By Antonio G. Papa, Ph.D.

Research shows that as much as 30 percent of the biogas sludge produced from a biogas digester can substitute for commercially produced hog feeds without significant differences in the growth and development of hogs and their carcass yield.

These significant findings were reported by Dr. Ruperto S. Sangalang, Dr. Camilo A. Polinga, and Dr. Elizabeth E. Polinga, and Engineers Jaime Q. Dilidili, Rosalie A. Pelle, and Rene R. Marasigan, officials and staff members of the Cavite State University – Affiliated Renewable Energy Center (CvSU-AREC).

The researchers reported the results based on the parameters of the study: 1) gain in weight, 2) feed conversion efficiency, and 3) carcass quality.

Gain in weight. The results indicated that the growth response of the hogs fed with sludge as feed substitute was as normal as the hogs fed with basic rations of 100 percent commercial feeds.

Feed conversion efficiency. Feed conversion efficiency (FCE) was observed in hogs fed with 100 percent commercial feeds with 26.22 percent, although it was not significantly different from the other treatments. Hogs fed with fifteen percent and 30 percent sludge substitutes gave 24.53 percent and 24.16 percent FCE, respectively.

Carcass quality. The hogs given diets with part of the commercial feeds substituted with sludge gave comparable carcass quality to those of hogs fed with the basic ration of 100 percent commercial feeds.

The researchers concluded that substituting biogas sludge for the feed ration of hogs has no adverse effect on their growth and development. Likewise, the substitution of 30 percent sludge by weight of feeds to the feed ration of hogs gives a desirable result since the amount of commercial feeds that would be consumed by the animals is reduced by as much as 30 percent or almost one-third of the total feeds given to hogs. Lastly, the results of the study proved that biogas sludge could substitute for the necessary feeds and nutrients required by hogs.

The researchers from CvSU-AREC, based on the findings of the study, recommended the following: 1) substitution of sludge for the feed ration of hogs at the amount of 30 percent by weight of feeds; 2) further studies be conducted on the utilization of sludge as feed substitute of hogs using higher levels to test the maximum level at which the hogs would gain better performance; and 3) a study be conducted on the utilization of biogas sludge as a substitute for percentages of the feedstuff of other farm animals.

This appeared in Agriculture Monthly’s May 2018 issue.