The objective was to examine the potential benefits of using different combinations of multiple quarter milk samples compared with a single sample for diagnosing intramammary infections (IMI) in dairy cattle. Data used in the analyses were derived from 7,076 samples from 667 quarters in 176 cows in ...

The objective was to identify postpartum risk factors between nutritional imbalance and health disorders affecting first-service conception risk (FSCR) in 21 commercial Holstein herds in Reunion Island. Multivariate logistic-regression models including herd as a random effect were used to analyze th...

The objectives of this paper are to provide an introduction to meta-analysis and systematic review and to discuss the rationale for this type of research and other general considerations. We highlight methods used to produce a rigorous meta-analysis and discuss some aspects of interpretation of meta...

A national surveillance programme for Salmonella Dublin, based on regular bulk-tank milk antibody screening and movements of cattle, was initiated in Denmark in 2002. From 2002 to end of 2009 the prevalence of test-positive dairy herds was reduced from 26% to 10%. However, new infections and spread ...

Criteria for diagnosing intramammary infections (IMI) have been debated for many years. Factors that may be considered in making a diagnosis include the organism of interest being found on culture, the number of colonies isolated, whether or not the organism was recovered in pure or mixed culture, a...

The Finnish Healthy Hooves project was set up to determine the frequency of, and risk factors for various hoof lesions in Finnish dairy herds. Data were collected in the years 2003 and 2004. A large dataset of over 74,000 cow-level observations recorded by hoof trimmers was merged with production da...

This manuscript is derived from a presentation at the 2006 AVEPM - Schwabe Symposium which honoured the 2006 recipient of the Calvin Schwabe Award - Dr. S. Wayne Martin. Throughout his career, Dr. Martin was instrumental in furthering the development of quantitative epidemiology. This manuscript hig...

Composite milk samples, in which milk from all 4 bovine quarters is collected in a single vial, are widely used in many developed dairy industries for detection of intramammary infections (IMI). These samples are more economical for use in culturing protocols than individual quarter samples, and may...

Randomized controlled trials of veterinary vaccines are essential if we are to have a reasonable understanding of how those vaccines can be expected to perform when used in the field. This manuscript reviews a few (but certainly not all) of the key elements that need to be considered in the design o...

The primary objective of this study was to determine the contribution of several management variables to average production per day of life (PPDL). A secondary objective was to compare PPDL between two geographic regions in North America and between dairy herds within the two regions. PPDL was deter...

Herd level measures of health and productivity in Prince Edward Island dairy herds, computed monthly over a 4 year period, were evaluated. Descriptive statistics for 11 key measures of health and productivity were computed. The parameters cover the areas of milk production, reproductive performance,...

Herd level measures of health and productivity in Prince Edward Island dairy herds, computed monthly over a 4 year period, were evaluated. Descriptive statistics for 11 key measures of health and productivity were computed. The parameters cover the areas of milk production, reproductive performance,...

Pattern diagnosis (establishing a diagnosis of a herd problem based on the distribution of health events within that herd) is only possible if information about the expected, or 'normal' distribution is available. This study examined the distribution of somatic cell count (SSC) patterns in Prince Ed...

A prospective cohort study was undertaken to determine calf-level factors that affect performance (growth) between birth and 14 months of age in a convenience sample of approximately 3300 female Holstein calves born in 1991 on two large Florida dairy farms. Data collected on each calf at birth inclu...

A case-control study was conducted to compare the physical hoof properties of digits responsible for clinical lameness with those of other digits on the same cows and with those of equivalent digits on non-lame control cows. The control cows were herd-mates matched by age, breed and stage of lactati...

Data from 1565 milk samples collected weekly from the University of Guelph mastitis research herd were used to evaluate somatic cell counts (SCC) as a screening test for prevalent intramammary infections. Changes in SCC were evaluated as a screening test for incident infections. The sensitivity and ...

We analysed the individual-animal data from six of the nine outbreaks of tuberculosis in Canadian cattle and cervids from 1985 to 1994. A 'positive/reactor' animal was one which had either a positive culture or a positive or suspicious reaction on a mid-cervical, comparative cervical, or gross or hi...

Gastrointestinal nematodes rarely cause signs of clinical disease in adult cattle. However, they have been shown to exert a negative impact on production in lactating animals, as seen by improved production following elimination of the worms using anthelmintics. A double blind, randomized clinical t...

The objectives of this study were: 1) to determine if bulk tank milk urea nitrogen (BTMUN) and whole herd weighted average of the individual cow MUN levels (WHMUN) were equivalent measurements of herd MUN status; and 2) to determine the seasonal variation in BTMUN concentrations in Prince Edward Isl...