Swedish Dairy Herds Research Articles

Foot/leg and udder health in relation to housing changes in Swedish dairy herds

Monthly herd disease incidence rate or prevalence estimates in 196 Swedish commercial dairy herds from 1988 to 1995 were collected retrospectively from the official milk-recording scheme and merged with county administrative and farmers’ data on housing and management. To study the effects of changes in housing system on the occurrence of veterinary-treated foot/leg disorders, clinical mastitis, teat injuries and high milk somatic cell counts (MSCCs), four marginal Poisson or negative-binomial regression models were applied to the data (6011–7063 herd–month records), using the generalized estimating-equations method. Monthly observations were treated as repeated measures within herds. There were significant transitory increases in the incidence of clinical foot/leg disorders when changing from tie-stalls to cubicles and decreases in the incidences of clinical mastitis and teat injuries when changing from tie-stalls to cubicle or straw-yard systems. Effects on foot/leg health generally lasted for <18 months after building finish, while udder-health improvements persisted >18 months. Reductions in the incidence of clinical mastitis were not accompanied by any clear changes in the prevalence of high MSCCs.

Topical treatment of digital dermatitis associated with severe heel-horn erosion in a Swedish dairy herd

Two experiments were run in a commercial dairy herd to test the efficacy of topical treatments of digital dermatitis associated with severe heel-horn erosion. In Experiment I, topical treatments with solutions of either glutaraldehyde or oxytetracycline were compared with foot trimming and cleansing alone. After trimming of all feet, one front and one rear foot in each cow were treated with either glutaraldehyde or oxytetracycline (regardless of dermatitis status), while the other feet were used as controls and only trimmed. Two hundred foot records were obtained from 34 Swedish Red and White and 16 Swedish Holstein cows. The proportions ( p) of feet cured from digital dermatitis were compared between each group of medically treated feet and the control feet, assuming the feet to be independent observations with respect to curing. Oxytetracycline was significantly more effective than hoof trimming alone ( p=0.87 and 0.34, respectively; P<0.001) and than glutaraldehyde ( p=0.41; P=0.004). Treatment with glutaraldehyde was no more effective than hoof trimming alone. In Experiment II, a specially designed footbath with two longitudinal compartments was used to study the effectiveness of a solution of acidic ionised copper in preventing or curing digital dermatitis. The footbath—using water in one compartment—was constructed to make within-cow comparisons of treatment efficacy possible. The hoof health of 44 dairy cows (also included in Experiment I) were studied when the animals first were turned out to pasture and at the end of the grazing season (approximately 6 months later). During the grazing season, the cows were walked through the footbath twice daily after milking for a total of 47 days, divided into five separate periods ranging in length from 3 to 16 days. As judged by a two-sample comparison of proportions, a higher proportion of the cows’ hind feet that were affected by dermatitis were cured by the copper solution (20/24) than by water alone (12/23). The copper solution had no significant preventive effect on healthy feet.

A field survey on the status of internal parasites in calves on organic dairy farms in southwestern Sweden

Infections with internal parasites are one of the most important causes of reduced productivity in first-grazing season cattle (FGSC). In conventional herds, nematode infections can be controlled by prophylactic anthelmintic treatments, but this is prohibited in organic production. The purpose of this investigation was to monitor the status of internal parasitism on 15 organic cattle enterprises in southwestern Sweden during the 1997 and 1998 grazing seasons, and to estimate the benefits of some management practices in parasite control. On each farm, the numbers of Eimeria alabamensis oocysts per gram of (opg) faeces were counted in seven fresh dung pats collected from the paddock 8–10 days after the turnout of FGSC. Faecal samples from 5 to 15 FGSC were also analysed for nematode eggs per gram (epg) faeces at four occasions during each grazing season. In addition, the FGSC and one group of second-grazing season cattle (SGSC) were weighed at turnout and housing and at the same time blood samples were collected, and analysed for serum pepsinogen concentration and antibodies against the lungworm, Dictyocaulus viviparus. On seven farms, 1–6 samples with more than 100 000 opg were found, indicating considerable pasture contamination by E. alabamensis. However, clinical signs of coccidiosis were not observed. The highest outputs of nematode eggs were observed 45–55 days after turnout. More than 500 epg were only observed in 12 (2.2%) of the calves in 1997 and in three (0.6%) animals in 1998. Only 1% of the serum samples had pepsinogen values exceeding 3.6 U tyrosine, indicative of subclinical Ostertagia ostertagi infection. Lungworm infection was detected in five and nine herds in 1997 and 1998, respectively. The number of seropositive animals on these farms ranged between one (10%) and seven (70%). Clinical signs of dictyocaulosis were observed on two farms. The results indicate that dictyocaulosis is a problem in organic dairy herds in Sweden. On the other hand, the study shows that good management such as usage of parasite safe pastures and supplementary feeding may help control gastrointestinal parasites.

Persistence of verocytotoxin-producing Escherichia coli O157:H7 in calves kept on pasture and in calves kept indoors during the summer months in a Swedish dairy herd

In 1997, a Swedish dairy farm was implicated in a human case of verocytotoxigenic Escherichia coli (VTEC) infection. The bacterium was found in a faecal sample from the human case and in faecal samples from cattle on the farm. Subtyping with pulsed field gel electrophoresis (PFGE) showed that the isolates were identical. The farm was further studied to assess the occurrence and the epidemiology of the agent at the farm level. The objective of this part of the study presented here was to examine the persistence of VTEC O157:H7 in calves that were kept on pasture and indoors, respectively, during the summer. Twelve calves in the herd, with one positive faecal sample each of VTEC O157:H7 in April 1999, were followed by faecal sampling during the summer months. Six calves were kept indoors and six were kept on pasture. Faecal samples from each calf were collected once a month on five occasions from April to September. Bacterial examination was performed with immunomagnetic separation (IMS) and cultivation on CT-SMAC. PCR was used to test for the presence of genes encoding for verocytotoxin (VT), intimin (eaeA), enterohemorrhagic E. coli-hemolysin (EHEC-Hly) and the flagellar antigen H7. PFGE was used for genotyping the isolates. The faecal samples from the calves kept on pasture were negative during the whole period. It is possible that the faecal samples had bacterial counts lower than the detection limits for our procedure, or that the faecal samples were free from the bacteria at the time of sampling. This suggests that calves on pasture may be less exposed to the bacteria or that they clear themselves. In the pen group, there were between one and six culture positive individuals per sampling occasion. One of the calves that was housed indoors was positive in faecal culture on four consecutive samplings.

Housing, Feeding and Management of Calves and Replacement Heifers in Swedish Dairy Herds

A questionnaire was sent to 1500 randomly selected dairy herds in Sweden, asking for general information about the herds, including routines from birth to first calving and also routines at breeding, calving and during the grazing period. Fifty-eight percent of the questionnaires were returned. The preweaned calves were kept in individual calf pens in 68% and in group housing systems in 28% of the herds. Pens with slatted floors were the main housing system for replacement heifers from weaning to breeding, and tie stalls from breeding to first calving. Whole milk was used in 44% and milk replacements in 42% of the herds. The calves received, as a median, 2.5 litres of milk per meal and 2 meals per day. The median age at weaning was 8 weeks. Age was the single most common criteria used for deciding both weaning and breeding time. The median age when the heifers were first turned out to pasture was 6 months. Prophylactic anthelmintic treatment was used by 65% of the herds. The most common diet for replacement heifers before calving was a combination of grain, hay and silage.

Parasite control methods in organic and conventional dairy herds in Sweden

The objectives of this study were to compare methods of parasite control and to get an indication of the magnitude of parasite infections in organic and conventional dairy herds in Sweden. In February 1997, a questionnaire with mainly multiple choice alternatives was distributed to 162 organic and 162 conventional dairy farms in central Sweden. The response rates were 84% and 72%, respectively. A majority (58%) of the conventional farmers reported that their animals were treated prophylactically, mainly with controlled-release intraruminal devices. In organic production, parasite control methods involving grazing management combined with nutritional supplementation with concentrates and/or forage was the most frequently reported anti-parasite strategy. The most common procedure was to turn calves out on pastures not grazed by any cattle in the current or previous grazing seasons. This was employed by significantly more organic than conventional farms (40% vs. 3%), as was alternating grazing with other livestock species (27% vs. 3%). Sixty percent of the organic and 52% of the conventional farmers reported that they used nutritional supplementation in the autumn, and 48% and 29% of the producers, respectively, that they used nutritional supplementation in the spring, as methods to restrict parasite problems in their calves. Outbreaks of diarrhoea in first grazing season cattle and a lower weight gain during the grazing season than in the previous winter season, problems that may be due to parasite infections, were reported more frequently from organic herds. Despite an apparently increased awareness of various worm control strategies, organic farmers thus seemed to have greater problems with parasite infections than did conventional farmers.

Nationwide survey of antibodies to bovine coronavirus in bulk milk from Swedish dairy herdsNationwide survey of antibodies to bovine coronavirus in bulk milk from Swedish dairy herds

Bulk milk samples from 2236 dairy herds randomly selected throughout Sweden in proportion to region and herd size were analysed for antibodies to bovine coronavirus (BCV) in an ELISA. The...

Incidences and Effects of Diseases on the Performance of Swedish Dairy Herds Stratified by Production

Incidences of diseases and their effects on reproductive performance and risk of culling in herds stratified by production and estrus detection efficiency were studied. Data were from the Swedish milk and disease recording systems and consisted of records for 33,748 first parity Swedish Friesian cows. A standardized mixed threshold model was used for statistical analyses of categorical outcome variables, and an ordinary linear mixed model was used for continuous outcome variables.An increase in production was associated with increased frequencies of treatments of most diseases, shorter intervals from calving to first artificial insemination, fewer days open, and lower culling rates. Cows treated for metritis, silent estrus, and cystic ovaries had an increased number of days to first artificial insemination and more days open. However, the negative consequences of these diseases on reproductive performance decreased as herd production increased. The risk of culling was higher for cows treated for dystocia, cystic ovaries, and mastitis, but the increase in the risk of culling was lower for higher producing herds. Similar trends were observed when herds were stratified by estrus detection efficiency. The results support the hypothesis that herd management, as characterized by milk production or estrus detection efficiency, is important in the incidences and consequences of diseases. Herd management, measured directly or indirectly, should be considered when the health status or cost of disease for a given herd is evaluated.

Laminitis in young dairy calves fed a high starch diet and with a history of bovine viral diarrhoea virus infection

Six of the 33 calves born in a Swedish dairy herd during a period of four months developed laminitis when they were eight to 12 weeks old. The clinical signs included difficulty in rising, a stiff gait, overgrown claws and hemorrhages in the sole horn.&#x0D; Full article published in Veterinary Record (1997) 140, 574-577

Laminitis in young dairy calves fed a high starch diet and with a history of bovine viral diarrhoea virus infection

Six of the 33 calves born in a Swedish dairy herd during a period of four months developed laminitis when they were eight to 12 weeks old. The clinical signs...

Effects of infection with bovine virus diarrhoea virus on health and reproductive performance in 213 dairy herds in one county in Sweden

Bulk tank milk samples, collected twice with a 1 year interval, from 213 Swedish dairy herds with no vaccination programme against bovine virus diarrhoea virus (BVDV), were tested for antibodies to BVDV using an indirect enzyme-linked immunosorbent assay. The herds were classified into four different BVDV groupings based on changes in the estimated prevalence of BVDV antibody-positive cows in the herds. The estimated mean prevalences of BVDV antibody-positive cows were maintained as > 80% in 58 (27.2%) and as < 10% in 84 (39.4%) of the herds. A recent introduction of the infection was deemed to have occurred in seven (3.3%) of the herds studied. The BVDV groups were compared with regard to parameters related to disease and fertility at herd level. Relationships were assessed using logistic and ordinary linear regression analyses. The risks for clinical mastitis, retained placenta and oestrus-stimulating treatments were higher and the calving intervals were longer in BVDV infected herds, i.e. those herds with an increasing or maintained high prevalence of BVDV antibody-positive cows.

Influence of feeding management, concentrate intake and energy intake on the risk of hyperketonæmia in Swedish dairy herds

The risk of hyperketonaemia (clinical and subclinical ketosis) and how it is influenced by feeding and management routines was analyzed in 291–354 dairy herds over a 3 year period. The overall frequencies of cows with milk acetone ≥ 0.40 mM ranged between 4.2 and 6.2% in Parity 1 and 12.7 and 13.8% in Parity 2+. The incidence was probably underestimated, as samples were taken once per 30 day period. The risk of hyperketonæmia was higher at low than at high feeding frequencies; most odds ratios (OR) were in the range of 1.0–2.7 for two versus four meals per day. The effect of feeding frequency was most evident on high concentrate rations. A larger amount of concentrate in early lactation was deemed to increase the risk of hyperketonæmia, but not consistently so; OR ranged between 0.4 and 2.7, with highest risks for the Swedish Red and White breed. Feeding forage before concentrate and feeding the cows a meal close to milking time reduced the risk of hyperketonæmia, but the results were inconsistent. Hyperketonæmia occurred more often in herds with feeding barriers than in short stall without feeding barrier. Our findings suggest that a high feeding frequency and a cautious feeding strategy of concentrate early in lactation are important factors in the prevention of subclinical or clinical ketosis.

Calf Diseases and Mortality in Swedish Dairy Herds

A survey of the mortality and morbidity affecting calves during the first 3 months of life was carried out. Results are reported from 131 herds with altogether 5,050 calvings. These herds kept individual calf cards for all calves born. The incidences of abortions and stillborn calves were 0.6% and 3.6%, respectively. During the period 0-90 days the mortality and morbidity were 2.6% and 11.0%, respectively. The frequencies of enteritis and pneumonia in calves were 7.2% and 0.8%. Mortality and morbidity were influenced by breed, season, age of the dam and time of first colostrum. The frequencies of abortions, stillborn calves, mortality and morbidity varied considerably between herds. Herd factors influencing mortality and morbidity during different periods of time were: herd size, yield, zero-grazing, whether the calf was allowed to feed by suckling, the design of the calf pens, and previous incidence of infectious enteritis in the herd. On average, both mortality and morbidity in calves were low, though in certain herds, temporarily high frequencies were registered.

The cleanliness of cows tied in stalls and the health of their hooves as influenced by the use of electric trainers

The influence of the cleanliness of cows' stalls on the cows' own cleanliness and on the health of their hooves was investigated in 52 dairy cows tied in stalls with long stanchions from 2 October 1989 to 7 May 1990 in one Swedish dairy herd. Twenty-six of the cows were provided with electric cow trainers throughout this period, 14 did not have trainers and 12 had trainers only for the period between 7 February and 7 May. The hooves of the hind feet were evaluated for Dermatitis interdigitalis (interdigital dermatitis) and Erosio ungulae (heel-horn erosion) on 2 October, 7 February and 7 May, and on this last occasion the dry matter content of the sole horn was measured. The average number of cow-pats deposited on the floors of the stalls with electric trainers was less than one-third of the number in the stalls without them, and the cows in stalls with trainers were approximately 30% cleaner. Between October and February, heel-horn erosion increased significantly only in the cows without electric trainers, and between February and May, heel-horn erosion decreased only in the cows which were provided with trainers on 7 February. The prevalence of inter-digital dermatitis decreased in all the cows throughout the period of housing and there was no significant difference in prevalence between the different groups. The dry matter content of the sole horn was significantly greater in the cows which had electric trainers than in the cows without trainers, and the difference was significant even in the cows which had the trainers only from February to May. There was a significant negative correlation between the dry matter content of the sole horn and the level of heel-horn erosion.

Relationships between herd bovine leukemia virus infection status and reproduction, disease incidence, and productivity in Swedish dairy herds

A program has been initiated in Sweden to eradicate bovine leukemia virus (BLV) infections in dairy and beef cattle. As the first step, all dairy herds were screened in order to identify those with BLV-infected animals. The objective of this study was to ascertain possible relationships between herd BLV infection status and measures describing disease incidence, reproduction and production. BLV infection status was determined in 14 424 herds, using an enzyme-linked immunosorbent assay (ELISA) test applied to bulk-milk samples. Relationships were assessed with logistic and ordinary linear regression analyses. There were many statistically significant associations between herd BLV infection status and measures of disease incidence, reproduction and production, but most were of low magnitude. The risk for diseases with infectious etiology seemed to be greater among BLV-infected herds, while the risk for non-infectious diseases did not differ. The culling rate was higher and milk production was lower in BLV-infected vs. BLV-free herds. The effect of BLV infection on fertility was only minor.

Effect of Milk Yield on Relationship Between Bulk Milk Somatic Cell Count and Prevalence of Mastitis

The possible dilution effect of increasing milk yield on bulk milk SCC was studied in a field trial. Data on breed distribution, numbers of cows, average milk yields, average bulk milk SCC, and estimated prevalences of mastitis were available for 15,514 Swedish dairy herds. The overall mean of herd prevalence of mastitis, as estimated by the definition employed, was 26.7%, and the overall mean of the geometric average of bulk milk SCC was 204,000 cells/ml. Correlations between prevalence of mastitis and average bulk milk SCC ranged between .53 and .77, and geometric averages were only marginally more correlated to prevalence of mastitis than were arithmetic averages. The average herd prevalence of mastitis was found to increase, within bulk milk SCC level, as milk production increased. The regression coefficients of average milk yield on bulk milk SCC, estimated conditionally on mastitis prevalence, show that the bulk milk SCC decreased by 11.1% for each increase in the milk yield of 1000kg of FCM. This implies that part of the decrease in average bulk milk SCC achieved during recent years may be an artifact due to the concurrent increase in milk production.

The Influence of Age, Breed, Rearing Intensity and Exercise on The Incidence of Spavin in Swedish Dairy Cattle

The hocks of tied cows of a Swedish dairy herd of different breeds were radiographed. Osteoarthrosis of the arthrodial joints (spavin) was found in 37 % of the animals. Changes were seen before the cows were 2 years old, and they increased in severity with increasing age. Macroscopic and histologic examination revealed that there was osteoarthrosis also in many radiologically normal hocks. The study shows that the frequency of spavin in tied dairy cows is higher than clinical signs indicate. Apparently only cows with fusion of the arthrodial joints show the stiff hind leg movements considered typical of spavin. Differences in the incidence of spavin were found between the different breeds. Cows of the Swedish Friesian breed had the lowest (20%) and cows of the Jersey breed had the highest (50%) incidence of spavin. However, as regards the Jersey breed this was due to the high incidence (71%) found in cows raised on a high intensity feeding during the young stock period. Among the SJB cows raised on a normal intensity feeding the incidence of spavin was 25 %. Such a relationship between high young stock feeding intensity and the incidence of spavin was not seen within the other breeds. The cows in another herd with loose housing had a lower frequency of spavin than the tied cows. Offspring of animals with spavin had a higher incidence of spavin than the offspring of animals without spavin.