Jan Hultgren

Prevalence and interrelationships of hoof lesions and lameness in Swedish dairy cows

The prevalence of hoof lesions and lameness in 4899 heifers and cows was determined at claw trimming one time in a cross-sectional study on 101 Swedish dairy farms, 1996-1998. The percentage of affected animals was 41% for heel-horn erosion, 30% for sole haemorrhages, 27% for erosive dermatitis, 21% for abnormal claw shape, 14% for white-line haemorrhages, 8.8% for white-line fissures, 8.6% for sole ulcers, 3.3% for double soles, 2.3% for verrucose dermatitis, and 1.8% for interdigital hyperplasia (IH). Seventy-two percent of all animals had at least one hoof lesion. The prevalence of lameness was 5.1%; most hoof lesions did not cause lameness. Differences between herds were substantial; the herd-specific, animal-level prevalence of lesions ranged from 25 to 98% and of lameness from 0 to 33%. Sole haemorrhages were found in all herds. The proportion of variance at the between-herd level was particularly high for heel-horn erosion (62%) and abnormal claw shape (54%). Strong correlations between lesions were found within hooves (and animals), e.g. for heel-horn erosion and dermatitis (Spearmans rank correlation, r(s)=0.36 and 0.37, respectively) and for sole and white-line haemorrhages (r(s)=0.25 and 0.28). Most hoof lesions affected hind and front hooves bilaterally, whereas the correlation between hind and front hooves generally was lower. Herds that ranked high for prevalence of sole ulcer also ranked high for sole haemorrhages and for abnormal claw shape and herds that ranked high for dermatitis also ranked high for heel-horn erosion, verrucose dermatitis and IH. Abnormal claw shape was strongly associated with sole ulcer (r(s)=0.41 at cow level)-suggesting the importance of maintaining a correct claw shape for the prevention of hoof-horn lesions.

The effect of claw trimming on the hoof health of Swedish dairy cattle

A 2-year experiment on the effect of claw trimming on hoof health was performed in 77 Swedish dairy herds (3444 dairy cattle) selected on herd size, breed composition and membership in the official milk-recording scheme. In the autumn, cows within each herd were blocked according to breed, parity and stage of lactation and allocated to two treatments: autumn trimming (AT) or no autumn trimming (NAT). Outcome variables were claw measurements and prevalence of hoof lesions and lameness (measured at spring trimming) and the need for hoof treatments between scheduled trimmings. At spring trimming, NAT cows had longer and shallower claws than AT cows. The average net growth of the toe wall was greater for AT than for NAT cattle, with a marked variation between housing systems. Most hoof lesions present at AT had disappeared at the subsequent spring trimming. Controlled for clustering by herd-within-year and for the effects of individual-and herd-level covariates, AT cattle at spring trimmings had significantly lower odds of lameness (OR=0.66) and of haemorrhages of the sole or white-line (OR=0.86), sole ulcer (OR=0.59) and white-line fissure or double sole (OR=0.71)-but not of moderate-to-severe heel-horn erosion or dermatitis (OR=0.96). Acute hoof treatments between claw trimmings were more common in the NAT group (OR=2.02).

Metabolic profiles in five high-producing Swedish dairy herds with a history of abomasal displacement and ketosis

BackgroundBody condition score and blood profiles have been used to monitor management and herd health in dairy cows. The aim of this study was to examine BCS and extended metabolic profiles, reflecting both energy metabolism and liver status around calving in high-producing herds with a high incidence of abomasal displacement and ketosis and to evaluate if such profiles can be used at herd level to pinpoint specific herd problems.MethodsBody condition score and metabolic profiles around calving in five high-producing herds with high incidences of abomasal displacement and ketosis were assessed using linear mixed models (94 cows, 326 examinations). Cows were examined and blood sampled every three weeks from four weeks ante partum (ap) to nine weeks postpartum (pp). Blood parameters studied were glucose, fructosamine, non-esterified fatty acids (NEFA), insulin, β-hydroxybutyrate, aspartate aminotransferase, glutamate dehydrogenase, haptoglobin and cholesterol.ResultsAll herds had overconditioned dry cows that lost body condition substantially the first 4–6 weeks pp. Two herds had elevated levels of NEFA ap and three herds had elevated levels pp. One herd had low levels of insulin ap and low levels of cholesterol pp. Haptoglobin was detected pp in all herds and its usefulness is discussed.ConclusionNEFA was the parameter that most closely reflected the body condition losses while these losses were not seen in glucose and fructosamine levels. Insulin and cholesterol were potentially useful in herd profiles but need further investigation. Increased glutamate dehydrogenase suggested liver cell damage in all herds.

Blood profiles in dairy cows with displaced abomasum

An observational study was carried out in Swedish dairy herds to investigate differences between cows with and without displaced abomasum (DA), in concentrations of glucose, insulin, fructosamine, nonesterified fatty acids (NEFA), β-hydroxybutyrate, cholesterol, haptoglobin, increased enzyme activity of aspartate aminotransferase and glutamate dehydrogenase, and the revised Quantitative Insulin Sensitivity Check Index (RQUICKI). A secondary aim was to study how blood profiles for DA cows vary with time in relation to calving. Sixty-nine DA cows within 2 to 56 d postpartum, in 60 herds, were clinically examined and blood samples were drawn at the time DA was diagnosed. At the same time, 104 healthy control cows matched by herd and stage of lactation were also sampled. The blood parameters were studied using mixed linear models, including herd as a random effect, and DA (case or control), parity, breed, sampling time in relation to calving, other diseases, and the interaction between DA and time as fixed effects. Concentrations were higher in DA cows than in control cows for NEFA (least squares means 1.36 vs. 0.34 mmol/L), β-hydroxybutyrate (1.56 vs. 0.90 mmol/L), aspartate aminotransferase (1.96 vs. 0.97 μkat/L), glutamate dehydrogenase (197 vs. 78 μkat/L), and haptoglobin (0.76 vs. 0.17 g/L), whereas concentrations were lower in DA cows than in control cows for insulin (3.61 vs. 8.48 mU/L) and cholesterol (3.04 vs. 3.75 mmol/L). Glucose (2.83 vs. 2.79 mmol/L) and fructosamine (266 vs. 252 μmol/L) concentrations were similar in both groups; however, a tendency toward lower RQUICKI values (0.42 vs. 0.46) in the DA cows was found, indicating reduced insulin sensitivity. For most blood parameters, differences between DA cows and controls remained constant over time. Seventy-two percent of the DA cows had at least one other disease in the period from 1 wk antepartum to 1 wk after the DA was diagnosed. Haptoglobin could potentially be used to detect treatable infectious or inflammatory conditions in the early postpartum period, possibly reducing the incidence of DA. Consequently, there were major changes in blood profiles in cows with DA compared with healthy control cows, indicating a negative energy balance, liver cell damage, and an inflammatory response. The results contribute to an understanding of the metabolic changes in DA cows.

Associations Between Housing, Management, and Morbidity During Rearing and Subsequent First-Lactation Milk Production of Dairy Cows in Southwest Sweden

Information regarding health, management, and housing from birth to first calving was collected for 1,029 Swedish Reds, 991 Swedish Holsteins, and 40 heifers of crossbreed or other breeds on bimonthly farm visits made by 3 project veterinarians to 107 dairy herds in southwest Sweden. Additional data were obtained from the official milk- and health-recording program. Milk production at first test day after calving [energy-corrected milk (ECM)1] and during the first 305 d of lactation (ECM305), respectively, were analyzed by 2-level (animal; herd) linear regression, after initial screening by univariable analyses of 67 potentially important predictors. The ECM1 ranged from 7.9 to 48.0 (median = 27.1) kg, and ECM305 ranged from 3,764 to 12,136 (median = 8,006) kg. In the final models, factors associated with ECM1 or ECM305 or both were age at first calving, body condition score at first service, breed, calfhood diarrhea, calving season, composite somatic cell count at first test day, daily weight gain from weaning to first service, housing system after calving, and increase in concentrate fed around calving. Higher age at calving was associated with higher production. Production also increased with higher daily weight gains from weaning to first service. Swedish Holsteins produced more than Swedish Reds, cows calving in May to September produced more than those calving during other months, and cows housed in short stalls after calving produced more than those in cubicles. Body condition scores > or =3.2 at first service were associated with lower ECM305 than scores < or =2.9. Animals that contracted mild diarrhea during their first 3 mo of life had lower ECM305 than animals without diarrhea, whereas animals receiving a high increase in concentrate pre- and postcalving had higher ECM305 than those subjected to a more moderate increase. Cows with a composite somatic cell count >1 million cells/milliliter at first test day produced less milk on the same day than cows with lower counts. It was concluded that rearing factors and calfhood health status can influence first lactation milk production.

Heifer rearing conditions affect length of productive life in Swedish dairy cows

Associations between rearing conditions and the risk of culling in dairy cows were studied by survival analysis. Data were collected from 1039 Swedish Red cows, 1029 Swedish Holsteins, and 56 cows of other milk or cross-breeds, representing all female animals born in 109 Swedish herds during 1998. Length of productive life was defined as the number of days from 1st calving to culling. The applied Weibull proportional hazards model included time-independent effects of breed, housing from 3 to 7 months of age, number of housing changes before calving, grazing before 1st calving, herd median age at 1st calving, age at 1st calving, cow housing, herd lactational incidence risk of veterinary-reported clinical mastitis, and the random effect of herd. Time-dependent effects were year, month, the interaction year by month, parity, number of breedings, pregnancy status, the interaction parity by pregnancy status, herd mean milk-production level, relative milk yield within breed-parity, and veterinary-reported clinical mastitis. The lactation was divided into six stages in which pregnancy status was assumed to be known by the farmer and culling could occur. Median productive life time in culled cows was 780 d and 14% of the records were censored due to terminated data collection. An individual calving age of 28.2-30.9 months was associated with the highest culling risk, 1.2-fold higher than calving at < or = 25.3 months, whereas the risk decreased almost linearly with a higher herd median age at 1st calving. Housing in slatted pens with >7 calves from 3 to 7 months was associated with a 1.7-fold increase in risk, relative to litter pens. If a cow had changed housing system 4 times before 1st calving it increased the risk of culling 1.4 times, relative to two housing changes. These results show that rearing factors affect the productive life time of dairy cows in Swedish family operations.

Evaluating the efficacy of serum haptoglobin concentration as an indicator of respiratory-tract disease in dairy calves

Abstract The serum concentration of haptoglobin (S-Hp) was measured in 833 group-housed dairy calves from nine herds in south-west Sweden once at 24–56 days of age to evaluate the potential of S-Hp as an indicator of clinical respiratory-tract disease (CRD). Presence of disease (treated and non-treated) was assessed clinically by farmers and by a project veterinarian visiting the farms every third week. The median S-Hp of healthy calves was 0.06g/L (80% central range: 0.04–0.23), of calves with diarrhoea within the 10 days before sampling 0.07g/L (80% central range: 0.04–0.63), and of calves with CRD within the 14 days before sampling 0.09g/L (80% central range: 0.04–0.69). Eight different cut-off values were used to define a positive S-Hp analysis result: >0.05, >0.06, >0.07, >0.08, >0.09, >0.10, >0.15 and >0.20g/L. A rectal temperature >39.5°C was denoted as fever. A positive result of five different diagnostic tests for CRD was defined as: (1) a positive S-Hp with fever absent, (2) a positive S-Hp with fever present, (3) either a positive S-Hp or fever, (4) both a positive S-Hp and fever, and (5) fever (regardless of S-Hp). The sensitivity (Se) and specificity (Sp) of each test were calculated from regression coefficients of generalized linear mixed models of the binary test results, applying a logit link. Apart from CRD status (within the 14 days before sampling; no or yes), the models included sex (bull or heifer), and for the test based on S-Hp alone, also rectal temperature (fever, no or yes). Confidence intervals (CI) of Se and Sp were estimated by simulation. Based on Se, Sp, and areas under Receiver Operating Characteristics curves, test 3 was considered the best. At optimal performance, giving equal importance to type I and II errors, i.e. at a S-Hp cut-off of 0.15g/L in heifer calves, Se was 0.64 (95% CI 0.50–0.77) and Sp 0.71 (95% CI 0.60–0.80), and at a S-Hp cut-off of 0.08g/L in bulls, Se was 0.52 (95% CI 0.40–0.64) and Sp 0.80 (95% CI 0.74–0.85). The other tests were judged as unsatisfactory indicators of CRD. In heifers, the proportion of CRD-positive calves in the herd was strongly associated with the proportion of test positives (S-Hp or fever; S-HP and fever), suggesting potential as a herd-level indicator.

Rearing conditions, morbidity and breeding performance in dairy heifers in southwest Sweden.

We carried out a longitudinal study of 122 dairy herds in southwest Sweden to investigate relationships of rearing conditions and health with heifer breeding performance and to estimate the incidence of clinical diseases and survival until 1st calving. A total of 3081 animals born in 1998 (47% Swedish Red; 50% Swedish Holstein breed) were followed from birth until calving, culling or death. Information about housing, management, breeds and dates of birth, breeding and calving was obtained from farmers. Diseases were recorded by farmers and veterinarians; antibiotic treatment was used in < 25% of all cases. Median time to breeding was 17.5 months, 64% of all heifers bred by AI conceived at 1st breeding, and median time to calving was 27.6 months. Age at 1st breeding (log-transformed), conception at 1st breeding (binary), and age at 1st calving (log-transformed) were analysed with three mixed models, accounting for clustering by considering random-intercept and random-slope effects at the herd level. Around 40 potential predictors or confounders were recorded and considered for modelling. Time to breeding and calving increase greatly with the time heifers spend grazing, although up to 5 months of grazing before 1st calving appears to be more favourable than no grazing at all. The effect of grazing differs depending on the season of birth. Zero-grazed heifers calve 20% later if exposed to indoor ammonia concentrations > 10 ppm after start of breeding. There is considerable variation between herds in breeding performance, except for conception at 1st breeding-limiting the potential for improving conception by herd measures. Observed total disease incidence rate was 14 per 100 animal-years from 7 months of age to estimated conception and 4.7 per 100 animal-years from conception to calving, with great variation between herds. Infectious diseases were predominant, and diarrhoea, respiratory disease and ringworm were the most common diagnoses. Eight hundred and fifty-three heifers left the study before calving, due to herd exits (incidence risk 0.073%), selling off live (0.061%), spontaneous deaths (0.050%) or slaughter (0.092%).

Perceived Physical and Psychosocial Exposure and Health Symptoms of Dairy Farm Staff and Possible Associations with Dairy Cow Health

The aim of this study was to gain a deeper understanding of work-related physical and psychosocial exposure and health symptoms of farm staff working in indoor loose-housing dairy systems in Sweden, and to examine possible associations between exposure and health symptoms of farm staff and disease incidence in their dairy herds. A sample of 41 farm owners or managers and 20 directly employed farm workers participated, each from a Swedish dairy farm with loose-housed cows. Mailed questionnaires comprising 29 questions were used to create four separate indices representing physical exposure, psychosocial exposure, physical symptoms, and psychosocial symptoms. Cow herd incidence rates of common veterinary-reported clinical diseases were calculated based on official records. Partial Spearman rank correlation was used to analyze associations. The study confirmed that physical and psychosocial exposure and health symptoms are not uncommon among owners/managers and employed workers. The study also found that farm owners/managers experience more physical symptoms in dairy herds with lower cow disease incidence rates, while more frequent or intensive exposure to negative psychosocial work environment factors among employed dairy workers is associated with a high herd disease incidence rate.

Pup mortality in laboratory mice - infanticide or not?

BackgroundDespite being the most commonly used mammal in biomedical research, problems with perinatal mortality in mice have received little attention and the causes of pup death are still poorly known. Females are often housed alone with their litters and since the lost pups are generally eaten, it is commonly assumed that the mother has killed them. However, more detailed observations than have been reported previously in the literature are required to establish if the cause of death is infanticide. Litter loss can only be prevented efficiently after underlying causes have been carefully investigated and interpreted. The aim of this study was to investigate if females actively kill their pups by observing the behaviour of females and pups in litters that later were lost. We used video recordings of females that lost their entire litter to observe females in detail from parturition until the pups died. In total, 10 C57BL/6 females (wildtype and the knockouts Hfe−/− and β2m−/−) were studied, housed in Makrolon II cages with or without access to a small amount of nesting material.ResultsThree of the females had pups that were never seen moving, and another three females had one or two pups that never moved, indicating that some pups were most likely still-born. In five females with live-born pups, detailed observations from the time when a pup was last seen moving until it died were possible to carry out. We observed females eating dead offspring and interacting with both moving and dead pups. However, we never observed a pup stop moving when manipulated by the female, nor were any wounds seen in the pups. Hence, we found no evidence of infanticide when studying females that had lost their entire litter.ConclusionThese results suggest that other causes than infanticide plays a major role in mouse pup death, and stress the need for more systematic and careful investigations of the causality of litter loss.