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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    Heritability of the backtest response in piglets and its genetic correlations with production traits
    Iversen, M.W. ; Bolhuis, J.E. ; Camerlink, I. ; Ursinus, W.W. ; Reimert, I. ; Duijvesteijn, N. - \ 2017
    Animal 11 (2017)4. - ISSN 1751-7311 - p. 556 - 563.
    backtest - genetic correlations - heritability - pigs - production traits
    The backtest response of a pig gives an indication of its coping style, that is, its preferred strategy to cope with stressful situations, which may in turn be related to production traits. The objective of this study was therefore to estimate the heritability of the backtest response and estimate genetic correlations with production traits (birth weight, growth, fat depth and loin depth). The backtest was performed by placing the piglet on its back for 60 s and the number of struggles (NrS) and vocalizations (NrV), and the latency to struggle and vocalize (LV) was recorded. In total, 992 piglets were subjected to the backtest. Heritability estimates for backtest traits were statistically moderate (although high for behavioral traits), with LV having the highest heritability estimate (0.56±0.10, P<0.001) and NrS having the lowest estimate (0.37±0.09, P<0.001). Backtest traits also had high genetic correlations with each other, with vocalization traits (NrV and LV) having the highest (−0.94±0.03, P<0.001), and NrS with NrV the lowest correlation (0.70±0.09, P<0.001). No significant correlations were found between backtest traits and production traits, but correlations between NrS and birth weight (−0.38±0.25), and NrV and loin depth (−0.28±0.19) approached significance (P=0.07). More research into genotype-by-environment interactions may be needed to assess possible connections between backtest traits and production traits, as this may depend on the circumstances (environment, experiences, etc.). In conclusion, heritability estimates of backtest traits are high and it would therefore be possible to select for them. The high genetic correlations between backtest traits indicate that it may be possible to only consider one or two traits for characterization and selection purposes. There were no significant genetic correlations found between backtest traits and production traits, although some of the correlations approached significance and hence warrant further research.
    Canonical-correlation analysis applied to selection-index methodology in quails
    Marubayashi Hidalgo, A. ; Silva, L.P. da; Mota, R.R. ; Martins, E.N. - \ 2014
    Livestock Science 169 (2014). - ISSN 1871-1413 - p. 35 - 41.
    random regression-models - monthly egg-production - genetic-parameters - sexual-maturity - body-weight - production traits - japanese-quail - carcass - pigs - age
    Genetic evaluations in dual-purpose quails (Coturnix coturnix) have demonstrated that overall genetic gains in a breeding program are achieved not only based on a specific trait, but on several. The most common technique to use all this information is the selection index. Another alternative may be the canonical-correlation analysis applied to selection index. There is, however, a lack of studies using canonical correlation in quails. Hence, the objectives of this study were to apply canonical-correlation analysis to estimate the relationship of nine traits and to compare genetic gains obtained by this methodology to desired-gain selection index in three lines of quails. Data for three lines of layer quails consisted of body weight at 28 days (W28), egg weight (EW), age at first egg (APE) and egg production at 30, 60, 90, 120, 150 and 180 days after onset of lay. Two sets of traits were established: the first one contained predictor variables (W28, EW and APE) and the second one contained variables related to egg production. A selection index was constructed using the standardized coefficients of canonical covariates as weighting factors when a given canonical correlation was significant. We constructed two desired-gain selection indices: DG-SI1 and DG-S12. The difference between them is that DG-S12 had a desired gain for body weight set to 0. The estimated canonical correlations were as follows: 0.811, 0.058 and 0.003 for the yellow, 0.821, 0.181 and 0.076 for the red, and 0.825, 0.117 and 0.038 for the blue line. Only the first pair of canonical variates was significant (P <0.05). AFE and early stages of egg production were very influent and showed great importance in defining the canonical variates and, consequently, the estimated canonical correlations. All lines had, in general, similar results for the canonical analysis indicating that traits that drive management decisions in these lines would be the same. The indices under study showed differences in response to selection; however, they generally resulted in consistent favorable genetic gains. For all lines, the canonical selection index resulted in the lowest AFE and highest egg production at 30 days. The DG-SI1 showed the highest genetic gains for W28 in all lines. There was a general lower genetic gain of other traits for DG-SI1 at the expense of the desired genetic gain for W28. Selection for AFE, according to the canonical-correlation analysis, would have a great impact on the number of eggs produced. Canonical selection index is a good alternative for a desired-gain selection index. (C) 2014 Elsevier B.V. All rights reserved.
    Estimation of residual energy intake and its genetic background during the growing period in pigs
    Shirali, M. ; Doeschl-Wilson, A. ; Duthie, C. ; Knap, P.W. ; Kanis, E. ; Arendonk, J.A.M. van; Roehe, R. - \ 2014
    Livestock Science 168 (2014). - ISSN 1871-1413 - p. 17 - 25.
    feed-intake - production traits - body-composition - nitrogen-excretion - chemical-analysis - yorkshire swine - growth - parameters - association - efficiency
    The aims of this study were to (i) compare models estimating residual energy intake (REI) using either lean and fat tissue growth or their proxy traits (average daily gain (ADG) and backfat thickness (BF)); (ii) determine genetic characteristics of REI at different growth stages and the entire test period; and (iii) examine 9 genetic and phenotypic relationships of REI with other production traits. Data from 315 pigs of an F2 generation were used which originated from crossing Pietrain sires with a commercial crossbred dam population. Average daily protein (APD) and lipid deposition (ALD), as measurements of lean and fat tissue growth, were obtained using the deuterium dilution technique on live animals. During growth from 60 to 140 kg, REI was estimated using 4 different models for energy intake that included, besides other systematic effects, (1) ADG and BF; (2) APD and ALD; (3) and (4) incorporated the same covariables as the first two models, respectively, but pre-adjusted for systematic effects. Genetic parameters and estimated breeding values were obtained based on univariate animal models using REML analysis. Over the entire growing period, heritabilities of different REI using different models were all estimated at 0.44 and their genetic correlations were at unity. At different growth stages heritabilities for REI were greater ranging from 0.47 to 0.50. Genetic correlations between REI estimates at different stages of growth, obtained using genetic model 4, indicated that REI at 60 to 90 kg was non-significantly (P>0.05) associated with REI at 90–120 kg (0.32±0.29) and 120–140 kg (0.28±0.28), but REI of the latter growth stages showed a significant (P
    Strategic test-day recording regimes to estimate lactation yield in tropical dairy animals
    McGill, D.M. ; Thomson, P.C. ; Mulder, H.A. ; Lievaart, J.J. - \ 2014
    Genetics, Selection, Evolution 46 (2014). - ISSN 0999-193X - 13 p.
    day milk-yield - genetic-parameters - sahiwal cattle - production traits - curves - cows - accuracy - models
    Background In developing dairy sectors, genetic improvement programs have limited resources and recording of herds is minimal. This study evaluated different methods to estimate lactation yield and sampling schedules with fewer test-day records per lactation to determine recording regimes that (1) estimate lactation yield with a minimal impact on the accuracy of selection and (2) optimise the available resources. Methods Using Sahiwal cattle as a tropical dairy breed example, weekly milk records from 464 cows were used in a simulation study to generate different shaped lactation curves. The daily milk yields from these simulated lactation curves were subset to equally spaced (weekly, monthly and quarterly) and unequally spaced (with four, five or six records per lactation) test-day intervals. Lactation yield estimates were calculated from these subsets using two methods: the test-interval method and Wood’s (Nature 216:164-165, 1967) lactation curve model. Using the resulting lactation yields, breeding values were predicted and comparisons were made between the sampling regimes and estimation methods. Results The results show that, based on the mean square error of prediction, use of Wood’s lactation curve model to estimate total yield was more accurate than use of the test-interval method. However, the differences in the ranking of animals were small, i.e. a 1 to 5% difference in accuracy. Comparisons between the different test-day sampling regimes showed that, with the same number of records per lactation (for example, quarterly and four test-days), strategically timed test-days can result in more accurate estimates of lactation yield than test-days at equal intervals. Conclusions An important outcome of these results is that combining Wood’s model for lactation yield estimation and as few as four, five or six strategically placed test-day records can produce estimates of lactation yield that are comparable with estimates based on monthly test-day records using the test-interval method. Furthermore, calculations show that although using fewer test-days results in a decrease in the accuracy of selection, it does provide an opportunity to progeny-test more sires. Thus, using strategically timed test-days and Wood’s model to estimate lactation yield, can lead to a more efficient use of the allocated resources.
    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.
    Plumage condition in laying hens: Genetic parameters for direct and indirect effects in two purebred layer lines
    Brinker, T. ; Bijma, P. ; Visscher, J. ; Rodenburg, T.B. ; Ellen, E.D. - \ 2014
    Genetics, Selection, Evolution 46 (2014). - ISSN 0999-193X - 10 p.
    feather pecking behavior - multilevel selection - social interactions - breeding programs - production traits - ground-pecking - animal-welfare - gallus-gallus - flock size - cannibalism
    Background: Feather pecking is a major welfare issue in laying hen industry that leads to mortality. Due to a ban on conventional cages in the EU and on beak trimming in some countries of the EU, feather pecking will become an even bigger problem. Its severity depends both on the victim receiving pecking and on its group mates inflicting pecking (indirect effects), which together determine plumage condition of the victim. Plumage condition may depend, therefore, on both the direct genetic effect of an individual itself and on the indirect genetic effects of its group mates. Here, we present estimated genetic parameters for direct and indirect effects on plumage condition of different body regions in two purebred layer lines, and estimates of genetic correlations between body regions. Methods: Feather condition scores (FCS) were recorded at 40 weeks of age for neck, back, rump and belly and these four scores were added-up into a total FCS. A classical animal model and a direct–indirect effects model were used to estimate genetic parameters for FCS. In addition, a bivariate model with mortality (0/1) was used to account for mortality before recording FCS. Due to mortality during the first 23 weeks of laying, 5363 (for W1) and 5089 (for WB) FCS records were available. Results: Total heritable variance for FCS ranged from 1.5% to 9.8% and from 9.8% to 53.6% when estimated respectively with the classical animal and the direct–indirect effects model. The direct–indirect effects model had a significantly higher likelihood. In both lines, 70% to 94% of the estimated total heritable variation in FCS was due to indirect effects. Using bivariate analysis of FCS and mortality did not affect estimates of genetic parameters. Genetic correlations were high between adjacent regions for FCS on neck, back, and rump but moderate to low for belly with other regions. Conclusion: Our results show that 70% to 94% of the heritable variation in FCS relates to indirect effects, indicating that methods of genetic selection that include indirect genetic effects offer perspectives to improve plumage condition in laying hens. This, in turn could reduce a major welfare problem.
    The influence of floor type before and after 10 weeks of age on osteochondrosis in growing gilts
    Koning, D.B. de; Grevenhof, E.M. van; Laurenssen, B.F.A. ; Weeren, P.R. van; Hazeleger, W. ; Kemp, B. - \ 2014
    Journal of Animal Science 92 (2014)8. - ISSN 0021-8812 - p. 3338 - 3347.
    different coping characteristics - leg weakness - finishing pigs - growth-rate - genetic-parameters - epiphyseal growth - production traits - stocking density - claw disorders - behavior
    Osteochondrosis (OC) is a degenerative joint condition developing in a short time frame in young growing gilts that may cause lameness at an older age, affecting welfare and leading to premature culling of breeding sows. Causes of OC are multifactorial including both genetic and environmental factors. Floor type has been suggested to affect OC prevalence and effects might be age dependent during the rearing period. The aim of this study was to investigate possible age-dependent effects of floor type, conventional concrete partially slatted versus wood shavings as deep bedding, on OC prevalence in gilts (Dutch Large White × Dutch Landrace) at slaughter (24 wk of age; 106.5 [14.7 SD] kg of BW). At weaning (4 wk of age; 6.9 [1.3 SD] kg of BW), 212 gilts were subjected to 1 of 4 flooring regimens. Gilts were either subjected to a conventional floor from weaning until slaughter (CC), wood shavings as bedding from weaning until slaughter (WW), a conventional floor from weaning until 10 wk of age after which gilts were switched to wood shavings as bedding (CW), or wood shavings as bedding from weaning until 10 wk of age after which gilts were switched to a conventional floor (WC). After slaughter the elbow, hock, and knee joints were macroscopically examined for OC and scored on a 5 point scale where 0 indicates no OC and 4 indicates the severest form of OC. There was no significant difference (P > 0.4) between treatments on the overall OC prevalence for any joint assessed or at the animal level (all joints combined). At the animal level, however, gilts had greater odds to have OC scores 3 and 4 in the CW treatment (odds ratios [OR] = 2.3; P = 0.05), WC treatment (OR = 2.6; P = 0.02), and WW treatment (OR = 3.7; P <0.001) compared with gilts in the CC treatment. The results indicate that there are no age-dependent effects of floor types on overall OC prevalence. However, wood shavings as bedding seems to increase the odds for severe OC and might affect animal welfare in the long term.
    Sire evaluation for total number born in pigs using a genomic reaction norms approach
    Silva, F.F. ; Mulder, H.A. ; Knol, E.F. ; Lopes, M.S. ; Guimaraes, S.E.F. ; Lopes, P.S. ; Mathur, P.K. ; Viana, J.M.S. ; Bastiaansen, J.W.M. - \ 2014
    Journal of Animal Science 92 (2014)9. - ISSN 0021-8812 - p. 3825 - 3834.
    environment interaction - dairy-cattle - genetic-parameters - production traits - genotype - models - pedigree - matrices - merit - milk
    In the era of genome-wide selection (GWS), genotype-by-environment (G×E) interactions can be studied using genomic information, thus enabling the estimation of SNP marker effects and the prediction of genomic estimated breeding values (GEBVs) for young candidates for selection in different environments. Although G×E studies in pigs are scarce, the use of artificial insemination has enabled the distribution of genetic material from sires across multiple environments. Given the relevance of reproductive traits such as the total number born (TNB) and the variation in environmental conditions encountered by commercial dams, understanding G×E interactions can be essential to choose the best sires for different environments. The present work proposes a two-step reaction norm approach for G×E analysis using genomic information. The first step provided estimates of environmental effects (herd-year-season - HYS), and the second step provided estimates of the intercept and slope for the TNB across different HYS levels, obtained from the first step, using a random regression model. In both steps, pedigree (A) and genomic (G) relationship matrices were considered. The genetic parameters (variance components, h2 and genetic correlations) were very similar when estimated using the A and G relationship matrices. The reaction norm graphs showed considerable differences in environmental sensitivity between sires, indicating a reranking of sires in terms of genetic merit across the HYS levels. Based on the G matrix analysis, SNP by environment interactions were observed. For some SNPs, the effects increased at increasing HYS levels, while for others, the effects decreased at increasing HYS levels or showed no changes between HYS levels. Cross-validation analysis demonstrated better performance of the genomic approach with respect to traditional pedigrees for both the G×E and standard models. The genomic reaction norm model resulted in an accuracy of GEBVs for “juvenile” boars varying from 0.14 to 0.44 across different HYS levels, while the accuracy of the standard genomic prediction model, without reaction norms, varied from 0.09 to 0.28. These results show that it is important and feasible to consider G×E interactions in evaluations of sires using genomic prediction models and that genomic information can increase the accuracy of selection across environments.
    Genomic selection for feed efficiency in dairy cattle
    Pryce, J.E. ; Wales, W.J. ; Haas, Y. de; Veerkamp, R.F. ; Hayes, B.J. - \ 2014
    Animal 8 (2014)01. - ISSN 1751-7311 - p. 1 - 10.
    body condition score - dry-matter intake - 1st 3 lactations - genetic-parameters - beef-cattle - methane production - production traits - energy-balance - live weight - random regression
    Feed is a major component of variable costs associated with dairy systems and is therefore an important consideration for breeding objectives. As a result, measures of feed efficiency are becoming popular traits for genetic analyses. Already, several countries account for feed efficiency in their breeding objectives by approximating the amount of energy required for milk production, maintenance, etc. However, variation in actual feed intake is currently not captured in dairy selection objectives, although this could be possible by evaluating traits such as residual feed intake (RFI), defined as the difference between actual and predicted feed (or energy) intake. As feed intake is expensive to accurately measure on large numbers of cows, phenotypes derived from it are obvious candidates for genomic selection provided that: (1) the trait is heritable; (2) the reliability of genomic predictions are acceptable to those using the breeding values; and (3) if breeding values are estimated for heifers, rather than cows then the heifer and cow traits need to be correlated. The accuracy of genomic prediction of dry matter intake (DMI) and RFI has been estimated to be around 0.4 in beef and dairy cattle studies. There are opportunities to increase the accuracy of prediction, for example, pooling data from three research herds (in Australia and Europe) has been shown to increase the accuracy of genomic prediction of DMI from 0.33 within country to 0.35 using a three-country reference population. Before including RFI as a selection objective, genetic correlations with other traits need to be estimated. Weak unfavourable genetic correlations between RFI and fertility have been published. This could be because RFI is mathematically similar to the calculation of energy balance and failure to account for mobilisation of body reserves correctly may result in selection for a trait that is similar to selecting for reduced (or negative) energy balance. So, if RFI is to become a selection objective, then including it in an overall multi-trait selection index where the breeding objective is net profit is sensible, as this would allow genetic correlations with other traits to be properly accounted for. If genetic parameters are accurately estimated then RFI is a logical breeding objective. If there is uncertainty in these, then DMI may be preferable.
    Genetic variance in micro-environmental sensitivity for milk and milk quality in Walloon Holstein cattle
    Vandenplas, J. ; Bastin, C. ; Gengler, N. ; Mulder, H.A. - \ 2013
    Journal of Dairy Science 96 (2013)9. - ISSN 0022-0302 - p. 5977 - 5990.
    generalized linear-models - residual variance - breeding values - fatty-acids - production traits - bovine-milk - heterogeneity - variability - prediction - components
    Animals that are robust to environmental changes are desirable in the current dairy industry. Genetic differences in micro-environmental sensitivity can be studied through heterogeneity of residual variance between animals. However, residual variance between animals is usually assumed to be homogeneous in traditional genetic evaluations. The aim of this study was to investigate genetic heterogeneity of residual variance by estimating variance components in residual variance for milk yield, somatic cell score, contents in milk (g/dL) of 2 groups of milk fatty acids (i.e., saturated and unsaturated fatty acids), and the content in milk of one individual fatty acid (i.e., oleic acid, C18:1 cis-9), for first-parity Holstein cows in the Walloon Region of Belgium. A total of 146,027 test-day records from 26,887 cows in 747 herds were available. All cows had at least 3 records and a known sire. These sires had at least 10 cows with records and each herd × test-day had at least 5 cows. The 5 traits were analyzed separately based on fixed lactation curve and random regression test-day models for the mean. Estimation of variance components was performed by running iteratively expectation maximization-REML algorithm by the implementation of double hierarchical generalized linear models. Based on fixed lactation curve test-day mean models, heritability for residual variances ranged between 1.01 × 10-3 and 4.17 × 10-3 for all traits. The genetic standard deviation in residual variance (i.e., approximately the genetic coefficient of variation of residual variance) ranged between 0.12 and 0.17. Therefore, some genetic variance in micro-environmental sensitivity existed in the Walloon Holstein dairy cattle for the 5 studied traits. The standard deviations due to herd × test-day and permanent environment in residual variance ranged between 0.36 and 0.45 for herd × test-day effect and between 0.55 and 0.97 for permanent environmental effect. Therefore, nongenetic effects also contributed substantially to micro-environmental sensitivity. Addition of random regressions to the mean model did not reduce heterogeneity in residual variance and that genetic heterogeneity of residual variance was not simply an effect of an incomplete mean model.
    Economic values for yield, survival, calving interval and beef daily gain for three breeds in Slovenia
    Haas, Y. de; Veerkamp, R.F. ; Shalloo, L. ; Dillon, P. ; Kuipers, A. ; Klopcic, M. - \ 2013
    Livestock Science 157 (2013)2-3. - ISSN 1871-1413 - p. 397 - 407.
    production circumstances - output limitations - production traits - selection - milk - fertility - objectives - efficiency - situations - weights
    Breeding indices need to be looked at periodically to evaluate the objective of the breeding program. In recent times the economic perspective of the breeding program has received a higher priority in deciding breeding objectives than in the past. However, prices of input and output products are becoming more difficult to predict with increased fluctuations in most prices, which adds a level of complexity to their inclusion in the selection index. With these challenges in mind, the breeding program in a new EU country (Slovenia) was evaluated. All three national Breeding Associations joined the deliberations. The aim of this study was to develop an economic selection index for three breeds (Simmental, Brown Swiss and Holstein-Friesian) in Slovenia. Because farming circumstances differ within Slovenia, differences in the production systems were also taken into account; e.g., flat land vs. hilly/mountainous areas, and for conventional vs. organic farming. Economic values (€) were calculated for milk, fat and protein yields (€/cow/year/kg), survival (€/cow/year/%survival), calving interval (€/cow/year/day), and beef daily gain (€/cow/year/kg). Economic values were calculated by changing one of these traits whilst keeping the other traits at the default level. Economic indices were calculated using a farm economic model (Moorepark Dairy Systems Model). Herd parameters (e.g., number of milking cows, replacements, young stock and calving pattern), milk production, feed requirements and ration, land use and labour requirements were re-parameterised in order to be relevant to the Slovenian circumstances. Absolute economic values were slightly negative for milk yield for all breeds (-0.02 to -0.04€ per kg milk), but positive for milk components (0.55 to 1.45€ per kg fat, and 2.89 to 3.38€ per kg protein). High absolute economic values were calculated for survival (7.37 to 9.55€ per %). Absolute economic values for calving interval were approximately -1€ per day for all breeds, while the economic value for beef daily gain was 0.14€ per kg for Brown Swiss and 0.32€ per kg for Simmental. The constructed economic indices ranked bulls in a significantly different manner than how the Slovenian Total Merit Indices ranked the bulls. The economic indices were robust towards changes in prices and farming system. Ranking was most sensitive towards variation in milk price. Assumptions concerning feed intake in relation to growth influenced the economic value for beef daily gain. Assumptions regarding the farming system (i.e., organic farming systems) only slightly affected the ranking of the bulls.
    The influence of dietary restriction before and after 10 weeks of age on osteochondrosis in growing gilts
    Koning, D.B. de; Grevenhof, E.M. van; Laurenssen, B.F.A. ; Weeren, P.R. van; Hazeleger, W. ; Kemp, B. - \ 2013
    Journal of Animal Science 91 (2013)11. - ISSN 0021-8812 - p. 5167 - 5176.
    leg weakness - growth-rate - articular chondrocytes - genetic-parameters - epiphyseal growth - production traits - pigs - cartilage - lesions - pathogenesis
    Osteochondrosis (OC) is one of the main causes of leg weakness causing premature culling in breeding sows and develops in a short time frame in young growing gilts. Dietary restriction may have different effects on OC prevalence depending on the age of the gilts. The aim of this study is to investigate age dependent effects of dietary restriction, ad libitum versus restricted (80% of ad libitum), on the occurrence of OC in gilts at slaughter (26 wk of age). At weaning (4 wk of age), 211 gilts were subjected to one of 4 treatments of feeding regime. Gilts were administered either ad libitum feeding from weaning until slaughter (AA); restricted feeding from weaning until slaughter (RR); ad libitum feeding from weaning until 10 wk of age, after which gilts were switched to restricted feeding (AR); or restricted feeding from weaning until 10 wk of age, after which gilts were switched to ad libitum feeding (RA). At slaughter, the elbow, hock, and knee joints were harvested. Joints were scored macroscopically for articular surface deformations indicative of OC. Gilts in the RA treatment had significantly higher odds to be affected with OC than gilts in the RR and AR treatments in the hock joint (OR = 3.3, P = 0.04 and OR = 8.5, P = 0.002, respectively), and at animal level (OR = 2.5, P = 0.001 and OR = 1.9, P = 0.01, respectively). Gilts in the AA treatment had higher odds to be affected with OC than gilts in the AR treatment in the hock joint (OR = 5.3, P = 0.01). The results indicate a possible pathway to reduce the prevalence of OC in breeding gilts which will have to last several parities. Switching from restricted feeding to ad libitum feeding after 10 wk of age increases OC prevalence as opposed to restricted feeding after 10 wk of age.
    Differences in milk fat composition predicted by mid-infrared spectrometry among dairy cattle breeds in the Netherlands
    Maurice - Van Eijndhoven, M.H.T. ; Bovenhuis, H. ; Soyeurt, H. ; Calus, M.P.L. - \ 2013
    Journal of Dairy Science 96 (2013)4. - ISSN 0022-0302 - p. 2570 - 2582.
    conjugated linoleic-acid - bovine-milk - genetic-parameters - production traits - short-communication - italian holsteins - desaturase gene - jersey cows - dgat1 gene - polymorphism
    The aim of this study was to estimate breed differences in milk fatty acid (FA) profile among 5 dairy cattle breeds present in the Netherlands: Holstein-Friesian (HF), Meuse-Rhine-Yssel (MRY), Dutch Friesian (DF), Groningen White Headed (GWH), and Jersey (JER). For this purpose, total fat percentage and detailed FA contents in milk (14 individual FA and 14 groups of FA) predicted from mid-infrared spectra were used. Mid-infrared spectrometry profiles were collected during regular milk recording from a range of herds with different combinations of breeds, including both purebred and crossbred cows. The data set used for the analyses contained 41,404 records from a total of 24,445 cows. In total 7,626 cows were crossbreds belonging to the breeds HF, MRY, DF, GWH, and JER; 1,769 purebreds (=87.5%) belonging to the breeds MRY, DF, GWH, and JER; and the other 15,050 cows were HF. Breed effects were estimated using a single-trait animal model. The content in milk of short-chain FA C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, and C16:0 was higher for JER and the content in milk of C16:0 was lower for GWH compared with the other breeds; when adjusting for breed differences in fat percentage, however, not all breed differences were significant. Breed differences were also found for cis-9 C14:1, cis-9 C16:1, C18:0, and a number of C18 unsaturated FA. In general, differences in fat composition in milk between HF, MRY, and DF were not significant. Jerseys tended to produce more saturated FA, whereas GWH tended to produce relatively less saturated FA. After adjusting for differences in fat percentage, breed differences in detailed fat composition disappeared or became smaller for several short- and medium-chain FA, whereas for several long-chain unsaturated FA, more significant breed differences were found. This indicates that short- and medium-chain FA are for all breeds more related to total fat percentage than long-chain FA. In conclusion, between breed differences were found in detailed FA composition and content of individual FA. Especially, for FA produced through de novo synthesis (short-chain FA, C12:0, C14:0, and partly C16:0) differences were found for JER and GWH, compared with the breeds HF, MRY, and DF
    Genetic correlation between composition of bovine milk fat in winter and summer, and DGAT1 and SCD1 by season interactions
    Duchemin, S.I. ; Bovenhuis, H. ; Stoop, W.M. ; Bouwman, A.C. ; Arendonk, J.A.M. van; Visker, M.H.P.W. - \ 2013
    Journal of Dairy Science 96 (2013)1. - ISSN 0022-0302 - p. 592 - 604.
    conjugated linoleic-acid - coa-diacylglycerol acyltransferase - dairy-cows - short communication - production traits - desaturase - parameters - enzyme - cla - biohydrogenation
    Milk fat composition shows substantial seasonal variation, most of which is probably caused by differences in the feeding of dairy cows. The present study aimed to know whether milk fat composition in winter is genetically the same trait as milk fat composition in summer. For this purpose, we estimated heritabilities, genetic correlations, effects of acyl-coenzyme A:diacylglycerol acyltransferase 1 (DGAT1) K232A, and stearoyl-coenzyme A desaturase 1 (SCD1) A293V polymorphisms for milk fat composition in winter and summer, and tested for genotype by season interactions of DGAT1 K232A and SCD1 A293V polymorphisms. Milk samples were obtained from 2,001 first-lactation Dutch Holstein-Friesian cows, most with records in both winter and summer. Summer milk contained higher amounts of unsaturated fatty acids (FA) and lower amounts of saturated FA compared with winter milk. Heritability estimates were comparable between seasons: moderate to high for short- and medium-chain FA (0.33 to 0.74) and moderate for long-chain FA (0.19 to 0.43) in both seasons. Genetic correlations between winter and summer milk were high, indicating that milk fat composition in winter and in summer can largely be considered as genetically the same trait. Effects of DGAT1 K232A and SCD1 A293V polymorphisms were similar across seasons for most FA. Allele DGAT1 232A in winter as well as in summer milk samples was negatively associated with most FA with less than 18 carbons, saturated FA, saturated FA to unsaturated FA ratio, and C10 to C16 unsaturation indices, and was positively associated with C14:0, unsaturated C18, unsaturated FA, and C18 and conjugated linoleic acid unsaturation indices. Allele SCD1 293V in winter as well as in summer milk samples was negatively associated with C18:0, C10:1 to cis-9 C14:1, trans-11 C18:1, and C10 to C14 unsaturation indices, and positively associated with C8:0 to C14:0, cis-9 C16:1, and C16 to conjugated linoleic acid unsaturation indices. In addition, significant DGAT1 K232A by season interaction was found for some FA and SCD1 A293V by season interaction was only found for trans-11 C18:1. These interactions were due to scaling of genotype effects.
    Short communication: A new bovine milk-protein variant: a-lactalbumin variant D.
    Visker, M.H.P.W. ; Heck, J.M. ; Valenberg, H.J.F. van; Arendonk, J.A.M. van; Bovenhuis, H. - \ 2012
    Journal of Dairy Science 95 (2012)4. - ISSN 0022-0302 - p. 2165 - 2169.
    single-base polymorphisms - lactose synthetase - production traits - region - gene - cows - sequence - synthase - cattle
    Capillary zone electrophoresis of 1,948 Holstein-Friesian cows suggested the presence of an unknown protein variant of α-lactalbumin (α-LA) in the milk of 1 cow. Sequencing genomic DNA of this cow showed a polymorphism in the α-LA gene (LAA) that appears to be responsible for this protein variant. This single nucleotide polymorphism g.600G > T was located in exon 2 of LAA and causes the amino acid change 65Gln > His in the α-LA protein. This α-LA protein variant is a new protein variant and should be called α-LA protein variant D. This amino acid change is not expected to affect protein function. Genomic DNA of 156 bulls of various dairy cattle breeds was screened to examine the presence of the new α-LA protein variant D. Single nucleotide polymorphism g.600G > T, responsible for α-LA protein variant D, was not found in any of the 156 bulls. However, 10 other polymorphisms in the coding and promoter regions of LAA were detected that were used to construct haplotypes.
    Predicting bovine milk protein composition based on Fourier transform infrared spectra
    Rutten, M.J.M. ; Bovenhuis, H. ; Heck, J.M.L. ; Arendonk, J.A.M. van - \ 2011
    Journal of Dairy Science 94 (2011)11. - ISSN 0022-0302 - p. 5683 - 5690.
    dutch holstein-friesians - genetic-parameters - beta-lactoglobulin - coagulation properties - production traits - fat composition - dairy-cows - casein - genotypes - spectroscopy
    Phenotypic information on individual protein composition of cows is important for many aspects of dairy processing with cheese production as the center of gravity. However, measuring individual protein composition is expensive and time consuming. In this study, we investigated whether protein composition can be predicted based on inexpensive and routinely measured milk Fourier transform infrared (FTIR) spectra. Based on 900 calibration and 900 validation samples that had both capillary zone electrophoresis (CZE)-determined protein composition and FTIR spectra available, low to moderate validation R2 were reached (from 0.18 for aS1-casein to 0.56 for ß-lactoglobulin). The potential usefulness of this model on the phenotypic level was investigated by means of achieved selection differentials for 25% of the best animals. For a-lactalbumin (R2 = 0.20), the selection differential amounted to 0.18 g/100 g and for casein index (R2 = 0.50) to 1.24 g/100 g. We concluded that predictions of protein composition were not accurate enough to enable selection of individual animals. However, for specific purposes when, for example, groups of animals that meet a certain threshold are to be selected, the presented model could be useful in practice on the phenotypic level. The potential usefulness of this model on the genetic level was investigated by means of genetic correlations between CZE-determined and FTIR-predicted protein composition traits. The genetic correlations ranged from 0.62 (ß-casein) to 0.97 (whey). Thus, predictions of protein composition, when used as input to estimate breeding values, provide an excellent means for genetic improvement of protein composition. In addition, estimated repeatabilities based on 3 repeated observations of predicted protein composition showed that a considerable amount of prediction error can be removed using repeated observations.
    Association of bovine ß-casein protein variant I with milk production and milk protein composition
    Visker, M.H.P.W. ; Dibbits, B.W. ; Kinders, S.M. ; Valenberg, H.J.F. van; Arendonk, J.A.M. van; Bovenhuis, H. - \ 2011
    Animal Genetics 42 (2011)2. - ISSN 0268-9146 - p. 212 - 218.
    finnish ayrshire cows - production traits - genetic-parameters - polymorphisms - genotypes - holstein - cattle - haplotypes
    The aim of this study was to detect new polymorphisms in the bovine ß-casein (ß-CN) gene and to evaluate association of (new) ß-CN protein variants with milk production traits and milk protein composition. Screening of the ß-CN gene in genomic DNA from 72 Holstein Friesian (HF) bulls resulted in detection of 19 polymorphisms and revealed the presence of ß-CN protein variant I in the Dutch HF population. Studies of association of ß-CN protein variants with milk composition usually do not discriminate protein variant I from variant A2. Association of ß-CN protein variants with milk composition was studied in 1857 first-lactation HF cows and showed that associations of protein variants A2 and I were quite different for several traits. ß-CN protein variant I was significantly associated with protein percentage and protein yield, and with as1-casein (as1-CN), as2-casein (as2-CN), ¿-casein (¿-CN), a-lactalbumin (a-LA), ß-lactoglobulin (ß-LG), casein index and casein yield. Inferring ß-¿-CN haplotypes showed that ß-CN protein variant I occurred only with ¿-CN variant B. Consequently, associations of ß-¿-CN haplotype IB with protein percentage, ¿-CN, a-LA, ß-LG and casein index are likely resulting from associations of ¿-CN protein variant B, while associations of ß-¿-CN haplotype IB with as1-CN and as2-CN seem to be resulting from associations of ß-CN variant I.
    The effects of housing system and feeding level on the joint-specific prevalence of osteochondrosis in fattening pigs
    Grevenhof, E.M. van; Ott, S. ; Hazeleger, W. ; Weeren, P.R. van; Bijma, P. ; Kemp, B. - \ 2011
    Livestock Science 135 (2011)1. - ISSN 1871-1413 - p. 53 - 61.
    leg weakness - finishing pigs - growth-rate - genetic-parameters - production traits - space allowance - slaughter pigs - protein-levels - arthrosis - swine
    Osteochondrosis (OC) is seen as the main cause of leg weakness in pigs, leading to welfare problems and economic losses. Environmental factors in pig husbandry, such as the housing system and feeding strategy are expected to influence the prevalence of OC. Therefore, this study investigated the effects of housing system and feeding strategy on the prevalence and severity of OC. In the experiment 345 pigs were used. At an age of 69 days intact boars and gilts were separated and assigned to groups of five or six individuals. A two by two factorial design of housing system and feeding strategy was applied. The housing system was either a conventional concrete floor partial slatted, or a deep litter floor with extra space allowance. The feeding strategy was either ad libitum or restricted to 80% of ad libitum. Pigs were slaughtered at the age of 161–176 days. In total, five joints of the left front and hind limbs were macroscopically assessed for OC on a five-point scale, ranged from no OC through (semi-)loose cartilage fragments. The prevalence of OC in the experimental population was 41.4%, and 12.4% of the individuals had severe lesions. The tarsocrural joint was most affected (30.2%) by OC. OC scores between the different joints were not correlated. Medial sections of joints were most affected (63–100%). Boars were more affected than gilts in the elbow joint. Conventionally housed pigs were more affected than deep litter housed pigs. Ad libitum fed pigs had more OC than restrictedly fed pigs. OC was most prevalent with 57.5% in the pigs on the conventional floor with ad libitum feeding. OC was least prevalent with 33.7% in pigs kept in deep litter housing with restricted feeding. The sex, housing system and feeding strategy did not affect OC in the femoropatellar, metacarpophalangeal, and metatarsophalangeal joints. Our results demonstrate that the OC prevalence can be reduced by applying deep litter floors with extra space allowance and/or restricted feeding in fattening pigs
    Genetic parameters for milk coagulation properties in Estonian Holstein cows.
    Vallas, M. ; Bovenhuis, H. ; Kaart, T. ; Parna, K. ; Kiiman, H. - \ 2010
    Journal of Dairy Science 93 (2010)8. - ISSN 0022-0302 - p. 3789 - 3796.
    cheese-making properties - finnish ayrshire cows - somatic-cell count - bovine-milk - chemical-composition - renneting properties - production traits - dairy-cows - physicochemical properties - protein-composition
    The objective of this study was to estimate heritabilities and repeatabilities for milk coagulation traits [milk coagulation time (RCT) and curd firmness (E30)] and genetic and phenotypic correlations between milk yield and composition traits (milk fat percentage and protein percentage, urea, somatic cell count, pH) in first-lactation Estonian Holstein dairy cattle. A total of 17,577 test-day records from 4,191 Estonian Holstein cows in 73 herds across the country were collected during routine milk recordings. Measurements of RCT and E30 determined with the Optigraph (Ysebaert, Frepillon, France) are based on an optical signal in the near-infrared region. The cows had at least 3 measurements taken during the period from April 2005 to January 2009. Data were analyzed using a repeatability animal model. There was substantial variation in milk coagulation traits with a coefficient of variation of 27% for E30 and 9% for the log-transformed RCT. The percentage of variation explained by herd was 3% for E30 and 4% for RCT, suggesting that milk coagulation traits are not strongly affected by herd conditions (e.g., feeding). Heritability was 0.28 for RCT and 0.41 for E30, and repeatability estimates were 0.45 and 0.50, respectively. Genetic correlation between both milk coagulation traits was negligible, suggesting that RCT and E30 have genetically different foundations. Milk coagulation time had a moderately high positive genetic (0.69) and phenotypic (0.61) correlation with milk pH indicating that a high pH is related to a less favorable RCT. Curd firmness had a moderate positive genetic (0.48) and phenotypic (0.45) correlation with the protein percentage. Therefore, a high protein percentage is associated with favorable curd firmness. All reported genetic parameters were statistically significantly different from zero. Additional univariate random regression analysis for milk coagulation traits yielded slightly higher average heritabilities of 0.38 and 0.47 for RCT and E30 compared with the heritabilities of the repeatability model.
    Genetic variation of natural antibodies in milk of Dutch Holstein-Friesian cows
    Ploegaert, T.C.W. ; Wijga, S. ; Tijhaar, E. ; Poel, J.J. van der; Lam, T.J.G.M. ; Savelkoul, H.F.J. ; Parmentier, H.K. ; Arendonk, J.A.M. van - \ 2010
    Journal of Dairy Science 93 (2010)11. - ISSN 0022-0302 - p. 5467 - 5473.
    humoral immune competence - production traits - lactoferrin content - urea nitrogen - laying hens - bovine-milk - parameters - autoantibodies - responses - paratuberculosis
    Defense mechanisms of dairy cows against diseases partly rest on their naturally present disease resistance capacity. Natural antibodies (NAb) form a soluble part of the innate immune system, being defined as antibodies circulating in animals without prior intentional antigenic stimulation. Genetic selection on NAb titers in milk, therefore, might improve disease resistance. We estimated genetic parameters of NAb titers binding lipopolysaccharide, lipoteichoic acid (LTA), peptidoglycan, and keyhole limpet hemocyanin, and titers of the NAb isotypes IgG1, IgM, and IgA binding LTA in milk of Dutch Holstein-Friesian heifers. Natural antibody titers were measured in 1 milk sample from each of 1,939 Holstein-Friesian heifers and used for estimating genetic parameters of NAb titers. The data show that phenotypic variation exists among heifers in NAb titers binding lipopolysaccharide, LTA, peptidoglycan, and keyhole limpet hemocyanin, and the NAb isotypes IgG1, IgM, and IgA binding LTA in milk. High genetic correlations among NAb (ranging from 0.45 to 0.99) indicated a common genetic basis for the levels of different NAb in bovine milk. Intra-herd heritability estimates for NAb ranged from 0.10 to 0.53. The results indicated that NAb levels have potential for genetic selection
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