Paratuberculosis sero-status and milk production, SCC and calving interval in Irish dairy herds

The objective of this study was to investigate the impact of paratuberculosis sero-status on milk yield, fat, protein, somatic cell count and calving interval in Irish dairy herds. Serum from all animals over 12 months of age (n = 2,602) in 34 dairy herds was tested for antibodies to Mycobacterium avium subsp. paratuberculosis using an ELISA. Herds were categorised by sero-status into positive, non-negative and negative, where a positive herd contained two or more positive cows, a non-negative herd contained only one positive cow and a negative herd contained no positive cows. Data at animal, parity and herd-level were analysed by multiple regression using general linear models. Positive herds (mean herd size = 129 cows) and non-negative herds (81 cows) were larger than negative herds (72 cows) (P < 0.01). Negative herds had the highest economic breeding index (EBI), while positive herds had the highest estimated breeding value (EBV) for milk yield. There was no significant effect of paratuberculosis sero-status at animal, parity or herd-level on milk yield, milk fat or protein production, somatic cell count score (SCCS) or calving interval. Negative herds tended to have a lower SCCS than positive and nonnegative herds (P = 0.087). This study only examined the effects of paratuberculosis sero-status but did not examine the clinical effects of Johne's disease at the farm or dairy industry levels

Systematic generation of in vivo G protein-coupled receptor mutants in the rat

G-protein-coupled receptors (GPCRs) constitute a large family of cell surface receptors that are involved in a wide range of physiological and pathological processes, and are targets for many therapeutic interventions. However, genetic models in the rat, one of the most widely used model organisms in physiological and pharmacological research, are largely lacking. Here, we applied N-ethyl-N-nitrosourea (ENU)-driven target-selected mutagenesis to generate an in vivo GPCR mutant collection in the rat. A pre-selected panel of 250 human GPCR homologs was screened for mutations in 813 rats, resulting in the identification of 131 non-synonymous mutations. From these, seven novel potential rat gene knockouts were established as well as 45 lines carrying missense mutations in various genes associated with or involved in human diseases. We provide extensive in silico modeling results of the missense mutations and show experimental data, suggesting loss-of-function phenotypes for several models, including Mc4r and Lpar1. Taken together, the approach used resulted not only in a set of novel gene knockouts, but also in allelic series of more subtle amino acid variants, similar as commonly observed in human disease. The mutants presented here may greatly benefit studies to understand specific GPCR function and support the development of novel therapeutic strategies

Temporal analysis of groundwater nitrate concentrations from wells in Prince Edward Island, Canada: application of a linear mixed effects model

Changes in nitrate concentration in groundwater from wells in Prince Edward Island, Canada were investigated over time using two datasets. Temporal trends in groundwater nitrate concentrations were assessed annually during 1981-1996 (1,299 observations), and both seasonally and monthly during 1988-1991 (1,868 observations). Data were analysed using linear mixed models with random effects and correlation structures. The average nitrate concentration in the monthly dataset was 3.99 mg/L as NO3-N, with January, May, and November concentrations being higher (p = 0.018). A seasonal effect was present when season was combined with land use type in an interaction term (p = 0.004). Wells located in agricultural areas had greater nitrate concentrations than urban areas, which in turn, had greater values than low human-impact areas. Row-cropped areas had higher groundwater nitrate concentrations in the summer, whereas manure storage areas were higher in the spring and autumn. Nitrate in groundwater in areas with low human impact and with centralized sewage disposal infrastructure remained relatively low and stable throughout the seasons. There was no significant annual trend (p = 0.954), but for individual sites, 9.6% significantly increased in nitrate concentration over time, and 6.6% significantly decreased over time. © Springer-Verlag 2007

Seroprevalence of Mycobacterium avium SSP paratuberculosis infection in Ethiopian dairy farms

This study aimed to determine the seroprevalence of antibodies for Mycobacterium avium subspecies paratuberculosis (MAP) in dairy cattle in the Jimma zone of Ethiopia in 2011. A random sample of 29 herds was selected, and all mature cattle within these herds had a blood sample taken. Serum was tested in duplicate, as recommended by the manufacturer, for evidence of infection with MAP, using an antibody ELISA. A questionnaire was used to collect information from the owner or farm manager on cow and herd demographics and management to allow for comparisons of our results with other studies. Herd sizes ranged from 3 to 17 cows per herd, with 95% of cows being Holstein crosses, ranging in age from 3 to 15 years old (mean of 5.5 years). Milk production ranged from 1 to 20 kg/cow/day, with an average of 8.4 kg/cow/day. All farms used tie-stalls for their cows, 59% of farms allowed newborn calves to suckle their dams on the day of calving, and 54% of farms purchased cattle in the last 5 years. Of the 242 cattle tested, 5 cows (2.1% with a 95% confidence interval – 95%CI - of 0.2% to 3.9%) were seropositive. Due to the low test sensitivity, the true animal prevalence estimate was calculated to be 2.6% (95%CI: 0.6% to 4.6%). At least one animal tested positive in 3 of the 29 herds (10.3% - 95%CI: 0% to 21.7%). Adjusting for the low test sensitivity, the true herd prevalence estimate was calculated to be 32.6 % (95%CI: 15.2% to 50.0%). This study provides the first immunological evidence of the prevalence of exposure of Ethiopian cattle to MAP, and at levels similar to other countries with small-scale dairy production. Corroboration of these prevalences with pathological, microbiological, and/or immunological MAP research in Ethiopia iswarranted.Keywords: Dairy Cattle, Johne’s, Paratuberculosis, Seroprevalence, Western Ethiopi

Food consumption and the risk of type 1 diabetes in children and youth: a population-based, case-control study in Prince Edward Island, Canada.

OBJECTIVE: The objective of this study was to determine if the consumption of certain foods during the year prior to diagnosis of type 1 diabetes mellitus (T1D) was associated with the risk of developing T1D in children and youth residing in Prince Edward Island, Canada. METHODS: Cases (n = 57) consisted of newly diagnosed patients with T1D during 2001 to 2004. Controls (n = 105) were randomly selected from the province's population, and matched to cases by age at diagnosis and sex. Food consumption in cases and controls was assessed using two previously validated food frequency questionnaires, and a survey was developed to collect information on potential environmental and genetic risk factors. RESULTS: The median age at diagnosis was nine years, and 67% of cases were male. After controlling for the matched variables and four significant environmental and genetic risk factors (family members with T1D, the number of infections during the first two years of life, place of residence, and father's education) in the final logistic regression model, the consumption of regular soft drinks (OR = 2.78, 95% CI = 1.21, 6.36) and eggs (OR = 2.50, 95% CI = 1.09, 5.75) were significant risk factors of T1D, when consumed once per week or more often. CONCLUSION: Diet may play a role in the development of T1D. However, further research is needed to confirm these observed associations