| 1. |
- Widgren, Stefan, et al.
(författare)
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Spatio-temporal modelling of verotoxigenic Escherichia coli O157 in cattle in Sweden: exploring options for control
- 2018
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Ingår i: Veterinary Research. - : Springer Science and Business Media LLC. - 0928-4249 .- 1297-9716. ; 49
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Tidskriftsartikel (refereegranskat)abstract
- A spatial data-driven stochastic model was developed to explore the spread of verotoxigenic Escherichia coli O157 (VTEC O157) by livestock movements and local transmission among neighbouring holdings in the complete Swedish cattle population. Livestock data were incorporated to model the time-varying contact network between holdings and population demographics. Furthermore, meteorological data with the average temperature at the geographical location of each holding was used to incorporate season. The model was fitted against observed data and extensive numerical experiments were conducted to investigate the model's response to control strategies aimed at reducing shedding and susceptibility, as well as interventions informed by network measures. The results showed that including local spread and season improved agreement with prevalence studies. Also, control strategies aimed at reducing the average shedding rate were more efficient in reducing the VTEC O157 prevalence than strategies based on network measures. The methodology presented in this study could provide a basis for developing disease surveillance on regional and national scales, where observed data are combined with readily available high-resolution data in simulations to get an overview of potential disease spread in unobserved regions.
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| 2. |
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| 3. |
- Blanco Penedo, Isabel, et al.
(författare)
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Effects of turning to 100% organic feed on metabolic status of Swedish organic dairy cows
- 2012
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Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 143, s. 242-248
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Tidskriftsartikel (refereegranskat)abstract
- Since January 2008 the ration for organic herds has been required to be 100% organic (Regulation No. 889/2008). However, this may not satisfy the high energy demands of early lactation cows. We thus investigated the possible effects of 100% organic feed on the energy balance in Swedish organic dairy herds as indicated by the following blood parameters (n = 739 observations): Beta-hydroxybutyrate (BHBA), non-esterified fatty acid (NEFA) and insulin, and the occurrence of clinical ketosis (n = 8769 observations). Thirteen organic and 13 conventional herds were visited and blood samples from 81 cows around parturition ( >= 3 cows per herd) were used. The metabolic status of the same herds under the previous rules was available for comparison. The BHBA, NEFA and insulin levels were different before and after the change of legislation, but the effects were similar in organic and conventional cows. The incidence of clinical ketosis was not associated with herd type or the change of legislation. Thus the change in legislation did not appear to have had any detrimental effects on the metabolic profiles of organic cows in early lactation and there was no evidence that organic cows were metabolically more challenged or had a severe negative energy balance. (C) 2011 Elsevier B.V. All rights reserved.
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| 4. |
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| 5. |
- Thorberg, Britt-Marie, et al.
(författare)
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Bovine subclinical mastitis caused by different types of coagulase-negative staphylococci
- 2009
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Ingår i: Journal of Dairy Science. - Amsterdam : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 92:10, s. 4962-4970
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Tidskriftsartikel (refereegranskat)abstract
- Subclinical mastitis caused by intramammary infections (IMI) with coagulase-negative staphylococci (CNS) is common in dairy cows and may cause herd problems. Control of CNS mastitis is complicated by the fact that CNS contain a large number of different species. The aim of the study was to investigate the epidemiology of different CNS species in dairy herds with problems caused by subclinical CNS mastitis. In 11 herds, udder quarter samples were taken twice 1 mo apart, and CNS isolates were identified to the species level by biochemical methods. The ability of different CNS species to induce a persistent infection, and their associations with milk production, cow milk somatic cell count, lactation number, and month of lactation in cows with subclinical mastitis were studied. Persistent IMI were common in quarters infected with Staphylococcus chromogenes, Staphylococcus epidermidis, and Staphylococcus simulans. The results did not indicate differences between these CNS species in their association with daily milk production, cow milk somatic cell count, and month of lactation in cows with subclinical mastitis. In cows with subclinical mastitis, S. epidermidis IMI were mainly found in multiparous cows, whereas S. chromogenes IMI were mainly found in primiparous cows.
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| 6. |
- Anglart, D, et al.
(författare)
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Detecting and predicting changes in milk homogeneity using data from automatic milking systems.
- 2021
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 104:10, s. 11009-11017
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Tidskriftsartikel (refereegranskat)abstract
- To ensure milk quality and detect cows with signs of mastitis, visual inspection of milk by prestripping quarters before milking is recommended in many countries. An objective method to find milk changed in homogeneity (i.e., with clots) is to use commercially available inline filters to inspect the milk. Due to the required manual labor, this method is not applicable in automatic milking systems (AMS). We investigated the possibility of detecting and predicting changes in milk homogeneity using data generated by AMS. In total, 21,335 quarter-level milk inspections were performed on 5,424 milkings of 624 unique cows on 4 farms by applying visual inspection of inline filters that assembled clots from the separate quarters during milking. Images of the filters with clots were scored for density, resulting in 892 observations with signs of clots for analysis (77% traces or mild cases, 15% moderate cases, and 8% heavy cases). The quarter density scores were combined into 1 score indicating the presence of clots during a single cow milking and into 2 scores summarizing the density scores in cow milkings during a 30-h sampling period. Data generated from the AMS, such as milk yield, milk flow, conductivity, and online somatic cell counts, were used as input to 4 multilayer perceptron models to detect or predict single milkings with clots and to detect milking periods with clots. All models resulted in high specificity (98-100%), showing that the models correctly classified cow milkings or cow milking periods with no clots observed. The ability to successfully classify cow milkings or cow periods with observed clots had a low sensitivity. The highest sensitivity (26%) was obtained by the model that detected clots in a single milking. The prevalence of clots in the data was low (2.4%), which was reflected in the results. The positive predictive value depends on the prevalence and was relatively high, with the highest positive predictive value (72%) reached in the model that detected clots during the 30-h sampling periods. The misclassification rate for cow milkings that included higher-density scores was lower, indicating that the models that detected or predicted clots in a single milking could better distinguish the heavier cases of clots. Using data from AMS to detect and predict changes in milk homogeneity seems to be possible, although the prediction performance for the definitions of clots used in this study was poor.
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| 7. |
- Hallén Sandgren, C, et al.
(författare)
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Homogeneity density scores of quarter milk in automatic milking systems.
- 2021
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Ingår i: Journal of Dairy Science. - : American Dairy Science Association. - 0022-0302 .- 1525-3198. ; 104:9, s. 10121-10130
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Tidskriftsartikel (refereegranskat)abstract
- Milk quality and clinical mastitis in dairy cows are monitored by detecting visually abnormal milk. A standardized method to evaluate clots in milk and studies of the incidence and dynamics of clots in milk at the quarter level are lacking. We validated a method to score clot density in quarter milk samples and describe the prevalence and dynamics of the density scores between consecutive samplings and periods in 4 farms with automatic milking systems. Using in-line filters, we collected quarter milk samples at each milking during 3 periods of 30 h each in each farm. Clot density was scored based on coverage of the filter area as 0 (negative), 1 (trace), 2 (mild), 3 (moderate), 4 (heavy), and 5 (very heavy). The score for a specific quarter and milking is referred to as the quarter milking score (QMS). Three assessors independently scored 902 images of filter samples with a Fleiss kappa value of 0.72. In total, 21,202 quarter milk samples from 5,398 milkings of 621 cows were collected. Of the quarter filter samples, 2.4% had visible clots, distributed as mild (1.4%), moderate (0.6%), heavy (0.3%), and very heavy (<0.1%, n = 8). Cases with a cow period sum of QMS ≥ 4, corresponding to 9.4% of all periods, harbored 86% and 94% of all QMS of 2 to 5 and 3 to 5, respectively. Of these cases, cows sampled in all 3 periods and clots in only 1 period had a quarter period sum score ≥ 1 in 1.8 different quarters in average. Corresponding numbers for the cows with clots or traces in 2 or 3 periods were 2.2 and 2.5 different quarters, respectively. A QMS of 2 to 5 in the preceding milking increased the chance of a QMS >1 in the following milking, with an average chance of 38%. The probability of a QMS > 1 increased with increasing previous QMS, a higher sum of QMS during the milking period, longer milking interval, and higher lactation number, but decreased with increasing days in milk. Our study showed that the method of clot-density scoring is feasible to perform and reproducible for investigating the occurrence and dynamics of clots in milk. Elevated clot-density scores clustered within certain cows and cow periods and appeared in new quarters of the cows over time. The low recurrence of QMS of 1 and 2 within quarters indicated that QMS 3 could be a reasonable threshold for detecting quarters with abnormal milk that require further attention.
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| 8. |
- Alvåsen, Karin, et al.
(författare)
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On-farm mortality of cows in Swedish dairy herds
- 2011
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Ingår i: Annual meeting of the European Association for Animal Production. - 1382-6077. ; 17, s. 364-364
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 10. |
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