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See detailReducing agent can be omitted in the incubation medium of the batch in vitro fermentation model of the pig intestines
Poelaert, Christine; Nollevaux, Geraldine; Boudry, Christelle et al

in Animal (in press)

Over the past decade, in vitro methods have been developed to study intestinal fermentation in pigs and its influence on the digestive physiology and health. In these methods, ingredients are fermented by ... [more ▼]

Over the past decade, in vitro methods have been developed to study intestinal fermentation in pigs and its influence on the digestive physiology and health. In these methods, ingredients are fermented by a bacterial inoculum diluted in a mineral buffer solution. Generally, a reducing agent such as Na2S or cysteine-HCl generates the required anaerobic environment by releasing metabolites similar to those produced when protein is fermented, possibly inducing a dysbiosis. An experiment was conducted to study the impact of two reducing agents on results yielded by such in vitro fermentation models. Protein (soybean proteins, casein) and carbohydrate (potato starch, cellulose) ingredients were fermented in vitro by bacteria isolated from fresh feces obtained from three sows in three carbonate-based incubation media differing in reducing agent: (i) Na2S, (ii) cysteine-HCl and (iii) control with a mere saturation with CO2 and devoid of reducing agent. The gas production during fermentation was recorded over 72 h. Short chain fatty acids (SCFA) production after 24 and 72 h and microbial composition of the fermentation broth after 24 h were compared between ingredients and between reducing agents. The fermentation residues after 24 h were also evaluated in terms of cytotoxicity using Caco-2 cell monolayers. Results showed that the effect of the ingredient induced higher differences than the reducing agent. Among the latter, cysteine-HCl induced the strongest differences compared with the control, whereas Na2S was similar to the control for most parameters. For all ingredients, final gas produced per g of substrate was similar ( P>0.10) for the three reducing agents whereas the maximum rate of gas production ( Rmax) was reduced ( P<0.05) when carbohydrate ingredients were fermented with cysteine-HCl in comparison to Na2S and the control. For all ingredients, total SCFA production was similar ( P>0.10) after 24 h of fermentation with Na2S and in the control without reducing agent. Molar ratios of branched chain-fatty acids were higher ( P<0.05) for protein (36.5% and 9.7% for casein and soybean proteins, respectively) than for carbohydrate (<4%) ingredients. Only fermentation residues of casein showed a possible cytotoxic effect regardless of the reducing agent ( P<0.05). Concerning the microbial composition of the fermentation broth, most significant differences in phyla and in genera ascribable to the reducing agent were found with potato starch and casein. In conclusion, saturating the incubation media with CO2 seems sufficient to generate a suitable anaerobic environment for intestinal microbes and the use of a reducing agent can be omitted. [less ▲]

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See detailThe feeding system impacts relationships between calving interval and economic results of dairy farms
Dalcq, Anne-Catherine ULiege; Beckers, Yves ULiege; Mayeres, Patrick et al

in Animal (2017)

The calving interval (CI) can potentially impact the economic results of dairy farms. This study highlighted the most profitable CI and innovated by describing this optimum as a function of the feeding ... [more ▼]

The calving interval (CI) can potentially impact the economic results of dairy farms. This study highlighted the most profitable CI and innovated by describing this optimum as a function of the feeding system of the farm. On-farm data were used to represent real farm conditions. A total of 1832 accounts of farms recorded from 2007 to 2014 provided economic, technical and feeding information per herd and per year. A multiple correspondence analysis created four feeding groups: extensive, low intensive, intensive and very intensive herds. The gross margin and some of its components were corrected to account for the effect of factors external to the farm, such as the market, biological status, etc. Then the corrected gross margin (cGMc) and its components were modelled by CI parameters in each feeding system by use of GLM. The relationship between cGMc and the proportion of cows with CI<380 days in each feeding group showed that keeping most of the cows in the herd with CI near to 1 year was not profitable for most farms (for the very intensive farms there was no effect of the proportion). Moreover, a low proportion of cows (0% to 20%) with a near-to-1-year CI was not profitable for the extensive and low intensive farms. Extending the proportion of cows with CI beyond 459 days until 635 days (i.e. data limitation) caused no significant economic loss for the extensive and low intensive farms, but was not profitable for the intensive and very intensive farms. Variations of the milk and feeding components explained mainly these significant differences of gross margin. A link between the feeding system and persistency, perceptible in the milk production and CI shown by the herd, could explain the different relationships observed between the extent of CI and the economic results in the feeding groups. This herd-level study tended to show different economic optima of CI as a function of the feeding system. A cow-level study would specify these tendencies to give CI objectives to dairy breeders as a function of their farm characteristics. [less ▲]

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See detailBayesian single-step genomic evaluations combining local and foreign information in Walloon Holsteins
Colinet, Frédéric ULiege; Vandenplas, J.; Vanderick, Sylvie ULiege et al

in Animal (2017)

Most dairy cattle populations found in different countries around the world are small to medium sized and use many artificial insemination bulls imported from different foreign countries. The Walloon ... [more ▼]

Most dairy cattle populations found in different countries around the world are small to medium sized and use many artificial insemination bulls imported from different foreign countries. The Walloon population in the southern part of Belgium is a good example for such a small-scale population. Wallonia has also a very active community of Holstein breeders requesting high level genetic evaluation services. Single-step Genomic BLUP (ssGBLUP) methods allow the simultaneous use of genomic, pedigree and phenotypic information and could reduce potential biases in the estimation of genomically enhanced breeding values (GEBV). Therefore, in the context of implementing a Walloon genomic evaluation system for Holsteins, it was considered as the best option. However, in contrast to multi-step genomic predictions, natively ssGBLUP will only use local phenotypic information and is unable to use directly important other sources of information coming from abroad, for example Multiple Across Country Evaluation (MACE) results as provided by the Interbull Center (Uppsala, Sweden). Therefore, we developed and implemented single-step Genomic Bayesian Prediction (ssGBayes), as an alternative method for the Walloon genomic evaluations. The ssGBayes method approximated the correct system of equations directly using estimated breeding values (EBV) and associated reliabilities (REL) without any explicit deregression step. In the Walloon genomic evaluation, local information refers to Walloon EBV and REL and foreign information refers to MACE EBV and associated REL. Combining simultaneously all available genotypes, pedigree, local and foreign information in an evaluation can be achieved but adding contributions to left-hand and right-hand sides subtracting double-counted contributions. Correct propagation of external information avoiding double counting of contributions due to relationships and due to records can be achieved. This ssGBayes method computed more accurate predictions for all types of animals. For example, for genotyped animals with low Walloon REL (<0.25) without MACE results but sired by genotyped bulls with MACE results, the average increase of REL for the studied traits was 0.38 points of which 0.08 points could be traced to the inclusion of MACE information. For other categories of genotyped animals, the contribution by MACE information was also high. The Walloon genomic evaluation system passed for the first time the Interbull GEBV tests for several traits in July 2013. Recent experiences reported here refer to its use in April 2016 for the routine genomic evaluations of milk production, udder health and type traits. Results showed that the proposed methodology should also be of interest for other, similar, populations. [less ▲]

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See detailThe effect of concentrate allocation on traffic and milk production of pasture based cows milked by an automatic milking system
Lessire, Françoise ULiege; Froidmont, Eric; Shortall, John et al

in Animal (2017), 11(4), 1-9

Increased economic, societal and environmental challenges facing agriculture are leading to a greater focus on effective way to combine grazing and automatic milking systems (AMS). One of the fundamental ... [more ▼]

Increased economic, societal and environmental challenges facing agriculture are leading to a greater focus on effective way to combine grazing and automatic milking systems (AMS). One of the fundamental aspects of robotic milking is cows’ traffic to the AMS. Numerous studies have identified feed provided, either as fresh grass or concentrate supplement, as the main incentive for cows to return to the robot. The aim of this study was to determine the effect of concentrate allocation on voluntary cow traffic from pasture to the robot during the grazing period, to highlight the interactions between grazed pasture and concentrate allocation in terms of substitution rate and the subsequent effect on average milk yield and composition. Thus, 29 grazing cows, milked by a mobile robot, were monitored for the grazing period (4 months). They were assigned to 2 groups: a low concentrate (LC) group (15 cows) and a high concentrate (HC) group (14 cows) receiving 2 kg and 4 kg concentrate per cow per day respectively. Two allocations per day of fresh pasture were provided at 0700h and 1600h. The cows had to go through the AMS to receive the fresh pasture allocation. The effect of concentrate level on robot visitation was calculated by summing milkings, refusals and failed milkings/cow per day. The impact on average daily milk yield and composition was also determined. The interaction between lactation number and month was used as an indicator of pasture availability. Concentrate allocation increased significantly robot visitations in HC (3.60 ± 0.07 visitations/cow per day in HC - 3.10 ± 0.07 visitations/cow per day in LC; P<0.001) while milkings/cow per day were similar in both groups (LC: 2.37 ± 0.02/day - HC: 2.39 ± 0.02/day; ns). The average daily milk yield over the grazing period was enhanced in HC (22.39 ± 0.22 kg/cow per day in HC- 21.33 ± 0.22 kg/cow per day in LC; P<0.001). However the gain in milk due to higher concentrate supply was limited with regards to the amount of provided concentrates. Milking frequency in HC primiparous compared with LC was increased. In the context of this study, considering high concentrate levels as an incentive for robot visitation might be questioned, as it had no impact on milking frequency and limited impact on average milk yield and composition. By contrast, increased concentrate supply could be targeted specifically to primiparous cows. [less ▲]

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See detailRelationships between milk mid-infrared predicted gastro-enteric methane production and the technical and financial performance of commercial dairy herds
Delhez, Pauline ULiege; Wyzen, Benoit; Dalcq, Anne-Catherine ULiege et al

in Animal (2017)

Considering economic and environmental issues is important in ensuring the sustainability of dairy farms. The objective of this study was to investigate univariate relationships between lactating dairy ... [more ▼]

Considering economic and environmental issues is important in ensuring the sustainability of dairy farms. The objective of this study was to investigate univariate relationships between lactating dairy cow gastro-enteric methane (CH4) production predicted from milk mid-infrared spectra and technico-economic variables by the use of large scale and on-farm data. A total of 525 697 individual CH4 predictions from milk mid-infrared spectra [MIR-CH4 (g/day)] of milk samples collected on 206 farms during the Walloon milk recording scheme were used to create a MIR-CH4 prediction for each herd and year (HYMIR-CH4). These predictions were merged with dairy herd accounting data. This allowed a simultaneous study of HYMIR-CH4 and 42 technical and economic variables for 1 024 herd and year records from 2007 to 2014. Pearson correlation coefficients (r) were used to assess significant relationships (P < 0.05). Low HYMIR-CH4 was significantly associated with, amongst others, lower fat and protein corrected milk (FPCM) yield (r = 0.18), lower milk fat and protein content (r = 0.38 and 0.33, respectively), lower quantity of milk produced from forages (r = 0.12) and suboptimal reproduction and health performance (e.g. longer calving interval (r = -0.21) and higher culling rate (r = -0.15)). Concerning economic results, low HYMIR-CH4 was significantly associated with lower gross margin per cow (r = -0.19) and per litre FPCM (r = -0.09). To conclude, this study suggested that low lactating dairy cow gastro-enteric CH4 production tended to be associated with more extensive or suboptimal management practices, which could lead to lower profitability. The observed low correlations suggest complex interactions between variables due to the use of on-farm data with large variability in technical and management practices. [less ▲]

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See detailAnalyses of reaction norms reveal new chromosome regions associated with tick resistance in cattle
REIS MOTA, Rodrigo ULiege; Fonseca e Silva, Fabyano; Lopes, Paulo Sávio et al

in Animal (2017)

Despite single nucleotide polymorphism (SNP) availability and frequent cost reduction has allowed genome-wide association studies even in complex traits as tick resistance, the use of this information ... [more ▼]

Despite single nucleotide polymorphism (SNP) availability and frequent cost reduction has allowed genome-wide association studies even in complex traits as tick resistance, the use of this information source in SNP by environment interaction context is unknown for many economically important traits in cattle. We aimed at identifying putative genomic regions explaining differences in tick resistance in Hereford and Braford cattle under SNP by environment point of view as well as to identify candidate genes derived from outliers/significant markers. The environment was defined as contemporary group means of tick counts, since they seemed to be the most appropriate entities to describe the environmental gradient in beef cattle. A total of 4363 animals having tick counts (n = 10 673) originated from 197 sires and 3966 dams were used. Genotypes were acquired on 3591 of these cattle.From top 1% SNPs (410) having the greatest effects in each environment, 75 were consistently relevant in all environments, whichindicated SNP by environment interaction. The outliers/significant SNPs were mapped on chromosomes 1, 2, 5, 6, 7, 9, 11, 13, 14, 15, 16, 18, 21, 23, 24, 26 and 28, and potential candidate genes were detected across environments. The presence of SNP by environment interaction for tick resistance indicates that genetic expression of resistance depends upon tick burden. Markers with major portion of genetic variance explained across environments appeared to be close to genes with different direct or indirect functions related to immune system, inflammatory process and mechanisms of tissue destruction/repair, such as energy metabolism and cell differentiation. [less ▲]

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See detailMediation analysis to estimate direct and indirect milk losses associated with bacterial load in bovine subclinical mammary infections
Detilleux, Johann ULiege; Theron, Léonard ULiege; Duprez, Jean-Noël ULiege et al

in Animal (2016)

Milk losses associated with mastitis can be attributed to either effects of pathogens per se (i.e. direct losses) or to effects of the immune response triggered by the presence of mammary pathogens (i.e ... [more ▼]

Milk losses associated with mastitis can be attributed to either effects of pathogens per se (i.e. direct losses) or to effects of the immune response triggered by the presence of mammary pathogens (i.e. indirect losses). Test-day milk somatic cell counts (SCC) and number of bacterial colony forming units (CFU) found in milk samples are putative measures of the level of immune response and of the bacterial load, respectively. Mediation models, in which one independent variable affects a second variable which, in turn, affects a third one, are conceivable models to estimate direct and indirect losses. Here, we evaluated the feasibility of a mediation model in which test-day SCC and milk were regressed toward bacterial CFU measured at three selected sampling dates, 1 week apart. We applied this method on cows free of clinical signs and with records on up to 3 test-days before and after the date of the first bacteriological samples. Most bacteriological cultures were negative (52.38%), others contained either staphylococci (23.08%), streptococci (9.16%), mixed bacteria (8.79%) or were contaminated (6.59%). Only losses mediated by an increase in SCC were significantly different from null. In cows with three consecutive bacteriological positive results, we estimated a decreased milk yield of 0.28 kg per day for each unit increase in log2-transformed CFU that elicited one unit increase in log2-transformed SCC. In cows with one or two bacteriological positive results, indirect milk loss was not significantly different from null although test-day milk decreased by 0.74 kg per day for each unit increase of log2-transformed SCC. These results highlight the importance of milk losses that are mediated by an increase in SCC during mammary infection and the feasibility of decomposing total milk loss into its direct and indirect components. © The Animal Consortium 2016 [less ▲]

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See detailFloor slat openings impact ammonia and greenhouse gas emissions associated with group-housed gestating sows
Philippe, François-Xavier ULiege; Laitat, Martine ULiege; Wavreille, José et al

in Animal (2016), 10(12), 2027-2033

According to EU legislation, group-housed gestating sows must have a minimum of 2.25m2 floor area per sow with at least 1.3m2 of continuous solid floor of which a maximum of 15% is reserved for drainage ... [more ▼]

According to EU legislation, group-housed gestating sows must have a minimum of 2.25m2 floor area per sow with at least 1.3m2 of continuous solid floor of which a maximum of 15% is reserved for drainage openings. The aim of the experiment was to quantify the impact of different drainage openings on ammonia and greenhouse gas emissions. Three successive batches of 10 gestating sows were used. Each batch was divided into two groups kept separately in two identical rooms with similar volume and surface. The solid part of the floor presented 15% drainage openings in the first room and 2.5% in the second room. The gas emissions (ammonia (NH3), methane (CH4), nitrous oxide (N2O), carbon dioxide (CO2) and water vapour (H2O)) were measured three times during 6 consecutive days. Gaseous emissions were significantly lower with 15% drainage openings with reductions of 19% for NH3 (12.77 v. 15.83 g/day per sow), 15% for CH4 (10.15 v. 11.91 g/day per sow), 10% for N2O (0.47 v. 0.52 g/day per sow), 9% for CO2 (2.41 v. 2.66 kg/day per sow) and 13% for H2O (3.25 v. 3.75 kg/day per sow). This trial showed the advantage, in an environmental point of view, to use 15% drainage openings on the solid part of partly slatted floors in pens for group-housed gestating sows. [less ▲]

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See detailInvited review: overview of new traits and phenotyping strategies in dairy cattle with a focus on functional traits
Egger-Danner, C.; Cole, J. B.; Pryce, J. E. et al

in Animal (2015), 9(2), 191-207

For several decades, breeding goals in dairy cattle focussed on increased milk production. However, many functional traits have negative genetic correlations with milk yield, and reductions in genetic ... [more ▼]

For several decades, breeding goals in dairy cattle focussed on increased milk production. However, many functional traits have negative genetic correlations with milk yield, and reductions in genetic merit for health and fitness have been observed. Herd management has been challenged to compensate for these effects and to balance fertility, udder health and metabolic diseases against increased production to maximize profit without compromising welfare. Functional traits, such as direct information on cow health, have also become more important because of growing concern about animal well-being and consumer demands for healthy and natural products. There are major concerns about the impact of drugs used in veterinary medicine on the spread of antibiotic-resistant strains of bacteria that can negatively impact human health. Sustainability and efficiency are also increasingly important because of the growing competition for high-quality, plant-based sources of energy and protein. Disruptions to global environments because of climate change may encourage yet more emphasis on these traits. To be successful, it is vital that there be a balance between the effort required for data recording and subsequent benefits. The motivation of farmers and other stakeholders involved in documentation and recording is essential to ensure good data quality. To keep labour costs reasonable, existing data sources should be used as much as possible. Examples include the use of milk composition data to provide additional information about the metabolic status or energy balance of the animals. Recent advances in the use of mid-infrared spectroscopy to measure milk have shown considerable promise, and may provide cost-effective alternative phenotypes for difficult or expensive-to-measure traits, such as feed efficiency. There are other valuable data sources in countries that have compulsory documentation of veterinary treatments and drug use. Additional sources of data outside of the farm include, for example, slaughter houses (meat composition and quality) and veterinary labs (specific pathogens, viral loads). At the farm level, many data are available from automated and semi-automated milking and management systems. Electronic devices measuring physiological status or activity parameters can be used to predict events such as oestrus, and also behavioural traits. Challenges concerning the predictive biology of indicator traits or standardization need to be solved. To develop effective selection programmes for new traits, the development of large databases is necessary so that high-reliability breeding values can be estimated. For expensive-to-record traits, extensive phenotyping in combination with genotyping of females is a possibility. [less ▲]

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See detailCyclic variations in incubation conditions induce adaptive responses to later heat exposure in chickens: a review
Loyau, T.; Bedrani, L.; Berri, C. et al

in Animal (2015), 9

Selection programs have enabled broiler chickens to gain muscle mass without similar enlargement of the cardiovascular and respiratory systems that are essential for thermoregulatory efficiency. Meat-type ... [more ▼]

Selection programs have enabled broiler chickens to gain muscle mass without similar enlargement of the cardiovascular and respiratory systems that are essential for thermoregulatory efficiency. Meat-type chickens cope with high ambient temperature by reducing feed intake and growth during chronic and moderate heat exposure. In case of acute heat exposure, a dramatic increase in morbidity and mortality can occur. In order to alleviate heat stress in the long term, research has recently focused on early thermal manipulation. Aimed at stimulation of long-term thermotolerance, the thermal manipulation of embryos is a method based on fine tuning of incubation conditions, taking into account the level and duration of increases in temperature and relative humidity during a critical period of embryogenesis. The consequences of thermal manipulation on the performance and meat quality of broiler chickens have been explored to ensure the potential application of this strategy. The physiological basis of the method is the induction of epigenetic and metabolic mechanisms that control body temperature in the long term. Early thermal manipulation can enhance poultry resistance to environmental changes without much effect on growth performance. This review presents the main strategies of early heat exposure and the physiological concepts on which these methods were based. The cellular mechanisms potentially underlying the adaptive response are discussed as well as the potential interest of thermal manipulation of embryos for poultry production. © The Animal Consortium 2014. [less ▲]

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See detailForage plants as alternative feed resource for sustainable pig production in the tropics: a review
Kambashi Mutiaka, Bienvenu ULiege; Boudry, Christelle ULiege; Picron, Pascale ULiege et al

in Animal (2014), 8(8), 1298-1311

Globally, pressure on concentrate feed resources is increasing, especially in the tropics where many countries are net importers of food. Forage plants are a possible alternative but their use as feed ... [more ▼]

Globally, pressure on concentrate feed resources is increasing, especially in the tropics where many countries are net importers of food. Forage plants are a possible alternative but their use as feed ingredients for pigs raises several issues related to their higher fibre and plant secondary metabolites contents as well as their lower nutritive value. In this paper, the nutritive value of several forage species as well as the parameters that influence this nutritive value in relationship to the plant family, the physiological stage, the plant part and the preservation method (fresh, hay and silage) are reviewed. The influence of the breed and the physiological status of the animal on animal voluntary intake of fibre-rich ingredients, digestibility as related to gastrointestinal volume and transit time and growth performances are also discussed. The final section highlights the assets and drawbacks of forage plants in pig diets and stresses the need for proper economic evaluation to conclude on the benefits of the use of forage plants in pig feed. [less ▲]

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See detailNon-genetic sources of variation of milk production and reproduction and interactions between both classes of traits in Sicilo-Sarde dairy sheep.
Merai, A.; Gengler, Nicolas ULiege; Hammami, Hedi ULiege et al

in Animal (2014), 8(9), 1534-9

This work aimed to study the sources of variation in productive and reproductive traits of the dairy Sicilo-Sarde ewes and to further investigate the interaction between both classes of traits. After ... [more ▼]

This work aimed to study the sources of variation in productive and reproductive traits of the dairy Sicilo-Sarde ewes and to further investigate the interaction between both classes of traits. After edits, a database containing 5935 lactation records collected during 6 successive years in eight dairy flocks in the North of Tunisia was used. Total milked milk (TMM) in the milking-only period was retained as productive trait. The interval from the start of the mating period to the subsequent lambing (IML) and the lambing status (LS) were designed as reproductive traits. Sicilo-Sarde ewes had an average TMM of 60.93 l (+/-44.12) during 132.8 days (+/-46.6) after a suckling period of 100.4 days (+/-24.9). Average IML was 165.7 days. In a first step, the major factors influencing milk production and reproductive traits were determined. The significant sources of variation identified for TMM were: flock, month of lambing, year of lambing, parity, suckling length, litter size and milking-only length. Flockxmonth of the start of the mating period, parity, year of mating and litter size were identified as significant factors of variation for IML, while flockxmonth of the start of the mating period, parity and year of mating were identified as significant sources of variation for LS. In a second step, variance components were estimated using a three traits threshold mixed model, which combined LS as categorical trait and TMM and IML as continuous traits. Repeatability estimates were 0.21 (+/-0.03) for TMM, 0.09 (+/-0.02) for IML, and 0.10 (+/-0.05) for LS. Moreover, TMM and IML were found to be favorably associated for the flockx year of lambing effect (-0.45+/-0.18) but unfavorably associated for the animal effect (0.20+/-0.09). [less ▲]

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See detailSpread of hatch and delayed feed access affect post hatch performance of female broiler chicks up to day 5.
Wang, Y.; Li, Yue; Willems, E. et al

in Animal (2014)

It is not rare that newly hatched chicks remain without feed for about 24 to 48 h before they are placed on farms due to a series of logistic operations. Furthermore, the spread in hatching time can also ... [more ▼]

It is not rare that newly hatched chicks remain without feed for about 24 to 48 h before they are placed on farms due to a series of logistic operations. Furthermore, the spread in hatching time can also mount up to 30 to 48 h for late v. early hatchers. In other words, the practice is a complex combination of spread of hatch and delayed feed access. The present study was aimed to investigate the combined effects of hatching time with a delay in feed access of 48 h, starting from their hatch-time (biological age). When chicks had access to feed immediately after hatch, late hatchers had a higher feed intake and relative growth rate up to day 5 compared with their early hatched counterparts. Feed deprivation during the first 48 h resulted in retarded early growth rate, which was further aggravated by an impaired feed intake after refeeding. In addition, the differential effects of hatching time on relative growth rate and feed intake observed in immediately fed chicks were eliminated by the 48 h feed delay. The yolk utilization after hatch was faster for the late hatchers up to biological day 2 regardless of the feeding treatments. Hatching muscle glycogen content was higher in the late hatchers compared with that of their early counterparts at hatch and at biological day 2 independent of feeding treatment. Moreover, the liver glycogen content of the late hatchers was also higher at hatch. For the immediately fed chicks, the proportional breast muscle weight of the late hatchers was higher at biological day 2 and 5. For the starved chicks, on the other hand, this effect was only observed after they had access to feed (biological day 5). The different plasma T3 levels at hatch may have contributed to the different post hatch performance. It is concluded that the spread of hatch influenced post hatch performance, especially appetite and growth at least until day 5. Moreover, the delay in feed access interacted with the hatching time and caused adverse effects on the post hatch performance. [less ▲]

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See detailEvaluating somatic cell scores with a Bayesian Gaussian linear state-space model.
Detilleux, Johann ULiege; Theron, Léonard ULiege; Reding, E. et al

in Animal (2014), 8(3), 477-83

Because accurate characterization of health state is important for managing dairy herds, we propose to validate the use of a linear state-space model (LSSM) for evaluating monthly somatic cell scores ... [more ▼]

Because accurate characterization of health state is important for managing dairy herds, we propose to validate the use of a linear state-space model (LSSM) for evaluating monthly somatic cell scores (SCSs). To do so, we retrieved SCS from a dairy database and collected reports on clinical mastitis collected in 20 farms, during the period from January 2008 to December 2011 in the Walloon region of Belgium. The dependent variable was the SCS, and the independent variables were the number of days from calving, year of calving and parity. The LSSM also incorporated an error-free underlying variable that described the trend across time as a function of previous clinical and subclinical status. We computed the mean sum of squared differences between observed SCS and median values of the posterior SCS distribution and constructed the receiver operating characteristic (ROC) curve for SCS thresholds going from 0 to 6. Our results show SCS estimates are close to observed SCS and area under the ROC curve is higher than 90%. We discuss the meaning of the parameters in light of our current knowledge of the disease and propose methods to incorporate, in LSSM, this knowledge often expressed in the form of ordinary differential equations. [less ▲]

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See detailValidation of fatty acid predictions in milk using mid-infrared spectrometry across cattle breeds.
Maurice – Van Eijndhoven, Myrthe; Soyeurt, Hélène ULiege; Dehareng, Frédéric et al

in Animal (2013), 7

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See detailThe use of SWOT analysis to explore and prioritize conservation and development strategies for local cattle breeds
Martin-Collado, D; Diaz, C; Mäki-Tanila, A et al

in Animal (2013), 7(6), 885-894

SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis is a tool widely used to help in decision making in complex systems. It suits to exploring the issues and measures related to the ... [more ▼]

SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis is a tool widely used to help in decision making in complex systems. It suits to exploring the issues and measures related to the conservation and development of local breeds, as it allows the integration of many driving factors influencing breed dynamics. We developed a quantified SWOT method as a ecisionmaking tool for identification and ranking of conservation and development strategies of local breeds, and applied it to a set of 13 cattle breeds of six European countries. The method has four steps: definition of the system, identification and grouping of the driving factors, quantification of the importance of driving factors and identification and prioritization of the strategies. The factors were determined following a multi-stakeholder approach and grouped with a three-level structure. Animal genetic resources expert groups ranked the factors, and a quantification process was implemented to identify and prioritize strategies. The proposed SWOT methodology allows analyzing the dynamics of local cattle breeds in a structured and systematic way. It is a flexible tool developed to assist different stakeholders in defining the strategies and actions. The quantification process allows the comparison of the driving factors and the prioritization of the strategies for the conservation and development of local cattle breeds. We identified 99 factors across the breeds. Although the situation is very heterogeneous, the future of these breeds may be promising. The most important strengths and weaknesses were related to production systems and farmers. The most important opportunities were found in marketing new products, whereas the most relevant threats were found in selling the current products. The across-breed strategies utility decreased as they gained specificity. Therefore, the strategies at European level should focus on general aspects and be flexible enough to be adapted to the country and breed specificities. [less ▲]

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See detailMid-Infrared prediction of lactoferrin content in bovine milk: Potential indicator of mastitis
Soyeurt, Hélène ULiege; Bastin, Catherine; Colinet, Frédéric ULiege et al

in Animal (2012), 6

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See detailPotential use of milk mid-infrared spectra to predict individual methane emission of dairy cows
Dehareng, Frédéric; Delfosse, Camille; Froidmont, Eric et al

in Animal (2012), 6(10), 1694-1701

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See detailEstimating myostatin gene effect on milk performance traits using estimated gene content for a large number of non-genotyped cows
Buske, Bernd ULiege; Szydlowski, Maciej; Verkenne, Catherine et al

in Animal (2011), 5(1), 43-47

The objective of this study was to estimate the myostatin (mh) gene’s effect on milk, protein and fat yield in a large heterogeneous cow population, of which only a small portion was genotyped. For this ... [more ▼]

The objective of this study was to estimate the myostatin (mh) gene’s effect on milk, protein and fat yield in a large heterogeneous cow population, of which only a small portion was genotyped. For this purpose, a total of 13 992 889 test-day records derived from 799 778 cows were available. The mh gene effect was estimated via BLUP using a multi-lactation, multi-trait random regression test-day model with an additional fixed regression on mh gene content. As only 1416 animals, (of which 1183 cows had test-day records) were genotyped, more animals of additional breeds with assumed known genotype were added to estimate the genotype (gene content) of the remaining cows more reliably. This was carried out using the conventional pedigree information between genotyped animals and their non-genotyped relatives. Applying this rule, mean estimated gene content over all cows with test-day records was 0.104, showing that most cows were homozygous 1/1. In contrast, when gene content estimation was only based on genotyped animals, mean estimated gene content over all cows with test-day records was with 1.349 overestimated. Therefore, the applied method for gene content estimation in large populations needs additional genotype assumptions about additional animals representing genetic diversity when the breed composition in the complete population is heterogeneous and only a few animals from predominantly one breed are genotyped. Concerning allele substitution effects for one copy of the ‘mh’ gene variant, significant decreases of 276.1 kg milk, 23.6 kg fat and 22.8 kg protein/lactation were obtained on average when gene content estimation was additionally based on animals with assumed known genotype. Based on this result, knowledge of the mh genotypes and their effects has the potential to improve milk performance traits in cattle. [less ▲]

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See detailA hidden Markov model to predict early mastitis from test-day somatic cell scores
Detilleux, Johann ULiege

in Animal (2011), 5(2), 175-181

In many countries, high somatic cell scores (SCS) in milk are used as an indicator for mastitis because they are collected on a routine basis. However, individual test-day SCS are not very accurate in ... [more ▼]

In many countries, high somatic cell scores (SCS) in milk are used as an indicator for mastitis because they are collected on a routine basis. However, individual test-day SCS are not very accurate in identifying infected cows. Mathematical models may improve the accuracy of the biological marker by making better use of the information contained in the available data. Here, a simple hidden Markov model (HMM) is described mathematically and applied to SCS recorded monthly on cows with or without clinical mastitis to evaluate its accuracy in estimating parameters (mean, variance and transition probabilities) under healthy or diseased states. The SCS means were estimated at 1.96 (s.d.50.16) and 4.73 (s.d.50.71) for the hidden healthy and infected states, and the common variance at 0.83 (s.d.50.11). The probability of remaining uninfected, recovering from infection, getting newly infected and remaining infected between consecutive test days was estimated at 78.84%, 60.49%, 11.70% and 15%, respectively. Three different health-related states were compared: clinical stages observed by farmers, subclinical cases defined for somatic cell counts below or above 250 000 cells/ml and infected stages obtained from the HMM. The results showed that HMM identifies infected cows before the appearance of clinical and subclinical signs, which may critically improve the power of the studies on the genetic determinants of SCS and reduce biases in predicting breeding values for SCS. [less ▲]

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