Bannink A.,Animal science Group |
Smits M.C.J.,Animal science Group |
Kebreab E.,University of California at Davis |
Mills J.A.N.,University of Reading |
And 4 more authors.
Journal of Agricultural Science | Year: 2010
A dynamic, mechanistic model of enteric fermentation was used to investigate the effect of type and quality of grass forage, dry matter intake (DMI) and proportion of concentrates in dietary dry matter (DM) on variation in methane (CH4) emission from enteric fermentation in dairy cows. The model represents substrate degradation and microbial fermentation processes in rumen and hindgut and, in particular, the effects of type of substrate fermented and of pH on the production of individual volatile fatty acids and CH4 as end-products of fermentation. Effects of type and quality of fresh and ensiled grass were evaluated by distinguishing two N fertilization rates of grassland and two stages of grass maturity. Simulation results indicated a strong impact of the amount and type of grass consumed on CH4 emission, with a maximum difference (across all forage types and all levels of DMI) of 49 and 77% in g CH4/kg fat and protein corrected milk (FCM) for diets with a proportion of concentrates in dietary DM of 01 and 04, respectively (values ranging from 102 to 195 g CH4/kg FCM). The lowest emission was established for early cut, high fertilized grass silage (GS) and high fertilized grass herbage (GH). The highest emission was found for late cut, low-fertilized GS. The N fertilization rate had the largest impact, followed by stage of grass maturity at harvesting and by the distinction between GH and GS. Emission expressed in g CH4/kg FCM declined on average 14% with an increase of DMI from 14 to 18 kg/day for grass forage diets with a proportion of concentrates of 01, and on average 29% with an increase of DMI from 14 to 23 kg/day for diets with a proportion of concentrates of 04. Simulation results indicated that a high proportion of concentrates in dietary DM may lead to a further reduction of CH4 emission per kg FCM mainly as a result of a higher DMI and milk yield, in comparison to low concentrate diets. Simulation results were evaluated against independent data obtained at three different laboratories in indirect calorimetry trials with cows consuming GH mainly. The model predicted the average of observed values reasonably, but systematic deviations remained between individual laboratories and root mean squared prediction error was a proportion of 012 of the observed mean. Both observed and predicted emission expressed in g CH4/kg DM intake decreased upon an increase in dietary N:organic matter (OM) ratio. The model reproduced reasonably well the variation in measured CH4 emission in cattle sheds on Dutch dairy farms and indicated that on average a fraction of 028 of the total emissions must have originated from manure under these circumstances. © 2009 Cambridge University Press.
Fieten H.,University Utrecht |
Hugen S.,University Utrecht |
van den Ingh T.S.G.A.M.,TCCI Consultancy BV |
Hendriks W.H.,Animal science Group |
And 5 more authors.
Veterinary Journal | Year: 2013
Hereditary copper-associated hepatitis in dogs resembles Wilson's disease, a copper storage disease in humans. Values for urinary copper excretion are well established in the diagnostic protocol of Wilson's disease, whereas in dogs these have not been evaluated. The objectives of this study were to characterize both basal and D-penicillamine induced urinary copper, zinc and iron excretion in dogs in relation to hepatic copper concentration. Beagles, Beagle-Bedlington terrier cross-breeds homozygous for the COMMD1 gene mutation that causes copper toxicosis, and Labrador retrievers with normal or increased hepatic copper concentrations were investigated. The hepatic copper phenotype was determined by histological evaluation of liver biopsies and measurement of the hepatic copper concentration by instrumental neutron activation analysis. Urinary excretion of copper, iron and zinc was measured via inductively coupled plasma optical emission spectrometry under basal conditions and after oral administration of a single dose (20. mg/kg bodyweight) of the chelator D-penicillamine. There was a rapid increase in urinary excretion of copper and zinc, but not iron after D-penicillamine administration. This increase was not different between dogs with high or normal hepatic copper concentrations. D-penicillamine-induced urinary copper excretion and the copper/creatinine ratio did not correlate with hepatic copper concentrations in the dogs studied, although basal urinary copper/zinc ratios did correlate with hepatic copper concentrations in Labrador retrievers. The latter parameter may be useful in diagnostic and follow-up protocols for copper-associated hepatitis in Labrador retrievers. © 2013 Elsevier Ltd.
McCarthy J.,Irish Cattle Breeding Federation |
Veerkamp R.F.,Animal Science Group
Journal of Dairy Science | Year: 2012
Variance components for test-day milk yield were estimated for primiparous animals in a seasonal calving system where 80% of calvings occur within a 5-mo period in the spring. The objective was to investigate if the variance components of milk production were affected by seasonality via month in milk and test month (TM). These effects were, therefore, fitted for both the permanent environment effect and additive genetic effect. Estimates of heritability (0.14-0.27) were found to be lowest during early and late lactation for all calving months. The peak in heritability (0.22-0.27) occurred later in lactation for animals that calved toward the end of the spring calving season. Genetic variance of test day milk yield for all calving months was found to be highest at the beginning of the lactation (2.23-3.36kg2), with a plateau toward the middle of the lactation. Genetic variance was found to be highest (2.98-3.36kg2) for animals calving early in the season. Genetic correlations between corresponding stages of lactation were strongest (0.99-1.00) between consecutive calving months. Genetic correlations were slightly weaker when intervals between calving months increased; however, they remained above 0.96 in all cases. Akaike's information criterion values from models both inclusive and exclusive of TM, suggest that the model exclusive of TM is the preferred model. Estimated breeding values of lactation milk yield from bulls with 20 or more daughters, predicted for a full 305-d lactation, were used to compare the model with the standard test-day model (i.e., exclusive of TM), based on DIM. Correlations were higher than 0.995 for milk yield (and higher than 0.930 for persistency) between models inclusive and exclusive of TM, suggesting that given the straightforward approach taken in the current study, an apparent benefit for including seasonality in the evaluation of test-day milk yield was not found; however, there may be benefits of including it in the estimation of persistency. © 2012 American Dairy Science Association.
Sedghi M.,Ferdowsi University of Mashhad |
Golian A.,Ferdowsi University of Mashhad |
Esmaeilipour O.,University of Jiroft |
Van Krimpen M.M.,Animal science Group
British Poultry Science | Year: 2014
1. In poultry investigations, the main interest is often to study the effects of many factors simultaneously. Two or three level factorial designs are the most commonly used for this type of investigation. However, it is often too costly to perform when number of factors increase. So a fractional factorial design, which is a subset or a fraction of a full factorial design, is an alternative. The Taguchi method has been proposed for simplifying and standardising fractional factorial designs.2. An experiment was conducted to evaluate the applicability of the Taguchi method to optimise in vitro intrinsic phytase activity (IPA) of rye, wheat and barley under different culture conditions.3. In order to have a solid base for judging the suitability of the Taguchi method, the results of the Taguchi method were compared with those of an experiment that was conducted as a 34 full factorial arrangement with three feed ingredients (rye, wheat and barley), three temperatures (20°C, 38°C and 55°C), three pH values (3.0, 5.5 and 8.0) and three incubation times (30, 60 and 120 min), with two replicates per treatment.4. After data collection, a Taguchi L 9 (34) orthogonal array was used to estimate the effects of different factors on the IPA, based on a subset of only 9 instead of 81 treatments. The data were analysed with both Taguchi and full factorial methods and the main effects and the optimal combinations of these 4 factors were obtained for each method.5. The results indicated that according to both the full factorial experimental design and the Taguchi method, the optimal culture conditions were obtained with the following combination: rye, pH = 3, temperature = 20 °C and time of incubation = 30 min. The comparison between the Taguchi and full factorial results showed that the Taguchi method is a sufficient and resource saving alternative to the full factorial design in poultry science. © 2014 British Poultry Science Ltd.
Zhang C.,Biobased Chemistry and Technology Group |
van Krimpen M.M.,Animal science Group |
Sanders J.P.M.,Biobased Chemistry and Technology Group |
Sanders J.P.M.,Food & Biobased Research |
And 2 more authors.
Food and Bioproducts Processing | Year: 2016
Rather than improving crop-production yield, developing biorefinery technology for unused biomass from the agri-food supply chain may be the crucial factor to reach sustainable global food security. A successful example of food-driven biorefinery is the extraction of protein from green tea residues, however, alkali usage is high and the resulting low protein quality limits its application. The research objective was to investigate the influence of pre-treatments with ethanol, Viscozyme® L and/or H2O2 on the subsequent alkaline protein extraction, and on their possible products for food applications. Polyphenols and/or pigments can be obtained by ethanol pre-treatment. Galacturonic acid and glucose can be obtained using Viscozyme® L. Pre-treatments using ethanol or Viscozyme® L individually reduced alkali consumption by 25% and improved protein extraction yield and purity. Their combination has the best effect. Additionally, pre-treatment using 50% ethanol reduced browning by 59% while pre-treatment using Viscozyme® L increased contents of arginine, threonine, and serine in the final alkaline protein extract. H2O2 pre-treatment had a negative effect on the alkaline protein extraction. These pre-treatments and protein extraction can be added to the existing process. © 2016 Institution of Chemical Engineers