Zitnan R, Sommer A, Gallo J, Lauková A, Bomba A, Venglovský J
Research Institute of Animal Production Nitra, Division Kosice, Slovak Republic.
Arch Tierernahr. 1994;46(1):51-60. doi: 10.1080/17450399409381757.
Observations were carried out on volatile fatty acid (VFA) concentrations, enzyme activities and the microflora of the rumen contents in heifers during transition from winter to pasture feeding and in the subsequent gazing cycles. After turn-out to pasture, total VFA concentrations in the rumen contents of heifers significantly decreased from 107.7 to 88.7 mmol.l-1 (P < 0.01). After subsequent increase the total VFA concentrations reached their highest value (117.0 mmol.l-1) in the 8th week of grazing. The proportion of the molar acetic acid concentration in the rumen content increased insignificantly whereas that of propionic acid decreased insignificantly. In the molar proportion of butyric acid no significant differences could be stated. In the subsequent weeks the molar proportions of acetic acid were rather balanced and ranged within 66.2 and 68.0 mol%; the molar proportion of propionic acid insignificantly increased in the 4th week (18.7 mol%). Molar proportions of butyric acid on pasture insignificantly increased in week 3 (15.2 mol%) and appeared as balanced, later acquiring values between 14.0 and 14.8 mol%. The energetic yield of VFA production in the rumen of heifers decreased insignificantly from 73.6 to 72.15; the acetate: propionate ratio revealed an insignificant increase from 3.66 to 4.18. The enzyme activity of cellulase (endoglucanase E.C.3.2.1.4 and cellobiohydrolase E.C.3.2.1.91.) decreased significantly from 17.83 to 16.64 micrograms.ml-1 (P < 0.01); in the subsequent weeks, however, a significant increase could be observed. The enzyme activity of alpha-amylase (E.C.3.2.1.1.) decreased significantly (P < 0.05). In the 4th week a significant increase of the former occurred. The numbers of cellulolytic bacteria in the rumen content decreased significantly from 8.08 to 7.61 log 10.ml-1 (P < 0.01) and then a significant increase to 8.39 log 10.ml-1 was observed again in the 3rd week of grazing (P < 0.05). During pasture, a significant increase of the numbers of lactate-utilizing bacteria was recorded. As to the numbers of lactobacilli a significant decrease (P < 0.05) with a subsequent insignificant increase during grazing could be observed. Throughout the grazing season, the numbers of Streptococci reached values that surpassed those recorded during the winter feeding period. After transition from winter feeding to pasture the adaptation of rumen fermentation took four weeks.
对处于从冬季舍饲转为放牧饲养以及随后放牧周期的小母牛瘤胃内容物中的挥发性脂肪酸（VFA）浓度、酶活性和微生物区系进行了观察。转入牧场后，小母牛瘤胃内容物中的总VFA浓度从107.7显著降至88.7 mmol·l-1（P<0.01）。随后升高，在放牧第8周时总VFA浓度达到最高值（117.0 mmol·l-1）。瘤胃内容物中摩尔乙酸浓度的比例略有增加，而丙酸的比例略有下降。丁酸的摩尔比例无显著差异。在随后几周中，乙酸的摩尔比例较为平衡，在66.2%至68.0%之间；丙酸的摩尔比例在第4周略有增加（18.7%）。牧场中丁酸的摩尔比例在第3周略有增加（15.2%），之后趋于平衡，随后值在14.0%至14.8%之间。小母牛瘤胃中VFA产生的能量产量从73.6略有降至72.15；乙酸与丙酸的比例从3.66略有增至4.18。纤维素酶（内切葡聚糖酶E.C.3.2.1.4和纤维二糖水解酶E.C.3.2.1.91.）的酶活性从17.83显著降至16.64微克·毫升-1（P<0.01）；然而，在随后几周中观察到显著增加。α-淀粉酶（E.C.3.2.1.1.）的酶活性显著下降（P<0.05）。在第4周，前者显著增加。瘤胃内容物中纤维素分解菌的数量从8.08显著降至7.61 log10·毫升-1（P<0.01），然后在放牧第3周再次观察到显著增加至8.39 log10·毫升-1（P<0.05）。在放牧期间，利用乳酸的细菌数量显著增加。至于乳酸杆菌的数量，观察到显著减少（P<0.05），随后在放牧期间略有增加。在整个放牧季节，链球菌的数量达到超过冬季舍饲期记录的值。从冬季舍饲转为放牧后，瘤胃发酵的适应需要四周时间。
