Breeding soundness evaluation of young beef bulls

The overall aims were to learn more about factors affecting fertility in Swedish beef sires in general and in yearling beef bulls in particular, focusing mainly on sexual maturity and hind limb health finding useful tools in order to be able to routinely perform a complete bull breeding soundness evaluations in Swedish beef bulls. Semen was collected from yearling beef bulls, postmortem, and the sperm morphology was evaluated. Using a strict definition, based on sperm morphology, we could demonstrate that less than half the number of the bulls was considered sexually mature at 12 months of age. Samples collected by transrectal massage were compared with the two most commonly used collection methods; artificial vagina and electroejaculation, and with samples collected by cauda epididymal dissection postmortem. Sperm morphology in semen collected by transrectal massage was as representative as in samples collected by artificial vagina and electroejaculation and to some extent also in those collected postmortem. However, reduction in volume, concentration and motility would need to be considered, especially if semen is collected outdoors under suboptimal conditions. In conclusion, the transrectal massage technique is a very useful semen collection method in the field when no other collection method is possible, thus enabling a complete bull breeding soundness evaluation. Femorotibial, femoropatellar (stifle), tarsocrural, talocalcaneus, and proximal intertarsal joints from young beef sires with impaired fertility, but no signs of lameness, were examined postmortem regarding the presence of joint lesions. A majority of the bulls had severe, bilateral lesions referred to as osteoarthritis secondary to osteochondrosis dissecans. We think that the osteoarthritis present in the hind limbs must have contributed to the infertility, rendering the bulls difficulties in mounting. The fact that most of the lesions were bilateral, could explain the absence of clinical lameness. The results of this study indicate that the poor fertility reported in these beef bulls can be a result of joint problems, secondary to osteochondrosis. Thus, joint lesions should always be taken into consideration as a contributory cause of reproductive failure in beef sires with or without symptoms of lameness

Refining fuel loads in LPJ-GUESS-SPITFIRE for wet-dry areas : with an emphasis on Kruger National Park in South Africa

Eld är en av de viktigaste störningsprocesserna som påverkar den terrestra biosfären genom att forma vegetationens spridning, komposition, struktur, växtdiversitet och biokemiska cykler. Några av de mest påverkade ekosystemen är våt-torra områden, här klassificerade som savann eller Medelhavsområden. Denna påverkan kan studeras på olika sätt, antingen genom ett långvarigt och fortlöpande experiment, som i Kruger National Park i Sydafrika, eller genom att använda sig av modeller, som till exempel LPJ-GUESS-SPITFIRE. SPITFIRE är en processbaserad eldmodell som har kopplats samman med en dynamisk vegetationsmodell för att förutspå eldens spridning, intensitet och hur länge det kan brinna. I LPJ-GUESS-SPITFIRE används en faktor som kallas omsättningshastigheten, vilket är ett halvtidsvärde för nedbrytning av biologiskt avfall vid en viss temperatur och fuktighet. Den används för att räkna ut hur mycket tillgängligt växtmaterial som finns i det modellerade området för att kunna bestämma eldintensiteten. Denna konstant är satt till 2.85 och är densamma i alla världens ekosystem. I verkligheten beror nedbrytningen på vilka de aktiva förhållandena är och det är därför orealistiskt att använda samma konstant. Data från experimentet i Kruger National Park användes för att förbättra parametrarna i DGVM LPJ_GUESS_SPITFIRE för att hitta mer representativa nedbrytningsvärden i våt-torra områden. Avfallet delades in i två pooler som är det huvudsakliga bränslet för markbränder; avfall i form av löv och trä och deras omsättningshastigheter studerades individuellt. En litteraturstudie visade att de nuvarande värdet för löv är för högt och för lågt satt för trä. Nya värden testades, avfallsmängder för olika eldintervall räknades ut och jämfördes med mätta mängder i Kruger National Park. En omsättningshastighet på 0.6 år visade sig vara bästa representanten för våt-torra områden för lövavfall utan träd. Ett värde för träavfall kunde inte hittas, då det inte fanns tillgång till data att jämföra värdena med. Däremot kunde effekten av omsättningshastigheten studeras för att få en bättre förståelse för vilken effekt det hade på dessa typer av ekosystem. Denna uppsats visar vikten av att förstå hur olika ekosystem fungerar och att det fortfarande kan göras förbättringar i den använda modellen.Fire is one of the most important disturbance processes affecting the terrestrial biosphere, altering the vegetation composition and distribution, structure, plant diversity and biogeochemical cycles. Some of the most influenced ecosystems are wet-dry areas, here classified as savannah or Mediterranean regions. The influence can be studied in different ways, either by long-term experiments like the burn plot trial in Kruger National Park in South Africa, or by the use of models, for example LPJ-GUESS-SPITFIRE. SPITFIRE is a process-based fire model which have been coupled to a dynamic global vegetation model in order to predict fire spread, intensity and residence time of fires. In LPJ-GUESS-SPITFIRE a variable called the turnover time, which is the logarithmic decomposition rate for litter at a defined temperature and moisture content is used to calculate how much available litter (or in other words fuel) is available in the modelled patch in order to determine the fire intensity. This constant is set to 2.85 and is used for all ecosystems around the world. In reality however, the turnover time varies depending on the existing circumstances, which makes it unrealistic to use the same constant. Data obtained from the burn plot trial in Kruger National Park was used for parameter refinements within the DGVM LPJ-GUESS-SPITFIRE in order to find more representative values. The litter pool was divided into two pools which are the main input for surface fires; leaf litter and wood litter and their turnover times were studied individually. A literature study showed that presently used values for the leaf turnover time are overestimated by the model and underestimated for wood. In order to find more suitable parameters, new values were tested, litter amounts for different fire return intervals were calculated and compared with measured litter amounts in the experiment in Kruger National Park. A turnover time of 0.6 years for leaf litter without trees was found to be the best representative for wet-dry areas. The turnover time for woody litter could not be adjusted, since there was no available data to compare them with. However, the effect of turnover times within the range found in the literature study was examined in order to better understand the effect wood litter had on these kinds of ecosystems. This thesis shows the importance to understand how different ecosystems work and that improvements still can be made in the used model

Pathogen group-specific risk factors for intramammary infection in water buffalo

A cross-sectional study was conducted to estimate the prevalence of intramammary infection (IMI) associated bacteria and to identify risk factors for pathogen group-specific IMI in water buffalo in Bangladesh. A California Mastitis Test (CMT) and bacteriological cultures were performed on 1,374 quarter milk samples collected from 763 water buffalo from 244 buffalo farms in nine districts in Bangladesh. Quarter, buffalo, and farm-related data were obtained through questionnaires and visual observations. A total of 618 quarter samples were found to be culture positive. Non-aureus staphylococci were the predominant IMI-associated bacterial species, and Staphylococcus (S.) chromogenes, S. hyicus, and S. epidermidis were the most common bacteria found. The proportion of non-aureus staphylococci or Mammaliicoccus sciuri (NASM), S. aureus, and other bacterial species identified in the buffalo quarter samples varied between buffalo farms. Therefore, different management practices, buffalo breeding factors, and nutrition were considered and further analyzed when estimating the IMI odds ratio (OR). The odds of IMI by any pathogen (OR: 1.8) or by NASM (OR: 2.2) was high in buffalo herds with poor milking hygiene. Poor cleanliness of the hind quarters had a high odds of IMI caused by any pathogen (OR: 2.0) or NASM (OR: 1.9). Twice daily milking (OR: 3.1) and farms with buffalo purchased from another herd (OR: 2.0) were associated with IMI by any pathogen. Asymmetrical udders were associated with IMI-caused by any bacteria (OR: 1.7). A poor body condition score showed higher odds of IMI by any pathogen (OR: 1.4) or by NASM (OR: 1.7). This study shows that the prevalence of IMI in water buffalo was high and varied between farms. In accordance with the literature, our data highlight that IMI can be partly controlled through better farm management, primarily by improving hygiene, milking management, breeding, and nutrition

Toxoplasma gondii som orsak till beteendeförändringar hos människa

Toxoplasma gondii är en obligat intracellulär parasit med kattdjur som huvudvärd och de flesta varmblodiga djur, inklusive människa, som mellanvärd. I mellanvärden bildas vävnadscystor, främst i nerv- och muskelceller, innehållande långsamt delande bradyzoiter. Smittan sprids framför allt via föda kontaminerad med oocystor från kattens faeces, otillräckligt upphettat kött innehållande infektiösa vävnadscystor eller via kongenital överföring. Infektionen är livslång och det har länge antagits att endast immunsupprimerade individer och gravida kvinnor uppvisar allvarliga kliniska symptom. Studier som visat beteendeförändringar hos infekterade immunkompetenta möss har dock lett till forskning gällande eventuella beteendeförändringar hos människa orsakade av T. gondii. Infektion med T. gondii har associerats med förändringar i den kemiska sammansättningen i hjärnan. I celler infekterade med T. gondii har ökade nivåer av dopamin samt ett, för dopamin, hastighetsbestämmande enzym setts. Även sänkta nivåer av tryptofan (vilket försvårar överlevnad för T. gondii) har visats. En normal nivå av tryptofan är nödvändig för syntesen av serotonin och låga nivåer kan således leda till sänkta nivåer serotonin. Obalanserade nivåer dopamin kan kopplas till schizofreni och sänkta nivåer serotonin har kopplats till bl.a. depression och aggression. Dessa mekanismer antas vara möjliga orsaker till de beteendeförändringar som studier kunnat visa hos infekterade människor. Ett flertal studier kan visa ett samband mellan schizofreni och latent toxoplasmos, men även kopplingar till självmord, självskadebeteende, personlighetsförändringar, samt försämrad reaktions- och koncentrationsförmåga har visats. Det senare antas vara en bidragande orsak till att infekterade personer i ett flertal studier visats löpa högre risk för trafikolyckor. Studier som undersökts i denna litteraturstudie visar ett samband mellan beteendeförändringar och nivåer av anti-T. gondii-IgG d.v.s. den kroniska formen av toxoplasmos. I flera studier har graden av beteendeförändringarna också visats öka med infektionens duration. Ett fåtal förändringar har kopplats till högre antikroppstitrar, vilket förekommer tidigt i infektionen eller om infektionen reaktiveras. Det senare anses dock vara mest sannolikt. Det mesta tyder på en association mellan T. gondii-infektion och beteendeförändringar, men huruvida orsaken är mekanismer i immunförsvaret eller hos parasiten själv är ännu inte klarlagt. Det är sannolikt en kombination mellan dessa två och mer forskning krävs för att klarlägga dessa mekanismer. Utökad forskning kan förhoppningsvis leda till utveckling av strategier för behandling av beteendeförändringar i kombination med T. gondii-infektion.Toxoplasma gondii is an obligate intracellular parasite. Any member of the feline species is suitable as a definite host and most warm-blooded animals, including humans, can act as intermediate hosts. Tissue cysts containing slowly dividing bradyzoites, mainly in nerve and muscle cells, are formed in the intermediate host upon infection. Infection is spread mainly through food contaminated with oocysts from feline faeces, insufficiently heated meat containing infectious tissue cysts, or through congenital ransmission. This life long infection has been thought to only cause severe clinical symptoms in immunosuppressed individuals and pregnant women. However, studies have shown behavioural changes in infected immunocompetent mice, which has led to further research regarding possible behavioural changes caused by T. gondii in humans. T. gondii infection has been associated with changes in the chemical composition in the brain. Elevated dopamine levels and a rate-limiting enzyme in the dopamine synthesis have been seen in cells infected with T. gondii. Lowered tryptophan levels (which complicates T. gondii survival) have also been shown. However, a normal level of tryptophan is needed for synthesis of serotonin and thus low levels of tryptophan might lead to lowered levels of serotonin. Unbalanced levels of dopamine are associated with Schizophrenia and lowered serotonin levels have been associated with depression and aggression. These mechanisms are thought to be possible causes to the behavioural changes that have been shown in studies of infected humans. Several studies show an association between Schizophrenia and T. gondii-seropositivity. An association between seropositivity and suicide, self-directed violence, changes in personality and reaction time has also been indicated. The latter is thought to be a contributing factor in the studies showing a higher risk of traffic accidents in infected people. An association between behavioural changes and anti-T. gondii-IgG levels, i.e. the chronic form of toxoplasmosis, has been shown in several studies. Studies have also shown that the degree of behavioural changes increases with the duration of infection. A few changes have been associated to higher antibody titres, which occur in early or reactivated infection. The latter is thought to be most probable. Most indicators suggest an association between T. gondii infection and behavioural changes, but whether the cause is mechanisms in human immune response or in the parasite itself is yet to be revealed. It is likely a combination between these two but more research is needed to understand these mechanisms. Extended research can hopefully lead to the development of strategies for treatment of behavioural changes in combination with T. gondii

Bisphenol A in urine from domestic dogs : a risk factor for prostatic changes?

Bisfenol A (BPA) är ett hormonstörande ämne som bl.a. används i tillverkningen av epoxi- och polykarbonatplaster, vilka i sin tur används i bl.a. nappflaskor och matförpackningar. Det är sedan länge känt att en stor del av befolkningen exponeras för BPA, framförallt via oralt intag, men även andra exponeringsvägar är kända. Huruvida tamhundar exponeras, till vilken grad och vilken effekt det kan tänkas ge finns det få studier på. Experimentella studier på gnagare har dock visat tydliga effekter på reproduktionssystemet, t.ex. förändringar på prostata och förstadier till prostatacancer. Prostataförändringar är vanligt förekommande hos äldre, intakta hanhundar och syftet med denna studie var därför att undersöka förekomst av BPA i urinen på tamhundar, samt om en eventuell förekomst av BPA skulle kunna anses vara en riskfaktor för prostataförändringar hos hund. Urinprov samlades in från åtta hundar med symptom på prostataförändringar eller prostataförändringar diagnosticerade med ultraljud samt från tio symptomfria, intakta kontrollhundar och analyserades sedan för förekomst av BPA. Djurägarna fick svara på ett antal frågor som berörde hundarnas hemmiljö. Resultaten visade att samtliga hundar i studien exponerats för BPA, men däremot fanns inget signifikant samband mellan BPA-halter i urinen och prostataförändringar. Inte heller sågs några signifikanta samband mellan hundarnas hemmiljö och BPA-halter i urinen. Halterna i urin (medel 1,22 ng/ml) låg i nivå med, eller något under, de halter som kunnat visas i olika studier på människa, förutom en hund som hade högre halter (128,43 ng/ml). Vid en jämförelse av hundarnas beräknade dagliga intag av BPA och tolererbart dagligt intag för människa är det inte troligt att BPA utgör någon risk för hund, men med tanke på det låga antalet hundar i studien och att en hund hade högre halter kan det inte heller helt uteslutas. Fler och större studier behövs för att fastställa ett samband samt kartlägga exponeringsvägar.Bisphenol A (BPA) is an endocrine-disrupting chemical used in epoxy- and polycarbonate plastics, which in turn are used in baby bottles and food packages, among other things. It is well known that the majority of the human population is exposed to BPA, mostly orally, but other ways of exposure are also known. Few studies have focused on whether domestic dogs are exposed, and if so, to which degree and what effect that level of exposure might have on the exposed dogs. Evident effects on the reproductive system have been shown in experimental studies on rodents, for example prostatic changes and changes associated with prostate cancer. Prostatic changes are common on aged, intact male dogs and the purpose of this study was to examine presence of BPA in the urine of domestic dogs and if BPA could be a possible risk factor for prostatic changes in domestic dogs. Urine samples were collected from eight dogs showing symptoms of prostatic changes or diagnosed with prostatic changes through ultrasound. In addition, ten urine samples were collected from intact male dogs without symptoms of prostatic changes. All samples were then analysed for BPA. The dog owners answered a survey containing questions about their dogs home environment. The results showed that all of the dogs in the study had been exposed to BPA, but no significant connection was found between occurrence of prostatic changes and the levels of BPA in urine samples. Neither did it show any significant connection between the dogs’ home environment and levels BPA in urine. The levels of BPA in urine (mean 1,22 ng/ml) were lower or similar to those that have been found in human urine samples, except from one dog that had higher levels (128,43 ng/ml). When comparing estimated daily intake of BPA for the dogs with human tolerable daily intake, it is not likely that BPA poses as a risk for dogs, but considering the low number of dogs in the study and that one dog had higher levels it can not be ruled out completely. More and larger studies are needed to confirm a possible correlation and to find different exposure routes

Effects of intra-genotypic variation, variance with height and time of season on BVOC emissions

Biogenic Volatile Organic Compounds (BVOCs) are trace gases other than CO2 and CH4 produced and emitted by the biosphere, where the amounts released depend on climatic factors such as temperature and solar irradiation. However, interpretation of leaf-level measurements is currently hampered by factors such as large within-genotypic variability, measurement height and time in the season. A campaign was performed between June and August in 2013 in Taastrup, Denmark to study these uncertainties. BVOC emissions were measured from leaves and needles at heights of 2 m, 5.5 m and 12.5 m in the canopy and for seven trees; four Norway spruces (Picea abies) of which two trees had a budburst approximately a week before the other two, two English oaks (Quercus robur) and one European beech (Fagus sylvatica). Differences in chemical composition and emission strength between June and August were observed between the different trees. English oak's main compound isoprene increased from 62–74 % of the total emission in June to approximately 97 % in August, which is linked to leaf development over the summer season. The total emission from all measured spruce trees decreased from July to August, but without a loss in the diversity of emitted compounds. The trees showed indications of drought stress as there was a period without precipitation lasting 21 days during the study. There were no differences in emission patterns within all of the measured Norway spruces. For measurement height, there was only a significant difference in emission pattern for European beech as the top of the canopy emitted 7–9 times more in relation to lower canopy levels. Our results suggest there was little within-genotype variability and the wide spacing between trees had an influence on the individual emission patterns. These results are important in order to understand the significance of within-genotypic variation, canopy height and seasonal development in relation to the emission patterns of the selected species. Furthermore, it will provide helpful insights for modelers who wish to improve their emission estimates

Farming practices in Sweden related to feeding milk and colostrum from cows treated with antimicrobials to dairy calves

BACKGROUND: Milk produced by cows in receipt of antimicrobial therapy may contain antimicrobial residues. Such antimicrobial-containing waste milk must be withdrawn from human consumption and is therefore sometimes used as calf feed. Unfortunately, this approach might promote selection of antimicrobial resistant bacteria in the calves’ intestinal microbiota. The objectives of this study were therefore to obtain an overview of waste milk feeding practices on Swedish dairy farms and to investigate if these practices were associated with certain farm characteristics. A representative group of 457 Swedish dairy farmers participated in a web-based survey with questions about the use of colostrum and milk from cows treated with antimicrobials at dry off or during lactation, respectively, as calf feed. RESULTS: Colostrum (milk from the first milking after calving) and transition milk (milk from the second milking to the fourth day after calving) from cows treated with antimicrobials at dry off was fed to calves on 89% and 85% of the farms in the study, respectively. When antimicrobial therapy was given to cows during lactation, 56% of the farms fed milk that was produced during the course of treatment to calves, whereas milk that was produced during the subsequent withdrawal period was fed to calves on 79% of the farms. Surveyed farmers were less prone to feed such milk if the antimicrobial therapy was due to mastitis than other infections. In Sweden, a majority of antimicrobial treatments during lactation are systemic administration of benzylpenicillin and thus, the bulk of waste milk in Sweden is likely to contain residues of this drug. Feeding waste milk to calves was more common on non-organic farms, and on farms located in Southern Sweden, and was less common on farms with cows housed in cold free stalls barns. CONCLUSIONS: Waste milk that may contain antimicrobial residues is, at least occasionally, used as feed for calves on a majority of surveyed Swedish dairy farms. Future work should focus on the effect of waste milk feeding on the occurrence of antimicrobial resistant bacteria in the calves’ intestinal microbiota

Potential of mapping forest damage from remotely sensed data

Remote sensing is an efficient tool for mapping, monitoring, and assessing forest damage and the risk of damage. This report presents ongoing research on those topics with preliminary results as well as research planned by the Department of Forest Resource Management, SLU in Umeå, in the near future. The damage types include spruce bark beetle attacks, storm damage, and forest fire. The report also outlines proposed continued research in the area and possible collaborations within and outside SLU

The prevalence and risk factors of subclinical mastitis in water buffalo (Bubalis bubalis) in Bangladesh

Subclinical mastitis (SCM) in water buffalo is responsible for reduced milk yield and quality. This cross-sectional study was carried out to a) estimate the prevalence of SCM, b) identify risk factors associated with SCM, and c) identify farm-level risk factors associated with bulk milk somatic cell count (BMSCC). The buffalo farms included in this study represented five rearing systems: free-range, semi-free-range, household, semi-intensive, and intensive, providing a total of 3491 functional quarters of 880 lactating buffalo on 248 farms. The California mastitis test score was used to identify SCM. Bulk milk samples (n = 242) were used for farm-level BMSCC. Quarter and buffalo-level risk factors for SCM were measured using questionnaires and observations. The overall SCM prevalence was high at 27.9% at the quarter-level (25th and 75th percentiles: 8.3% and 41.7%) and 51.5% at buffalo-level (25th and 75th percentiles: 33.3% and 66.7%). The geometric mean BMSCC was 217,000 cells/mL of milk (ranging from 36,000-1,213,000 cells/mL), which is low on average, but some farms could improve substantially. The buffalo rearing system, udder location (left versus right), teat shape, udder asymmetry, number of milkers, and having a quarantine facility were associated with buffalo udder health. Our findings suggest that mainly using free-range rearing systems may help decrease the prevalence of SCM primarily by employing buffalo breeding and better farm biosecurity, and udder health control strategies can be designed based on our findings

The Crystal Structure of H-2Dd MHC Class I Complexed with the HIV-1-Derived Peptide P18-I10 at 2.4 Å Resolution Implications for T Cell and NK Cell Recognition

AbstractThe structure of H-2Dd complexed with the HIV-derived peptide P18-I10 (RGPGRAFVTI) has been determined by X-ray crystallography at 2.4 Å resolution. This MHC class I molecule has an unusual binding motif with four anchor residues in the peptide (G2, P3, R/K/H5, and I/L/F9 or 10). The cleft architecture of H-2Dd includes a deep narrow passage accomodating the N-terminal part of the peptide, explaining the obligatory G2P3 anchor motif. Toward the C-terminal half of the peptide, p5R to p8V form a type I′ reverse turn; residues p6A to p9T, and in particular p7F, are readily exposed. The structure is discussed in relation to functional data available for T cell and natural killer cell recognition of the H-2Dd molecule