Publications - Publikationer

Hestebønner kan erstatte soja og raps

Hansen, N. P., Johansen, M., Larsen, T., Wiking, L., Røjen, B., Weisbjerg, M. R. — Mon, 01 Jan 2018 02:40:05 +0100

Staldfodring med frisk græs

Hansen, N. P., Weisbjerg, M. R., Kristensen, T. — Wed, 01 Jan 2020 02:40:05 +0100

Hestebønner – foder og proteinværdi ved forskellig konservering og behandling

Weisbjerg, M. R., Wang, W., Hansen, N. P., et al. — Tue, 07 Sep 2021 02:40:05 +0200

Methane emission from grazing dairy cattle

Wed, 01 Jan 2025 02:40:05 +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 02:40:05 +0200

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

Mon, 01 Sep 2025 02:40:05 +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 02:40:05 +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 02:40:05 +0200

Forbedret holdbarhed hos økologiske malkekøer

Lærke, H. N. — Fri, 11 Apr 2025 02:40:05 +0200

Økologiske aminosyrer til grise og fjerkræ

Lærke, H. N. — Thu, 02 Jan 2025 02:40:05 +0100

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

Lærke, H. N. — Mon, 31 Mar 2025 02:40:05 +0200

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

Sat, 01 Jan 2022 02:40:05 +0100

Global equine parasite control guidelines

Nielsen, M. K., Pyatt, A., Perrett, J., et al. — Fri, 01 Aug 2025 02:40:05 +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 02:40:05 +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 02:40:05 +0100

Kan hestebønner erstatte raps og soja som proteinkilder til malkekøer?

Hansen, N. P., Weisbjerg, M. R. — Sun, 01 Jan 2017 02:40:05 +0100

Manganese handling in the shore crab Carcinus maenas

Bjerregaard, P., Hastrup, M., Nowack, K., Malmkvist, J. — Fri, 01 Aug 2025 02:40:05 +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 02:40:05 +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 02:40:05 +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 02:40:05 +0100

Fodring af græspulp kan snart blive en realitet

Hansen, N. P., Jensen , S. — Wed, 01 Jan 2020 02:40:05 +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 02:40:05 +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 02:40:05 +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 02:40:05 +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 02:40:05 +0200

Shelter use by horses and beef cattle during the winter

Fogsgaard, K. K., Thodberg, K., Christensen, J. W. — Sun, 01 Jan 2023 02:40:05 +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 02:40:05 +0100

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

Danfær, A. C. — Mon, 01 Jan 1990 02:40:05 +0100

Dam Rearing of Dairy Calves

Jensen, E. H. — Tue, 09 Apr 2024 02:40:05 +0200

I konventionel mælkeproduktion bliver ko og kalv typisk adskilt kort efter kælvning. Denne procedure bliver kritiseret af forbrugere, og både landmænd og forskere undersøger i stigende grad alternativer, hvor ko-kalv kontakten kan blive forlænget. Tidligere forskning har typisk fokuseret på kalvens perspektiv, dog vil dette ph.d.-projekt fokusere på koen. Med forlænget ko-kalv kontakt kommer nogle udfordringer: landmanden får højst sandsynligt et reduceret udbytte af salgbar mælk, og både ko og kalv oplever større stress ved adskillelse, da de har kunnet danne et stærkere bånd. Der er derfor et behov for at holde ko og kalv sammen på en måde, hvor både tab af mælk og separationsstress kan reduceres. To foreslåede løsninger er 1) kun at holde ko og kalv sammen i en del af døgnet, og 2) at gradvist fravænne kalven. Under naturlige forhold vil koen gradvist afvise kalvens patteforsøg, men om koen er motiveret for at give kalven die er endnu ukendt. Formålet med dette ph.d.-projekt er derfor at kvantificere køers maternelle motivationer. Mere specifikt 1) at sammenligne styrken af det maternelle bånd mellem malkekøer med enten fuldtids kalvekontakt, deltids kalvekontakt, eller ingen kalvekontakt, og 2) at sammenligne motivationen til at give die mellem køer hvis daglige kalvekontakt gradvist bliver reduceret og køer uden reduceret kalvekontakt.
Denne ph.d.-afhandling bygger på tre videnskabelige studier, der alle var del af det samme store eksperiment. Fireogfirs ko-kalv par blev rekrutteret til eksperimentet og fordelt på tre ko-kalv kontaktbehandlinger: fuldtidskontakt (23 timers kontakt/dagen, kun adskilt mens koen bliver malket i malkestalden), deltidskontakt (10 timers kontakt/dagen, adskilt mellem eftermiddags- og morgenmalkning) og ingen kontakt (0 timers kontakt/dagen, adskilt 48 timer efter kælvning). Disse behandlinger kørte over syv uger (den generelle opfostringsperiode) og var efterfulgt af en periode på to uger med reduceret kontakt. I perioden med reduceret kontakt blev den daglige kontakt for halvdelen af alle fuldtids- og deltidspar reduceret. I den første uge blev daglig kontakt reduceret til omkring 50% af den oprindelige kontakt (til 9,5 timer/dag for fuldtid og 4,5 timer/dag for deltid). I den næste uge blev daglig kontakt yderligere reduceret til omkring 25% af den oprindelige kontakt (til 4,5 timer/dag for fuldtid og 2 timer/dag for deltid). Den daglige kontakt for de resterende køer forblev uændret fra hvad de havde oplevet de første syv uger. Reduceret kontakt blev implementeret for at reducere den daglige mulighed for at patte eller give die, og det var derfor forventet at kalve med reduceret kontakt blev mere ernæringsmæssigt uafhængige af deres mødre og på den måde bedre forberedt på fravænning. I den tiende uge af eksperimentet blev alle køer og kalve permanent separeret.
I Studie I blev den maternelle adfærd hos fuld- og deltidskøer observeret over 24 timer i den tredje uge af den generelle opfostringsperiode. Derudover blev patteadfærden af deres kalve observeret over 24 timer to gange i perioden med reduceret kontakt, én gang efter hver reduktion in kontakt. Studie II og III undersøgte køernes motivationer. Begge studier brugte metoden maksimalt betalte pris. Køerne blev trænet til at passere en låge for at nå ind til deres kalv. Med hver succesfuld passage blev lågen tungere og tungere, og når koen to dage i træk mislykkedes med at passere lågen blev hun noteret som at have nået sin maksimale pris. Jo højere pris betalt, jo stærkere motivation. I Studie II blev køernes maternelle motivation estimeret, mens Studie III estimerede køernes motivation til at give die. Maternel motivation blev målt under den generelle opfostringsperiode, mens diemotivationen blev målt i perioden med reduceret kontakt. Der er en risiko for at dyr bliver frustrerede under maksimalpristesten, og køerne havde derfor altid muligheden for at passere en lettere låge for adgang til en mindre attraktiv ressource. I testen for maternelt bånd var alternativet en fremmed kalv, mens det for diemotivation var delvis kontakt til kalven, hvor diegivning var forhindret. Et sekundært formål for denne ph.d.-afhandling blev derfor at evaluere effekten af at tilbyde disse alternativer i en testsituation.
Studie I fandt at fuldtidskøer brugte mere tid end deltidskøer på diegivning og soignering af kalven, men der var ingen forskel i andelen af die der fandt sted i invers parallel position eller i sandsynligheden for at give die til en fremmed kalv. De to sidste adfærdsmønstre kan fungere som indikatorer for styrken af det maternelle bånd. Reduceret kontakt reducerede ikke nødvendigvis kalvenes patteadfærd for hverken fuld- eller deltidskalve. Studie II fandt ingen forskel i den maternelle motivation mellem fuld- og deltidskøer, mens køer uden kalvekontakt var signifikant mindre motiverede. Studie III viste at reduceret kontakt øgede køers motivation til at give die (signifikant for fuldtid, numerisk for deltid). Køerne udnyttede de tilgængelige alternativer mindre end hvad var forventet ved tilfældighed i begge motivationstests.
Disse resultater indikerer at selvom deltidskøer brugte mindre tid på diegivning end fuldtidskøer, så blev der ikke fundet forskel på de to behandlinger i styrken af det maternelle bånd. Dette resultat kunne indikere at deltidskontakt er et godt alternativ til fuldtid, da det muliggør ko-kalv kontakt, hvilket motivationstestene viser er vigtigt for køerne. På den anden side er den natlig adskillelse muligvis stressende for både ko og kalv. Formålet med perioden med reduceret kontakt var at reducere kalvenes pattetid og på den måde gøre dem mere uafhængige af deres mødre. Køernes motivation til at give die var forventet at blive reduceret af dette. Dog viste det sig at kalve med reduceret kontakt var, til en vis grad, i stand til at bevare deres pattetid. Derudover var køer med reduceret kontakt mere motiveret til at give die, end køer med uændret kontakt. Det lykkedes derfor ikke at inducere fravænning, tværtimod fremstod køerne med reduceret kontakt som endnu mere motiverede til at give die. Dette kunne skyldes kalvenes alder. Kalve var omkring 60 dage gamle, da perioden med reduceret kontakt begyndte. Dette er meget yngre end den naturligt forventede fravænningsalder, som er mellem 6 og 11 måneder. Sandsynligvis havde køerne derfor intet incitament for at fravænne deres kalve på dette tidspunkt. Yderligere forskning i deltidskontakts effekt på køers velfærd, samt hvordan gradvis fravænning i systemer med ko-kalv kontakt bedst initieres, er derfor nødvendig. Derudover bør alternative metoder til at reducere risikoen for frustration i motivationstests også undersøges.

Nutritional and Digestive Factors Affecting Health and Performance in Weaned Pigs

Engelsmann, M. C. N. — Thu, 01 Jun 2023 02:40:05 +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 02:40:05 +0100

Long-term molecular and functional programming of adipose tissue by pre- and early postnatal malnutrition in a precocial sheep model

Ahmad, S. — Sat, 01 Jan 2022 02:40:05 +0100

Over the past few decades, adipose tissue has become a focus of interest due to it involvements in various pathological diseases such as obesity and other metabolic disarrangements. Known as a tissue with higher degree of plasticity than other organs, it is very sensitive toward environmental cues, especially nutrition. Therefore, this study aimed to investigate long-term effects of pre-and postnatal malnutrition on the expandability and functional traits of four main adipose depots, namely subcutaneous (SUB), mesenteric (MES), perirenal (PER), and epicardial (EPI) adipose tissues at adolescence (6 months of age) and adulthood (2 ½ years old). To unravel the molecular and biological pathways underlying impaired adipose functionality and predisposition for metabolic diseases, we performed the Differential Expressed Gene (DEG) analysis of two of these adipose tissues (SUB and PER) and performed functional enrichment analysis using freely available software and established bioinformatics pipelines. In this study, adolescent lambs and adult sheep were born from dams (twin-pregnant) subjected to either normal (100% of energy and protein requirements; NORM), undernutrition (50% of energy and protein requirements; LOW) or overnutrition (150%/110% of energy/protein requirements; HIGH) in the last 6 weeks pre-partum (term~147 days). From day three post-partum, twin lamb were assigned to either a low-fat hay-based diet (CONV) or a high-carbohydrate-high-fat diet (HCHF) until 6 months of age, where subgroups of animals were then euthanized. The remaining animals were fed the same moderate low-fat diet for 2 years until adulthood, and were then euthanized at 2 ½ years of age. SUB was sampled above the longissimus dorsi muscle at the level of the 13th rib and EPI from the anterior surface of the heart, whereas MES and PER were randomly sampled after separation of the adipose tissue from their respective organs. Assessments of adipose tissue cellularity (i.e. proportion of adipocytes and membrane area) were performed using Visiopharm® software (Visiopharm®, Hoersholm, Denmark), mRNA expression of adipose-related markers (i.e. adipogenic, lipid metabolisms, inflammatory) were characterized by quantitative real-time polymerase chain reaction, and analyses for DEG (SUB and PER) applying deep RNA sequencing and it respective bioinformatic pipelines. By the end of adolescence (6-months old lambs), both prenatal LOW and HIGH predisposed for development of abdominal adiposity and extreme perirenal adipocyte hypertrophy by depressing non-obese cellularity in SUB and MES and by impairing SUB, MES, and PER hyperplasic (healthy) as opposed to hypertrophic (unhealthy) expandability, when challenged with postnatal HCHF diet-induced obesity. In PER, prenatal LOW (but not HIGH) upregulated inflammatory markers. The early postnatal HCHF diet induced hypertrophic expansion of adipose mass, particularly in PER, and in concomitant with upregulated inflammatory markers in all depots studied. In adulthood, depot- and sex specific long-term effects of pre-and postnatal nutrition was found, with sex-specific upper-limits for fat cell numbers and sizes (males

"A well-cared for cow produces more milk"

Overstreet, K. — Tue, 01 Jan 2019 02:40:05 +0100

This dissertation examines intersections of care and production on commercial dairy farms in southern Wisconsin where farmers and their cows must produce ever more milk to keep farms in business. The maxim, “a well-cared for cow produces more milk,” is common sense in the dairy worlds of Wisconsin. It invokes the notion that putting time and money into caring for cows makes financial sense, but it obfuscates how optimizing cows toward milk production goals can instead create suffering. Amidst the moral knotting of this care-production logic expressed in a plethora of technical and scientific interventions into the dairy production system, humans and cows negotiate the everyday work of making milk. This thesis traces these forms of intervention and negotiation.
Farms, I argue, are patches, crosscut by multiple discourses that shape what it means to be a farmer and what it means to be a cow. Productivist discourse, which places pounds of milk at the heart of industry goals, justifies biotechnological interventions that seek to turn cows into machines of optimal milk and calf (re)production. These interventions target particular parts of cow bodies, as mechanistic components, in order to fine-tune them toward high milk production.
This dissertation performs a figurative (dis)assembly of human and bovine lives by unfolding the worlds and discourses that emerge through partitioning and tinkering with bodily parts: rumens, genes, ovaries, udders, and senses of taste. Through this unfolding, the multiple spatiotemporalities of production and the pursuit of efficiency become visible as material ways that cow bodies are optimized. A chapter on rumens demonstrates how cows are figured as cow-athletes that must have specialized diets, geared toward speeding up metabolism and thus the production of milk. A chapter on genes evokes the speculative futures where the imaginary Supercow and its yet unrealized production capacities await. A chapter on ovaries traces the hormonal manipulation of cow bodies toward synchronous reproduction and hides the toll of high-milk production. A chapter on udders takes us into milking time, where infrastructures shape the possibilities of cow-human work, cooperation, intimacy, and exploitation.
Taste, too, is partitioned, as a sensory capacity of the palate. A chapter on taste demonstrates how cows are made into subjects of nutritional discourse through caring practice that brings cow and human senses into recursive and mutual attunement.
By following the partitioning of cows, a key discursive move in the cow-as-machine paradigm, this dissertation follows how biotechnological interventions geared toward maximizing milk (re)production contribute to reimagining life and work on Wisconsin dairy farms in the midst of significant farm restructuring toward larger herds on fewer farms. This (dis)assembly, however violent, requires practices of care in order to hold cow bodies together as efficient producers. In following the discourses and practices that unfold around bodily (dis)assembly it is also possible to excavate the forms of resistance however small and the recuperative possibilities therein.

Risk factors for piglet mortality in Danish organic sow herds

Rangstrup-Christensen, L. — Fri, 03 Nov 2017 02:40:05 +0100

Green forages for dairy cows

Johansen, M. — Sun, 01 Jan 2017 02:40:05 +0100

Protein kinase D1 and inflammatory bowel diseases – A study on protein kinase D1 and its influence on the wound healing process and intestinal inflammation in vitro

Nielsen, D. S. G. — Thu, 12 Oct 2017 02:40:05 +0200

Manipulation of body condition in dairy cows during the periparturient period - influence on production and metabolism

Bjerre-Harpøth, V. — Mon, 18 May 2015 02:40:05 +0200

Effect of dietary interventions based on dairy products on diarrhea development and immune responses in E.coli challenged piglets after weaning

Sugiharto, S. — Mon, 01 Sep 2014 02:40:05 +0200

Exploiting the enzyme potential of cereals in liquid feed for pigs – possibilities and limitations

Christensen, J. B. — Thu, 01 Aug 2013 02:40:05 +0200

Characterizing bovine host responses to mastitis pathogens by targeted proteomics

Bislev, S. L. — Wed, 18 Apr 2012 02:40:05 +0200

Mastitis, som er betændelse i yverkirtlen forårsaget af indtrængende patogener, udgør en betydelig udfordring for dyresundhed- og velfærd i malkekvægsbesætninger. Identifikation af følsomme diagnostiske mastitismarkører vil kunne hjælpe med at stille en tidligere diagnose og gavne effekten af behandling. Patogenspecifikke biomarkører, der kan måles direkte i mælk, er lovende for at diagnosticere mastitis i de tidligste stadier af sygdommen. Dermed kan den korrekte antibiotika behandling påbegyndes, så snart en infektion i yveret opdages. Den massive tilstedeværelse af de dominerende mælkeproteiner såsom kasein er dog med til at komplicere analyserne af følsomme biomarkører i mælk. De seneste år er målrettet kvantitativ proteomics ved hjælp af metoden ’selected reaction monitoring’ (SRM) blevet udbredt. Ved SRM metoden bliver peptider fra et udvalgt protein detekteret og kvantificeret i en kompleks prøve med stor masse nøjagtighed, øget selektivitet og specificitet. Formålet med denne afhandling er at karakterisere koens reaktion mod grampositive og gramnegative bakterier samt at identificere proteom karakteristika, som adskiller koens respons til grampositive og gramnegative bakterier fra hinanden. For at opfylde dette formål blev der udviklet en SRM metode rettet mod proteiner, som formodes at spille en stor rolle i mastitis.

Under udviklingen af SRM metoden blev der først udvalgt 20 biomarkørkandidater, der relaterer til inflammation og mastitis. Derefter skulle der udvælges peptider, som viste gode egenskaber i masse spektrometeret og som unikt stammer fra ét protein. Til dette formål blev der fremstillet en kvæg peptiddatabase (Bovine PeptideAtlas) baseret på data fra tidligere shotgun proteomics eksperimenter af mælk, yverceller og yvervæv udført i vores laboratorium. Manuskript I beskriver dette Bovine PeptideAtlas og dets indbyggede værktøjer til at understøtte SRM metoder. Ved hjælp af Bovine PeptideAtlas blev der udvalgt kvantificerbare og observerbare peptider, der er velegnede til udvikling af SRM metoden. To peptider per protein blev herefter genetisk udtrykt i et QconCAT protein som tungt isotop mærkede peptider. I manuskript II præsenteres udviklingen og valideringen af SRM metoden i yvervæv ved brug af QconCAT peptider rettet mod 20 proteiner. Resultaterne af dette forsøg var en solid bestemmelse af 17 kandidatproteiner og en pålidelig kvantificering af 12 af disse. I manuskript III blev de 17 kandidatproteiner analyseret i mælkeprøver fra køer stimuleret direkte i yveret med peptidoglycan (PGN) fra Staphylococcus aureus og lipopolysaccharid (LPS) fra Escherichia coli. Resultaterne fra dette studie viser, at reguleringen af proteiner er meget større efter stimulering med LPS end med PGN. Desuden blev proteinerne alpha 1-antitrypsin, alpha 2-macroglobulin, haptoglobin, serum amyloid A3, interleukin 8, interleukin-1 receptor antagonist og Vanin-1 foreslået som potentielle biomarkører til at skelne mellem coliform mastitis og grampositiv mastitis.
Det kan konkluderes, at den nyudviklede SRM metode er velegnet til at kvantificere mastitisrelaterede proteiner i komplekse prøver som yvervæv og mælk. Analyserne i mælk fra køer stimuleret med PGN og LPS understøttede evidensen for, at gramnegative bakterier forårsager en meget mere akut reaktion end grampositive bakterier. Yderligere vil SRM metoden være velegnet til at undersøge potentialerne af kandidat biomarkører i et meget større dyremateriale i fremtidige studier og dyremodeller.

Physiological properties of dietary carbohydrates for sows

Serena, A. — Sat, 01 Jan 2005 02:40:05 +0100

Immunogenetical analyses of MHC (class I) related resistance to viral diseases in chickens

Dalgaard, T. — Thu, 01 Jan 2004 02:40:05 +0100

Udvikling af en matematisk model af et system, der producerer kælvekvier

Sørensen, J. T. — Thu, 01 Jan 1987 02:40:05 +0100

Teat canal associated defence mechanisms against mastitis

Paulrud, C. O. — Wed, 01 Jan 2003 02:40:05 +0100

The effect of forage type on passage kinetics and digestibility of fibre in dairy cows

Lund, P. — Tue, 01 Jan 2002 02:40:05 +0100

From in vitro produced embryo to newborn calf - Impact of in vitro culture on perinatal parameters

Jacobsen, H. — Mon, 01 Jan 2001 02:40:05 +0100

Pigs’ physiological need for zinc from weaning to 30 kg

Hansen, S. — Fri, 26 Apr 2024 02:40:05 +0200

Energy and nutrient digestibility and utilization in gestating sows fed fiber-rich co-products

Wisbech, S. J. — Fri, 01 Dec 2023 02:40:05 +0100

Comparing Cow-Calf Contact Systems

Bertelsen, M. — Mon, 01 May 2023 02:40:05 +0200

The separation of the dairy cow and her calf within hours of birth is a common management practice, criticised from an animal welfare perspective. Cow-calf contact systems are an interesting alternative which can be organised in different ways depending on the farmer's prioritisation of practical, economical, ethical and image-related considerations. Half-day contact between the cow and her calf reduces the amount of positive social interaction compared to whole-day contact, without substantially improving the weaning and separation. Using a fence-line weaning approach does however improve the weaning and separation of dam-reared calves.

Protein supply and methane emission in dairy cows

Wang, W. — Sun, 01 Jan 2023 02:40:05 +0100

Among the aims in ruminant nutrition research, improving N efficiency and reducing methane emission are two of the most important ones at present, especially under the situation of global climate changing increasingly. This thesis aims to improve N efficiency and mitigate methane emission in dairy cows at the same time, and to investigate the relationship between N supply, nitrate supplementation, genetic yield index on methane emission, and to investigate the effect of nitrate supplementation on methane and nitrous oxide emission by conducting three studies below.
In paper Ⅰ, two different processing methods (grinded vs. rolled; untoasted vs. toasted) were applied on fava beans to improve the metabolizable protein and energy supply, and two forage sources (75:25 or 25:75 ratio between grass-clover silage and maize silage) were examined combined with the fava beans processed by three different methods for the effect on rumen fermentation, methane emission and digestion. Six Danish Holstein dairy cows fitted with ruminal, duodenal, and ileal cannulas were used in a 6 × 4 incomplete Latin square design with 4 periods of 21 d duration. Cows were fed ad libitum with 6 experimental diets: diets high in either grass-clover silage or corn silage were combined with ground untoasted, ground toasted, or rolled untoasted fava beans. Cr2O3 and TiO2 were used as flow markers for calculating nutrient digestibilities, gas exchange were measured by respiration chamber in the last 4 d of each period. In paper Ⅱ, three maize feeds (maize meal, maize gluten, and maize gluten feed) were used to formulate diets with three dietary protein levels (147, 153, and 158 CP g/kg DM), nitrate and urea supplementation were applied to examine effects of dietary protein level and nitrate supplementation on N metabolism and methane emission and their interactions. Forty-eight intact Danish Holstein dairy cows were used in a 6 × 4 incomplete Latin square design with 4 periods of 21 d duration. Six diets were formulated in a 2 × 3 factorial arrangement with 3 different dietary protein levels (low (Low), medium (Med), high (High)) combined with either urea (Urea) or nitrate (Nitrate) addition. TiO2 was used as flow markers for measuring nutrient digestibilities and gas exchange was measured by four GreenFeed units in the last 7 d of each period. In paper Ⅲ, urea and nitrate supplementation were applied to four Danish Holstein dairy cows fitted with ruminal cannula to investigate the effect of nitrate supplementation on ruminal methane and nitrous oxide emission. Cows were used in a 2 × 2 crossover design with 2 periods of 14 d duration. Gas exchange was measured by respiration chamber from d 11 to d 14 of each period and rumen headspace gas samples were collected at d 12 and d 14 in each period for analyzing ruminal headspace methane and nitrous oxide concentrations.
It was concluded in paper Ⅰ that neither forage source, nor rolling and toasting of fava beans affected on MP supply. Compared with grinding, rolling of fava beans reduced ruminal fermentation and apparent ruminal and total-tract digestibility of nutrients, except for NDF, where digestibility was increased. Rolling of fava beans also reduced the microbial protein synthesis compared with ground untoasted fava beans. Toasting of fava beans had no effect on digestibility, except for an interaction with forage source on DM and OM apparent ruminal digestibility. Results from paper Ⅱ shows that there is no interaction between dietary protein level, nitrate supplementation, and genetic yield index on methane emission. Increased dietary protein level by reducing the proportion of corn meal and corn gluten, and increasing the proportion of corn gluten feed in the diet resulted in a decreased milk yield but CH4 production was unaffected. The reduction in DMI, CH4 production, and yield of milk protein and lactose, and the increase in H2 production caused by nitrate supplementation were greater in multiparous cows than in primiparous cows. DMI and ECM were positively correlated to genetic yield index, while CH4 production, CH4 yield, and CH4 intensity were unaffected by genetic yield index. In paper Ⅲ, the results shows that with a dose of 10 g NO-¦3 per kg of DM addition, nitrate supplementation reduced CH4 production and yield and tended to reduce CH4 intensity, and increased H2 production and yield compared with urea supplementation. Nitrate supplementation also reduced N2O headspace volume proportion in the rumen and N2O production compared with urea supplementation.
This thesis shows that forage source and processing methods on fava beans applied in this project had no effect on MP supply. Dietary protein level had no effect on the methane emission and methane mitigation effect of nitrate supplementation, nitrate supplementation results in a greater increase in H2 multiparous cows than in primiparous cows, and nitrate supplementation reduced methane emission but increased N2O production.