Effects of direct feeding of a probiotic feed additive on fecal odor and compost quality of manure and productivity of dairy animals

The efficacy of a probiotic feed was tested at the Dairy Training and Research Inst.[College, Laguna, Philippines] using ten haifers(1 1/2 to 2 years, research station scenario). The study aimed to (1) determine the effects of feeding a probiotic feed on mal odor strength of feces produced by dairy animals (2) determine the over-all effects of feeding a probiotic feed on health and productivity of the animals and (3) evaluate the effects of using manure of animals fed probiotic feed on the rate of composting a farm wastes (cattle manure and feed refusals). The animals were randomly alloted to two groups; 1) control animals and 2) animals fed probiotic feed. The animals were given chopped Napier grass at 2.0% of the body weight in DM, 12 kg of brewer's spent grains and 1 kg concentrates. Five grams of the probiotic feed was given along with the concentrate. Animals were weighed at day 11, day 35 and day 60(final weight). Fecal samples were collected at day 0 and 15 days after and were analyzed for concentrations of NH3, H2S, and total mercaptan using a portable gas monitor. The animals were maintained under the same feeding and management system for 2 months. Control animals gained a total of 179 kg or an average of 35.8 kg per head, which is equivalent to an ADG[average daily gain] of 0.6 kg. Animals fed with the probiotic feed gained 201 kg or an average of 40.2 kg which is equivalent to 0.7 kg. There was however greater variability on the weight gains of the animals that received probiotic feed (range: 19-53 kg) as compared to control animals(range: 29-49 kg). In fact, two of the probiotic fed animals lost weights(8-10 kg) from day 35 to day 60. Analysis of the gases produced from incubated fecal samples showed the presence of trace amounts of NH3(5-50 ppm). H2S and total mercaptan were undetected. Differences in the concentrations of NH3 between control and treated animals before and after 15 days into the feeding experiment were however not significant(p 0.05). The gas monitor was not sensitive enough to detect minute concentrations of the different component gases. A gas chromatograph would be neede to measure the low concentration of gases. Apparently, any significant difference between the gas concentrations of feces collected from control and probiotic fed animals would be an indication of the probiotic feed in reducing fecal odor. The conduct of the feeding experiment was not pursued under other management levels(i.e. smallhold and commercial dairy farming) as results using the available equipment showed no clear benefits from feeding probiotic feed additive.