Staff Publications

Staff Publications

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    '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.

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Effect of feed-related farm characteristics on relative values of genetic traits in dairy cows to reduce greenhouse gas emissions along the chain
Middelaar, C.E. van; Berentsen, P.B.M. ; Dijkstra, J. ; Arendonk, J.A.M. van; Boer, I.J.M. de - \ 2015
Journal of Dairy Science 98 (2015)7. - ISSN 0022-0302 - p. 4889 - 4903.
life-cycle assessment - genomic selection - economic values - milk-production - methane - cattle - mitigation - impact - level - model
Breeding has the potential to reduce greenhouse gas (GHG) emissions from dairy farming. Evaluating the effect of a 1-unit change (i.e., 1 genetic standard deviation improvement) in genetic traits on GHG emissions along the chain provides insight into the relative importance of genetic traits to reduce GHG emissions. Relative GHG values of genetic traits, however, might depend on feed-related farm characteristics. The objective of this study was to evaluate the effect of feed-related farm characteristics on GHG values by comparing the values of milk yield and longevity for an efficient farm and a less efficient farm. The less efficient farm did not apply precision feeding and had lower feed production per hectare than the efficient farm. Greenhouse gas values of milk yield and longevity were calculated by using a whole-farm model and 2 different optimization methods. Method 1 optimized farm management before and after a change in genetic trait by maximizing labor income; the effect on GHG emissions (i.e., from production of farm inputs up to the farm gate) was considered a side effect. Method 2 optimized farm management after a change in genetic trait by minimizing GHG emissions per kilogram of milk while maintaining labor income and milk production at least at the level before the change in trait; the effect on labor income was considered a side effect. Based on maximizing labor income (method 1), GHG values of milk yield and longevity were, respectively, 279 and 143 kg of CO2 equivalents (CO2e)/unit change per cow per year on the less efficient farm, and 247 and 210 kg of CO2e/unit change per cow per year on the efficient farm. Based on minimizing GHG emissions (method 2), GHG values of milk yield and longevity were, respectively, 538 and 563 kg of CO2e/unit change per cow per year on the less efficient farm, and 453 and 441 kg of CO2e/unit change per cow per year on the efficient farm. Sensitivity analysis showed that, for both methods, the absolute effect of a change in genetic trait depends on model inputs, including prices and emission factors. Substantial changes in relative importance between traits due to a change in model inputs occurred only in case of maximizing labor income. We concluded that assumptions regarding feed-related farm characteristics affect the absolute level of GHG values, as well as the relative importance of traits to reduce emissions when using a method based on maximizing labor income. This is because optimizing farm management based on maximizing labor income does not give any incentive for lowering GHG emissions. When using a method based on minimizing GHG emissions, feedrelated farm characteristics affected the absolute level of the GHG values, but the relative importance of the traits scarcely changed: at each level of efficiency, milk yield and longevity were equally important. Key words: breeding, milk yield, longevity, economic value.
Effect of maternal dry period length on colostrum immunoglobulin content and natural and specific antibody titers in calves
Mayasari, N. ; Vries Reilingh, G. de; Nieuwland, M.G.B. ; Remmelink, G.J. ; Parmentier, H.K. ; Kemp, B. ; Knegsel, A.T.M. van - \ 2015
Journal of Dairy Science 98 (2015)6. - ISSN 0022-0302 - p. 3969 - 3979.
dairy-cows - energy-balance - milk-production - bovine somatotropin - metabolic status - performance - responses - lactation - pathogen - antigen
The objective was to study the effect of dry period length in dairy cows on immunoglobulin content and natural antibodies (NAb) titers in colostrum, growth, and plasma natural and specific antibody titers in plasma of calves. Holstein-Friesian dairy cows (n = 167) were randomly assigned to 3 dry period lengths (0, 30, or 60 d). Colostrum production, concentration of colostrum IgG and IgM, and titers of NAb (isotypes IgG and IgM) binding keyhole limpet hemocyanin (KLH) and human serum albumin (HuSA) in colostrum were measured. Female calves were immunized with both KLH and HuSA at wk 6 and 10 of life. Titers of NAb and specific antibody (SpAb) for isotypes IgG, IgM, and total immunoglobulin (IgT) binding KLH or HuSA were determined in plasma of female calves. Primary and secondary antibody responses to KLH or HuSA from wk 6 and 10 were expressed as the increase in antibody titers to wk 10 and 11 of life after primary and secondary challenges, respectively. Pregnancy length for cows with a 0-d dry period was 3 d shorter compared with cows with a 30- or 60-d dry period. Birth weight of calves from cows with a 0-d dry period was lower compared with calves from cows with a 30-d dry period. Growth of calves until 12 wk of life was not affected by dry period length. Colostrum production and IgG and IgM concentration in colostrum were lower for cows with a 0-d dry period than a 60-d dry period. Natural IgG and IgM titers binding KLH or HuSA were lower in colostrum from cows with a 0-d dry period compared with cows with a 60-d dry period. Natural antibody titers (IgG, IgM, and IgT) binding KLH or HuSA in plasma were lower during the first 2 wk of life for calves from cows with a 0-d dry period compared with calves from cows with a 30- or 60-d dry period. After primary and secondary immunization of calves with KLH and HuSA, SpAb titers of calves were not affected by dry period length. After secondary immunization, the response of IgG and IgT binding KLH was higher in plasma of calves from cows with a 0-d dry period. The results of this study demonstrate that, although omission of the dry period of dairy cows leads to lower plasma NAb titers in calves during the first 2 wk of life, SpAb titers in calves were not affected and even the secondary antibody responses were enhanced compared with calves from cows with a 30- or 60-d dry period.
Mutrivariate and univariate analysis of energy balance data from lactating dairy cows
Moraes, L.E. ; Kebreab, E. ; Strathe, A.B. ; Dijkstra, J. ; France, J. ; Casper, D.P. ; Fadel, J.G. - \ 2015
Journal of Dairy Science 98 (2015)6. - ISSN 0022-0302 - p. 4012 - 4029.
body tissue mobilization - random regression - equation models - milk-production - major advances - genetic merit - growing pigs - net energy - efficiency - expression
The objectives of the study were to develop a multivariate framework for analyzing energy balance data from lactating cows and investigate potential changes in maintenance requirements and partial efficiencies of energy utilization by lactating cows over the years. The proposed model accounted for the fact that metabolizable energy intake, milk energy output, and tissue energy balance are random variables that interact mutually. The model was specified through structural equations implemented in a Bayesian framework. The structural equations, along with a model traditionally used to estimate energetic parameters, were fitted to a large database of indirect calorimetry records from lactating cows. Maintenance requirements and partial efficiencies for both models were similar to values reported in the literature. In particular, the estimated parameters (with 95% credible interval in parentheses) for the proposed model were: net energy requirement for maintenance equal to 0.36 (0.34, 0.38) MJ/kg of metabolic body weight·day; the efficiency of utilizing dietary energy for milk production and tissue gain were 0.63 (0.61, 0.64) and 0.70 (0.68, 0.72), respectively; the efficiency of utilizing body stores for milk production was 0.89 (0.87, 0.91). Furthermore, additional analyses were conducted for which energetic parameters were allowed to depend on the decade in which studies were conducted. These models investigated potential changes in maintenance requirements and partial efficiencies over the years. Canonical correlation analysis was used to investigate the association between changes in energetic parameters with additional dietary and animal characteristics available in the database. For both models, net energy requirement for maintenance and the efficiency of utilizing dietary energy for milk production and tissue gain increased in the more recent decades, whereas the efficiency of utilizing body stores for milk production remained unchanged. The increase in maintenance requirements in modern milk production systems is consistent with the literature that describes increased fasting heat production in cows of higher genetic merit. The increase in utilization of dietary energy for milk production and tissue gain was partially attributed to the changes in dietary composition, in particular to the increase in dietary ether extract to levels closer to currently observed in modern milk production systems. Therefore, the estimated energetic parameters from this study can be used to update maintenance requirements and partial efficiencies of energy utilization in North American feeding systems for lactating cows.
Effect of nitrogen fertilization rate and regrowth interval of grass herbage on methane emission of zero-grazing lactating dairy cows
Warner, D. ; Podesta, S.C. ; Hatew, B. ; Klop, G. ; Laar, H. van; Bannink, A. ; Dijkstra, J. - \ 2015
Journal of Dairy Science 98 (2015)5. - ISSN 0022-0302 - p. 3383 - 3393.
special topics-mitigation - oxide emissions - passage kinetics - milk-production - management - options - silage - cattle - supplementation - fermentation
Dairy cattle farming in temperate regions often relies on grass herbage (GH)-based diets but the effect of several grass management options on enteric CH4 emission has not been fully investigated yet. We investigated the combined effect of N fertilization rate and length of regrowth period of GH (predominantly ryegrass) on CH4 emission from lactating dairy cows. In a randomized block design, 28 lactating Holstein-Friesian dairy cows received a basal diet of GH and compound feed [85:15; dry matter (DM) basis]. Treatments consisted of GH cut after 3 or 5 weeks of regrowth, after receiving either a low (20 kg of N/ha) or a high (90 kg of N/ha) fertilization rate after initial cut. Feed intake, digestibility, milk production and composition, N and energy balance, and CH4 emission were measured during a 5-d period in climate respiration chambers after an adaptation to the diet for 12 d. Cows were restricted-fed during measurements and mean DM intake was 15.0 ± 0.16 kg/d. Herbage crude protein content varied between 76 and 161 g/kg of DM, and sugar content between 186 and 303 g/kg of DM. Fat- and protein-corrected milk (FPCM) and feed digestibility increased with increased N fertilization rates and a shorter regrowth interval. Increasing the N fertilization rate increased daily CH4 emission per cow (+10%) and per unit of DM intake (+9%), tended to increase the fraction of gross energy intake emitted as CH4 (+7%), and (partly because of the low crude protein content for the low fertilized GH) only numerically reduced CH4 per unit of FPCM. The longer regrowth interval increased CH4 emission per unit of FPCM (+14%) compared with the shorter regrowth interval, but did not affect CH4 emission expressed in any other unit. With increasing N fertilization CH4 emission decreased per unit of digestible neutral detergent fiber intake (-13%) but not per unit of digestible organic matter intake. There was no interaction of the effect of N fertilization rate and regrowth interval on CH4 emission, but effects of N fertilization were generally most distinct with GH of 5 wk regrowth. The present results suggest that altering grass quality through an increase of N fertilization and a shorter regrowth interval can reduce CH4 emission in zero-grazing dairy cows, depending on the unit in which it is expressed. The larger amount of CH4 produced per day and cow with the more intensively managed GH is compensated by a higher feed digestibility and FPCM yield.
Comparison of locomotion scoring for dairy cows by experienced and inexperienced raters using live or video observation methods.
Schlageter-Tello, A. ; Bokkers, E.A.M. ; Groot Koerkamp, P.W.G. ; Hertem, T. van; Viazzi, S. ; Romanini, C.E.B. ; Halachmi, I. ; Bahr, C. ; Berckmans, D. ; Lokhorst, K. - \ 2015
Animal Welfare 24 (2015). - ISSN 0962-7286 - p. 69 - 79.
ensure high repeatability - training-program - milk-production - weighted kappa - holstein cows - risk-factors - lameness - cattle - agreement - reliability
Lameness is considered a major problem in dairy production. Lameness is commonly detected with locomotion scores assigned to cows under farm conditions, but raters are often trained and assessed for reliability and agreement by using video recordings. The aim of this study was to evaluate intra- and inter-rater reliability and agreement of experienced and inexperienced raters for locomotion scoring performed live and from video, and to calculate the influence of raters and the method of observation (live or video) on the probability of classifying a cow as lame. Using a five-level locomotion score, cows were scored twice live and twice from video by three experienced and two inexperienced raters for three weeks. Every week different cows were scored. Intra- and inter-rater reliability (expressed as weighted kappa, ¿w)) and agreement (expressed as percentage of agreement, PA) for live/live, live/video and video/video comparisons were determined. A logistic regression was performed to estimate the influence of the rater and method of observation on the probability of classifying a cow as lame in live and video observation. Experienced raters had higher values for intra-rater reliability and agreement for video/video than for live/live and live/video comparison. Inexperienced raters, however, did not differ for intra- and inter-rater reliability and agreement for live/live, live/video and video/video comparisons. The logistic regression indicated that raters were responsible for the main effect and the method of observation (live or from video) had a minor effect on the probability for classifying a cow as lame (locomotion score =3). In conclusion, under the present experimental conditions, experienced raters performed better than unexperienced raters when locomotion scoring was done from video. Since video observation did not show any important influence in the probability of classifying a cow as lame, video observation seems to be an acceptable method for locomotion scoring and lameness assessment in dairy cows.
Effects of dry period length and dietary energy source on metabolic status and hepatic gene expression of dairy cows in early lactation
Chen, J.C. ; Gross, J.J. ; Dorland, H.A. van; Remmelink, G.J. ; Bruckmaier, R.M. ; Kemp, B. ; Knegsel, A.T.M. van - \ 2015
Journal of Dairy Science 98 (2015)2. - ISSN 0022-0302 - p. 1033 - 1045.
organic nutrient metabolism - messenger-rna - transition period - somatotropic axis - milk-production - fatty-acids - liver - balance - system - performance
In a prior study, we observed that cows with a 0-d dry period had greater energy balance and lower milk production compared with cows with a 30- or 60-d dry period in early lactation. The objective of the current study was to evaluate the influence of dry period length on metabolic status and hepatic gene expression in cows fed a lipogenic or glucogenic diet in early lactation. Holstein-Friesian dairy cows (n = 167) were assigned randomly to 3 × 2 factorial design with 3 dry period lengths (n = 56, 55, and 56 for 0-, 30-, and 60-d dry, respectively) and 2 early lactation diets (n = 84 and 83 for glucogenic and lipogenic diet, respectively). Cows were fed a glucogenic or lipogenic diet from 10 d before the expected calving date and onward. The main ingredient for a glucogenic concentrate was corn, and the main ingredients for a lipogenic concentrate were sugar beet pulp, palm kernel, and rumen-protected palm oil. Blood was sampled weekly from 95 cows from wk 3 precalving to wk 8 postcalving. Liver samples were collected from 76 cows in wk -2, 2, and 4 relative to calving. Liver samples were analyzed for triacylglycerol concentrations and mRNA expression of 12 candidate genes. Precalving, cows with a 0-d dry period had greater plasma ß-hydroxybutyrate, urea, and insulin concentrations compared with cows with a 30- or 60-d dry period. Postcalving, cows with a 0-d dry period had lower liver triacylglycerol and plasma nonesterified fatty acids concentrations (0.20, 0.32, and 0.36 mmol/L for 0-, 30-, and 60-d dry period, respectively), greater plasma glucose, insulin-like growth factor-I, and insulin (24.38, 14.02, and 11.08 µIU/mL for 0-, 30-, and 60-d dry period, respectively) concentrations, and lower hepatic mRNA expression of pyruvate carboxylase, compared with cows with a 30- or 60-d dry period. Plasma urea and ß-hydroxybutyrate concentrations were greater in cows fed a lipogenic diet compared with cows fed a glucogenic diet. In conclusion, cows with a 0-d dry period had an improved metabolic status in early lactation, indicated by lower plasma concentrations of nonesterified fatty acids, greater plasma concentrations of glucose, insulin-like growth factor-I, and insulin, and lower mRNA expression of pyruvate carboxylase in the liver, compared with cows with a 30- or 60-d dry period. Independent of dry period length, the glucogenic diet also improved the metabolic status compared with the lipogenic diet.
Effects of supplementation level and particle size of alfalfa hay on growth characteristics and rumen development in dairy calves
Mirzaei, M. ; Khorvash, M. ; Ghorbani, G.R. ; Kazemi-Bonchenari, M. ; Riasi, A. ; Nabipour, A. ; Borne, J.J.G.C. van den - \ 2015
Journal of Animal Physiology and Animal Nutrition 99 (2015)3. - ISSN 0931-2439 - p. 553 - 564.
neutral detergent fiber - early-weaned calf - feeding-behavior - holstein calves - sodium-butyrate - milk-production - early lactation - acid production - physical form - food-intake
The aim of this study was to assess the effects of particle size (PS) of alfalfa hay on growth characteristics and rumen development in dairy calves at two levels of alfalfa supplementation. Fifty newborn dairy calves (42.7 ± 2.2 kg BW) were used in a 2 × 2 factorial arrangement with the factors supplementation level (low, 8%; or high, 16% on DM basis) and PS (medium, 2.92 mm; or long, 5.04 mm as geometrical means) of alfalfa hay. In addition, a control group without alfalfa hay was used. Hence, treatments were: control (C); low level with medium PS (LM); low level with long PS (LL); high level with medium PS (HM) or high level with long PS (HL). Growth performance of alfalfa-fed calves did not differ from control calves, but alfalfa supplementation decreased corneum thickness of the rumen wall. In alfalfa-fed calves, post-weaning starter intake was greater for LL calves than for LM calves. During the entire rearing period, starter intake was 26–32% higher for LL and HM calves than for LM calves. Pre-weaning average daily gain was higher for LL and HM calves than for HL calves, but this effect was not persistent over the entire rearing period. Final body weight decreased from 86 to 79 kg when the level of long PS alfalfa hay increased from 8 to 16%, but increased from 78 to 87 kg when the level of medium PS alfalfa increased from 8 to 16%. Regardless of PS and level, morphometric characteristics of rumen wall were generally similar among alfalfa feeding groups, but corneum thickness decreased from 8.7 to 6.1 µm with greater PS at the low level. These results indicate that adequate, but not excessive, physical stimulation is required for appropriate rumen development and growth performance of dairy calves.
Effects of dietary starch content and rate of fermentation on methane production in lactating dairy cows
Hatew, B. ; Podesta, S.C. ; Laar, H. van; Pellikaan, W.F. ; St-Pierre, J.L. ; Dijkstra, J. ; Bannink, A. - \ 2015
Journal of Dairy Science 98 (2015)1. - ISSN 0022-0302 - p. 486 - 499.
microbial protein-synthesis - high-moisture corn - cattle fed barley - milk-production - ruminal fermentation - feed-intake - rumen fermentation - enteric methane - n balance - beet pulp
The objective of this study was to investigate the effects of starch varying in rate of fermentation and level of inclusion in the diet in exchange for fiber on methane (CH4) production of dairy cows. Forty Holstein-Friesian lactating dairy cows of which 16 were rumen cannulated were grouped in 10 blocks of 4 cows each. Cows received diets consisting of 60% grass silage and 40% concentrate (dry matter basis). Cows within block were randomly assigned to 1 of 4 different diets composed of concentrates that varied in rate of starch fermentation [slowly (S) vs. rapidly (R) rumen fermentable; native vs. gelatinized corn grain] and level of starch (low vs. high; 270 vs. 530 g/kg of concentrate dry matter). Results of rumen in situ incubations confirmed that the fractional rate of degradation of starch was higher for R than S starch. Effective rumen degradability of organic matter was higher for high than low starch and also higher for R than S starch. Increased level of starch, but not starch fermentability, decreased dry matter intake and daily CH4 production. Milk yield (mean 24.0 ± 1.02 kg/d), milk fat content (mean 5.05 ± 0.16%), and milk protein content (mean 3.64 ± 0.05%) did not differ between diets. Methane expressed per kilogram of fat- and protein-corrected milk, per kilogram of dry matter intake, or as a fraction of gross energy intake did not differ between diets. Methane expressed per kilogram of estimated rumen-fermentable organic matter (eRFOM) was higher for S than R starch–based diets (47.4 vs. 42.6 g/kg of eRFOM) and for low than high starch–based diets (46.9 vs. 43.1 g/kg of eRFOM). Apparent total-tract digestibility of neutral detergent fiber and crude protein were not affected by diets, but starch digestibility was higher for diets based on R starch (97.2%) compared with S starch (95.5%). Both total volatile fatty acid concentration (109.2 vs. 97.5 mM) and propionate proportion (16.5 vs. 15.8 mol/100 mol) were higher for R starch– compared with S starch–based diets but unaffected by the level of starch. Total N excretion in feces plus urine and N retained were unaffected by dietary treatments, and similarly energy intake and output of energy in milk expressed per unit of metabolic body weight were not affected by treatments. In conclusion, an increased rate of starch fermentation and increased level of starch in the diet of dairy cattle reduced CH4 produced per unit of eRFOM but did not affect CH4 production per unit of feed dry matter intake or per unit of milk produced.
A mechanistic model for electricity consumption on dairy farms: Definition, validation, and demonstration
Upton, J.R. ; Murphy, M. ; Shallo, L. ; Groot Koerkamp, P.W.G. ; Boer, I.J.M. de - \ 2014
Journal of Dairy Science 97 (2014)8. - ISSN 0022-0302 - p. 4973 - 4984.
artificial neural-networks - greenhouse-gas emissions - lactation curve - milk-production - cows - systems - yield
Our objective was to define and demonstrate a mechanistic model that enables dairy farmers to explore the impact of a technical or managerial innovation on electricity consumption, associated CO2 emissions, and electricity costs. We, therefore, (1) defined a model for electricity consumption on dairy farms (MECD) capable of simulating total electricity consumption along with related CO2 emissions and electricity costs on dairy farms on a monthly basis; (2) validated the MECD using empirical data of 1 yr on commercial spring calving, grass-based dairy farms with 45, 88, and 195 milking cows; and (3) demonstrated the functionality of the model by applying 2 electricity tariffs to the electricity consumption data and examining the effect on total dairy farm electricity costs. The MECD was developed using a mechanistic modeling approach and required the key inputs of milk production, cow number, and details relating to the milk-cooling system, milking machine system, water-heating system, lighting systems, water pump systems, and the winter housing facilities as well as details relating to the management of the farm (e.g., season of calving). Model validation showed an overall relative prediction error (RPE) of less than 10% for total electricity consumption. More than 87% of the mean square prediction error of total electricity consumption was accounted for by random variation. The RPE values of the milk-cooling systems, water-heating systems, and milking machine systems were less than 20%. The RPE values for automatic scraper systems, lighting systems, and water pump systems varied from 18 to 113%, indicating a poor prediction for these metrics. However, automatic scrapers, lighting, and water pumps made up only 14% of total electricity consumption across all farms, reducing the overall impact of these poor predictions. Demonstration of the model showed that total farm electricity costs increased by between 29 and 38% by moving from a day and night tariff to a flat tariff.
Selecting an appropriate genetic evaluation model for selection in a developing dairy sector
McGill, D.M. ; Mulder, H.A. ; Thomson, P.C. ; Lievaart, J.J. - \ 2014
Animal 8 (2014)10. - ISSN 1751-7311 - p. 1577 - 1585.
contemporary groups - production traits - breeding values - milk-production - sahiwal cattle - population - prediction - covariances - variances - yield
This study aimed to identify genetic evaluation models (GEM) to accurately select cattle for milk production when only limited data are available. It is based on a data set from the Pakistani Sahiwal progeny testing programme which includes records from five government herds, each consisting of 100 to 350 animals, with lactation records dating back to 1968. Different types of GEM were compared, namely: (1) multivariate v. repeatability model when using the first three lactations, (2) an animal v. a sire model, (3) different fixed effects models to account for effects such as herd, year and season; and (4) fitting a model with genetic parameters fixed v. estimating the genetic parameters as part of the model fitting process. Two methods were used for the comparison of models. The first method used simulated data based on the Pakistani progeny testing system and compared estimated breeding values with true breeding values. The second method used cross-validation to determine the best model in subsets of actual Australian herd-recorded data. Subsets were chosen to reflect the Pakistani data in terms of herd size and number of herds. Based on the simulation and the cross-validation method, the multivariate animal model using fixed genetic parameters was generally the superior GEM, but problems arise in determining suitable values for fixing the parameters. Using mean square error of prediction, the best fixed effects structure could not be conclusively determined. The simulation method indicated the simplest fixed effects structure to be superior whereas in contrast, the cross-validation method on actual data concluded that the most complex one was the best. In conclusion it is difficult to propose a universally best GEM that can be used in any data set of this size. However, some general recommendations are that it is more appropriate to estimate the genetic parameters when evaluating for selection purposes, the animal model was superior to the sire model and that in the Pakistani situation the repeatability model is more suitable than a multivariate.
Economic comparison of a sixty day dry period with no dry period on Dutch dairy farms
Heeren, J.A.H. ; Steeneveld, W. ; Berentsen, P.B.M. - \ 2014
Livestock Science 168 (2014). - ISSN 1871-1413 - p. 149 - 158.
milk-production - energy-balance - holstein herds - short 35-d - cows - lactation - performance - lengths - health - reproduction
In the Netherlands it is general practice that dairy cows have a dry period of six to eight weeks. Research, however, shows that omission of the dry period avoids the negative energy balance after calving with its potential negative effects on metabolic disorders, infectious diseases, and fertility. On the downside, no dry period (NDP) causes a loss of milk production per cow compared with a conventional dry period (CDP). The objective of this research was to make an economic comparison between CDP with a sixty day dry period and NDP. Data on milk production per cow and on replacement rate, being the possible result of improved health, were taken from five farms involved in a research project on the effects of NDP, both from the year before and the year after switching from CDP to NDP. These data show that the replacement rate was on average 37% in the CDP situation while it was 24% in the NDP situation. Milk production was on average 13% lower in the NDP situation while fat and protein content of the milk were 0.21% and 0.42% points higher. A whole farm dairy linear programming model maximizing labor income (returns to family labor and management) was used to determine the technical and economic results for the situation with CDP and NDP. Results were calculated for three scenarios (one with milk quota and two without milk quota), representing differences in possibilities for increasing the farm size. Results show that under each scenario NDP is more profitable than CDP. The increase in labor income varies from 20% to 42%. This means that the negative effect of a lower milk production per cow is outweighed by the positive effect of a lower replacement rate and higher milk components. Sensitivity analysis shows that under a milk quota scenario NDP always results in a higher labor income than CDP irrespective of the change in replacement rate and milk production loss. Under the scenarios without milk quota a replacement rate of 34–35% or a milk production loss of 19–21% with NDP would result in a comparable labor income. The conclusion of this research is that NDP gives better economic results than CDP in a dairy quota situation for a broad range of replacement rate reduction and milk production reduction. In a situation without dairy quota, the replacement rate should be at least 3% points lower and milk production should be not more than 19% lower in the NDP situation to end up with better economic results.
Handling multi-functionality of livestock in a life cycle assessment: the case of smallholder dairying in Kenya
Weiler, V. ; Udo, H.M.J. ; Viets, T.C. ; Crane, T.A. ; Boer, I.J.M. de - \ 2014
Current Opinion in Environmental Sustainability 8 (2014). - ISSN 1877-3435 - p. 29 - 38.
milk-production - food-production - systems - highlands - benefits
Life cycle assessment (LCA) is an acknowledged method to assess the contribution of livestock production to greenhouse gas (GHG) emissions. Most LCA studies so far allocate GHG emissions of livestock to marketable outputs. Smallholder systems, however, provide several products and services besides the production of marketable products. We explored how to account for multi-functionality within the LCA method in a case of smallholder milk production in the Kaptumo area in Kenya. Expressed per kg of milk, GHG emissions were 2.0 (0.9–4.3) kg CO2-e, respectively in case of food allocation, 1.6 (0.8–2.9) kg CO2-e in case of economic function allocation and 1.1 (0.5–1.7) kg CO2-e in case of livelihood allocation. The two Carbon Footprint (CF) estimates of milk production considering multi-functionality were comparable to CF estimates of milk in intensive milk production systems. Future LCA's of smallholder systems should account for multi-functionality, because CF results and consequently mitigation options change depending on the functions included.
Methods to determine the relative value of genetic traits in dairy cows to reduce greenhouse gas emissions along the chain
Middelaar, C.E. van; Berentsen, P.B.M. ; Dijkstra, J. ; Arendonk, J.A.M. van; Boer, I.J.M. de - \ 2014
Journal of Dairy Science 97 (2014)8. - ISSN 0022-0302 - p. 5191 - 5205.
enteric methane emissions - life-cycle assessment - land-use change - economic values - milk-production - grazing behavior - farm-level - model - cattle - rumen
Current decisions on breeding in dairy farming are mainly based on economic values of heritable traits, as earning an income is a primary objective of farmers. Recent literature, however, shows that breeding also has potential to reduce greenhouse gas (GHG) emissions. The objective of this paper was to compare 2 methods to determine GHG values of genetic traits. Method 1 calculates GHG values using the current strategy (i.e., maximizing labor income), whereas method 2 is based on minimizing GHG per kilogram of milk and shows what can be achieved if the breeding results are fully directed at minimizing GHG emissions. A whole-farm optimization model was used to determine results before and after 1 genetic standard deviation improvement (i.e., unit change) of milk yield and longevity. The objective function of the model differed between method 1 and 2. Method 1 maximizes labor income; method 2 minimizes GHG emissions per kilogram of milk while maintaining labor income and total milk production at least at the level before the change in trait. Results show that the full potential of the traits to reduce GHG emissions given the boundaries that were set for income and milk production (453 and 441 kg of CO2 equivalents/unit change per cow per year for milk yield and longevity, respectively) is about twice as high as the reduction based on maximizing labor income (247 and 210 kg of CO2 equivalents/unit change per cow per year for milk yield and longevity, respectively). The GHG value of milk yield is higher than that of longevity, especially when the focus is on maximizing labor income. Based on a sensitivity analysis, it was shown that including emissions from land use change and using different methods for handling the interaction between milk and meat production can change results, generally in favor of milk yield. Results can be used by breeding organizations that want to include GHG values in their breeding goal. To verify GHG values, the effect of prices and emissions factors should be considered, as well as the potential effect of variation between farm types.
Cow characteristics and their association with production performance with different dry period lengths
Steeneveld, W. ; Knegsel, A.T.M. van; Remmelink, G.J. ; Kemp, B. ; Vernooij, J.C.M. ; Hogeveen, H. - \ 2014
Journal of Dairy Science 97 (2014). - ISSN 0022-0302 - p. 4922 - 4931.
dairy-cows - milk-production - energy-balance - bovine somatotropin - metabolic status - holstein herds - short 35-d - lactation - health - yield
Shortening or omitting the dry period (DP) has been proposed as a management strategy to improve energy balance of dairy cows in early lactation. Both shortening and complete omission of the DP reduces milk production in the subsequent lactation compared with a conventional DP length of 60 d. Some cows have less milk production loss than other cows after applying no DP or a short DP. The aim of this study is to evaluate which cow characteristics are associated with the amount of milk production losses following no DP or a short DP (30 d). Daily production information from the lactation before and after the DP was available from 161 dairy cows (54 cows with a 0-d DP, 51 cows with a 30-d DP, and 56 cows with a 60-d DP) from a research herd. Daily production (milk, fat, and protein) until 305 d in milk was estimated for all cows. Subsequently, total fat- and protein-corrected milk yield from 60 d before the expected calving date until 305 d in the following lactation (FPCMtotal) was estimated. A statistical analysis was performed to evaluate which cow characteristics were associated with limited or no production losses following no DP or a short DP, compared with a conventional DP length of 60 d. Average FPCMtotal was 9,341, 10,499, and 10,795 kg for cows with no DP, a 30-d DP, and a 60-d DP, respectively. The cow characteristics parity, daily milk production at 12 wk before the expected calving date, and reduction in daily milk production between 16 and 12 wk before the expected calving date were associated with production loss due to a short (30 d) or no DP. Compared with 60 d DP, multiparous cows had less production loss (987 kg) following no DP than primiparous cows (2,132 kg). The difference in FPCMtotal between the 3 DP groups was largest for cows with a low milk production (e.g., 10 kg/d) at 12 wk before the expected calving date. The greater the reduction in milk production between 16 and 12 wk before the expected calving date, the larger the difference in FPCMtotal between the 3 DP groups. The difference in FPCMtotal between cows with no DP and 60 d DP at a reduction in milk production between 16 and 12 wk of 10% was 665 kg, whereas this difference was 1,138 kg at a reduction of 70%. The cow characteristics found can be used to select cows for specific DP lengths in a decision-support model to support the farmer on the economic optimal DP length for each individual cow. Output of such a decision-support model can be, for instance, to advise a 30-d DP for multiparous cows with high milk production (e.g., 25 kg/d) at 12 wk before the expected calving date.
Exploring the value of routinely collected herd data for estimating dairy cattle welfare
Vries, M. de; Bokkers, E.A.M. ; Schaik, G. van; Engel, B. ; Dijkstra, T. ; Boer, I.J.M. de - \ 2014
Journal of Dairy Science 97 (2014)2. - ISSN 0022-0302 - p. 715 - 730.
body condition score - somatic-cell count - milk-production - reproductive-performance - social-dominance - animal-welfare - cows - behavior - weight - productivity
Routine on-farm assessment of dairy cattle welfare is time consuming and, therefore, expensive. A promising strategy to assess dairy cattle welfare more efficiently is to estimate the level of animal welfare based on herd data available in national databases. Our aim was to explore the value of routine herd data (RHD) for estimating dairy cattle welfare at the herd level. From November 2009 through March 2010, 7 trained observers collected data for 41 welfare indicators in a selected sample of 183 loose-housed and 13 tethered Dutch dairy herds (herd size: 10 to 211 cows) using the Welfare Quality protocol for cattle. For the same herds, RHD relating to identification and registration, management, milk production and composition, and fertility were extracted from several national databases. The RHD were used as potential predictors for each welfare indicator in logistic regression at the herd level. Nineteen welfare indicators were excluded from the predictions, because they showed a prevalence below 5% (15 indicators), or were already listed as RHD (4 indicators). Predictions were less accurate for 7 welfare indicators, moderately accurate for 14 indicators, and highly accurate for 1 indicator. By forcing to detect almost all herds with a welfare problem (sensitivity of at least 97.5%), specificity ranged from 0 to 81%. By forcing almost no herds to be incorrectly classified as having a welfare problem (specificity of at least 97.5%), sensitivity ranged from 0 to 67%. Overall, the best-performing prediction models were those for the indicators access to at least 2 drinkers (resource based), percentage of very lean cows, cows lying outside the supposed lying area, and cows with vulvar discharge (animal based). The most frequently included predictors in final models were percentages of on-farm mortality in different lactation stages. It was concluded that, for most welfare indicators, RHD have value for estimating dairy cattle welfare. The RHD can serve as a prescreening tool for detecting herds with a welfare problem, but this should be followed by a verification of the level of welfare in an on-farm assessment to identify false-positive herds. Consequently, the number of farm visits needed for routine welfare assessments can be reduced. The RHD also hold value for continuous monitoring of dairy cattle welfare. Prediction models developed in this study, however, should first be validated in additional field studies.
Cost-effectiveness of feeding strategies to reduce greenhouse gas emissions from dairy farming
Middelaar, C.E. van; Dijkstra, J. ; Berentsen, P.B.M. ; Boer, I.J.M. de - \ 2014
Journal of Dairy Science 97 (2014)4. - ISSN 0022-0302 - p. 2427 - 2439.
nitrous-oxide emissions - dietary nitrate supplementation - enteric methane mitigation - special topics-mitigation - milk-production - fat supplementation - rumen fermentation - grazing behavior - linseed oil - cows
The objective of this paper was to evaluate the cost-effectiveness of 3 feeding strategies to reduce enteric CH4 production in dairy cows by calculating the effect on labor income at the farm level and on greenhouse gas (GHG) emissions at the chain level (i.e., from production of farm inputs to the farm gate). Strategies included were (1) dietary supplementation of an extruded linseed product (56% linseed; 1 kg/cow per day in summer and 2 kg/cow per day in winter), (2) dietary supplementation of a nitrate source (75% nitrate; 1% of dry matter intake), and (3) reducing the maturity stage of grass and grass silage (grazing at 1,400 instead of 1,700 kg of dry matter/ha and harvesting at 3,000 instead of 3,500 kg of dry matter/ha). A dairy farm linear programing model was used to define an average Dutch dairy farm on sandy soil without a predefined feeding strategy (reference situation). Subsequently, 1 of the 3 feeding strategies was implemented and the model was optimized again to determine the new economically optimal farm situation. Enteric CH4 production in the reference situation and after implementing the strategies was calculated based on a mechanistic model for enteric CH4 and empirical formulas explaining the effect of fat and nitrate supplementation on enteric CH4 production. Other GHG emissions along the chain were calculated using life cycle assessment. Total GHG emissions in the reference situation added up to 840 kg of CO2 equivalents (CO2e) per t of fat- and protein-corrected milk (FPCM) and yearly labor income of €42,605. Supplementation of the extruded linseed product reduced emissions by 9 kg of CO2e/t of FPCM and labor income by €16,041; supplementation of the dietary nitrate source reduced emissions by 32 kg of CO2e/t of FPCM and labor income by €5,463; reducing the maturity stage of grass and grass silage reduced emissions by 11 kg of CO2e/t of FPCM and labor income by €463. Of the 3 strategies, reducing grass maturity was the most cost-effective (€57/t of CO2e compared with €241/t of CO2e for nitrate supplementation and €2,594/t of CO2e for linseed supplementation) and had the greatest potential to be used in practice because the additional costs were low.
Stable isotope-labelled feed nutrients to assess nutrient-specific feed passage kinetics in ruminants
Warner, D. ; Dijkstra, J. ; Hendriks, W.H. ; Pellikaan, W.F. - \ 2014
Journal of the Science of Food and Agriculture 94 (2014)5. - ISSN 0022-5142 - p. 819 - 824.
functional specific-gravity - small-particle kinetics - dairy-cows - grass silages - gastrointestinal-tract - mechanistic model - digestive-tract - milk-production - organic-matter - stem fractions
Knowledge of digesta passage kinetics in ruminants is essential to predict nutrient supply to the animal in relation to optimal animal performance, environmental pollution and animal health. Fractional passage rates (FPR) of feed are widely used in modern feed evaluation systems and mechanistic rumen models, but data on nutrient-specific FPR are scarce. Such models generally rely on conventional externalmarker techniques, which do not always describe digesta passage kinetics in a satisfactorymanner.Heretheuse of stable isotope-labelled dietary nutrients as apromising novel tool to assess nutrient-specific passage kinetics is discussed. Some major limitations of this technique include a potential marker migration, a poor isotope distribution in the labelled feed and a differential disappearance rate of isotopes upon microbial fermentation in non-steady state conditions. Such limitations can often be circumvented by using intrinsically stable isotope-labelled plant material. Data are limited but indicate that external particulate markers overestimate rumen FPR of plant fibre compared with the internal stable isotope markers. Stable isotopes undergo the same digestive mechanism as the labelled feed components and are thus of particular interest to specifically measure passage kinetics of digestible dietary nutrients.
The impact of uncertainties on predicted GHG emissions of dairy cow production systems
Zehetmeier, M. ; Gandorfer, M. ; Hoffmann, H. ; Muller, U.K. ; Boer, I.J.M. de - \ 2014
Journal of Cleaner Production 73 (2014). - ISSN 0959-6526 - p. 116 - 124.
nitrous-oxide emissions - life-cycle assessment - environmental-impact - carbon footprint - milk-production - agriculture - methane - sensitivity - strategies - germany
Dairy farms produce significant greenhouse gas (GHG) emissions and are therefore a focal point for GHG-mitigation practices. To develop viable mitigation options, we need robust (insensitive to changes in model parameters and assumptions) predictions of GHG emissions. To this end, we developed a stochastic model to estimate the robustness of predictions based on input parameters (GHG emission factors and production traits) and their uncertainties. In our study we explored how sensitive predictions of GHG emissions are to three factors: (1) system boundaries of the emission model (2) the uncertainty of input parameters due to quality of data or methodological choices (epistemic uncertainty) and (3) inherent variability in input parameters (variability uncertainty). To assess the effect of system boundaries, we compared two different boundaries: the “dairy farm gate” boundary (all GHG emissions are allocated to milk) and “system expansion” (the model gives a GHG credit to beef derived from culled cows and bull, heifer and calf fattening of surplus dairy calves outside the farm). Results using the farm-gate boundary provide guidance to dairy farmers to reduce GHG emissions of milk production. The results using system expansion are important for defining GHG abatement policies for milk and beef production. We found that the choice of system boundary had the strongest impact on the level and variation of predicted GHG emissions. Model predictions were least robust for lower-yielding dairy cow production systems and when we used system expansion. We also explored which GHG-abatement strategies have the most leverage by assessing the influence of each input parameter on model predictions. Predicted GHG emissions were least sensitive to variability-related uncertainty in production traits (i.e. replacement rate, calving interval). Lower-yielding production systems had the highest variation, indicating the highest potential for GHG mitigation of all production systems studied. Variation in predicted GHG emissions increased substantially when both epistemic and variability uncertainty in emission factors and variability uncertainty in production traits were included in the model. If the system boundary was set at the farm gate, the emission factor of N2O from nitrogen input into the soil had the highest impact on variation in predicted GHG emissions. This variation stems from uncertainties in predicting N2O emissions (epistemic uncertainty) but also from inherent variability of N2O emissions over time and space. The uncertainty of predicted GHG emissions can be reduced by increasing the precision in predicting N2O emissions. However, this additional information does not reduce GHG emissions itself. Knowing site specific variability of N2O emissions can help reduce GHG emissions by specific management (e.g. reduce soil compaction, adopted manure management, choice of suitable crops). In case of system expansion, uncertainty in GHG emission credit for dairy beef contributed the most to increasing the variation in predicted GHG emissions. The stochastic-model approach gave important insights into the robustness of model outcomes, which is crucial in the search for cost-effective GHG-abatement options. Despite the high degree of uncertainty when using system expansion, its results help identifying global GHG mitigation options of combined milk and beef production
Energy demand on dairy farms in Ireland
Upton, J.R. ; Humphreys, J. ; Groot Koerkamp, P.W.G. ; French, P. ; Dillon, P. ; Boer, I.J.M. de - \ 2013
Journal of Dairy Science 96 (2013)10. - ISSN 0022-0302 - p. 6489 - 6498.
life-cycle assessment - milk-production - impact
Reducing electricity consumption in Irish milk production is a topical issue for 2 reasons. First, the introduction of a dynamic electricity pricing system, with peak and off-peak prices, will be a reality for 80% of electricity consumers by 2020. The proposed pricing schedule intends to discourage energy consumption during peak periods (i.e., when electricity demand on the national grid is high) and to incentivize energy consumption during off-peak periods. If farmers, for example, carry out their evening milking during the peak period, energy costs may increase, which would affect farm profitability. Second, electricity consumption is identified in contributing to about 25% of energy use along the life cycle of pasture-based milk. The objectives of this study, therefore, were to document electricity use per kilogram of milk sold and to identify strategies that reduce its overall use while maximizing its use in off-peak periods (currently from 0000 to 0900 h). We assessed, therefore, average daily and seasonal trends in electricity consumption on 22 Irish dairy farms, through detailed auditing of electricity-consuming processes. To determine the potential of identified strategies to save energy, we also assessed total energy use of Irish milk, which is the sum of the direct (i.e., energy use on farm) and indirect energy use (i.e., energy needed to produce farm inputs). On average, a total of 31.73 MJ was required to produce 1 kg of milk solids, of which 20% was direct and 80% was indirect energy use. Electricity accounted for 60% of the direct energy use, and mainly resulted from milk cooling (31%), water heating (23%), and milking (20%). Analysis of trends in electricity consumption revealed that 62% of daily electricity was used at peak periods. Electricity use on Irish dairy farms, therefore, is substantial and centered around milk harvesting. To improve the competitiveness of milk production in a dynamic electricity pricing environment, therefore, management changes and technologies are required that decouple energy use during milking processes from peak periods
The association of ruminal pH and some metabolic parameters with conception rate at first artificial insemination in Thai dairy cows
Inchaisri, C. ; Somchai Chantsavang, ; Noordhuizen, J.P.T.M. ; Hogeveen, H. - \ 2013
Tropical Animal Health and Production 45 (2013)5. - ISSN 0049-4747 - p. 1183 - 1190.
body condition score - milk-production - holstein cows - acidosis - fertility - herds - cattle - yield - ovulation - lipopolysaccharide
The objective of this study was to determine the association of metabolic parameters and cow associated factors with the conception rate at first insemination (FCR) in Thai dairy cows. The investigation was performed with 529 lactations from 32 smallholder dairy farms. At 3–6 weeks after parturition, blood samples and ruminal fluid were collected. Body condition scores (BCS) of cows were scored 1 week before expected calving date and at blood sampling date. Ruminal pH was measured at 2–4 h after morning feeding in ruminal fluid collected by ruminocentesis. Serum betahydroxybutyrate and serum urea nitrogen were measured by kinetic enzyme method. Cows with first insemination (AI) between 41 and 114 days postpartum were identified after pregnancy diagnosis for FCR. Breed, parity, interval from calving to first AI, BCS before calving, BCS after calving, loss in BCS after calving, SBHB, SUN, ruminal pH, and postpartum problems were selected as independent variables for a model with FCR as a dependent variable. A multivariable logistic regression model was used with farm as a random effect. Overall FCR was 27.2 %. The FCR depended on interval from calving to first AI, BCS before calving, and ruminal pH. The FCR between 69 and 91 days postpartum was significantly highest (45 %). Before calving, a cow with high BCS (=3.5) had significantly greater FCR than a cow with low BCS (=3.25; P
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