K.-H. Südekum

Estimating ruminal crude protein degradation with in situ and chemical fractionation procedures

The objective of this study was to utilize the fractionation of feed crude protein (CP) of the Cornell net carbohydrate and protein system (CNCPS) as a basis for estimating undegraded dietary protein (UDP) values of feedstuffs obtained from in situ trials. In addition, the experiments comprised a comparison between in situ UDP values of feedstuffs and CP solubility estimated from the protein dispersibility index. Eleven dairy compound feeds and 21 feedstuffs were inserted in polyester bags and incubated in the rumen of three steers. Values for in situ UDP at assumed ruminal passage rates of 2, 5, and 8% h ˇ1 , respectively, ranged from 63 to 616, 129 to 785, and 167 to 842 g kg ˇ1 of CP. When fish meal data (na2) were excluded from the data set, multiple regression equations that were based on concentrations of CP and cell wall, and on the A, B, and C fractions of the CNCPS fractionation schedule, explained 87, 93, and 94%, respectively, of the variation in UDP values at assumed ruminal passage rates of 2, 5, and 8% h ˇ1 . We conclude that in situ UDP values, which serve as one key variable in many protein evaluation systems for dairy cattle, may be reliably and accurately predicted from chemical fractionation of feed CP according to the CNCPS. The coefficients of determination of estimating UDP values at assumed ruminal passage rates of 2, 5, and 8% h ˇ1 , respectively, from the protein dispersibility index were only 0.30, 0.29, and 0.33. Hence, the protein dispersibility index was not suitable as a predictor of UDP values for the feedstuffs used in the present study. # 2000 Elsevier Science B.V. All rights reserved.

Physical characteristics of rumen contents in two small ruminants of different feeding type, the mouflon (Ovis ammon musimon) and the roe deer (Capreolus capreolus)

In domestic ruminants, the stratification of forestomach contents - the results of flotation and sedimentation processes - is an important prerequisite for the selective particle retention in this organ. A series of anatomical and physiological measurements suggests that the degree of this stratification varies between browsing and grazing wild ruminants. We investigated the forestomach contents of free-ranging mouflon and roe deer shot during regular hunting procedures. There was no difference between the species in the degree by which forestomach ingesta separated according to size due to buoyancy characteristics in vitro. However, forestomach fluid of roe deer was more viscous than that of mouflon, and no difference in moisture content was evident between the dorsal and the ventral rumen in roe deer, in contrast to mouflon. Hence, the forestomach milieu in roe deer appears less favourable for gas or particle separation due to buoyancy characteristics. These findings are in accord with notable differences in forestomach papillation between the two species. In roe deer, particle separation is most likely restricted to the reticulum, whereas in mouflon, the whole rumen may pre-sort particles to a higher degree. The results suggest that differences in forestomach physiology may occur across ruminant species.

Rumen contents and ruminal and faecal particle size distribution in steers fed a mixed diet at three amounts of intake

Abstract This study was conducted to investigate the effects of intake of a mixed diet by cattle and time post-feeding on rumen contents and on particle size distribution of ruminal digesta. Six ruminally cannulated steers received a mixed diet consisting on an average of (% of dry matter) 43 perennial ryegrass silage, 25 maize silage, 30 concentrate and 2 mineral-vitamin mix. The experimental design was a repeated 3 × 3 Latin square with 21 day periods. The diet was offered twice daily (07:00 and 19:00 h) at approximately 1, 1.5 and 2 times of estimated maintenance energy requirements (denoted low, medium and high intake, respectively). The rumens were evacuated manually at 3 and 7.5 h post-feeding and total ruminal contents separated into mat and bailable liquids. Dry matter weight distribution of total recovered particles was determined by a wet-sieving procedure and used to partition ruminal mat and bailable liquids among percentages of large (≥ 4.0 mm), medium (

Site and extent of cell-wall neutral monosaccharide digestion in dairy cows receiving diets with ear and husk meal maize silages from three different stages of maturity

In this study, the effect of stage of maturity of maize (Zea mays L., cultivar ‘Felix’) on site and extent of cell-wall neutral monosaccharide (CWM) digestion in dairy cows receiving diets with ear and husk meal (EHM)-silages was investigated. Ears and husks were harvested at the early, soft and hard dough stages of maturity, respectively, chopped and ensiled. Three diets were formulated to contain (percentage of diet dry matter) EHM-silage (42%), grass hay (39%), soybean meal (17%) and mineral-vitamin mix (2%). Diets containing EHM-silages from the early, soft and hard dough stages of maturity were designated ED, SD and HD, respectively. Three lactating German Friesian cows equipped with ruminai, duodenal and ileal cannulae were used in a 3 × 3 Latin square design to evaluate apparent organic matter (OM) and CWM digestibilities in the whole-tract, and in the rumen, and in the small and the large intestines, respectively. Titanium (IV)-oxide and chromium ethylene diamine-tetra-acetic acid were used as flow markers. In all diets, glucose was more digestible in the whole-tract and in the rumen than xylose, the main hemicellulose constituent. Apparent wholetract digestibilities of OM (ED, 74.6%; SD, 71.8%; HD, 72.1%) and total CWM (ED, 78.1%; SD, 71.7%; HD, 73.7%) were higher with ED compared to SD and HD, but none of these differences were significant. Ruminal characteristics (pH values and NH3-N) were not different among diets (P > 0.10) and indicated similar conditions for rumen microbial CWM fermentation. However, apparent ruminal CWM digestibilities were higher with ED compared with SD and HD, and differences were significant (P < 0.10) for glucose (ED, 72.2%; SD, 59.6%; HD, 61.3%), arabinose (ED, 85.2%; SD, 78.3%; HD, 74.8%) and mannose (ED, 84.1%; SD, 80.4%; HD, 81.3%). Apparent digestibilities in the small intestine (up to 7.6% for glucose with SD) indicated appreciable microbial fermentation in the ileum. Extremely negative apparent digestibilities (ED, −71.3% for arabinose) were also observed. Apparent OM, total CWM, glucose and xylose digestibilities in the large intestine were similar across all diets and constituents, ranging from 18.7 to 24%.

Site and extent of cell-wall neutral monosaccharide digestion in dairy cows receiving diets with rolled cereal grains

The effect of source of rolled cereal grain on the site and extent of cell-wall neutral monosaccharide (CWM) digestion in dairy cows was investigated in this study. Three diets were formulated on a starch equivalent basis to contain (percentage of diet dry matter, DM) rolled oats (36%), rye (29%) or barley (31.5%). The remainder of diet DM was made up of grass hay (35.5–39.5%) and coconut meal (26.5–29.5%). Diets containing rolled oats, rye and barley were designated O, R and B, respectively. Three dairy cows (two lactating, one non-lactating) equipped with ruminal, duodenal and ileal cannulae were used in a 3 × 3 Latin square design to measure the digestibility of organic matter (OM) and CWM in the whole tract and its partition in the rumen, and in the large intestine. Titanium (IV)-oxide and chromium ethylenediamine tetra-acetic acid were used as flow markers. In all diets, CW glucose was more digestible in the whole tract and in the rumen than CW xylose. Apparent whole-tract digestibilities of OM (O, 69.8%; R, 73.8%; B, 73.0%) and total CWM (O, 72.7%; R, 79.5%; B, 77.7%) were lower (P < 0.01) for O compared with R and B. Ruminal characteristics (pH values and NH3-N) were only slightly different among diets, indicating similar conditions for microbial CWM fermentation. However, apparent ruminal CWM digestibilities were lower for O as compared with R and B. The greatest differences were obtained for xylose (O, 39.7%; R, 59.5%; B, 52.6%; P < 0.05) and for glucose (O, 61.1%; R, 70.2%; B, 67.3%; P < 0.05). In the small intestine, both positive and negative digestibilities were observed. Although numerical values varied largely among and within CWM, no significant contribution of the small intestine to total CWM digestion could be detected. The contribution of the large intestine to total CWM digestion was similar across diets, 20.6%, 23.2% and 18.2% for O, R and B, respectively. It was concluded that CWM from oats per se were less digestible than CWM from rye and barley in all parts of the gastrointestinal tract and that xylose was the least digestible CWM.

Effects of intake of a mixed diet and time postfeeding on amount and fibre composition of ruminal and faecal particles and on digesta passage from the reticulo-rumen of steers

Abstract This study was conducted to examine the effects of intake of a mixed diet by cattle and time postfeeding on amount and detergent fibre contents of ruminal and faecal particle fractions and on digesta passage from the reticulo-rumen. Six ruminally cannulated steers received a mixed diet consisting on an average of (g/kg of dry matter) 430 Italian ryegrass silage, 250 maize silage, 300 concentrate and 20 mineral–vitamin mix. The experimental design was a repeated 3×3 Latin square with 21 day periods. The diet was offered twice daily (07:00 and 19:00 h) at approximately 1.0, 1.5 and 2.0 times of estimated maintenance energy requirements (denoted low, medium and high intake, respectively). The rumens were emptied manually at 3 h and 7.5 h postfeeding and total ruminal contents separated into mat and bailable liquids. Dry matter weight distribution of total recovered particles was determined by a wet-sieving procedure and used to partition ruminal mat and bailable liquids among percentages of large (≥4.0 mm), medium (

Comparison of Sheep Ruminal Fluid with Sheep and Horse Faeces as Inoculum for In Vitro Gas Production Measurements

Abstract Can, A., Hummel, J., Mobashar, M., Boeser, U. and Südekum, K-H. 2009. Comparison of sheep ruminal fluid with sheep and horse faeces as inoculum for in vitro gas production measurements. J. Appl. Anim. Res., 35: 143–148. A total of 22 ruminant feedstuffs, 14 forages and 8 concentrates, originating from Turkey were used to determine kinetics of in vitro gas production using the Hohenheim gas test (HGT) protocol with multiple readings. Three different inocula sources were ruminal fluid (RF) from fistulated sheep, horse faecal suspension (HFS) and sheep faecal suspension (SFS). Maximum rate of gas production was highest with SFS 2.21 ml/h. The best regression equation for predicting 24 h rumen fluid gas production (ml) was obtained with HFS at 48 h [y = 0.92 ±0.03 × + 9.90 ±1.17; residual standard deviation, 4.43; coefficient of determination, 0.86]. However, more research is required to standardize and optimize the HFS method.

Nutritive defaunation of the rumen in steers with subsequent refaunation using a cryopreserved monoculture of Entodinium caudatum

This study evaluated a technique for the nutritive defaunation of the rumen of cattle with subsequent single species refaunation using a cryopreserved monoculture of Entodinium caudatum (family Ophryoscolecidae). Four mature steers were nutritionally defaunated in two periods using two steers in each period. A diet containing (dry matter basis) 68% ground wheat grain, 7% wheat bran, 8% soybean oil and 17% wheat straw was used to decrease the pH of ruminal contents and to eliminate rumen ciliate protozoa. Protozoa-free rumens were observed on day 8 and 9 in the first and second period, respectively, after the start of defaunation. A monoculture of E. caudatum (34/89/94) was transported from the Institute of Animal Physiology, Slovak Academy of Sciences in Kosice to the University of Kiel (Germany) in liquid nitrogen in October 1996. The inoculation was accomplished on day 15 in the second period by applying 30 ml culture medium with a monoculture of E. caudatum (34/89/94; average concentration of protozoal cells 2 650/ml) into the rumen of a defaunated steer via the ruminal fistula. The mono-faunated steer was successfully inoculated with an average concentration of E. caudatum cells at 4.1 x 10(3)/ml (SD = 0.2) on day 2 after the inoculation.