Risk factors for the presence and extent of Developmental Orthopaedic Disease in the limbs of young horses: Insights from a count model

Incidence of disease, injury and death in Thoroughbred foals and yearlings on stud farms in the UK and Ireland

BACKGROUND

Up-to-date estimates of early-life morbidity and mortality in Thoroughbreds are lacking.

METHODS

A birth cohort was established on Thoroughbred stud farms across the UK and Ireland. All veterinary interventions for disease or injury between birth and 18 months of age or leaving the study were recorded. Multilevel Poisson regression models with farm and foal as random effects were fitted to estimate incidence rates.

RESULTS

Data were available for 3328 foal-months at risk for 275 foals on seven farms. The overall rates of disease and injury requiring veterinary intervention and mortality were 11.9 cases/100 foal-months at risk (95% confidence interval [CI] 8.6-16.2) and 0.2 cases/100 foal-months at risk (95% CI 0.1-0.4), respectively. Almost half (n = 133/273, 49%, 95% CI 43-55) of the live-born cohort required veterinary intervention for musculoskeletal disease or injury, equating to 5.8 cases/100 foal-months at risk (95% CI 4.1-8.2), predominantly reported as developmental orthopaedic disease (DOD).

LIMITATIONS

Convenience sampling of participants may affect the generalisability of the findings.

CONCLUSIONS

Rates of musculoskeletal disease and injury, in particular DOD, on Thoroughbred stud farms were high. Further work to identify modifiable risk factors and further understanding of the economic impact of these conditions and long-term consequences for musculoskeletal health and performance is required.

Dairy cattle management factors that influence on-farm density of European starlings in Ohio, 2007-2009

Potential dairy farm management and environmental factors that attract European starlings (Sturnus vulgaris) to dairy farms were explored. During the period from 2007 to 2009, 150 dairy farms were each visited twice (once during the summer and again in the fall) and the number of starlings was recorded. Risk factors were assessed for possible association with the number of starlings per milking cow (starling density), using a zero-inflated negative binomial model. Starling density was higher on farms visited in 2007 compared to those visited in 2008 or 2009. The interaction term between feeding method and feeding site was significantly associated with starling density on farm; generally, feeding outdoors was associated with increased starling density. The odds of a zero starling count (compared to a count greater than zero) was higher on farms that removed manure from barns weekly or less frequently than weekly compared to those that removed manure daily or after every milking. The odds of a zero starling count decreased with increasing distance of a farm from the closest night roost. Identifying on farm risk factors that expose farms to starlings will help farmers develop strategies that minimize the number of birds on their farms and thereby reduce physical damage to the farms as well as the potential for pathogen transmission from birds to cattle and humans.

Herd-level risk factors for Campylobacter fetus infection, Brucella seropositivity and within-herd seroprevalence of brucellosis in cattle in northern Nigeria

Brucellosis and campylobacteriosis are economically important diseases affecting bovine reproductive efficiency in Nigeria. A questionnaire-based survey was conducted in 271 cattle herds in Adamawa, Kaduna and Kano states of northern Nigeria using multistage cluster sampling. Serum from 4745 mature animals was tested for Brucella antibodies using the Rose-Bengal plate test and positives were confirmed in series-testing protocol using competitive enzyme-linked immunosorbent assay. Preputial scrapings from 602 bulls were tested using culture and identification for Campylobacter fetus. For each disease, a herd was classified as positive if one or more animals tested positive. For each herd, information on potential managemental and environmental risk factors was collected through a questionnaire administered during an interview with the manager, owner or herdsman. Multiple logistic regression models were used to model the odds of herd infection for each disease. A zero-inflated Poisson model was used to model the count of Brucella-positive animals within herds, with the number tested as an exposure variable. The presence of small ruminants (sheep and/or goats) on the same farm, and buying-in of >3 new animals in the previous year or failure to practice quarantine were associated with increased odds of herd-level campylobacteriosis and brucellosis, as well as increased within-herd counts of Brucella-positive animals. In addition, high rainfall, initial acquisition of animals from markets, practice of gynaecological examination and failure to practice herd prophylactic measures were positively associated with the odds of C. fetus infection in the herd. Herd size of >15, pastoral management system and presence of handling facility on the farm were associated with increased odds, and gynaecological examination with reduced odds of herd-level Brucella seropositivity. Furthermore, the zero-inflated Poisson model showed that borrowing or sharing of bulls was associated with higher counts, and provision of mineral supplement with lower counts of Brucella-positive cattle within herds. Identification of risk factors for bovine campylobacteriosis and brucellosis can help to identify appropriate control measures, and the use of zero-inflated count model can provide more specific information on these risk factors.

Association of growth, feeding practices and exercise conditions with the severity of the osteoarticular status of limbs in French foals

The aim of this study was to identify the risk factors for the severity of Juvenile OsteoChondral Conditions (JOCC) in limbs of French foals. Twenty-one farms in Normandy, France, were sampled and enrolled in a cohort study including 378 foals from three breeds, followed from the 8th month of pregnancy of the mares until the foals were approximately 6months old. Data on growth, feeding practices and exercise conditions were regularly collected. The carpus, the front and hind digits, the hock and the stifle of the foals were radiographed at the end of follow-up. JOCC severity in each foal was described using a global appraisal of its osteoarticular status (OAS) depending on the number and the severity of radiographic findings. Of the 378 foals, 53% had a good OAS, 34% had an intermediate OAS and 13% had a poor OAS. The breed (Selle Français and French Trotter Standardbred vs. Thoroughbred), a high girth perimeter at early age and an irregular exercise were significantly associated with a poor OAS. This study contributes to the understanding of the development of JOCC. An increased growth and reduced or irregular physical activity during the first weeks of life would be responsible for more severe lesions. Growth and exercise conditions should be carefully monitored to reduce the prevalence of severe JOCC in foals.

Factors affecting European badger (Meles meles) capture numbers in one county in Ireland

Understanding factors affecting the number of badgers captured at and around badger setts (burrows) is of considerable applied importance. These factors could be used to estimate probable badger densities for bovine tuberculosis (bTB) control and also for monitoring badger populations from a conservation perspective. Furthermore, badger management and vaccination programs would benefit by increasing the probability of efficiently capturing the target badger populations. Within this context, it was investigated whether badger capture numbers can be estimated from field signs and previous capture histories. Badger capture records (initial and repeated capture numbers at a sett) from a large-scale removal program (405 km(2), 643 setts) were used. Univariable count models indicated that there were a number of significant potential predictors of badger numbers, during initial capture attempts. Using a multivariable zero-inflated Poisson (ZIP) model of initial captures we found that badger capture numbers were significantly affected by sett type, season, year, and the number of sett entrances in active use. Badger capture numbers were also affected by the total previous catch during repeated capture events and by the number of previous capture attempts. There was a significant negative trend in badger captures across events. Measures of the ability of these models to estimate badger captures suggested that the models might be useful in estimating badger numbers across a population; however the confidence intervals associated with these predictions were large.