
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