Christel Nielsen

Economic consequences of mastitis and withdrawal of milk with high somatic cell count in Swedish dairy herds.

The main aim was to assess the impact of mastitis on technical and economic results of a dairy herd under current Swedish farming conditions. The second aim was to investigate the effects obtained by withdrawing milk with high somatic cell count (SCC). A dynamic and stochastic simulation model, SimHerd, was used to study the effects of mastitis in a herd with 150 cows. Results given the initial incidence of mastitis (32 and 33 clinical and subclinical cases per 100 cow-years, respectively) were studied, together with the consequences of reducing or increasing the incidence of mastitis by 50%, modelling no clinical mastitis (CM) while keeping the incidence of subclinical mastitis (SCM) constant and vice versa. Six different strategies to withdraw milk with high SCC were compared. The decision to withdraw milk was based on herd-level information in three scenarios: withdrawal was initiated when the predicted bulk tank SCC exceeded 220 000, 200 000 or 180 000 cells/ml, and on cow-level information in three scenarios: withdrawal was initiated when the predicted SCC in an individual cows milk exceeded 1 000 000, 750 000 or 500 000 cells/ml. The accuracy with which SCC was measured and predicted was assumed to affect the profitability of withdrawing milk with high SCC and this was investigated by applying high, low or no uncertainty to true SCC. The yearly avoidable cost of mastitis was estimated at €8235, assuming that the initial incidence of mastitis could be reduced by 50%. This cost corresponded to 5% of the herd net return given the initial incidence of mastitis. Expressed per cow-year, the avoidable cost of mastitis was €55. The costs per case of CM and SCM were estimated at €278 and €60, respectively. Withdrawing milk with high SCC was never profitable because this generated a substantial amount of milk withdrawal that was not offset by a sufficient increase in the average price per delivered kg milk. It had the most negative impact on net return when high incidence of mastitis was simulated. Withdrawing milk with high SCC based on low-uncertainty information reduced the amount of withdrawn milk and thus resulted in less negative effect on net return. It was concluded that the current milk-pricing system makes it more profitable for farmers to sell a larger amount of milk with higher SCC than to withdraw milk with high SCC to obtain payment premiums, at least in herds with mastitis incidences within the simulated ranges.

Which preventive measures against mastitis can increase the technical efficiency of dairy farms

The aim of this paper was to explore if, and in that case how, various preventive measures against mastitis influenced the whole-farm economic outcome, measured as technical efficiency, of a sample of specialised dairy farms in Sweden. In particular, the paper aimed at analysing whether a change to preventive measures applied by fully efficient farms would be a way for inefficient farms to become fully efficient. First, technical efficiency was assessed for each farm in the sample based on farm-level accounting data and the data envelopment analysis. In a second step, the effects of preventive measures against mastitis (collected through a mail questionnaire) on technical efficiency were assessed with logistic regression. Keeping cows in a loose-housing barn, stimulating udders manually during milking, and having cows standing on clean bedding during milking were found to significantly increase the probability of a farm being fully efficient. Once the farmer considers the somatic cell count (SCC) to be too high, undertaking measures such as contacting a veterinarian, checking overall hygiene routines, and culling cows with high SCC were found to significantly increase the probability of a farm being fully efficient. Thus, these measures may be plausible targets for advisory services aimed at assisting farmers to become fully efficient, especially if they are confirmed in future studies. Several common preventive measures against mastitis, that is, choice of bedding material, frequency of cleaning stalls, pre-milking, post-milking teat disinfection, applying a milking order based on the SCC of cows, and milking high-SCC cows with a separate cluster, were found to have no statistically significant effect on farm economic outcome. However, these measures may still be valuable for non-economic goals, such as increased animal welfare, and the results imply that they can be implemented without negative impact on the economic performance of the farm.

Mastitis control in Swedish dairy herds

The aim of this study was to investigate which preventive measures targeting mastitis are implemented in Swedish dairy herds with different housing and milking systems. Data were collected through a self-administered postal questionnaire sent to 898 dairy farmers, stratified by housing and milking system, in May 2011. The questionnaire contained general questions about the herd and the person responsible for the udder health of the cows, and specific questions about perceived udder health and the implementation of preventive measures. The response rate was 48%. The median herd size of participating herds was 80 cows, and the median herd average milk yield per cow was 9,586 kg of milk. External validity was assessed by comparing participating herds with nonresponders in respect to key performance indicators in the Swedish official milk recording system; no significant differences were found. When herds with combined systems had been removed, 400 herds with tiestalls and pipeline milking, freestalls and parlor milking, and freestalls with an automatic milking system remained. Differences between herd types were analyzed using the Kruskal-Wallis test and Fishers exact test. The results showed that herd types differed in their rates of implementation of different preventive measures. Freestall herds with milking parlors implemented more preventive measures related to milking hygiene and milking routines than did tiestall herds. A milking order based on the udder health status of the cows was frequently implemented in tiestall herds, but not in most herds with an automatic milking system or most freestall herds with milking parlors. Irrespective of herd type, the proportion of herds in which cows were kept standing for at least 30 min after milking was low. A substantial proportion of herds ignored the udder health status of lactating cows when grouping them, and few herds grouped dry cows according to udder health status, although this occurred more frequently in tiestall herds. A large proportion of herds, especially those with tiestalls, did not allow cows and heifers to calve in single pens that were cleaned between animal occupations. These findings can be used to tailor advice on mastitis specifically to different herd types and thus improve the efficiency of mastitis control.

The reactivity of the back revisited. Are there differences in reactivity in different parts of the back

In the contact dermatitis literature, it is regularly stated that the patch test reactivity on various areas of the back differs, which might have a large impact on the reproducibility of patch testing.

Relationship between herd-level incidence rate of energy-related postpartum diseases, general risk factors and claw lesions in individual dairy cows recorded at maintenance claw trimming

BackgroundLaminitis and energy-related postpartum diseases share several risk factors, indicating a common etiology. Thus, a herd’s incidence rate of energy-related postpartum diseases, such as displaced abomasum and clinical ketosis, might reflect the likelihood of cows to suffer from laminitis-related claw lesions. The aim of this study was to investigate the association between herd-level incidence rate of displaced abomasum and clinical ketosis, general risk factors, and claw lesions in individual cows recorded at maintenance claw trimming.MethodsThe dataset consisted of 6773 trimmings, performed between 2004 and 2006 by professional trimmers, from 3607 Swedish Red and Swedish Holstein cows in 26 herds. The herds were classified as having a high, inconsistent-high or low incidence rate of energy-related postpartum diseases, based on the number of recorded cases of veterinary-diagnosed displaced abomasum and clinical ketosis in the Swedish national animal disease recording system during 2002 to 2006, and observations and interviews in connections with herd visits. Generalized linear mixed models were used to investigate the association between herd-level incidence rate of energy-related postpartum diseases and laminitis-related lesions including sole ulcer and sole hemorrhage; and hygiene-related lesions including interdigital dermatitis, digital dermatitis, heel-horn erosion, verrucose dermatitis, and interdigital hyperplasia; and absence of any claw lesion. Systematic effects, including first-order interactions, with P < 0.05 were included in the models. Herd classification was forced into the models, and a random effect of herd was included.ResultsIn comparison to herds with a high incidence rate of energy-related postpartum diseases, low-incidence herds showed a lower odds ratio (OR; 0.2) for laminitis-related lesions in cows trimmed during the summer months. Low-incidence herds also showed numerically lower OR estimates for laminitis-related lesions in all parity classes and a numerically lower OR for hygiene-related lesions. In addition, low-incidence herds showed tendencies towards a numerically higher OR for absence of any lesion, irrespective of trimming season or parity.ConclusionsOnly a few statistically significant associations were found, but several tendencies pointed towards better claw health in herds with low as compared with high incidence rate of energy-related postpartum diseases.

Short communication: Weak associations between mastitis control measures and bulk milk somatic cell counts in Swedish dairy herds

Despite the fact that control programs have been available for several decades, mastitis remains an important problem in dairy herds around the world. Possible reasons for this include poor uptake and application of recommended mastitis control measures; poor or variable compliance; or variability in the effects of these measures. The objective of this study was to evaluate the associations between implemented mastitis control measures and bulk milk somatic cell count (BMSCC) in Swedish dairy herds. Data for this study were collected primarily from an extensive self-administered postal questionnaire about the herds, the people responsible for udder health, and details of udder health and mastitis management. A total of 898 questionnaires were distributed, and 428 questionnaires were returned (overall response rate of 48%), but we used the information from only 395 herds in this study. For all herds, we collected data on herd size and geometric average calculated BMSCC from the Swedish Official Milk Recording Scheme. We used logistic regression to assess the association between mastitis control measures and BMSCC, dichotomized as low (<200,000 cells/mL) or high (>200,000 cells/mL). We investigated 21 measures that have been suggested for mastitis control, but found only 2 to be associated with udder health as measured by BMSCC. Not providing dry cows with a specialized mineral feed was significantly associated with increased risk of high BMSCC, and not using post-milking teat disinfectant tended to be associated with increased risk. The lack of association for all other measures was not likely due to low power (because most of these measures had variable implementation rates) but could be due to the relatively narrow range of BMSCC in our study (range 61,000-524,000 cells/mL). However, our results agreed well with those of other recent studies, supporting the call for a thorough review of the current knowledge of mastitis control and for wider application of intervention studies to verify the actual effects of suggested control measures.

Mammography and Osteoporosis Screening-Clinical Risk Factors and Their Association With Digital X-Ray Radiogrammetry Bone Mineral Density.

The aim of this study was to study the association between digital X-ray radiogrammetry (DXR) T-score and clinical risk factors for osteoporosis. Women were recruited 2 d per wk at a single mammography screening center between year 2010 and 2012. Included women answered a questionnaire about risk factors for osteoporosis, and a radiograph of the nondominant hand was obtained for DXR analysis. Univariate associations between DXR T-score and risk factors were examined. A generalized linear regression model was fitted to independent variables with univariate associations at p<0.05. The multivariable model was reduced through manual backward elimination, with p>0.1 as the exclusion criterion. Seventy-six percent of the women chose to participate in the study (n=8810). The difference in number of daily mammograms performed on study vs nonstudy days was not significant. All univariate associations between DXR T-score and potential risk factors were highly significant. The multivariable model included height, weight, age, right-handedness, menopause before age 45, alcohol consumption, cortisone treatment, rheumatic disease, and age×smoking status. The coefficient of determination of the model was 0.37. The association between risk factors for osteoporosis and DXR T-score is similar to previously reported associations with dual-energy X-ray absorptiometry.

The Southern Sweden Adolescent Allergy-Cohort: Prevalence of allergic diseases and cross-sectional associations with individual and social factors

ABSTRACT Objectives: Asthma and allergic diseases are the most frequent chronic diseases in childhood worldwide, and considered a burden for the affected children and their families. The diseases impose an economic burden on society if not diagnosed and treated properly and management of and these diseases are challenging for healthcare professionals. The aim of the present investigation was to assess the prevalence of allergic diseases in an unselected cohort of adolescents in southern Sweden. Additionally, associations with sociodemographic factors were investigated, as well as impact on daily life. Methods: This cross-sectional study was based on a cohort of n = 1 530 school children, aged 13 to 14, from 13 municipalities in southern Sweden. Data were collected through web-based questionnaires. Results: Of all children 32% reported at least one allergic disease. 67% reported one allergic disease and 33% reported more than one. No allergy-related disease were reported by 68%. Current asthma was reported by 9.8% and current rhino-conjunctivitis was reported by 13%. The prevalence of food hypersensitivity was 12% and the prevalence of eczema was 11%. One to three wheezing attacks were reported from 55% and 40% reported more than four attacks of wheezing in the preceding year. The self-reported allergic diseases were diagnosed by a doctor in; 36% (food hypersensitivity) to 69% (rhinoconjunctivitis) of the cases. Conclusions: A high number of affected children were identified. Some children being undiagnosed and some not receiving satisfactory treatment. These results suggest that additional studies to evaluate treatment procedures in order to improve healthcare for allergic children are warranted.