Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

    Records 1 - 15 / 15

    • help
    • print

      Print search results

    • export

      Export search results

    Check title to add to marked list
    Evaluation of the SF6 tracer technique for estimating methane emission rates with reference to dairy cows using a mechanistic model
    Berends, H. ; Gerrits, W.J.J. ; France, J. ; Ellis, J.L. ; Zijderveld, S.M. van; Dijkstra, J. - \ 2014
    Journal of Theoretical Biology 353 (2014). - ISSN 0022-5193 - p. 1 - 8.
    sulfur-hexafluoride tracer - chamber techniques - eructated gas - cattle - rumen - sheep - methanogenesis - performance - ruminants - digestion
    A dynamic, mechanistic model of the sulfur hexafluoride (SF6) tracer technique, used for estimating methane (CH4) emission rates from ruminants, was constructed to evaluate the accuracy of the technique. The model consists of six state variables and six zero-pools representing the quantities of SF6 and CH4 in rumen and hindgut fluid, in rumen and hindgut headspace, and in blood and collection canister. The model simulates flows of CH4 and SF6 through the body, subsequent eructation and exhalation and accumulation in a collection canister. The model predicts CH4 emission by multiplying the SF6 release rate of a permeation device in the rumen by the ratio of CH4:SF6 in collected air. This prediction is compared with the actual CH4 production rate, assumed to be continuous and used as a driving variable in the model. A sensitivity analysis was conducted to evaluate the effect of changes in several parameters. The predicted CH4 emission appeared sensitive to parameters affected by the difference in CH4:SF6 ratio in exhaled and eructed air respectively, viz., hindgut fractional passage rate and hindgut CH4 production. This is caused by the difference in solubility of CH4 and SF6 and by hindgut CH4 production. In addition, the predicted CH4 emission rate appeared sensitive to factors that affect proportions of exhaled and eructed air sampled, i.e., eructation time fraction, exhalation time fraction, and distance from sampling point to mouth/nostrils. Changes in rumen fractional passage rate, eructation rate, SF6 release rate, background values and air sampling rate did not noticeably affect the predicted CH4 emission. Simulations with 13CH4 as an alternative tracer show that the differences and sensitivity to parameters greatly disappear. The model is considered a useful tool to evaluate critical points in the SF6 technique. Data from in vivo experiments are needed to further evaluate model simulations.
    Dietary nitrate supplementation reduces methane emission in beef cattle fed sugarcane-based diets
    Hulshof, R.B.A. ; Berndt, A. ; Gerrits, W.J.J. ; Dijkstra, J. ; Zijderveld, S.M. van; Newbold, J.R. ; Perdok, H.B. - \ 2012
    Journal of Animal Science 90 (2012)7. - ISSN 0021-8812 - p. 2317 - 2323.
    rumen fermentation - sheep - methanogenesis - manipulation - mitigation - livestock - nitrite - dairy - urea - wall
    The objective of this study was to determine the effect of dietary nitrate on methane emission and rumen fermentation parameters in Nellore × Guzera (Bos indicus) beef cattle fed a sugarcane based diet. The experiment was conducted with 16 steers weighing 283 ± 49 kg (mean ± SD), 6 rumen cannulated and 10 intact steers, in a cross-over design. The animals were blocked according to BW and presence or absence of rumen cannula and randomly allocated to either the nitrate diet (22 g nitrate/kg DM) or the control diet made isonitrogenous by the addition of urea. The diets consisted of freshly chopped sugarcane and concentrate (60:40 on DM basis), fed as a mixed ration. A 16-d adaptation period was used to allow the rumen microbes to adapt to dietary nitrate. Methane emission was measured using the sulfur hexafluoride tracer technique. Dry matter intake (P = 0.09) tended to be less when nitrate was present in the diet compared with the control, 6.60 and 7.05 kg/d DMI, respectively. The daily methane production was reduced (P <0.01) by 32% when steers were fed the nitrate diet (85 g/d) compared with the urea diet (125 g/d). Methane emission per kilogram DMI was 27% less (P <0.01) on the nitrate diet (13.3 g methane/kg DMI) than on the control diet (18.2 g methane/kg DMI). Methane losses as a fraction of gross energy intake (GEI) were less (P <0.01) on the nitrate diet (4.2% of GEI) than on the control diet (5.9% of GEI). Nitrate mitigated enteric methane production by 87% of the theoretical potential. The rumen fluid ammonia-nitrogen (NH3-N) concentration was significantly greater (P <0.05) for the nitrate diet. The total concentration of VFA was not affected (P = 0.61) by nitrate in the diet, while the proportion of acetic acid tended to be greater (P = 0.09), propionic acid less (P = 0.06) and acetate/propionate ratio tended to be greater (P = 0.06) for the nitrate diet. Dietary nitrate reduced enteric methane emission in beef cattle fed sugarcane based diet.
    The effect of incremental levels of Sandalwood oil on methane emissions and animal performance in sheep
    Veneman, J. ; Newbold, J.R. ; Perdok, H. ; Gerrits, W.J.J. ; Dijkstra, J. ; Zijderveld, S.M. van - \ 2011
    In: Proceedings of the 8th International Symposium on the Nutrition of Herbivores (ISHN8), Aberystwyth, Wales, UK, 6-9 September 2011. - Cambridge : Cambridge University Press - p. 513 - 513.
    Persistency of methane mitigation by dietary nitrate supplementation in dairy cows
    Zijderveld, S.M. van; Gerrits, W.J.J. ; Dijkstra, J. ; Newbold, J.R. ; Hulshof, R.B.A. ; Perdok, H.B. - \ 2011
    Journal of Dairy Science 94 (2011)8. - ISSN 0022-0302 - p. 4028 - 4038.
    rumen fermentation - l-cysteine - sheep - manipulation - combination - ruminants - hydrogen - nitrite - cattle
    Feeding nitrate to dairy cows may lower ruminal methane production by competing for reducing equivalents with methanogenesis. Twenty lactating Holstein-Friesian dairy cows (33.2±6.0 kg of milk/d; 104±58 d in milk at the start of the experiment) were fed a total mixed ration (corn silage-based; forage to concentrate ratio 66:34), containing either a dietary urea or a dietary nitrate source [21 g of nitrate/kg of dry matter (DM)] during 4 successive 24-d periods, to assess the methane-mitigating potential of dietary nitrate and its persistency. The study was conducted as paired comparisons in a randomized design with repeated measurements. Cows were blocked by parity, lactation stage, and milk production at the start of the experiment. A 4-wk adaptation period allowed the rumen microbes to adapt to dietary urea and nitrate. Diets were isoenergetic and isonitrogenous. Methane production, energy balance, and diet digestibility were measured in open-circuit indirect calorimetry chambers. Cows were limit-fed during measurements. Nitrate persistently decreased methane production by 16%, whether expressed in grams per day, grams per kilogram of dry matter intake (DMI), or as percentage of gross energy intake, which was sustained for the full experimental period (mean 368 vs. 310±12.5 g/d; 19.4 vs. 16.2±0.47 g/kg of DMI; 5.9 vs.4.9±0.15% of gross energy intake for urea vs. nitrate, respectively). This decrease was smaller than the stoichiometrical methane mitigation potential of nitrate (full potential=28% methane reduction). The decreased energy loss from methane resulted in an improved conversion of dietary energy intake into metabolizable energy (57.3 vs. 58.6±0.70%, urea vs. nitrate, respectively). Despite this, milk energy output or energy retention was not affected by dietary nitrate. Nitrate did not affect milk yield or apparent digestibility of crude fat, neutral detergent fiber, and starch. Milk protein content (3.21 vs. 3.05±0.058%, urea vs. nitrate respectively) but not protein yield was lower for dietary nitrate. Hydrogen production between morning and afternoon milking was measured during the last experimental period. Cows fed nitrate emitted more hydrogen. Cows fed nitrate displayed higher blood methemoglobin levels (0.5 vs. 4.0±1.07% of hemoglobin, urea vs. nitrate respectively) and lower hemoglobin levels (7.1 vs. 6.3±0.11 mmol/L, urea vs. nitrate respectively). Dietary nitrate persistently decreased methane production from lactating dairy cows fed restricted amounts of feed, but the reduction in energy losses did not improve milk production or energy balance
    Dietary inclusion of diallyl disulfide, yucca powder, calcium fumarate, an extruded linseed product, or medium-chain fatty acids does not affect methane production in lactating dairy cows
    Zijderveld, S.M. van; Dijkstra, J. ; Perdok, H.B. ; Newbold, J.R. ; Gerrits, W.J.J. - \ 2011
    Journal of Dairy Science 94 (2011)6. - ISSN 0022-0302 - p. 3094 - 3104.
    production in-vitro - rumen microbial fermentation - ruminal fermentation - linolenic acids - essential oils - beef-cattle - garlic oil - metaanalysis - metabolism - schidigera
    Two similar experiments were conducted to assess the effect of diallyl disulfide (DADS), yucca powder (YP), calcium fumarate (CAFU), an extruded linseed product (UNSAT), or a mixture of capric and caprylic acid (MCFA) on methane production, energy balance, and dairy cow performance. In experiment 1, a control diet (CON1) and diets supplemented with 56 mg of DADS/kg of dry matter (DM), 3g of YP/kg of DM, or 25 g of CAFU/kg of DM were evaluated. In experiment 2, an inert saturated fat source in the control diet (CON2) was exchanged isolipidically for an extruded linseed source (100g/kg of DM; UNSAT) or a mixture of C8:0 and C10:0 (MCFA; 20.3g/kg of DM). In experiment 2, a higher inclusion level of DADS (200mg/kg of DM) was also tested. Both experiments were conducted using 40 lactating Holstein-Friesian dairy cows. Cows were adapted to the diet for 12 d and were subsequently kept in respiration chambers for 5 d to evaluate methane production, diet digestibility, energy balance, and animal performance. Feed intake was restricted to avoid confounding effects of possible differences in ad libitum feed intake on methane production. Feed intake was, on average, 17.5 and 16.6 kg of DM/d in experiments 1 and 2, respectively. None of the additives reduced methane production in vivo. Methane production in experiment 1 was 450, 453, 446, and 423 g/d for CON1 and the diets supplemented with DADS, YP, and CAFU, respectively. In experiment 2, methane production was 371, 394, 388, and 386 g/d for CON2 and the diets supplemented with UNSAT, MCFA, and DADS, respectively. No effects of the additives on energy balance or neutral detergent fiber digestibility were observed. The addition of MCFA increased milk fat content (5.38% vs. 4.82% for control) and fat digestibility (78.5% vs. 59.8% for control), but did not affect milk yield or other milk components. The other products did not affect milk yield or composition. Results from these experiments emphasize the need to confirm methane reductions observed in vitro with in vivo data.
    Dietary strategies to reduce methane emissions from ruminants
    Zijderveld, S.M. van - \ 2011
    Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Jan Dijkstra; Walter Gerrits. - [S.l.] : S.n. - ISBN 9789461730220 - 132
    rundvee - diervoedering - melkkoeien - voedertoevoegingen - methaanproductie - cattle - animal feeding - dairy cows - feed additives - methane production

    Ruminant products form an important part of the human diet. The demand for ruminant products is expected to increase due to the increase in the size of the human population and its increasing wealth. The production of ruminant meat and milk is associated with a relatively large environmental impact when compared to other animal products. This is, for a large part, caused by the fact that ruminants produce enteric methane, a greenhouse gas, during the digestion of their feed. Many dietary strategies have been proposed to lower methane production in ruminants, although most of these have only been tested in vitro. In this thesis, a number of dietary strategies, that had been proven effective in vitro, were evaluated for their in vivo efficacy in methane reduction. A mixture of lauric acid, myristic acid, linseed oil and calcium fumarate lowered methane production by 10% in lactating dairy cows. However, fat and protein corrected milk production was negatively affected by feeding this mixture. Despite the methane reduction, energy balance was unaltered in this study. Diallyldisulfide, yucca powder, calcium fumarate, an extruded linseed product and a mixture of capric and caprylic acid did not affect methane production in lactating dairy cows, although their efficacy had been demonstrated in vitro. The addition of nitrate and sulfate to sheep diets lowered in vivo methane emissions (-32% and -16%, respectively), presumably by acting as a hydrogen sink in the rumen. No negative side-effects of feeding nitrate or sulfate were observed in this study. The use of nitrate in methane mitigation was further evaluated in a long-term study with dairy cows. Dietary nitrate persistently lowered methane production by 16% in dairy cows over the 89-d experimental period. Despite this reduction in methane production, milk production or energy retention were not improved. Methemoglobin levels in blood were slightly elevated, when nitrate was fed to dairy cows. Further analysis of the efficacy of nitrate in methane mitigation demonstrated that the efficacy of nitrate in methane mitigation decreased with increasing dose of nitrate (expressed in g nitrate/kg 0.75 per day). The conversion of metabolizable energy gained from a lowering of methane production may be less efficient than is commonly assumed. This could originate from a shift from methane to hydrogen emissions, when methane is specifically inhibited, or from erroneous assumptions made in the calculation of heat production during indirect respiration calorimetry. Dietary fat addition may be an effective strategy to lower methane production from ruminants, although the fatty acid profile of the added fat does not appear to have additional effects on methane production from ruminants. When assessing the environmental impact of ruminant products, it is generally overlooked that ruminants are capable of transforming feed not accessible to humans into human food.

    Relationships between methane production and milk fatty acid profiles in dairy cattle
    Dijkstra, J. ; Zijderveld, S.M. van; Apajalahti, J.A. ; Bannink, A. ; Gerrits, W.J.J. ; Newbold, J.R. ; Perdok, H.B. ; Berends, H. - \ 2011
    Animal Feed Science and Technology 166-167 (2011). - ISSN 0377-8401 - p. 590 - 595.
    rumen fermentation - lactating cows - supplementation
    There is a need to develop simple ways of quantifying and estimating CH4 production in cattle. Our aim was to evaluate the relationship between CH4 production and milk fatty acid (FA) profile in order to use milk FA profiles to predict CH4 production in dairy cattle. Data from 3 experiments with dairy cattle with a total of 10 dietary treatments and 50 observations were used. Dietary treatments included supplementation with calcium fumarate, diallyldisulfide, caprylic acid, capric acid, lauric acid, myristic acid, extruded linseed, linseed oil and yucca powder. Methane was measured using open circuit indirect respiration calorimetry chambers and expressed as g/kg dry matter (DM) intake. Milk FA were analyzed by gas chromatography and individual FA expressed as a fraction of total FA. To determine relationships between milk FA profile and CH4 production, univariate mixed model regression techniques were applied including a random experiment effect. A multivariate model was developed using a stepwise procedure with selection of FA based on the Schwarz Bayesian Information Criterion. Dry matter intake was 17.7 ± 1.83 kg/day, milk production was 27.0 ± 4.64 kg/day, and methane production was 21.5 ± 1.69 g/kg DM. Milk C8:0, C10:0, C11:0, C14:0 iso, C15:0 iso, C16:0 and C17:0 anteiso were positively related (P
    Effects of a combination of feed additives on methane production, diet digestibility, and animal performance in lactating dairy cows
    Zijderveld, S.M. van; Fonken, B.C.J. ; Dijkstra, J. ; Gerrits, W.J.J. ; Perdok, H.B. ; Fokkink, W.B. ; Newbold, J.R. - \ 2011
    Journal of Dairy Science 94 (2011)3. - ISSN 0022-0302 - p. 1445 - 1454.
    chain fatty-acids - ruminal methanogenesis - fumaric-acid - beef-cattle - coconut oil - linseed oil - extruded linseed - detergent fiber - myristic acid - crude linseed
    Two experiments were conducted to assess the effects of a mixture of dietary additives on enteric methane production, rumen fermentation, diet digestibility, energy balance, and animal performance in lactating dairy cows. Identical diets were fed in both experiments. The mixture of feed additives investigated contained lauric acid, myristic acid, linseed oil, and calcium fumarate. These additives were included at 0.4, 1.2, 1.5, and 0.7% of dietary dry matter, respectively (treatment ADD). Experimental fat sources were exchanged for a rumen inert source of fat in the control diet (treatment CON) to maintain isolipidic rations. Cows (experiment 1, n = 20; experiment 2, n = 12) were fed restricted amounts of feed to avoid confounding effects of dry matter intake on methane production. In experiment 1, methane production and energy balance were studied using open-circuit indirect calorimetry. In experiment 2, 10 rumen-fistulated animals were used to measure rumen fermentation characteristics. In both experiments animal performance was monitored. The inclusion of dietary additives decreased methane emissions (g/d) by 10%. Milk yield and milk fat content tended to be lower for ADD in experiment 1. In experiment 2, milk production was not affected by ADD, but milk fat content was lower. Fat- and protein-corrected milk was lower for ADD in both experiments. Milk urea nitrogen content was lowered by ADD in experiment 1 and tended to be lower in experiment 2. Apparent total tract digestibility of fat, but not that of starch or neutral detergent fiber, was higher for ADD. Energy retention did not differ between treatments. The decrease in methane production (g/d) was not evident when methane emission was expressed per kilogram of milk produced. Feeding ADD resulted in increases of C12:0 and C14:0 and the intermediates of linseed oil biohydrogenation in milk in both experiments. In experiment 2, ADD-fed cows tended to have a decreased number of protozoa in rumen fluid when compared with that in control cows. Total volatile fatty acid concentrations were lower for ADD, whereas molar proportions of propionate increased at the expense of acetate and butyrate
    Relationships of milk fatty acid profile with methane production in dairy cattle
    Dijkstra, J. ; Apajalahti, J.A. ; Bannink, A. ; Gerrits, W.J.J. ; Newbold, J.R. ; Perdok, H.B. ; Zijderveld, S.M. van; Berends, H. - \ 2010
    In: Proceedings of the 4th international conference on greenhouse gases and animal agriculture, Banff, Canada, 3-8 October, 2010. - Banff : - p. 169 - 169.
    The development of simple indicators to quantify methane production in cattle is of interest, both for research and for practical purposes on-farm. The profile of milk fatty acids (FA) may be related to methane production, given that diet composition affects rumen microbial metabolism and methanogenesis, as well as the supply of preformed FA and FA precursors to the mammary gland. The aim of this experiment was to evaluate the relationship of milk FA profile with methane production in dairy cattle. Data from three experiments with dairy cattle, encompassing 10 dietary treatments and 50 observations, were used. Dietary treatments included supplementation with calcium fumarate, diallyldisulfide, caprylic acid, capric acid, lauric acid, myristic acid, extruded linseed, linseed oil, and yucca powder. Methane was measured using open-circuit indirect respiration calorimetry chambers and expressed as g per kg dry matter intake (DMI). After extraction and methylation, milk FA were analyzed by gas chromatography and individual FA expressed as % of total FA. To determine the relationship between milk FA profile and methane production, mixed model regression techniques (PROC MIXED of SAS) were applied including a random experiment effect. A multivariate model was developed using a stepwise procedure (PROC GLMSELECT of SAS) with selection of FA based on the Schwarz Bayesian Information Criterion. Observations were weighted by the n of the experiment. Dry matter intake was 17.7 ± 1.83 kg/d, milk production was 27.0 ± 4.64 kg/d, and methane production was 376 ± 55.7 g/d (values expressed as means ± SD). Milk C10:0, C11:0, C14:0iso, C15:0iso, and C16:0 were positively related (P
    Dietary nitrate persistently reduces enteric methane production in lactating dairy cows
    Zijderveld, S.M. van; Dijkstra, J. ; Gerrits, W.J.J. ; Newbold, J.R. ; Perdok, H.B. - \ 2010
    In: Proceedings of the 4th international conference on greenhouse gases and animal agriculture, Banff, Canada, 3-8 October, 2010. - Banff : Greenhouse Gases and Animal Agriculture - p. 127 - 127.
    The anaerobic reduction of 1 mole of nitrate to ammonia consumes 8 moles of hydrogen and is thermodynamically more favourable than methanogenesis, which also consumes 8 moles of H2. Nitrate may therefore function as an alternative hydrogen sink to enteric methanogenesis when fed to ruminants. The ammonia generated can be utilized for microbial growth in diets low in crude protein. The aim of this experiment was to evaluate the methane mitigating effect of a dietary nitrate source and the persistency of this effect when this nitrate source is fed to dairy cows. Besides effects on methane production, the effects on animal performance and health were also monitored. Twenty lactating Holstein-Friesian dairy cows (milk production 33.2 + 6.0 kg/day; 104 + 58 DIM) were paired according to parity, milk production and lactation stage. Within a pair, cows were randomly allotted to one of two maize silage based diets containing either urea or nitrate (1.2 and 2.2% of diet DM, respectively) as non-protein nitrogen sources. Diets were formulated to be iso-nitrogenous. Cows were adapted to the diets for a period of 4 wks. During this adaptation period the concentrates containing the non-protein nitrogen sources gradually replaced a soybean meal based concentrate (25% per wk). After the adaptation period, cows were housed in indirect calorimetry respiration chambers for a period of 5 d to monitor methane production and animal performance. During the period in the chambers, animals were fed restrictedly (95% of ad libitum DMI) to avoid treatment effects on DMI and hence indirect effects on methane production. The measurement periods were repeated 3 times with 23-d intervals. Cows were kept on the same diets during the entire experiment. Nitrate intake averaged 398 g/day for the cows on the nitrate treatment. Methane production was reduced by 16% (P =0.009) in the nitrate-fed cows and this reduction was not affected by time (treatment*time interaction P=0.961), indicating that the methane reducing effect was persistent over a 4-month period. Milk production was unaffected by treatment (P= 0.452), but milk protein content was lower (P=0.041) for the nitrate-fed animals. Methemoglobin concentrations in blood were elevated (4.0% of Hb) in the nitrate-fed animals relative to the control (0.4% of Hb), but animals displayed no clinical signs of methemoglobinemia. Dietary inclusion of nitrate may be a useful tool to persistently lower enteric methane emissions from dairy cows.
    Nitrate and sulfate: effective alternative hydrogen sinks for mitigation of ruminal methane production in sheep
    Zijderveld, S.M. van; Gerrits, W.J.J. ; Apajalahti, J.A. ; Newbold, J.R. ; Dijkstra, J. ; Leng, R.A. ; Perdok, H.B. - \ 2010
    Journal of Dairy Science 93 (2010)12. - ISSN 0022-0302 - p. 5856 - 5866.
    real-time pcr - fumaric-acid - feed-intake - in-vitro - rumen - methanogenesis - emissions - reduction - nitrogen - cattle
    Twenty male crossbred Texel lambs were used in a 2 x 2 factorial design experiment to assess the effect of dietary addition of nitrate (2.6% of dry matter) and sulfate (2.6% of dry matter) on enteric methane emissions, rumen volatile fatty acid concentrations, rumen microbial composition, and the occurrence of methemoglobinemia. Lambs were gradually introduced to nitrate and sulfate in a corn silage-based diet over a period of 4 wk, and methane production was subsequently determined in respiration chambers. Diets were given at 95% of the lowest ad libitum intake observed within one block in the week before methane yield was measured to ensure equal feed intake of animals between treatments. All diets were formulated to be isonitrogenous. Methane production decreased with both supplements (nitrate: -32%, sulfate: -16%, and nitrate + sulfate: -47% relative to control). The decrease in methane production due to nitrate feeding was most pronounced in the period immediately after feeding, whereas the decrease in methane yield due to sulfate feeding was observed during the entire day. Methane-suppressing effects of nitrate and sulfate were independent and additive. The highest methemoglobin value observed in the blood of the nitrate-fed animals was 7% of hemoglobin. When nitrate was fed in combination with sulfate, methemoglobin remained below the detection limit of 2% of hemoglobin. Dietary nitrate decreased heat production (-7%), whereas supplementation with sulfate increased heat production (+3%). Feeding nitrate or sulfate had no effects on volatile fatty acid concentrations in rumen fluid samples taken 24 h after feeding, except for the molar proportion of branched-chain volatile fatty acids, which was higher when sulfate was fed and lower when nitrate was fed, but not different when both products were included in the diet. The total number of rumen bacteria increased as a result of sulfate inclusion in the diet. The number of methanogens was reduced when nitrate was fed. Enhanced levels of sulfate in the diet increased the number of sulfate-reducing bacteria. The number of protozoa was not affected by nitrate or sulfate addition. Supplementation of a diet with nitrate and sulfate is an effective means for mitigating enteric methane emissions from sheep.
    Evaluation of the SF6 tracer technique to determine methane emissions rates using a mechanistic model
    Berends, H. ; Dijkstra, J. ; Gerrits, W.J.J. ; Zijderveld, S.M. van - \ 2009
    In: Proceedings of the 34th Animal Nutrition Research Forum, Melle, Belgium, 3 April 2009. - ILVO Animal Sciences - p. 15 - 16.
    Effects of extruded linseed, a mixture of C8:0 and C10:0 fatty acids, and diallyldisulfide on methane emission in dairy cows
    Zijderveld, S.M. van; Gerrits, W.J.J. ; Dijkstra, J. ; Newbold, J.R. ; Deswysen, D. ; Perdok, H.B. - \ 2009
    In: XIth International Symposium on Ruminant Physiology, Clermont-Ferrand, France, 6 - 9 September, 2009. - Wageningen : Wageningen Academic Publishers - p. 384 - 385.
    Effects of a combination of feed additives on methane production, diet digestibility and animal performance in lactating dairy cows.
    Zijderveld, S.M. van; Fonken, B.C.J. ; Newbold, J.R. ; Fokkink, W.B. ; Dijkstra, J. ; Gerrits, W.J.J. ; Perdok, H.B. - \ 2008
    Journal of Dairy Science 91 (2008)E-Suppl 1. - ISSN 0022-0302 - p. 335 - 335.
    An experiment was conducted to study the effects of a mixture of lauric acid (C12:0), myristic acid (C14:0), linseed oil and calcium fumarate on methane production, diet digestibility and milk production. Inclusion rates of the additives were 0.4, 1.2, 1.5 and 0.7% of DM, respectively. The basal diet comprised (DM basis) 37.1% grass silage, 37.1% corn silage, 1.7% wheat straw and 42.0% concentrate. The experiment was designed as a randomized block design and conducted using 20 lactating Holstein-Friesian dairy cows (FPCM production 32.8 ± 4.9 kg/d, 176 ± 76 DIM at the start of the experiment). Cows were assigned to either the control treatment (CON) or the treatment receiving the additives (ADD) for treatment periods of 22 days. In the ADD ration, rumen-inert fat from palm oil was substituted for lauric acid, myristic acid and linseed oil to maintain diets isolipidic. Cows were housed in 2 identical, open-circuit, indirect climate respiration chambers (2 cows per chamber) during experimental observations in the third week. As a consequence of restricted feeding, DMI did not differ between treatments (16.7 and 16.5 kg DM/ day for CON and ADD, respectively). Apparent digestibility of OM, N, starch and sugar were unaffected, apparent fat digestibility was higher for ADD (65.6 vs 75.6%, P= 0.01). Daily milk yield did not differ between treatments (27.8 vs. 27.2 kg/ day, P=0.70). Milk fat concentration tended to be lower (P = 0.06) in ADD (41.0 g/kg) than in CON (46.3 g/kg). FPCM production was lower for ADD as a result of the lower fat content for this treatment (29.4 vs 27.4 kg/d, P= 0.02). MUN levels were significantly lower for ADD (10.3 vs. 8.0 mg/dl, P=0.02), possibly reflecting a defaunating effect of the additives, with a consequentially lower rumen ammonia production. Methane production was lower for ADD relative to CON (362 vs. 326 g methane/cow/day, P = 0.02).
    Effects of a combination of feed additives on methane production, diet digestibility and animal performance in lactating dairy cows
    Zijderveld, S.M. van; Fonken, B.C.J. ; Newbold, J.R. ; Fokkink, W.B. ; Dijkstra, J. ; Gerrits, W.J.J. ; Perdok, H.B. - \ 2008
    Journal of Animal Science 86 (2008)E-Suppl 2. - ISSN 0021-8812
    Check title to add to marked list

    Show 20 50 100 records per page

     
    Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.