Beharka A A, Nagaraja T G, Morrill J L, Kennedy G A, Klemm R D
Department of Animal Sciences, Kansas State University, Manhattan 66506-1600, USA.
J Dairy Sci. 1998 Jul;81(7):1946-55. doi: 10.3168/jds.S0022-0302(98)75768-6.
Eight neonatal, Holstein bull calves were paired by birth date and birth weight and randomly assigned to either a finely ground or unground control diet (chopped hay and rolled grain) to study the effects of the physical form of the diet on anatomical, microbial, and fermentative development of the rumen. The diets varied in particle size but were identical in composition (25% alfalfa hay and 75% grain mix). Calves were fed milk at 8% of birth weight daily until weaning. Feed intake was equalized for each pair of calves. Ruminal fluid samples were collected from ruminal cannulas to determine pH, fermentation products, and buffering capacity and to enumerate bacteria. Calves were slaughtered at 10 wk of age, and weights of the full and empty reticulorumen, abomasum, and omasum were recorded. Ruminal tissue samples were taken to assess papillary development by morphometric measurements. Calves had similar body weights at wk 10. Ruminal pH was affected by age and was lower for calves fed the ground diet. Total anaerobic bacterial counts were not affected by the physical form of the diet; however, calves fed the ground diet had lower numbers of cellulolytic bacteria and higher numbers of amylolytic bacteria than did calves fed the unground diet. Physical form of the diet did not affect the weights of the reticulorumen whether full or empty. However, calves fed the ground diet had heavier omasum weights, both full and empty. Physical form of the diet affected papillary size and shape but did not influence the muscle thickness of rumen. Results indicated that the physical form of the diet had a significant influence on the anatomical and microbial development of the forestomac and, therefore, might influence future performance.
选取8头新生荷斯坦公牛犊，根据出生日期和出生体重进行配对，然后随机分配到精细研磨或未研磨的对照日粮组（切碎的干草和压片谷物），以研究日粮物理形态对瘤胃解剖结构、微生物和发酵发育的影响。日粮的粒度不同，但组成相同（25%苜蓿干草和75%谷物混合物）。犊牛每天按出生体重的8%饲喂牛奶，直至断奶。每对犊牛的采食量保持均衡。从瘤胃瘘管采集瘤胃液样本，以测定pH值、发酵产物和缓冲能力，并对细菌进行计数。犊牛在10周龄时屠宰，记录瘤网胃、皱胃和瓣胃的充盈和排空重量。采集瘤胃组织样本，通过形态测量评估乳头发育情况。10周龄时犊牛体重相似。瘤胃pH值受年龄影响，饲喂研磨日粮的犊牛瘤胃pH值较低。日粮的物理形态不影响厌氧菌总数；然而，与饲喂未研磨日粮的犊牛相比，饲喂研磨日粮的犊牛纤维素分解菌数量较少，淀粉分解菌数量较多。日粮的物理形态不影响瘤网胃的充盈或排空重量。然而，饲喂研磨日粮的犊牛瓣胃的充盈和排空重量均较重。日粮的物理形态影响乳头大小和形状，但不影响瘤胃肌肉厚度。结果表明，日粮的物理形态对前胃的解剖结构和微生物发育有显著影响，因此可能会影响未来的生产性能。
