Koens fysiologiske status og indflydelse heraf på produktion og sundhed omkring kælvning afhængig af foderniveau og næringsstofforsyning

Selvforsyning er ikke et regelkrav, men i tråd med det økologiske nærhedsprincip, dvs. at arbejde mest muligt i lukkede næringsstofkredsløb og dermed en fodring baseret på udelukkende hjemmeavlede fodermidler dyrket inden for bedriftens eget arealgrundlag. Det nuværende regelsæt har en minimumsgrænse for grovfodertildeling: 60% af tørstof i den daglige ration, dog 50% af tørstof til køer mindre end 3 måneder fra kælvning. I forbindelse med regelsættet er der imidlertid en række spørgsmål vedrørende dyrenes sundhed og produktion. På den baggrund er der gennemført forsøg med det formål at belyse produktion og metabolske parametre for tre typer 100% økologiske rationer baseret på korn, rapsfrø og kløvergræs dyrket på et givent areal pr. ko

Coccidiose hos kvæg: En oversigt over coccidiearter, patogenese, epidemiologi og forebyggelse specielt i økologiske besætninger

Coccidiose hos kalve forårsages af arter af de encellede parasitter, Eimeria, der findes vidt udbredt i alle verdensdele, og som giver anledning til diarré og utrivelighed hos især unge og modtagelige dyr. Hos kvæg findes 12 forskellige Eimeria arter, der adskiller sig fra hinanden med hensyn til morfologi, livscyklus og patogenitet. Infektion med Eimeria kan diagnosticeres ved forskellige la-boratoriemetoder, hvorved bl.a. antallet og arten af coccidier forsøges fastslået. Således skabes grundlag for bestemmelse af hvilke forebyggende tiltag, der eventuelt bør iværksættes. Ved under-søgelse af 258 kalve fra 25 danske økologiske malkekvægsbesætninger fandt vi Eimeria-arter i alle (100%) besætninger og i 88% af kalvene. De fleste kalve udskilte meget lavgradige mængder af coccidier i gødningen, medens nogle havde særdeles høje coccidieudskillelser. Coccidiose er en multifaktoriel sygdom, og sværhedsgraderne af sygdommen varierer derfor fra subkliniske tilfælde til nogle med løs, pastøs fæces af en enkelt dags varighed eller profus diarré med dysenteri, tenesmus og evt. mors. De kliniske symptomer tillægges traditionelt tilstedeværelsen af coccidiearterne Eimeria zuernii og E. bovis. Kalvens modtagelighed for coccidiose afhænger bl.a. af råmælksforsyning og immunitet, ernæringsstatus, stress, og evt. forekomst af andre sygdomme (f.eks. samtidige helminth- eller virusinfektioner). Endelig har også miljøet betydning for udvikling af coccidiose, herunder opstaldningstæthed, klima og hygiejne. Total udryddelse af coccidier er ikke muligt pga. parasittens ubikvitære forekomst og resistens i miljøet, men kalven kan styrkes ved sikring af tilstrækkelige råmælksmængder og ved opretholdelse af høj hygiejne i kælvningsboksen, samt efterfølgende opstaldningsforhold. Aktiv immunisering (vaccination) har endnu ikke vist sig effektiv i større målestok. Der foreligger ikke yderligere retningslinier for forebyggelse i perspektiv af de økologiske regler. Kalve, der har klinisk coccidiose, bør isoleres fra de øvrige kalve og gives væsketerapi for at opretholde væskebalancen. Den bedste behandling er imidlertid forebyggelse - med fokus på belægningsgrad og høj hygiejne inklusive rigeligt med tør strøelse

Gene expression profiling of liver from dairy cows treated intra-mammary with lipopolysaccharide

<p>Abstract</p> <p>Background</p> <p>Liver plays a profound role in the acute phase response (APR) observed in the early phase of acute bovine mastitis caused by <it>Escherichia coli </it>(<it>E. coli</it>). To gain an insight into the genes and pathways involved in hepatic APR of dairy cows we performed a global gene expression analysis of liver tissue sampled at different time points before and after intra-mammary (IM) exposure to <it>E. coli </it>lipopolysaccharide (LPS) treatment.</p> <p>Results</p> <p>Approximately 20% target transcripts were differentially expressed and eight co-expression clusters were identified. Each cluster had a unique time-dependent expression profile and consisted of genes involved in different biological processes. Our findings suggest that APR in the liver is triggered by the activation of signaling pathways that are involved with common and hepatic-specific transcription factors and pro-inflammatory cytokines. These mediators in turn stimulated or repressed the expression of genes encoding acute phase proteins (APP), collectins, complement components, chemokines, cell adhesion molecules and key metabolic enzymes during the APR. Hormones, anti-inflammatory and other hypothalamus-pituitary-adrenal axis (HPAA) linked mediators also seemed to participate in APR.</p> <p>Conclusion</p> <p>Performing global gene expression analysis on liver tissue from IM LPS treated cows verified that the liver plays a major role in the APR of <it>E. coli </it>mastitis, and that the bovine hepatic APR follows the same pattern as other mammals when they are challenged with LPS. Our work presents the first insight into the dynamic changes in gene expression in the liver that influences the induction, kinetics and clinical outcome of the APR in dairy cows.</p

ENERGY LEVEL AND STRATEGY OF FEEDING FOR DAIRY COWS IN THE DRY PERIOD

Djelovanje strategije hranidbe u suhostaju na proizvodnju i zdravlje istaživalo se u dva pokusa što su obuhvatila 80 i 96 mliječnih krava. U pokusu br. 1 ispitivalo se djelovanje razine energije (normalna i visoka (1.5 x N) i djelovanje dnevnog sagorjevanja kratkolančanih masnih kiselina (KLMK) u preživača (+ i -) u zadnja četiri tjedna suhostaja. U pokusu br. 2 uključeno je samo sagorjevanje KLMK. Šesnaest je krava zaklano radi ruminalnog pregleda. Sagorjevanje KLMK je inducirano davanjem 4.5 kg ječma u jutro i kabaste hrane (roughage) na večer. Nakon telenja koncentracija je postepeno povećavana do razine od 9 kg ST a sliaža trave bila ad lib. u obje skupine. Sagorjevanje KLMK povećalo je uzimanje silaže trave u prvih pet tjedana post parfum u pokusu br. 1, ali ne u pokusu br. 2. U pokusu br. 1 postojalo je međusobno djelovanje između razine hranjena i sagorjevanja KLMK na proizvodnju mlijeka, dok u pokusu br. 2 nije primijenjena nikakva razlika. U krava s pojačanim sagorjevanjem KLMK došlo je do rjeđe pojave ketoze i probavnih smetnji u prvom pokusu ali ne u drugom, te je postojala tendencija povećanja aktivnosti u mukozi rumena, no bez makroskopskih razlika. Zaključeno je da se sagorjevanjem KLMK ne postiže nikakvo ili samo neznatno pozitivno djelovanje u suhostaju na uzimanje hrane, proizvodnju, zdravlje i reprodukciju.The effect of feeding strategy in the dry period on performance and health was investigated in two experiments comprising 80 and 96 dairy cows. In exp. 1 the effect of energy level (Normal and High (1.5 x N) and the effect of a daily ruminal SCFA-burst (+ and -) in the last 4 weeks of the dry period were examined. In exp. 2. only SCFA-burst was included. Sixteen cows were slaughtered for ruminal examination. SCFA-burst was induced by allocating 4.5 kg barley in the morning and roughage in the evening. After calving concentrate was gradually increased to a level of 9 kg DM and grass silage was ad. lib in all groups. The SCFA-burst increased grass silage intake in the first 5 weeks post partum in exp. 1 but not in exp. 2. In exp. I there was an interaction between feeding level and SCFA-burst on milk production, while no difference between treatments were seen in exp. 2. The SCFA bursted cows had a lover incidence of ketose and digestive disorders in the first experiment but not in the second, and there was a tendency to increased activity in the ruminal mucosa but without any macroscopical differences. It is concluded that none or only small benefits are obtained from SCFA- bursts in the dry period on feed intake, performance, health, and reproduction

Sundhed og velfærd i kalveholdet

Gennem de seneste år har vi arbejdet med en forståelse af dyrevelfærd i økologiske besætninger, hvor begrebet “naturlighed” har fået stor betydning. I en malkekvægbesætning er det ikke muligt at tilbyde køerne 100% naturlige forhold, men man kan tilstræbe at dyrene får mulighed for at udføre deres naturlige adfærd, har en stor grad af valgfrihed, har frisk luft, dagslys og adgang til udearealer. Det stiller imidlertid større krav til de mennesker, som arbejder med dyrene, bl.a. i forhold til øget opsyn samt til bedre at kunne vurdere, hvordan dyrene har det. I projektet er der bl.a. blevet udviklet en model til vurdering af velfærd hos kalve. Den første version er blevet implementeret i rådgivning af økologiske besætninger. Den forventes endvidere afprøvet i Norge, Storbritannien og Holland

Changes in various metabolic parameters in blood and milk during experimental Escherichia coli mastitis for primiparous Holstein dairy cows during early lactation

The objective of this study was to characterize the changes in various metabolic parameters in blood and milk during IMI challenge with Escherichia coli (E. coli) for dairy cows during early lactation. Thirty, healthy primiparous Holstein cows were infused (h = 0) with ~20-40 cfu of live E. coli into one front mammary quarter at ~4-6 wk in lactation. Daily feed intake and milk yield were recorded. At –12, 0, 3, 6, 12, 18, 24, 36, 48, 60, 72, 96, 108, 120, 132, 144, 156, 168, 180 and 192 h relative to challenge rectal temperatures were recorded and quarter foremilk was collected for analysis of shedding of E. coli. Composite milk samples were collected at -180, -132, -84, -36, -12, 12, 24, 36, 48, 60, 72, 84, 96, 132 and 180 h relative to challenge (h = 0) and analyzed for lactate dehydrogenase (LDH), somatic cell count, fat, protein, lactose, citrate, beta-hydroxybutyrate (BHBA), free glucose (fglu), and glucose-6-phosphate (G6P). Blood was collected at -12, 0, 3, 6, 12, 18, 24, 36, 60, 72, 84, 132 and 180 h relative to challenge and analyzed for plasma non-esterified fatty acids (NEFA), BHBA and glucose concentration. A generalized linear mixed model was used to determine the effect of IMI challenge on metabolic responses of cows during early lactation. By 12 h, E. coli was recovered from challenged quarters and shedding continued through 72 h. Rectal temperature peaked by 12 h post-challenge and returned to pre-challenge values by 36 h post-IMI challenge. Daily feed intake and milk yield decreased (P <0.05) by 1 and 2 d, respectively, after mastitis challenge. Plasma BHBA decreased (12 h; P <0.05) from 0.96 ± 1.1 at 0 h to 0.57 ± 0.64 mmol/L by 18 h whereas concentration of plasma NEFA (18 h) and glucose (24 h) were significantly greater, 11 and 27%, respectively, after challenge. In milk, fglu, lactose, citrate, fat and protein yield were lower whereas yield of BHBA and G6P were higher after challenge when compared to pre-challenge values. Changes in metabolites in blood and milk were most likely associated with drops in feed intake and milk yield. However, the early rise in plasma NEFA may also signify enhanced adipose tissue lipolysis. Lower concentrations of plasma BHBA may be attributed to an increase transfer into milk after IMI. Decreases in both milk lactose yield and % after challenge may be partly attributed to reduced conversion of fglu to lactose. Rises in G6P yield and concentration in milk after challenge (24 h) may signify increased conversion of fglu to G6P. Results identify changes in various metabolic parameters in blood and milk after IMI challenge with E. coli in dairy cows that may partly explain the partitioning of nutrients and changes in milk components after IMI for cows during early lactation.https://doi.org/10.1186/2049-1891-5-4

Genome-wide association for metabolic clusters in early-lactation Holstein dairy cows

The aim of this study was to detect the genomic region or regions associated with metabolic clusters in early-lactation Holstein cows. This study was carried out in 2 experiments. In experiment I, which was carried out on 105 multiparous Holstein cows, animals were classified through k-means clustering on log-transformed and standardized concentrations of blood glucose, insulin-like growth factor I, free fatty acids, and β-hydroxybutyrate at 14 and 35 d in milk (DIM), into metabolic clusters, either balanced (BAL) or other (OTR). Forty percent of the animals were categorized in the BAL group, and the remainder were categorized as OTR. The cows were genotyped for a total of 777,962 SNP. A genome-wide association study was performed, using a case-control approach through the GEMMA software, accounting for population structure. We found 8 SNP (BTA11, BTA23, and BTAX) associated with the predicted metabolic clusters. In experiment II, carried out on 4,267 second-parity Holstein cows, milk samples collected starting from the first week until 50 DIM were used to determine Fourier-transform mid-infrared (FT-MIR) spectra and subsequently to classify the animals into the same metabolic clusters (BAL vs. OTR). Twenty-eight percent of the animals were categorized in the BAL group, and the remainder were classified in the OTR category. Although daily milk yield was lower in BAL cows, we found no difference in daily fat- and protein-corrected milk yield in cows from the BAL metabolic cluster compared with those in the OTR metabolic cluster. In the next step, a single-step genomic BLUP was used to identify the genomic region(s) associated with the predicted metabolic clusters. The results revealed that prediction of metabolic clusters is a highly polygenic trait regulated by many small-sized effects. The region of 36,258 to 36,295 kb on BTA27 was the highly associated region for the predicted metabolic clusters, with the closest genes to this region (ANK1 and miR-486) being related to hematopoiesis, erythropoiesis, and mammary gland development. The heritability for metabolic clustering was 0.17 (SD 0.03), indicating that the use of FT-MIR spectra in milk to predict metabolic clusters in early-lactation across a large number of cows has satisfactory potential to be included in genetic selection programs for modern dairy cows