Four rumen-fistulated Korean native goats were assigned to a 2 × 2 switch back design, to four diets obtained from the fractional combination of two forage to concentrate ratios{20:80(Trial I) and 40:60(Trial II)} and two concentrations of lasalocid sodium(0 or 30ppm in concentrate). Rumen fluids were collected and examined just before feeding(0 hour) and 2, 6, 12 hours after feeding on ruminal pH, volatile fatty acids(VFA), colony counts of Streptococcus bovis, ruminal NH₃-N, ruminal microbial protein synthesis and digestibility of experimental diets.
Addition of lasalocid in Trial I and Il tended to significantly higher ruminal pH at 0, 2, 6 hours after feeding(p$lt;.05) and increase total ruminal VFA concentration (p$lt;.05) at 0, 2, 6, 12 hours after feeding. Ruminal propionate percentage was increased more by addition of lasalocid to the low forage diet than by addition of lasalocid to the high forage diet. Ruminal Streptococcus bovis colony counts tended to decrease when lasalocid was added to the low forage diet(p$lt;.05), and the result of Trial II was similar(p$lt;.05). Addition of lasalocid in Trial I and II tended to be lower ruminal NH₃-N concentration and lower ruminal microbial protein synthesis without affecting digestibility of dry matter, organic matter, crude protein, neutral. detergent fiber, acid detergent fiber and hemicellulose.
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