Publications - Publications

Bindingsproteiner i foderet kan modvirke diarré

Lærke, H. N. — Mon, 30 Jun 2025 06:52:39 +0200

Input til vidensindsamling som grundlag for udarbejdelse af ensartede betingelser for driftsregler for husdyrbrug (UCOL) jævnfør artikel 70i i IE-direktiv 2024/1785 (IED-2.0)

Kai, P., Brask, M. J., Hansen, M. J., Dalby, F. R., Kamp, J. N., Pedersen, J. — Wed, 02 Jul 2025 06:52:39 +0200

PFAS i planter, insekter og orme og risiko for overførsel til æg fra fritgående hobbyhøns

Nørgaard, J. V. — Wed, 02 Jul 2025 06:52:39 +0200

In-feed provision of binding proteins sustains piglet gut health and mitigates ETEC-induced post-weaning diarrhea

Xu, J., Andrani, M., Kjærup, R. B., et al. — Mon, 02 Jun 2025 06:52:39 +0200

BACKGROUND: Post-weaning diarrhea (PWD) in piglets, often caused by F4+ enterotoxigenic Escherichia coli (ETEC), poses significant challenges in pig production. Traditional solutions like antibiotics and zinc oxide face increasing restrictions due to growing concerns over antibiotic resistance and environmental sustainability. This study investigates the application of bivalent heavy chain variable domain (VHH) constructs (BL1.2 and BL2.2) targeting ETEC virulence factors, administered in feed to mitigate ETEC-induced PWD in weaned piglets.

RESULTS: The supplementation of BL1.2 and BL2.2 in both mash and pelleted feed significantly reduced the diarrhea incidence and fecal shedding of F4+ ETEC in challenged piglets. Pelleted feed containing VHH constructs helped to preserve gut barrier integrity by maintaining levels of the tight junction protein occludin in the small intestine. Additionally, the constructs maintained blood granulocyte counts at a similar level to the non-challenged control group, including neutrophils, and ameliorated the acute phase protein response after challenge. Notably, even at low feed intake immediately after weaning, VHH constructs helped maintain piglet health by mitigating ETEC-induced inflammation and the resulting diarrhea.

CONCLUSIONS: Our findings demonstrated that using VHH constructs as feed additives could serve as an effective strategy to help manage ETEC-associated PWD, by reducing F4+ ETEC gut colonization and supporting gut barrier function of weaned piglets. The high stability of these VHH constructs supports their incorporation into industrial feed manufacturing processes, offering a more sustainable preventive strategy compared to traditional antimicrobial interventions, which could contribute to sustainable farming practices.

FIBERMÆLK – Reduceret klima- og miljøaftryk fra mælkeproduktionen gennem øget fiberfordøjelighed af græs- og bælgplanteafgrøder

Hansen, N. P., Brito Gomes, M., Weisbjerg, M. R. — Wed, 04 Jun 2025 06:52:39 +0200

Effect of zero-grazing herbage on ruminal fermentation and methane yield in dairy cows

Hansen, N. P., Weisbjerg, M. R., Lund, P., Larsen, M. — Mon, 01 Jan 2024 06:52:39 +0100

Deck height did not affect behavioural measures of ‘natural movements’ and ‘adequate ventilation’ during 8 h and 23 h transport of weaner pigs

Mon, 01 Sep 2025 06:52:39 +0200

Annually, more than 30 million weaner pigs cross borders between EU member states mainly transported for further production. The current EU regulation states that the internal deck height of the transport vehicles must on no account hinder natural movements and provide adequate ventilation but without including specific norms. The aim of the present study was to examine impact of deck height (60 vs 80 cm and 70 vs 90 cm) on behaviour reflecting natural movements and adequate ventilation during 16 short (8 h) and 16 long (23 h) journeys of 20–25 kg pigs, mimicking commercial conditions. A secondary aim was to describe the behaviour progressed from departure to arrival including the driver break during short journeys. To address the aim, the first task was to select appropriate behavioural measures that could robustly be annotated with the limited vertical space. As a consequence, head butting against the ceiling and drinking behaviour were omitted in pilot observations. The final behaviours were body posture including huddling and huddling location analysed using 15 min interval instantaneous scan sampling. The frequency of aggression and a pig standing on another pig was recorded using continuous sampling during selected 20 min recording sessions (in total 160 and 120 min for short and long journeys, respectively). During short journeys, this included recording sessions placed immediately before, during and after the mandatory break of the livestock driver. Mixed effects models were used to analyse effects of deck height and the following co-variates: hour since departure, microclimatic conditions and vehicle speed. No effect of deck height was found on any of the selected behavioural measures. When examining behaviour of the pigs before, during and after the break, no differences in lying behaviour were found, but for one of the vehicle elements, the trailer, an increase in aggressive behaviour was observed during the break. Overall, the results showed a complex pattern of relations affecting the behaviour of the pigs, such as the microclimatic conditions and driving speed interacting with hour since departure. These findings varied to some extent depending on vehicle element (lorry or trailer) and journey duration (8 h or 23 h, with the associated different stocking densities). Taken together, the results showed that increasing the deck height did not lead to detectable changes in the behaviour of the weaner pigs, but that many other factors influenced the behaviour of weaners during transport and may thus also influence their welfare.

In vitro processes alter the embryonic disc epigenome and transcriptome in the pre-implantation elongated bovine embryo

Behrens, T., Balasubramanian, J., Ivask, M., et al. — Fri, 13 Jun 2025 06:52:39 +0200

The objective was to quantify the effect of the in vitro procedures on the epigenome and transcriptome of the embryonic disc (ED) and extra-embryonic membranes (EEM) of day 15 in vitro produced (IVP) conceptuses compared to in vivo (IVV) counterparts. IVP embryos (n = 7) were cultured serum-free until transfer at day 7. IVV embryos (n = 9) were conceived by artificial insemination. Animals were flushed at day 15 of gestation, and sections of ED and EEM were subjected to DNA and mRNA extraction for whole genome bisulfite or RNA sequencing. Raw fastq files were aligned to the ARS-UCD1.3 bovine genome. Processed data were integrated through a multi-omics approach based on machine learning to determine the key ontological terms characterizing each embryonic tissue lineage according to their methylome and transcriptome, followed by overrepresentation analyses (adjusted p-value<0.05) of differentially methylated genes (DMG), differentially expressed genes (DEG) or genes both differentially methylated and differentially expressed in the ED or EEM of IVP compared to IVV conceptuses. Results demonstrated that identified critical ontological terms for the ED (such as somitogenesis, mesoderm formation, gastrulation) and the BMP and Wnt signaling pathways were enriched among hypermethylated DMG, down-regulated DEG, and genes hypermethylated in the promoter and inhibited in expression, in the ED of IVP embryos. Genes hypermethylated in the promoter and inhibited in expression in the EEM of IVP conceptuses were involved in epigenetic regulation. In conclusion, the in vitro process alters the development of main linage tissues in the pre-implantation embryo, even after interaction with the maternal environment.

Vurdering af dyrevelfærd i forbindelse med tidlig ko-kalv separation

Vaarst, M., Jensen, M. B. — Mon, 23 Jun 2025 06:52:39 +0200

Kvalitet i arter af græs og græsmarksbælgplanter – konsekvenser for foderplanlægning og markdriften

Weisbjerg, M. R., Hansen, N. P. — Mon, 01 Jan 2024 06:52:39 +0100

Fodring, mælkeydelse og metan ved staldfodring med frisk græs i stedet for græsensilage

Larsen, M., Hansen, N. P., Weisbjerg, M. R. — Mon, 01 Jan 2024 06:52:39 +0100

Værdien af frisk græs som foder

Hansen, N. P., Larsen , M. ., Weisbjerg, M. R. — Sun, 01 Jan 2023 06:52:39 +0100

Skruepresning af græs ved bioraffinering øgede fiberfordøjelighed og proteinkvalitet hos køer

Hansen, N. P., Weisbjerg, M. R., Jensen , S. — Tue, 24 Aug 2021 06:52:39 +0200

Effect of zero-grazing herbage on ruminal fermentation and methane yield in dairy cows

Hansen, N. P., Weisbjerg, M. R., Lund, P., Larsen, M. — Mon, 01 Jan 2024 06:52:39 +0100

Grass-based feeding strategies for organic growing-finishing pigs during temperate summer conditions

Stødkilde, L., Jensen, M. S., Jørgensen, E. T., Ambye-Jensen, M., Eskildsen, M. — Fri, 01 Aug 2025 06:52:39 +0200

This study evaluated substituting soy press cake with Green protein—derived from biorefined grass-clover—and the provision of grass-clover-based roughage for organic growing-finishing pigs under temperate summer conditions. A total of 150 pigs were assigned to five dietary treatments combining soy or Green protein-based compound feed with either fresh grass-clover or silage. Growth performance, feed intake, lean meat percentage, and blood metabolite levels were assessed. Replacing soy with Green protein did not negatively impact growth performance and pigs fed Green protein and fresh grass-clover had higher lean meat percentage than those fed soy with silage (P < 0.01). Roughage intake was greater with fresh grass-clover than with silage (P < 0.01), contributing with more nitrogen (N; P < 0.01). A 10 % reduction in lysine in the Green protein compound feed, when paired with fresh grass-clover, did not compromise productivity and increased lean meat percentage compared to the soy-silage group. Blood metabolite levels were only minimally affected by dietary treatment. In conclusion, Green protein can replace soy in organic pig feed without compromising animal performance, offering a promising alternative. The higher lean meat percentage associated with Green protein indicated a more favourable amino acid profile for growth compared to soy. While the overall nutrient contribution from grass-based roughages remained limited, the inclusion of fresh grass-clover allowed for a reduction in Green protein-based compound feed. This adjustment could positively impact both feed cost efficiency and the reduction of nutrient leaching into the environment.

Hestebønner som alternativ til soja og raps

Hansen, N. P., Johansen, M., Wiking, L., Larsen, T., Weisbjerg, M. R. — Mon, 01 Jan 2018 06:52:39 +0100

Effect of fermented cereal liquid feed supplemented with Pediococcus acidilactici on gut microbiota, mucosal immunity, and growth in suckling and post-weaning piglets.

Xu, J. — Thu, 01 May 2025 06:52:39 +0200

Parasitbekæmpelse hos heste – på vej mod ensartet vejledning?

Lærke, H. N. — Mon, 16 Jun 2025 06:52:39 +0200

Kontrol med indvoldsorm i heste håndteres forskelligt fra land til land på baggrund af forskellige vejledninger. Nu har forskere og fagfolk bag disse vejledninger sat sig sammen for at se på, hvorfor de er forskellige og om de bør gøres mere ens.

Living labs opened dialogues about antibiotic use in dairy cattle and pig sectors - Insights from a Danish case study based on participatory action research

Vaarst, M., Studnitz, M., Krogh, M. A., Kongsted, H. — Tue, 17 Jun 2025 06:52:39 +0200

BACKGROUND: Prudent antimicrobial use (AMU) is paramount for future sustainable animal production. Continuous efforts are required to have a low and well-regulated AMU. Living Labs (LLs) are multistakeholder open innovation platforms that have the potential to allow multiple stakeholders to explore common ground, create dialogues and find solutions to jointly identified problems. The purpose of this study was to stimulate multistakeholder dialogues leading to transitions towards a more prudent AMU in the Danish dairy and pig sectors.

RESULTS: The two LLs, which focused on pig farms and dairy cattle farms, worked in parallel for 30 months. Stakeholders in the pig and dairy sectors pointed to systemic structures such as logistic conditions and global market structures as the main drivers of the current AMU. Both LLs expressed conflicting interests and perceptions around the concept of prudent AMU related to animal welfare and today's production systems. Thus, the LLs in the Danish context became spaces for opening dialogues and negotiating difficult and sensitive issues in addition to being open-innovation platforms. Both LLs expressed scepticism around the connections between AMU in animal farming and the global threat of antimicrobial resistance to humans. However, this scepticism was more dominant for the stakeholders of the pig sector. The feeling of being a global front-runner in prudent AMU, legislation and transparent monitoring of AMU existed in both sectors, but both LLs identified possibilities and room for improvement. The need to reduce AMU was most consistently articulated in the dairy cattle LL, where the stakeholders increasingly focused on calves from dairy farms and the systemic drivers, which made it challenging to reduce AMU. Some actors in the pig LL kept questioning whether a change towards more prudent AMU was needed in Denmark.

CONCLUSION: The LL approach fostered important dialogues and insights between central stakeholders in the sectors and was thereby helpful in terms of opening and contributing to dialogues about antibiotic usage in dairy cattle and pigs within and across sectors.

Hestebønner kan erstatte soja og raps

Hansen, N. P., Johansen, M., Larsen, T., Wiking, L., Røjen, B., Weisbjerg, M. R. — Mon, 01 Jan 2018 06:52:39 +0100

Staldfodring med frisk græs

Hansen, N. P., Weisbjerg, M. R., Kristensen, T. — Wed, 01 Jan 2020 06:52:39 +0100

Hestebønner – foder og proteinværdi ved forskellig konservering og behandling

Weisbjerg, M. R., Wang, W., Hansen, N. P., et al. — Tue, 07 Sep 2021 06:52:39 +0200

Methane emission from grazing dairy cattle

Wed, 01 Jan 2025 06:52:39 +0100

Isolation of Hydrogenotrophic Bacteria and their impact on Hydrogen Levels in Rumen Fluid Under Inhibited Methanogenesis Conditions

Noel, S. J., Liboriussen, H. H., Nielsen, M. O., Hojberg, O., Thorsteinsson, M. — Sun, 01 Jun 2025 06:52:39 +0200

Determination of carbohydrate and lignin content in feedstuffs for monogastric animals using near-infrared spectroscopy

Mon, 01 Sep 2025 06:52:39 +0200

Carbohydrates (CHO) are the principal constituents of the diets given to monogastric animals around the world. They supply the largest part of the energy to the animal, despite the fact only monosaccharides, disaccharides and starch can be enzymatically broken down in the small intestine into monosaccharides that are readily absorbed. In contrast, oligosaccharides (OS), resistant starch, non-starch polysaccharides (NSP) and lignin resist enzymatic digestion and thus cannot be absorbed directly. They compose the so-called dietary fiber. The soluble fraction of fiber is almost completely fermentable and causes benefits to the gastrointestinal tract while the insoluble fibre is less degraded and therefore lead to a decrease in nutrient and energy digestibility. The CHO fraction and its composition is highly variable among feed ingredients but also amongst the different varieties of the same ingredient. To improve the nutrient utilization and to formulate animal diets that are more efficient it is necessary to characterize the CHO fraction of the ingredients. In addition, with the growing use of supplementary enzymes, such as xylanase, β-glucanase or mannanase to mitigate the anti-nutritive effect of fiber the determination of the CHO components is essential. To make a full account of the CHO and lignin constituents, several wet chemical enzymatic, chromatographic and gravimetric methods need to be employed, which are expensive and time-consuming. Near-infrared spectroscopy (NIRS) overcomes these limitations because it is a rapid, non-destructive, multi-parametric technique and requires minimal sample preparation. In this work, around 300 samples of animal feedstuffs, consisting of cereals, cereal co-products, protein-rich and fiber-rich feedstuffs were used to develop and validate near-infrared (NIR) partial least square regression (PLSR) models. Spectral pretreatment optimization, sample selection and outlier detection were considered for each model. Robust predictions (R2P>0.90) were obtained for digestible carbohydrates (sugars and starch) and for most of the total or insoluble components of dietary fiber (lignin, NSP, cellulose, β-glucan, non-cellulosic polysaccharides (NCP), arabinose, xylose, galactose, rhamnose and uronic acids). The OS, fructans were well predicted in cereals (R2P=0.94) and linearity (R2CV>0.70) was also found for α-galactosides (raffinose, stachyose and verbascose) in protein-rich feedstuffs. The obtained results were in general very satisfactory and demonstrate that NIRS is a reliable tool to characterize the carbohydrate fraction of a variety of feedstuffs.

Optimal dietary protein content and essential amino acid limitation in larvae of the black soldier fly (Hermetia illucens)

Berggreen, I. E., Schøn, M. L., Nørgaard, J. V., Jensen, K. — Wed, 01 Jan 2025 06:52:39 +0100

A balanced diet is known to maximize animal performance, but a direct effect of dietary essential amino acid imbalance has rarely been demonstrated in insects. We show that deficiency in certain essential amino acids can be measured directly by growth in larvae of the black soldier fly (Hermetia illucens (L.)). Our results identified an optimal dietary protein content of 19.4% protein, corresponding to a P:C ratio of 1:2.8, for maximal total larval dry mass production. To test if each of the ten amino acids known to be essential for rats were also essential for H. illucens larvae, we added all but the specific amino acid to the artificial part of a semi-artificial diet based on 35% chicken feed. Significantly lower growth was measured when lysine, isoleucine, leucine, phenylalanine, threonine, tryptophan, valine, or arginine was not included in the artificial part of the diet, demonstrating that these amino acids are essential for growth in H. illucens larvae. In addition, we found that larvae with lowered growth caused by essential amino acid deficiency in most cases had higher proportional lipid content compared to larvae reared on a diet with all essential amino acids included in the artificial part. Our study highlights that the profile of essential amino acids needs to be balanced to maximize larval productivity in H. illucens. Determining the minimal level of each essential amino acid to maximize growth and thereby the rate of protein and feed conversion may reduce the cost of required feed by reducing dietary protein demands.

Fluelarver skal have den rette kost for at forvandle madaffald til protein

Lærke, H. N. — Tue, 03 Jun 2025 06:52:39 +0200

Forbedret holdbarhed hos økologiske malkekøer

Lærke, H. N. — Fri, 11 Apr 2025 06:52:39 +0200

Økologiske aminosyrer til grise og fjerkræ

Lærke, H. N. — Thu, 02 Jan 2025 06:52:39 +0100

Flueknepperi – ny viden om soldaterfluers sexliv kan bane vejen for mere bæredygtig fødevareproduktion

Lærke, H. N. — Mon, 31 Mar 2025 06:52:39 +0200

Effects of sillage additives on the ensiling characteristics of pulp from bio-refining

Sat, 01 Jan 2022 06:52:39 +0100

Global equine parasite control guidelines

Nielsen, M. K., Pyatt, A., Perrett, J., et al. — Fri, 01 Aug 2025 06:52:39 +0200

Equine parasite control has historically been characterized by confusing and conflicting information, posing significant challenges for veterinarians and horse owners to make evidence-based decisions. Since 2012, equine parasite control guidelines have been developed and published for different parts of the world to address this situation and provide trusted sources of current guidance. At the 2024 International Equine Infectious Disease Conference in Deauville, Normandy, France, lead authors of equine parasite control guideline documents published in the USA, UK, Sweden, Denmark, the Netherlands, Australia, and Europe convened and presented their guidelines. This led to a discussion of differences and similarities between the guidelines and an effort to identify current research needs in this area. In general, all guidelines recommend a surveillance-based approach for equine parasite control, emphasizing the importance of anthelmintic resistance testing. Some guidelines have a focus on controlling Strongylus vulgaris, while others primarily focus on cyathostomins, ascarids and tapeworms. Although the same four anthelmintic drug classes are marketed in most countries, there are some differences between product portfolios available, most notably between Australia and other countries. European countries have various degrees of prescription-only restrictions on anthelmintic products, whereas products are available over the counter in Australia and the USA. Commercially available diagnostic portfolios differed somewhat between countries and affected recommendations made as well. In conclusion, the guidelines are in general agreement and are based on the same general principles. One major challenge is communicating the recommendations effectively to end-users, which should be made a priority going forward.

Comparison of external and internal markers for flow measurements in the digestive tract of dairy cows

Hansen, N. P., Weisbjerg, M. R. — Sun, 01 Jan 2023 06:52:39 +0100

Non-constant rate of degradation of NDF in primary growth of grass, clover, and lucerne

Hansen, N. P., Weisbjerg, M. R. — Mon, 01 Jan 2024 06:52:39 +0100

Kan hestebønner erstatte raps og soja som proteinkilder til malkekøer?

Hansen, N. P., Weisbjerg, M. R. — Sun, 01 Jan 2017 06:52:40 +0100

Manganese handling in the shore crab Carcinus maenas

Bjerregaard, P., Hastrup, M., Nowack, K., Malmkvist, J. — Fri, 01 Aug 2025 06:52:40 +0200

Manganese leaching from reduced sediments during oxygen depletion events may expose benthic organisms to elevated manganese concentrations. Various aspects of manganese handling in Carcinus maenas were investigated. Exposure to up to 400 mg Mn L⁻¹ for 4 d caused no mortality. Crabs accumulated ⁵⁴Mn from water almost linearly with time, reaching a whole-body concentration factor of 21 after 22 d. After uptake from food or water, major parts of the body burden were eliminated with half-lives of 96 and 44 d, respectively. Most of the manganese entering the haemolymph (by feeding or injection) was removed within 24 h, a substantial part being transferred to the exoskeleton. Exposure to 50 and 300 μg Mn⁺⁺ L⁻¹ in the water led to increased manganese concentrations in most tissues. Hypoxic conditions (19 % oxygen saturation) had only moderate effects on manganese accumulation in midgut gland and exoskeleton, and none in gills. Investigations at field locations confirmed that smaller crabs have higher manganese concentrations in their exoskeleton than larger ones. The most important findings in these experiments are: 1) manganese and calcium compete for uptake over the gills into the haemolymph and 2) manganese in the haemolymph may be translocated to the exoskeleton, thus supporting the possibility that the different behavior of smaller and larger crabs during postmoult calcification of the exoskeleton - by uptake of Ca⁺⁺ from the sea water - may explain their different manganese body burdens (of which ≈95 % is found in the exoskeleton).

GRÆSMÆLK – Mælk fra køer fodret med store græsmængder

Hansen, N. P., Kristensen, T., Weisbjerg, M. R. — Tue, 01 Jan 2019 06:52:40 +0100

Estimating the influence of dietary composition and management on nutrient intake and excretion and methane emission in different pig categories

Lashkari, S., Dalby, F. R., Krogh, U., Sattarova, E., Børsting, C. F. — Thu, 01 May 2025 06:52:40 +0200

The study aimed to estimate the effect of diet composition, pig production stage, in-housing conditions, and manure management on methane (CH₄) emissions from enteric fermentation, manure stored in the barn, and the outdoor storage tank. For each pig category, an estimation for emissions was made for a standard Danish pig diet based on wheat, barley, and soybean meal. Within each category of pigs, emissions were also estimated for diets with different levels and types of dietary fiber from sugar beet pulp, wheat bran, oats, wheat, or soy hulls, which were included as a partial substitution for wheat or barley. In all diets within four pig categories, feed intake, excreted dry matter, feces mass, and urine volume (g/d per animal) increased in sugar beet pulp, wheat bran, oat, or soy hull diets compared to the average Danish diet. In grower-finisher pigs, the sum of CH₄ emissions from enteric fermentation, manure stored in the barn, and the outdoor storage tank were 9.8, 10.2, 11.0, 11.0, and 11.2 (kg/year/animal place) for wheat diet, average Danish diet, oat diet, wheat bran diet, and sugar beet pulp diet, respectively, while in gestating sows, were 16.9, 17.5, 18.4, 19.6, 19.7, and 23.2 (kg/year/animal place) in wheat diet, average Danish diet, oat diet, sugar beet pulp diet, wheat bran diet, and soy hull diet, respectively. Contribution of CH₄ emissions from manure stored in the barn plus outdoor storage tank for the average Danish diet accounted for 95, 90, 83, and 84% of total CH₄ emissions in weaned pigs, grower-finisher pigs, lactating sows, and gestating sows, respectively. In conclusion, feed composition has a considerable impact on CH₄ emissions. Enteric CH₄ and CH₄ emissions from manure stored in the barn and in the outdoor storage tank were increased by elevated concentration of residual fiber in all four pig categories except for enteric CH₄ in weaned pigs.

AU forskere undersøger foderværdien af pulp til malkekøer

Hansen, N. P., Weisbjerg, M. R., Jensen, S. K. — Wed, 01 Jan 2020 06:52:40 +0100

Fodring af græspulp kan snart blive en realitet

Hansen, N. P., Jensen , S. — Wed, 01 Jan 2020 06:52:40 +0100

Indications of trained innate immunity by Escherichia coli vaccination or chitin feed supplementation assessed during Ascaridia galli infection in chickens

Tue, 01 Jul 2025 06:52:40 +0200

Infections with the gastrointestinal roundworm Ascaridia galli, cause health problems and economic losses in laying hen husbandry, particularly in organic and free-range systems. This study aimed to evaluate induction of trained innate immunity through priming with a live attenuated Escherichia coli vaccine or chitin supplementation in the feed as a novel approach to mitigate A. galli infection. The study comprised four groups of chickens: chitin-fed (day 1–7 of age), E. coli-vaccinated (day 1 of age), an untreated control group, and a naïve uninfected group. On day 7 of age, the first three groups were infected with A. galli. Immune parameters were assessed after initial treatments and post the parasite infection. Also, faecal excretion of nematode eggs and total worm burden were monitored post-infection. The chitin and E. coli treatments induced changed proportions of leukocytes in bone marrow as well as changes in cell surface receptor expression. Moreover, treatments altered the immune response to the A. galli infection, e.g. observed for numbers of heterophils and TCRγδ+CD8- T-cells in the circulation but also expression levels of cell surface receptors CD41/61, Bu-1 and MHC-II on circulating leukocyte subsets. However, neither treatment affected worm burden, faecal egg excretion or the induction of A. galli-specific IgY. The results demonstrate potential in vivo training of the avian innate immune system but further research is needed to identify strategies to explore this in relation to control of nematode infections.

Short communication

Zaalberg, R. M., Andersen, L. B., Hansen, L. S., et al. — Sun, 01 Jun 2025 06:52:40 +0200

An underutilised tool to optimise the production of black soldier fly larvae (Hermetia illucens L.; Diptera: Stratiomyidae) is selective breeding. We validated that larval size is moderately heritable and should, therefore, respond to selection. We tested this premise by estimating additive genetic variation for larval size assessed as individual larval surface area (ISA), group surface area (GSA), and group weight (GW). A full-/half-sib design was used, where one virgin male fly was offered the opportunity to mate four virgin females. Each male had between one and three females that produced larvae, with a mean of 1.85 females per male. For each female that produced larvae, two cups with feed were prepared and fifty larvae were transferred to each cup. On day twelve after egg hatching, thirty larvae (full sibs) from each cup were randomly selected, and ISA was recorded (9 486 larvae from 92 sires and 169 dams). The GW of the thirty larvae was then recorded, and the GSA was calculated from the ISA of the thirty larvae in the group (317 full-sib groups). The data were analysed using sire-dam models including population average and batch as fixed effects and sire, dam and cup as random effects. The results showed moderate heritability for ISA (0.40), with a moderate effect of the common environment (0.21). For GSA and GW, moderate heritabilities were observed (0.39 and 0.30). These results show that there is great potential for black soldier fly breeders to implement selection for bigger larval size in their breeding programmes.

A pilot study on alternative blood sampling methods in pigs

Xavier, C., Eugenio, F. A., Gondret, F., et al. — Mon, 01 Dec 2025 06:52:40 +0100

Background: The collection of blood samples allows the monitoring of animal health and can be achieved by puncture or catheterization of specific veins. However, this process raises ethical concerns regarding animal welfare. As an alternative to traditional invasive blood collection methods, we tested the use of kissing bugs (Dipetalogaster maxima, a blood-sucking insect) and devices derived from human medicine, such as vascular imaging (VeinViewer^®) and prick lancets used for finger pricking. These methods were compared against the catheter collection method, which is considered the gold standard method for repeated blood sampling. The blood collection methods were tested in six female Large White pigs at four time points. Methods were compared for ease of collection, animal stress indicators, and obtained concentrations of plasma cortisol and glucose. Results: Among the methods, the catheter and insects were the least stressful, followed by the prick lancet, and the VeinViewer^®. The VeinViewer^® was the most stressful, mainly because the pig had to be restrained with a snout rope. According to the operators, the VeinViewer^® and prick lancet sampling were the most difficult methods to perform, whereas catheter and kissing bug sampling were easier. However, kissing bug sampling took up to 50 min compared to other methods (2–3 min). The method of sampling has a significant effect on glucose concentrations, with lower concentrations obtained with prick lancet (6.1 mg/dL, p < 0.05) and kissing bugs (73.8 mg/dL, p > 0.05) compared to the catheter method (93.2 mg/dL) and the VeinViewer^® (94.7 mg/dL). Glucose concentrations obtained by catheter were significantly correlated with those obtained by the VeinViewer^® (r = 0.47) or kissing bugs (r = 0.54). Differences in cortisol levels were less pronounced, with only the prick lancet method showing lower concentrations (2.9 ng/dL, p < 0.05) compared to the other methods (catheter 19.3 ng/dL, kissing bugs 20.8 ng/dL, and VeinViewer^® 20.4 ng/dL). Significant Spearman’s correlations were observed between cortisol concentration of samples obtained by catheter and VeinViewer^® (r = 0.64) or prick lancet (r = 0.52). Conclusions: These findings underscore the reliability of catheterization as the gold standard, although the prick lancet appears promising to reduce pig’s stress. However, the method could be further refined, both in terms of animal acceptability and especially analytical procedures.

Feeding experiments with insects and assessment of feed related risks from kitchen- and food waste: Risks associated with meat and fish

van Zadelhoff, K. L., Berggreen, I. E., Nørgaard, J. V., Jensen, K. — Wed, 04 Jun 2025 06:52:40 +0200

Shelter use by horses and beef cattle during the winter

Fogsgaard, K. K., Thodberg, K., Christensen, J. W. — Sun, 01 Jan 2023 06:52:40 +0100

In vitro methods for analysing nutrient digestibility - and their implementation in present and future feed evaluation systems for pigs

Boisen, S. — Tue, 01 Jan 2002 06:52:40 +0100

A dynamic Model of Nutrient Digestion and Metabolism in Lactating Dairy cows

Danfær, A. C. — Mon, 01 Jan 1990 06:52:40 +0100

Dam Rearing of Dairy Calves

Jensen, E. H. — Tue, 09 Apr 2024 06:52:40 +0200

In dairy production, cow and calf are typically separated shortly after calving. This procedure is criticised by consumers, and both farmers and researchers are increasingly investigating ways to prolong cow-calf contact (CCC). Previous research has mainly focused on the perspectives of the calf; however, the present PhD thesis will focus on the cow. Extended CCC provides some challenges: the farmer may obtain less saleable milk, and cow and calf experience increased stress at separation due to them having formed a strong bond. There is thus a need for managing cows and calves in a way that can reduce saleable milk loss and separation stress. Two suggested solutions are 1) to keep cow and calf together only part of the day and 2) to gradually wean the calf. In natural conditions, the cow will increasingly reject the calf’s suckling attempts, but whether cows are motivated to nurse their calf has not yet been investigated. The current PhD therefore aimed to quantify the maternal motivations of dairy cows. Specifically, it aimed to 1) compare the strength of the maternal bond between dairy cows with full-time calf contact, part-time calf contact, and no calf contact; and 2) compare the nursing motivation of dairy cows with a gradual reduction in daily CCC to that of cows not experiencing a reduction in calf contact.
This PhD project is comprised three studies, which were all part of the same large experiment. Eighty-four cow-calf pairs were enrolled and allocated to one of three CCC treatments: full-time contact (23 h contact/d, only separated when cows were milked in the parlour); part-time contact (10 h contact/d, separated between afternoon and morning milking); or no contact (0 h contact/d, separated 48 h postpartum). These treatments were maintained for seven weeks (the main rearing period) and followed by period of reduced contact for two weeks. In the reduced contact period, half of full- and part-time cow-calf pairs experienced a gradual reduction in daily contact (reduced contact, RC). In the first week of the reduced contact period, the daily contact of RC pairs was reduced to approximately 50% of their original contact (9.5 h/d for full-time, 4.5 h/d for part-time). In the second week, contact was reduced even further to approximately 25% of the original amount (4.5 h/d for full-time, 2 h/d for part-time). The remaining cow-calf pairs maintained the same amount of contact as the first seven weeks (unchanged contact). The RC treatment was implemented as a way of gradually reducing nursing/suckling opportunity and was therefore expected to increase the calves’ nutritional independence, preparing them for weaning. In the tenth week of the experiment, all cows and calves were completely separated.
In Study I, the maternal behaviour of full- and part-time cows was observed for 24 h in the third week of the main rearing period, and the suckling behaviour of their calves was observed twice for 24 h during the reduced contact period; once following each reduction in CCC. In Study II and III, the cows’ motivations were assessed; both times using the maximum price paid (MPP) method. Cows were trained to pass through a push gate to reach their calf. The gate became increasingly heavier with every successful passing, and when the cow two days in a row failed to reach her calf, she was recorded as having reached her maximum price. The higher maximum price paid, the stronger the motivation. In Study II, the strength of the cows’ maternal bond was assessed, and in Study III, cows’ motivation to nurse was assessed. The maternal bond strength was measured during the main rearing period, while nursing motivation was measured during the reduced contact period. As there is a risk of animals becoming frustrated during MPP tests, cows always had the option of an easy-available, but less preferred alternative to the valued resource; in the maternal bond test, an unfamiliar calf was available as alternative to the cow’s own calf, and in the nursing motivation test, partial calf contact, where nursing was prevented, was available as an alternative to full contact, where nursing was possible. A secondary aim of the present PhD thesis was to appraise the effect of providing these alternatives in the MPP test.
In Study I, full-time cows spent more time nursing and grooming their calves than part-time cows did; however, no difference could be found regarding amount of nursing taking place in inverse parallel position nor the likelihood of a cow nursing an unrelated calf. These last two behaviours have been suggested as proxies for maternal bond strength. The observations on the calves revealed that reduced contact did not consistently reduce suckling time of neither full- or part-time calves. In Study II, no difference in maternal motivation was found between full- and part-time cows, while no-contact cows were significantly less maternally motivated. In Study III, reduced contact increased cows’ motivation to nurse compared to cows with unchanged calf contact (significantly for full-time, numerically for part-time). The alternative options provided in both motivation tests were used less than expected by random.
These results indicate, that even though part-time cows spent less time nursing their calves than full-time cows did, no difference was found in the strength of the maternal bonds formed. This finding may indicate that part-time contact is a good alternative to full-time contact, as it allows cows to be with their calves, which the motivation tests shows is highly important to them. On the other hand, the repeated nightly separation may be stressful to both cow and calf. The aim of the reduced contact period was to reduce calves’ suckling time and make them less dependent on their dam, which was expected to reduce the cows’ motivation to nurse. However, calves with reduced contact appeared able to compensate and maintain some suckling time. Additionally, cows with reduced calf contact were more motivated to nurse their calf than cows with unchanged contact. The gradual reduction was therefore unsuccessful in inducing weaning, instead cows were even more motivated to nurse their calves. This could be due to the age of the calves; the reduced contact period was initiated when calves were around 60 days old, which is much earlier than the expected natural weaning of 6 to 11 months, and the cows may simply not have had incentive to wean their calves at this point in time. Neither an unfamiliar calf nor partial contact appeared able to substitute own calf or ability to nurse, respectively. Further research on the welfare implications of part-time CCC and how to better induce weaning in CCC systems is therefore needed. Additionally, other methods to reduce potential frustration at testing should be investigated.

Nutritional and Digestive Factors Affecting Health and Performance in Weaned Pigs

Engelsmann, M. C. N. — Thu, 01 Jun 2023 06:52:40 +0200

In pig production, the majority of antibiotics is used to treat gastrointestinal disorders causing diarrhoea during the weaning period. The risk of transmitting antibiotic resistant bacteria from animals to humans has increased the demand for lowering antibiotic use in animals. Together with the ban of medical levels of zinc oxide from June 2022, pig farmers are challenged when it comes to treating diarrhoea and lowering the consumption of antibiotics. The overall objective of this thesis was to increase knowledge on strategies to reduce the consumption of antibiotics used for intestinal disorders during the weaning period.
This PhD comprised three experiments, which aimed to answer four research questions; 1) does weaning pigs’ protein digestibility increase over time after weaning? 2) Does threonine (Thr) supplementation above nutrient recommendation reduce the risk of diarrhoea on a commercial farm? 3) Can supplementation of Thr and/or tryptophan (Trp) above nutrient recommendation benefit parameters of gut health and appetite? 4) Is a high feed intake (FI) during the first 4 days after weaning beneficial for parameters of gut health and does it decrease the risk of diarrhoea?
Protein digestibility increased with time after weaning. During the first two weeks, the protein digestibility was very low compared to the digestibility coefficients used to formulate diets. A low protein digestibility results in increased flow of undigested nitrogen to the lower gastrointestinal tract and may contribute to the high probability of diarrhoea during the first two weeks post-weaning (PW). To answer the next two research questions, one experiment on a commercial farm and one at the experimental facility at AU Foulum were performed. Increasing Thr levels above the nutrient recommendation on a commercial farm did not result in reduced probability of diarrhoea between day 21 to 32 PW or had any positive effect on growth performance. Diarrhoea probability was also not affected by the supplementation of 20% extra Thr and/or Trp above nutrient recommendation from weaning until PW Day 28. Supplementation with Thr and Trp together did, however, stimulate neutral mucin production in the large intestine and pigs were treated less with antibiotics against diarrhoea. Overall, this suggests that supplementation with Thr and/or Trp above nutrient recommendation is not an effective strategy to lower diarrhoea during the weaning period. Contrary to expectation, a high versus a low FI during PW day 0 to 4 was not beneficial for diarrhoea probability or other gut health parameters, besides stimulation of acid mucin production in the small intestine. Pigs with a high FI level were found to have an increased probability of diarrhoea and increased number of days treated with antibiotics.
This PhD work concluded that protein digestibility increases with age, a high FI just after weaning increases the risk of diarrhoea, and supplementation of Thr and/or Trp above nutrient recommendation was not able to reduce the probability of diarrhoea.

Intact seaweeds as functional milk supplements for preweaning dairy calves

Samarasinghe, M. B. — Sun, 01 Jan 2023 06:52:40 +0100

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Dam Rearing of Dairy Calves

Nutritional and Digestive Factors Affecting Health and Performance in Weaned Pigs

Intact seaweeds as functional milk supplements for preweaning dairy calves

Deck height did not affect behavioural measures of ‘natural movements’ and ‘adequate ventilation’ during 8 h and 23 h transport of weaner pigs