Farm- and host-level risk factors for papillomatous digital dermatitis in Chilean dairy cattle.

A cross-sectional study was conducted in southern Chile between January and March, 1996, to identify risk factors for papillomatous digital dermatitis (PDD) in lactating dairy and dual-purpose cows. A total of 3,265 cows from 22 farms were examined in the milking parlor for PDD lesions. Additional information was collected from dairies' computerized records and by direct interview of managers. Data were analyzed using logistic and logistic-binomial regression (with dairy as a random-effect term). German Red-Pied (dual-purpose) cows were significantly (P < 0.05) less likely (odds ratio (OR) = 0.3) to have PDD lesions than German Black-Pied and Holstein crossbreds. First-parity cows had the highest odds of PDD, and odds diminished, in a dose-effect manner, as parity increased. Odds of PDD increased with increasing days in lactation. Cows that calved during winter were more likely to have PDD (OR = 1.4) than those calving at any other season. Cows on farms that bought heifers in the past 10 years had a 3-fold increase in the odds of PDD compared to those on farms that never bought heifers. Loose-housed cows had a higher risk of PDD (OR = 7), followed by cows in free stalls or in open corrals (OR = 2.8 and 1.3, respectively), compared to cows on pasture all year. Cows on dairies that used a footbath during 1996 were less likely (OR = 0.3) to have PDD than those in dairies not using one. Parlor type was associated with PDD, but this was likely an effect of parlor design on ease of inspection of cows' feet. A policy of trimming all cows' vs. only lame cows' feet and a policy about buying adult cows did not have significant effects on PDD risk.

Papillomatous digital dermatitis in Chilean dairies and evaluation of a screening method.

Outbreaks of papillomatous digital dermatitis (PDD) have been reported from many countries, but there is little information on prevalence and geographic distribution of the disease. Our objectives were to describe prevalence of PDD on dairies belonging to the two main dairy-producer associations in Chile, and to evaluate a milking-parlor screening method for detection of PDD in dairy cows. First, a self-administered questionnaire was sent to all 214 association dairy managers. Seventy percent of the 119 respondents had observed PDD on their dairies. About 83% of the 63 responding managers had first seen PDD during the previous 10 years. Subsequently, a random sample of 43 dairies stratified by association was selected from the total 214 for PDD screening. During milking, we inspected cows' feet for PDD lesions; 91% of dairies had cows affected by PDD; median PDD prevalence for milking cows in dairies was 6.1%. Finally, in one dairy, PDD screening at the parlor was compared to PDD diagnosis by inspecting restrained cows in a chute. The screening method had a sensitivity of 0.72, and a specificity of 0.99. This study demonstrated that PDD was widespread on study dairies in Chile. The screening test presented can be used as a cost efficient method to estimate prevalence of PDD either on individual dairies or in large-scale surveys.

Incidence and risk factors for bumblefoot (pododermatitis) in rehabilitated raptors.

A retrospective cohort study was conducted on 821 raptors of 12 representative species, admitted to the California Raptor Center (CRC), during 1980-1990. The incidence rate for bumblefoot was 52 cases per 100 bird-years at risk. Eagles and hawks (buteos) were more likely to develop bumblefoot, and did so earlier during their captivity than other species. Also, raptors admitted with a limb fracture had the greatest risk (OR = 4.2) of developing bumblefoot than any other condition on entry. Median time from admission to development of bumblefoot was 52 days, and median duration of bumblefoot was 23 days.

Papillomatous digital dermatitis on a commercial dairy farm in Mexicali, Mexico: incidence and effect on reproduction and milk production.

This retrospective study of papillomatous digital dermatitis (PDD) was performed using data for cows that calved between July 1993 and June 1994 on a Mexicali, Mexico, dairy farm in order to calculate incidence rates, and to compare milk yield and reproduction data between affected and nonaffected dairy cows. A total of 190 out of 577 (33%) cows were affected during lactation and six (1%) during the dry period. Fifty-two of 77 (68%) cows that had lesions in the previous lactation and were also present on the farm in the current lactation had lesions in the current lactation. The highest risk for PDD occurred during the first month of lactation (9%). The yearly estimated cumulative incidence risk was 35% and the incidence density rate was 44.6 cases per 1000 cow-months. More animals were affected in summer and fall than in winter and spring. Purchased animals were 3.4 times more likely to be affected than animals born on the farm. Survival analyses indicated healthy cows conceived 93 days after calving (median), but affected cows conceived 113 days after calving (median) (P < 0.01). PDD-affected animals produced less milk than healthy cows, but the difference was not statistically significant in the multiple regression.

Papillomatous digital dermatitis in 458 dairies.

OBJECTIVE: To estimate prevalence of papillomatous digital dermatitis (PDD) in California dairies during 1993, to describe temporal and spatial patterns of PDD and response of cows to treatment, and to evaluate herd-related risk factors for PDD. DESIGN: Epidemiologic survey. SAMPLE POPULATION: All southern California dairies and a 50% random sample of the rest of California dairies. PROCEDURE: A questionnaire was mailed to managers of 1,429 selected dairies. RESULTS: Prevalence of PDD during 1993 was significantly higher for dairies in the south (75.3%) and central (68.8%) regions, compared with north coast (33.3%) and north (23.1%) regions of the state. Herd mean and median proportions of affected cows in PDD-affected herds were 11.6 (SEM = 0.9) and 5%, respectively. Most (74%) dairy managers surveyed observed PDD for the first time during 1992 or 1993. Highest PDD activity was reported as taking place in summer in the south and in fall and winter in the north coast and north regions; an obvious pattern was not determined for the central region. CLINICAL IMPLICATIONS: PDD was widespread in California dairies during 1993 and affected a high proportion of cows, especially in the south and central regions of the state.