采食不同组合全饲粮颗粒料羔羊的瘤胃液代谢参数

将40只陶塞特(♂)与藏羊(♀)的杂交一代羔羊(4～4.5月龄,公、羯各半)按同质原则分为4组。预试期(21天)后的50天中,各组试羊分别喂以按2×2析因设计的4种等营养水平、不同组合精料型的全饲粮颗粒料。从各组分别选出6只羊,于饲养试验结束后连续两天采集不同时段的瘤胃液样,测定了其中pH值、NH3-N和VFA含量。结果表明:⑴ 各组羔羊不同时段瘤胃液pH值多在6.30～7.5之间,食后速降,5 h后恢复弱碱性;NH3-N含量变化类似于pH值;此二指标的变化似可说明饲喂间隔4 h的合理性。⑵ 各组羔羊瘤胃发酵均为高丙酸型,乙酸为41.72 %～44.60 % TVFA,丙酸为36.77 %～43.43 % TVFA,有采食含小麦饲粮(A1)丙酸比例较食含甜菜渣饲粮(A2)高的趋势。⑶ 食A1羔羊瘤胃液pH值呈低于食A2者的趋势,食含大豆粕饲粮(B1)羊瘤胃液pH值下降幅度也呈高于食含菜籽粕饲粮(B2)的趋势;瘤胃液NH3-N的组间差异亦有类似趋势。

Metabolic parameters of rumen fluid from lambs fed on complete diet pellets with different combinations

Forty F1 crossbred lambs of Poll Dorset (♂) and Tibetan sheep (♀)(4～4.5 months old, 20 males and 20 wethers) were divided into four groups. After 21 days preliminary period,the four group of lambs were fed respectively with complete diet pellets in different combinations by 2×2 factorial designing for 50 days. At the end of feeding trail, rumen fluids were sampled from 6 lambs in each group to determine pH , NH3-N and VFA of rumen fluid,. Results show that: (1) pH values of rumen fluid sampled in different phases of all groups were 6. 3～7.5 and it dropped quickly after eating and went up to weak alkaline at five hours after eating; Variations of NH3-N level were similar; changes of pH and NH3-N level indicated that 4h of interval between the two times of feeding was reasonable. (2) The proportions of acetic and propionic acids in TVFA of rumen fluid in mean value of each group were 41.72 %～44.60 % and 36.77 %～43.43 %; the proportion of propionic acid from groups fed with wheat (diet A1) was higher than the groups fed with beets (diet A2). (3) There was a tendency that pH and NH3-N in rumen fluid from lambs with A1 diet were lower than those with A2 diet, but comparing with B2 diet, those contents of lambs with B1 diet were much higher. Differences of NH3-N in rumen fluid among the four groups trended towards similarly.