Biomedical subjects

H Steingass

Publications and source records attributed to H Steingass.

17 recordsLinked to original sources

PubMed2006

Relationship between thiamine concentration and fermentation patterns in the rumen fluid of dairy cows fed with graded concentrate levels.

The objective of this study was to investigate the relationship between the thiamine concentration and the fermentation patterns [pH, concentration of short-chain fatty acids (SCFA)] in the free liquid (FRL) and particle-associated liquid (PARL) of the rumen in dairy cows fed with graded concentrate levels in the diet. Four ruminally cannulated Holstein cows in mid lactation were fed [semi-ad libitum, 18 kg dry matter (DM)/day] diets consisting of hay (H) and slowly degradable concentrate (C), offered in five different H:C ratios (% DM basis) in the following sequence: period 1, 30:70; period 2, 40:60; period 3, 50:50; period 4, 60:40 and period 5, 75:25. A negative quadratic relationship was observed between thiamine concentration in FRL and intake of dietary thiamine (R(2) = 0.36), of concentrate (R(2) = 0.38) and of digestible non-fibre carbohydrates (R(2) = 0.37). The thiamine concentration in PARL was higher (p < or = 0.05) compared to FRL. The ruminal thiamine concentration correlated negatively to pH and positively to concentrations of SCFA and propionate in the rumen. R(2) of these relationships varied markedly (0.002 and 0.77), depending on time after feeding and fluid digesta compartment. The higher R(2) were observed at 8 and 11 h after the morning feeding for FRL (R(2) 0.46-0.71) and PARL (R(2) 0.41-0.77), respectively.

Animal Feed↗

PubMed2006

Effects of physically effective fiber on digestive processes and milk fat content in early lactating dairy cows fed total mixed rations.

Data from recent research studies were analyzed quantitatively, and the random effect of experiment was assessed to define the physiological responses of dairy cows in early lactation to intake of physically effective neutral detergent fiber (peNDF). All studies were conducted with lactating Holstein cows (84.8 +/- 3.54 days in milk) in Latin square designs, and feeds were offered ad libitum as total mixed rations (TMR). The peNDF was estimated by 2 measurement techniques, the NDF content of TMR multiplied by amount of dry matter (DM) retained on a 1.18-mm screen (peNDF(> 1.18)) and NDF content of TMR multiplied by the proportion of DM retained by 19- and 8-mm Penn State Particle Separator screens (peNDF(> 8)). Other factors, including concentrations of NDF, forage NDF, non-fiber carbohydrates, the amount of digestible organic matter of forages (FDOM), and the intake of ruminally degradable starch (RDSI) from grain in the diet were also investigated. The studied animal response variables included feed intake, ruminal fermentation, chewing activity, fiber digestibility, and milk production and composition. The ruminal pH (day mean) in this study ranged from 5.30 to 6.59. Using peNDF(> 1.18) approach, the requirements for physically effective fiber in high-yielding dairy cows fed TMR in an ad libitum intake were estimated to be about 19% of ration DM or 4.1 kg/d or 0.6 kg/100 kg of body weight to maintain a ruminal pH of about 6.0. When peNDF was measured as peNDF(> 8), ruminal pH responded in a quadratic fashion but the confidence of estimation was lower (R(2) = 0.27) compared with the peNDF(> 1.18) approach (R(2) = 0.67). Results of these data analyses showed that peNDF(> 1.18) provided a satisfactory estimation of the mean ruminal pH (R(2) = 0.67) and NDF digestibility (R(2) = 0.56). Furthermore, peNDF(> 1.18) was poorly, although positively, correlated to daily chewing (R(2) = 0.17), and rumination (R(2) = 0.24) activity. On the other hand, results from these analyses showed that milk parameters are less sensitive to the effects of dietary peNDF than other variables, such as ruminal pH, chewing activity, and fiber digestibility. Dietary FDOM correlated positively (moderately) to ruminal pH (R(2) = 0.24), daily chewing (R(2) = 0.23), and rumination (R(2) = 0.29) activity, whereas the daily RDSI from grain correlated negatively to ruminal pH (R(2) = 0.55) and positively to total volatile fatty acids (R(2) = 0.27). Inclusion of FDOM and RDSI from grain along with peNDF(> 1.18) in the models that predict rumen pH further improved the accuracy of prediction. This approach appeared to further complement the concept of peNDF that does not account for differences in ruminal fermentability of feeds.

Animal Feed↗

PubMed2004

Digesta characteristics of dorsal, middle and ventral rumen of cows fed with different hay qualities and concentrate levels.

The influence of fibre content of hay (H) and concentrate level (C) on local differences in the composition of ruminal digesta (ratio of solid to fluid digesta, DM, NDF, ADF and ADL content), particle size (MPL), specific gravity (SG) and fermentation (pH and concentrations of SCFA and bicarbonate) have been tested on two ruminally cannulated Friesian cows (520 kg BW) which were fed restricted, using individual cows as experimental units. Digesta samples were collected via cannula from three rumen layers: 5 to 10 cm (top) and 25-35 cm beneath the top of the particle mat (middle) and 5-10 cm above the rumen floor (bottom). For a main plot treatment (H x C), repeated samples were collected at four time intervals (1 h before and 2, 5 and 10 h after morning feeding) on each of two days. From top to bottom rumen the share of solid digesta mass (SM), DM and NDF contents of squeezed digesta fluid (SRF) and concentration of SCFA decreased (P < 0.05); pH and bicarbonate concentration increased (P < 0.05), while DM, NDF, ADF and ADL contents in SM, MPL and SG did not differ. Higher NDF content of hay (from 47-62%) increased SM, fibre fractions in SM, MPL, pH and concentration of bicarbonate in ruminal digesta, especially when 50% concentrate was given, while SG decreased. When the concentrate level was enhanced from 20 to 50%, digesta SM, MPL and the content of DM and NDF in SRF increased, while pH, concentrations of SCFA and acetate decreased when low-fibre hay was given. With longer time after feeding the digesta SM was reduced and fibre content in SM increased. The increase of the fibre content of hay reduced the possible negative effect of high concentrate level on the stratification of ruminal digesta. The decrease of the fibre content of hay promised better conditions for fibre digestion in the rumen when concentrate availability is limited.

Animal Feed↗

PubMed2004

Energy requirements of cattle for standing and for ingestion, estimated by a ruminal emptying technique.

Energy requirements for ingestion and standing were determined in open-circuit respiration chambers with four ruminally cannulated German Red Pied steers weighing 617 +/- 53 kg of BW (mean +/- SD). The requirement for standing over lying was derived by regressing heat production on time spent standing within 2-h periods when no feed was offered to avoid any interference with eating activity, and amounted to 14 kJ/(d x kg of BW). The energy requirement for ingestion was determined by calculating the difference between heat production during a 2-h period without feed and during a consecutive 2-h period in which straw of different particle sizes, fresh and conserved grass, or rolled barley were offered for ad libitum intake. Before measurements, the rumens of the steers were emptied, washed, and filled with a buffer solution to avoid heat production by metabolism of absorbed nutrients from the feed ingested during the experimental periods. The mean value for all feeds tested was 20 J/(min of ingestion x kg BW). Relating heat production to the amount of DM or fiber ingested did not decrease variation among feeds. This confirms the observations of earlier studies, that energy requirement for ingestion is mainly determined by time spent eating. Results of additional measurements, in which the same amounts of the respective feeds ingested in preceding periods were put into the emptied rumens via the cannulas, showed that the presence of the feed in the rumen did not increase heat production, indicating that the increment of heat production during eating is mainly caused by ingesting and chewing the feed. Further measurements in the same animals with an ingesta-filled rumen showed that ingestion of straw led to an increase in heat production per minute of chewing similar to those with emptied rumens, which confirms the validity of the experimental procedure using ruminally emptied animals to determine the energy requirement for ingestion.

Animal Feed↗

PubMed2003

Crowding and winter emergency feeding as predisposing factors for kerato-conjunctivitis in semi-domesticated reindeer in Norway.

Due to the hard environmental and climatic situation in late winter 1999, a herd of about 200 free-ranging, semi-domesticated reindeer was gathered in a paddock in northern Norway for emergency feeding. About the same number of reindeer was not corralled but supplementary fed on their winter pastures. The fodder was of relatively good quality but very dusty and fed in a very dry environment. Six weeks later, an outbreak of eye-infection was diagnosed in one third of the corralled reindeer; mild symptoms were observed in most of them, but 11 animals showed severe signs of disease. No signs of disease were found in the non-corralled animals. Ten reindeer died through emaciation, the eleventh was sacrificed. Histopathological diagnosis of two severely affected eyes revealed a severe purulent kerato-conjunctivitis with bacteria and plant particles embedded in purulent exudates on the cornea and conjunctiva. In one eye from the two most affected animals Actinomyces pyogenes, coagulase-negative Staphylococci and Escherichia coli and in the other one Staphylococcus aureus and Escherichia coli were found. The bacteria encountered in this study are not considered the primary cause of disease. They seem rather to be opportunistic infectious agents of eyes that have been irritated mechanically through exposure to dusty fodder in a dry environment. The stress through unfamiliar corralling of the reindeer, that followed an insufficient fodder supply, could be considered as an additional infection supporting factor. This case-report emphasises on the importance of different factors involved in favouring outbreaks of disease in reindeer, under intensified husbandry conditions. Even though crowding and emergency feeding may be, at certain circumstances, the only means of survival for reindeer, a negative impact of implied crowding diseases on their productivity, must be considered, as well.

Animal Feed↗

PubMed2002

Merremia tridentata as a supplementary feed to the grass Panicum maximum for young West African Dwarf sheep.

The provision ad libitum of the browse plant Merremia tridentata as a free-choice supplement to the grass Panicum maximum led to a significant increase in the total food intake of groups of five West African Dwarf sheep, although the increase in weight gain was not significant. The protein content of M. tridentata was higher than that of the grass and its tannin content was not sufficient to render it unpalatable.

Animal Feed↗

PubMed2001

Sugar beet mash silage as a component of a total-mixed-ration for dairy cows--effects on parameters of digestion and animal performance.

Sugar beet mash silage (BMS) was offered in amounts up to 35% of DM to dairy cows as a component of a total-mixed-ration (TMR). Barley and molasses in the control ration were replaced by BMS half in ration BMS 1/2 and in total in ration BMS 1/1 on the basis of the calculated contents of net energy for lactation. Two trials were carried out. In trial I each ration was tested on parameters of rumen fermentation and digestibility of crude nutrients using 4 Holstein cows with rumen fistula. Chewing activity was tested on 2 Holstein cows for each ration. With the BMS rations the ruminal NH3 concentration was lower and the drop in pH was less than in the control ration. The pattern of volatile fatty acids in the rumen fluid from the BMS groups tended towards more propionic and butyric acid. The feeding of BMS showed no negative impact on chewing and rumination. Energy digestibility raised significantly from 59.8% in the control ration to 72.6% in the BMS 1/1 ration. In trial II the same rations were fed in a change-overdesign to a herd of 24 Holstein cows to test feed intake and animal performance. The results showed no significant effects of BMS rations on DM intake and milk production. The results of both trials indicate that even high amounts of cereals can be replaced by BMS without negative effects on rumen fermentation, milk yield and milk composition with slight drop in fat content. For a better handling of BMS, it is of advantage to include it in a TMR.

Ammonia↗

PubMed2001

Influence of hay particle size at different concentrate and feeding levels on digestive processes and feed intake in ruminants. 2. Passage, digestibility and feed intake.

In order to study the main effects of particle size, three ruminally fistulated cows (550 to 580 kg BW) were fed a constant low concentrate level (3.56 kg DM/d, 20% of total DMI) and a fibre-rich hay (approximately 60% NDF in DM) in long (28.7 mm), chopped (9.2 mm) and fine ground (2.9 mm) form in a 3 x 3 Latin square design. In another three factorial experiment with 8 wethers (4 animals were ruminally fistulated, mean BW = 68 kg) the main effects and interactions of the above mentioned hay particle sizes at two concentrate levels (10.4 to 13.3% and 29.5 to 40.1% of DMI, resp.) and two intake levels (restricted and ad libitum) were investigated. In comparison to long hay (28.7 mm), feeding of chopped hay (9.2 mm) at low concentrate levels, increased not only the hay intake (7% in dairy cows and 13% in sheep) but also the intake of digestible organic matter (12% in dairy cows and 32% in sheep), due to an increase in the apparent digestibility of OM by 3.8% in dairy cows and 8.2% in sheep. Ad libitum feeding of fine ground hay in combination with low concentrate amount in the ration increased the passage rate in the hindgut and consequently the hay intake, but not the intake of DOM, due to a significant depression of digestibility, especially of fibre fractions (4 to 7% in dairy cows and 4.5 to 14% in sheep), in comparison to 28.7 and 9.2 mm hay particle sizes. The digestibility decreased significantly with restricted feeding of fine ground hay in sheep only in comparison to 9.2 mm particle size. A threefold increase of concentrate amount leveled out all effects of the particle size reduction. The effect of particle size was more pronounced in sheep than in dairy cows.

Animal Feed↗

PubMed2001

Effect of feeding regime on the metabolism of ochratoxin A during the in vitro incubation in buffered rumen fluid from cows.

Pure ochratoxin A (OA) was added to buffered rumen fluid collected from two fistulated cows and incubated under anaerobic conditions. Both animals were fed six diets containing grass, grass silage or hay, and two different amounts of concentrate consisting of barley and soybean meal. Four incubations per animal and diet were carried out at consecutive days. The concentration of OA declined exponentially to a very low or non-detectable level under all conditions examined, with half-lives at 0.51 to 2.76 h. The disappearance of OA was accompanied by the appearance of ochratoxin alpha (O alpha) with an average amount of O alpha formed relative to the disappearance of OA near 100%, independent of diet and animal. Based on four incubations per animal and diet the rate of OA disappearance was affected (P < 0.1) by the origin of rumen fluid from two animals, as well as by the type of basic component and amount of concentrate in the diet, with interactions between these factors. The disappearance of OA mostly was accelerated (P < 0.1) by replacing grass silage or hay by fresh grass and by increasing the content of concentrate from 10 to 50% of dry matter. It is concluded that the capacity of the rumen to detoxify OA is not limited by the yield of Oa from OA but is strongly dependent on animal and diet.

Animal Feed↗

PubMed2001

Research note: a method for studying local differences in ruminal fermentation in dairy cattle.

A method was developed for studying local differences in ruminal fermentation. The developed sampler consisted of an acrylic glass container (460 cm3) with an aperture for digesta sampling, which could be opened and closed by the scaled "T" rod. The scale was a reference for defined rumen layers: top, middle, 5 to 10 cm and 25 to 35 cm beneath the top of particles mat, respectively, and bottom 5 to 10 cm above the rumen floor. The repeatability of the method was proved in two rumen cannulated cows. Particle/fluid ratio, pH and sample amount were measured 2 to 2 1/2 h after morning feeding in four replicates each day (over 5 days), rumen layer and animal. No significant differences between replicates were observed. The coefficients of variation (CV) of the particle/fluid ratio varied between 8.7% and 13.6%. Top layer had higher CV than middle and bottom layer. CV of pH ranged between 0.59% and 1.27%. The developed method of sampling showed satisfactory repeatability for investigation of digesta properties and fermentation in different rumen layers.

Animals↗

PubMed2000

Acceptance and digestibility of some selected browse feeds with varying tannin content as supplements in sheep nutrition in west Africa.

In 1994 and 1995 leaves from 10 selected West African trees and shrubs with varying tannin content were tested to determine their suitability as an alternative and supplementary browse feed for West African dwarf sheep to improve productivity in small-scale holdings in Benin. Dry matter intake per kg metabolic body weight (DM g/kg W0.75) varied between the different browse feeds and between the different trials and ranged from zero (Leucaena leucocephala) up to 26.7 DM g/kg W0.75 (Margaritaria discoidea). The digestibility of the organic matter varied between 58.9% (L. leucocephala) and 68.2% (Mallotus oppositifolius). Agelaea obliqua showed the highest levels of total phenols (10.2%), tannin phenols (8.8%) and extractable condensed tannins (8.0%). Leaves from various browse feeds are a good and protein-rich supplementary fodder in addition to the grass Panicum maximum. However, feeding of A. obliqua and Cnestis ferruginea should be avoided due to toxic components.

Animal Feed↗

PubMed2000

The chemical composition of Phyllanthus discoideus and its effect on the ruminal ammonia and volatile fatty acid concentration when fed to west African dwarf sheep.

The feeding value of Phyllanthus discoideus (also called Margaritaria discoidea) leaves was evaluated using eight two-year-old West African Dwarf sheep fed natural grass hay. Four of the animals were fistulated ruminally and used for ammonia and volatile fatty acid determination in the fluid. Dried leaves of Phyllanthus discoideus were offered at two levels (25% and 50% of DMI, diets D25% and D50%, respectively) as supplements to the basal hay diet. The CP content of the control, D25% and D50% diets were 11.5, 12.6 and 13.6%, respectively, and their digestible energy amounted to 58.2, 61.1 and 56.9%, respectively. Rumen liquor was sampled one hour before and one, three and five hours after the morning feeding. Sheep fed the control diet had a higher ruminal ammonia concentration than those fed diet D25%. Similarly, ruminal ammonia concentration was higher in sheep fed the control diet than those fed the diet D50%. Five hours after feeding the ruminal ammonia concentration was significantly lower than one hour after feeding. The VFA concentrations in rumen fluid of sheep fed the control diet was inferior to those fed diets D25% and D50%. Sheep fed diet D50% showed significantly higher VFA concentrations than those fed diet D25%. Digestibility of organic matter and digestible energy did not show any significant difference. However, a marginal increase in organic matter digestibility of 3.5% was observed in diet D25% compared with the control diet. There was no significant difference in the N-digestibility in sheep fed the control, D25% and D50% diets. Nevertheless, a marginal improvement in N-digestibility (1.5%) and N-retention (2.7%) was observed with the highest level of Phyllanthus discoideus (D50%). In conclusion, Phyllanthus discoideus appears as a particularly valuable feedstuff because it contains low levels of condensed tannins (12.8 g/kg), high CP content (156 g/kg) and a relatively high GE content (19.3 kJ/g DM). Although the improvement in N-digestibility and N-retention were only marginal the feeding of Phyllanthus discoideus could be justified under extreme shortage of feed resources during dry season. It should also be mentioned that a much more pronounced effect by supplementation with Phyllanthus discoideus could be expected when poor quality grass hay prevalent in West Africa during the dry season is fed. Phyllanthus discoideus could serve as a supplement to poor quality grass at 25% to 50% of supplementation.

Ammonia↗

PubMed1999

[Effect of hay particle size at different concentrations and feeding levels on digestive processes and feed intake in ruminants. 1. Chewing activity and fermentation in the rumen].

In order to study the main effects of particle size three ruminally fistulated cows were fed a hay rich in fibre in long (28.7 mm), chopped (9.2 mm) and ground (2.9 mm) form in a 3 x 3 Latin square design. In another three factorial experiment with 8 wethers (4 animals were ruminally fistulated) the main effects and interactions of the above mentioned hay particle size at two concentrate levels (10.4 to 13.3 and 29.5 to 40.1% in the ration) and at two feeding levels (restricted and ad libitum) were investigated. There was no effect of chopped hay (9.2 mm) on chewing activity, whereas ground hay (2.9 mm) reduced rumination time (52% in sheep and 36% in dairy cows) and chewing expense (time/unit of DM or NDF intake). These effects were more pronounced at high concentrate intake. Sheep increased feed intake more through reduction of rumination expense than through the extension of rumination time. pH-value, concentration of bicarbonate and C2:C3-ratio indicate favourable fermentation conditions in long (28.7 mm) and chopped hay (9.2 mm), whereas a negative influence of ground hay (2.9 mm) or ruminal fermentation could be observed.

Animal Feed↗

PubMed1997

The relationship between in vitro gas production, in vitro microbial biomass yield and 15N incorporation and its implications for the prediction of voluntary feed intake of roughages.

The relationship between in vitro gas production, concomitant in vitro apparent and true DM degradability has been examined in forty-two roughages. The partitioning of truly-degraded substrate between gas volume and microbial biomass yield and 15N incorporation into cells was also investigated. The relevance of this partitioning for the regulation of DM intake (DMI) was examined for fifty-four roughages. The results can be summarized as follows. In vitro gas production and in vitro apparent and true degradability are highly correlated (P < 0.0001), r being 0.96 and 0.95 respectively. There is an inverse relationship between in vitro gas production and microbial biomass yield (r--0.67, (P < 0.0001) and also 15N enrichment (P < 0.001) when the variables were related to a given unit of substrate truly degraded. Selecting roughages by in vitro gas production may well be a selection against maximum microbial yield and a combination of in vitro gas volume measurements with a complementary determination of the substrate truly degraded is proposed, to calculate a partitioning factor (PF) reflecting the variation of short-chain fatty acid production per unit substrate degraded. PF is calculated as the ratio, substrate truly degraded: gas produced by it. PF was highly significant (P < 0.0001) in DMI prediction when included in stepwise multiple correlations together with in vitro gas volume variables reflecting the extent and rate of gas production; 11% of the variation in DMI was accounted for by the PF. The total model, including extent and rate of gas production and the PF, accounted for 84% of the variation in DMI. Roughages producing proportionally less gas per unit substrate truly degraded had higher feed intakes.

Animal Feed↗

PubMed1996

Prediction of the net energy content of raw materials and compound feeds for ruminants by different laboratory methods.

In this study three different laboratory procedures were compared as predictors of net energy content of raw materials and compound feeds for ruminants. Laboratory measurements included an enzymatic technique (pepsin-cellulase method) and a rumen fluid technique (Hohenheim gas test). An estimate based on crude nutrients only was also tested. A total of 98 feed samples with known in vivo digestibility were available. By multivariate regression analysis equations for the prediction of the net energy content were calculated. The results suggest that in case of compound feeds for dairy the cellulase technique and the gas test are suitable in vitro techniques. With both procedures the relationships between energy contents estimated in vitro and energy contents measured in vivo showed residual errors of less than 4 percent. However for the evaluation of raw materials the gas test was superior. Compared to the cellulase technique the risk of extreme under- or overestimations is apparently reduced and this was found to be the case for own prediction equations as well as equations from literature. Crude nutrients proved to be very poor predictors for all feed samples.

Animal Feed↗

PubMed1991

Preliminary observations on the relationship between gas production and microbial protein synthesis in vitro.

The relationship between gas production and microbial protein synthesis was studied in vitro using the method of MENKE et al. (1979). 150 mg starch or cellulose or a mixture of 10% glucose, 40% starch and 50% cellulose was used as the carbohydrate source. The microbial protein synthesis and gas production occurring during 2 hrs after the 5th, 10th, and 23rd hr of incubation were studied. Total and net microbial synthesis were estimated using 32P as a microbial marker and by the net disappearance of NH3-N respectively. The data indicate that the type of carbohydrate and the rate of carbohydrate fermentation influence microbial protein synthesis per unit volume of gas produced. However, the relationship between total synthesis and cumulative gas production (up to 8 hrs incubation) with carbohydrate mixture as the substrate was linear. With reference to these observations, the possibilities and difficulties in using cumulative gas production as an index of microbial growth potential of the feedstuffs are discussed.

Animals↗

PubMedDate not supplied

Studies on in vitro degradation and in vivo digestion of a slow ammonia releasing urea product.

a slow ammonia releasing urea product (Uromalt) has been produced by autoclaving and drying of germinated barley and urea. In vitro degradability of nitrogen (IVDN, Raab et al., 1983) was in average 62 +/- 9% in 4 hours, compared to 76 +/- 8% with an autoclaved and dried mixture of urea and not-germinated barley. Mixtures of urea with Leucaena l. or Azadarichta indica (Neem cake) showed degradabilities of about 80 and 93%, respectively, when dried at 39 degrees C, but of 65% when dried at 100 degrees C. For comparison, degradabilities of proteins of ground nut, guar, sunflower, mustard, rape and sesame cake/meal have been determined. When growing lambs were fed a ration containing 15% Uromalt, faecal N-excretion was significantly higher on the expense of urinary N-excretion, compared with groups fed isonitrogenous rations containing soya bean meal with or without urea and molasses. N-retention was not significantly affected. It is concluded that this slow ammonia releasing urea product can be used in cases where molasses or other feedingstuffs rich in rapidly fermentable carbohydrates are not available.

Ammonia↗