Seedetrakti algloomnakkuste mõju mäletsejaliste ägeda järgu vastusele neonataalperioodil

A thesis for applying for the degree of Doctor of Philosophy in Veterinary SciencesAfter birth, neonatal ruminants go through crucial and sensitive period of rapid development and growth. During this period, they may interact with variety of microorganisms found in the surrounding environment. It would be beneficial for both the farmer and the veterinarian to have general biomarkers, useful in managing of this adaptation process. Such a tool could help in improving the prediction of the animals’ performance in the herd. The interactions between the ruminant and infectious agents can damage tissues in the host and trigger the innate immune response starting with the acute phase response (APR). This process can lead to an increase or decrease of specific acute phase proteins (APPs) in the blood serum. Fluctuations in concentrations of APPs may serve as proxies for assessing the inflammatory processes during the adaptation period of newborn animal. Particularly when the animal is transitioning from a low microbe environment in the uterus to the high microbe environment of the extrauterine life. In addition, there is growing evidence, that strong APR in the first weeks of life could influence the success as a production animal, such as the growth rate. The studies presented in the dissertation were longitudinal studies and each study focused on different ruminant species: reindeer calves, dairy calves and lambs. In each study, the focus was on the neonatal period (first three weeks of age), during which blood and faecal samples were collected and the growth rate was measured. In the study of lambs, a significant association with APPs was found at second week of life and the growth rate. Similar result was seen dairy calves that had an APR during the neonatal period, which had a negative association with the growth rate in older age. Additionally, Cryptosporidium infections was associated as a positive effect with APR in dairy calves. In reindeer calves, the APR was had a positive association with Giardia infections. In conclusion, current results offers promise of developing more precise indicators for measuring the outcome of the adaptation process of the immune system during the neonatal period.Pärast poegimist läbivad vastsündinud mäletsejalised väga tähtsa ja tundliku ajajärgu. Sellel ajal puutuvad nad kokku ümbritsevas keskkonnas leiduvate erinevate mikroorganismidega. Nii loomaarstile kui ka loomakasvatajale on kasulik, kui neil oleksid hindamise skaala ja/või astmik, mille põhjal saaks kohanemisprotsessi edukust täpsemalt mõõta ja hinnata. Haigustekitajad, näiteks parasiidid, võivad ägeda nakkuse ajal kahjustada peremeesorganismi kudesid, mis omakorda kutsub esile kaasasündinud immuunsüsteemi reaktsiooni, mille ühe osana võib käivituda ägeda järgu vastus (acute phase response, APR). Selle tulemusena suureneb või väheneb teatud valkude kogus vereseerumis – neid nimetatakse ägeda järgu valkudeks (acute phase proteins, APP). Nende valkude koguse muutust seerumis saab kasutada haigustekitaja poolt vallandatud põletikureaktsiooni tugevuse mõõtmiseks. Samuti on leitud, et esimestel elunädalatel toimunud APP-de kontsentratsiooni suuremal muutusel on märkimisväärne seos hilisema massi-iibega. Doktoritöö hõlmab kolme vaatlusuuringut erinevatel mäletsejaliste liikidel: põhjapõdravasikad, piimaveisevasikad ja lambatalled. Igas uuringus oli vaatluse all neonataalne periood (sünd kuni kolm nädalat), mille jooksul koguti ja analüüsiti loomadelt vere¬- ja roojaproove ning mõõdeti nende massi-iivet. Uuringute tulemusena leiti oluline seos just teisel elunädalal toimunud APP-de muutuste ja hilisema massi-iibe vahel lambatallede puhul, ka piimaveisevasikate APR-i tugevus oli seotud sama näitajaga. Samuti leiti märkimisväärne seos ainurakse parasiidi krüptosporiidi ja APR-i vahel piimaveisevasikatel. Põhjapõdravasikate puhul täheldati positiivset seost APR-i ja Giardia-nakkuse vahel. Kokkuvõttes – antud töö tulemused on lootustandvad täpsemate hindamise skaalade leidmiseks, et hinnata immuunsüsteemi kohanemisprotsessi edukust mäletsejaliste neonataalperioodil.The publication of this dissertation is granted by the Graduate School in Biomedicine and Biotechnology and by the Estonian University of Life Sciences

Multiblock analysis reveals key areas and risk factors for dairy cow losses

Describe the relative contribution of the production areas (thematic blocks) to cow losses characterized by herd on farm mortality risk (MR), culling rates (CR) and mean age of culled cows (MAofCC). Also, the study aimed to identify within each block, the variables mostly contributing to the cow losses.This work was financed by the Estonian Research Council grant (PSG 268).This work was financed by the Estonian Research Council grant (PSG 268

Faecal microbiota in two-week-old female dairy calves during acute cryptosporidiosis outbreak-Association with systemic inflammatory response

In the present study, relationships between the intestinal microbiota and innate immunity response, acute cryptosporidiosis, and weight gain in female dairy calves were investigated. A total of 112 calves born during a natural outbreak of cryptosporidiosis on one dairy farm was included in the study. Microbiota composition was analysed by means of 16S ribosomal RNA gene amplicon sequencing from faecal samples collected during the second week of life, while the status of Cryptosporidium spp. infection was determined using immunofluorescence. Serum samples from the second week of life were colourimetrically analysed for the following markers of acute inflammation: acute-phase proteins (serum amyloid A and haptoglobin) and pro-inflammatory cytokines (interleukin-1 beta, interleukin-6, and tumour necrosis factor-alpha). Statistical analyses were performed using random forest analysis, variance-partitioning, and negative binomial regression. The faecal microbiota of the two-week old calves was composed of the phyla Firmicutes, Bacteroidetes, Proteobacteria, Fusobacteria, and Actinobacteria (in order of decreasing abundance). Microbial diversity, measured in terms of the Shannon index, increased with the age of the calves and decreased if a high count of Cryptosporidium spp. oocysts was found in the faeces. Fusobacterium was positively associated with Cryptosporidium spp. oocyst count and serum amyloid A concentration. Peptostreptococcus was positively associated with haptoglobin and serum amyloid A concentrations, and negatively associated with average daily weight gain at 9 months of age. The markers of innate immunity, in combination with age, explained 6% of the microbial variation. These results suggest that some components of the intestinal microbiota may have a long-lasting negative effect on animal growth through the stimulation of the systemic innate immune response.Peer reviewe

Scanning European Needs and Expectations Related to Livestock Biosecurity Training by Using the World Café Method

The European Union Animal Health Law (2016/429) emphasizes disease prevention, underpinned by livestock biosecurity, surveillance, and traceability, as key aspects to minimize the risk of animal diseases. An important element of biosecurity is the training of key actors involved in implementing it. However, their needs and expectations regarding this training are poorly known. Under the COST action BETTER (CA20103), a World Café was organized to identify the needs and expectations of biosecurity training for farmers, veterinary practitioners, veterinary students, and other actors. A total of 78 participants distributed in four groups participated in the World Café. Needs and expectations were identified and ranked in decreasing order of importance. For farmers, the most important aspects were training focusing on practical aspects, the planning of training sessions in the day to accommodate workload, the need to prepare multiple reminders of upcoming training, and the short duration of events. For veterinary practitioners, it was considered that a mixed approach, including a theoretical and a practical part where people are invited to create a biosecurity plan and a follow-up report, were the most important features of training. For veterinary students, creating a good knowledge of the main principles of biosecurity was found as an essential element of training. Regarding other actors, gaining an understanding in the spread of pathogens and the repercussions on the cost of animal products that diseases might have (consumers), training on good/best practices of cleaning and disinfection and the development of clear protocols (transporters), and a mixture of formal and informal training and training on communication skills (other actors) were considered important. The World Café was a useful method to have a first identification, discussion, and differentiation on livestock biosecurity training needs and expectations of the key actors, although additional follow-up research involving more participants from more diverse countries with different coverage of cultures and education would be beneficial. These needs and expectations are relevant and should be considered when designing new training courses

Giardia and Cryptosporidium infections in neonatal reindeer calves : Relation to the acute phase response

This longitudinal observational study was conducted to investigate the spontaneous effect of Giardia and Cryptosporidium infections on acute phase response (APR) in reindeer calves (Rangifer tarandus tarandus) in Finnish Lapland. Serum (n = 609) and faecal samples (n = 366) were collected from 54 reindeer calves aged zero to 33 days. The samples were analysed for Giardia, Cryptosporidium, acute phase proteins (APP) and gamma-globulins. Linear regression models were used to investigate associations of early Giardia infection (before 12 days of life) with the response of APPs and acquiring of passive immunity. Giardia was detected in 100% and Cryptosporidium in 23% of calves. There was a negative association between early Giardia infection and gamma-globulin concentrations (p = 0.032) and a positive association with serum amyloid A (SAA) concentrations (p = 0.042). The results suggest a protective effect of colostrum against Giardia infection and that early infection may induce activation of APR.Peer reviewe

Biosecurity Levels and Farm Characteristics of African Swine Fever Outbreak and Unaffected Farms in Estonia—What Can Be Learned from Them?

Risk factors related to external biosecurity have been considered to play a major role in the introduction and spread of African swine fever (ASF) in domestic pig populations. The aim of the study was to describe the biosecurity levels and management practices of ASF outbreak and uninfected herds and to identify potential risk factors for ASF introduction. Data collected from the outbreak herds during outbreak investigations and from the randomly selected uninfected herds were analyzed. The biosecurity score in ASF outbreak herds was significantly lower compared to uninfected herds. However, this may reflect general improvement in the application of biosecurity measures in pig farms over time as the data on uninfected herds were collected later, at a time when intensified official controls may have had their effect. Larger herds were more at risk of being outbreak herds compared to smaller herds. The biosecurity parameters significantly associated with the outbreak herd status in multiple correspondence analysis were mostly related to indirect contacts with the outside farm environment. The biosecurity barriers applied in Estonian pig farms have not been sufficient to avoid ASF introduction and need critical evaluation and improvement. Reduction of all contacts between the farm and the external environment should be emphasized in a situation where ASF is circulating in wild boar populations close to pig farms

Associations of neonatal acute phase response with first lactation performance in dairy cows

ABSTRACT: During the first 3 wk of life, the immune system of newborn ruminants starts to work, as indicated by fluctuations in the concentrations of proinflammatory cytokines and acute phase proteins (APP). They have been shown to be markers for short and long-term weight gain in ruminants. This observational study investigated these proteins as possible indicators of first lactation performance of dairy cows. A total of 117 dairy calves from a single farm were enrolled in the study. Serum and fecal samples were taken once a week for the first 3 wk of life. Cryptosporidium spp. infection and its treatment were monitored and accounted for in statistical analysis. The concentrations of the APP serum amyloid A (SAA) and haptoglobin (Hp), and the proinflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) were analyzed in serum. After the first lactation, health and performance data of the cows were retrieved, and associations between APP and cytokine concentrations with first lactation outcomes were investigated through linear and logistic regression. This study found a negative association between the concentration of Hp in the second week of life and average daily weight gain at one year. The SAA concentration measured during the second and third weeks of life was positively associated with age at first calving. IL-6, SAA, and Hp measured in the second week of life were positively associated with calving to conception interval. The concentrations of IL-6 and TNF-α during the first week of life were associated with higher odds of reproductive issues during the first lactation period. These markers can be used to help understand underlying processes that influence animal health and production. In conclusion, inflammatory responses during the first week of life are related to reproductive success, whereas the second and third weeks of life seem to influence the future productive performance in dairy cows

Investigation of Salmonella, hepatitis E virus (HEV) and viral indicators of fecal contamination in four Italian pig slaughterhouses, 2021–2022

In the pork production chain, the control at slaughterhouse aims to ensure safe food thanks to proper hygienic conditions during all steps of the slaughtering. Salmonella is one of the main foodborne pathogens in the EU causing a great number of human cases, and pigs also contribute to its spreading. Pig is the main reservoir of the zoonotic hepatitis E virus (HEV) that can be present in liver, bile, feces and even rarely in blood and muscle. The aim of this study was to assess the presence of both Salmonella and HEV in several points of the slaughtering chain, including pig trucks. Other viruses hosted in the gut flora of pigs and shed in feces were also assayed (porcine adenovirus PAdV, rotavirus, norovirus, and mammalian orthoreovirus MRV). Torque teno sus virus (TTSuV) present in both feces, liver and blood was also considered. Four Italian pig abattoirs were sampled in 12 critical points, 5 of which were the outer surface of carcasses before processing. HEV and rotavirus (RVA) were not detected. Norovirus was detected once. Salmonella was detected in two of the 4 abattoirs: in the two lairage pens, in the site of evisceration and on one carcass, indicating the presence of Salmonella if carcass is improper handled. The sampling sites positive for Salmonella were also positive for PAdV. MRV was detected in 10 swabs, from only two abattoirs, mainly in outer surface of carcasses. TTSuV was also detected in all abattoirs. Our study has revealed a diverse group of viruses, each serving as indicator of either fecal (NoV, RVA, PAdV, MRV) or blood contamination (TTSuV). TTSuV could be relevant as blood contamination indicators, crucial for viruses with a viremic stage, such as HEV. The simultaneous presence of PAdV with Salmonella is relevant, suggesting PAdV as a promising indicator for fecal contamination for both bacterial and viruses. In conclusion, even in the absence of HEV, the widespread presence of Salmonella at various points in the chain, underscores the need for vigilant monitoring and mitigation strategies which could be achieved by testing not only bacteria indicators as expected by current regulation, but also some viruses (PAdV, TTSuV, MRV) which could represent other sources of fecal contamination