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

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 degrees 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.

The effect of group size on health and growth rate of Swedish dairy calves housed in pens with automatic milk-feeders.

Group pens equipped with automatic milk-feeding systems are increasingly being used for young dairy calves in Sweden. The system is, however, associated with an increased risk of clinical respiratory-tract disease and a reduced growth rate. In an experimental study we compared the health and growth rate of two different group sizes of calves (6-9 versus 12-18) kept in pens with automatic milk-feeders. The experiment was performed from September 2002 to February 2004, in nine commercial dairy farms in south-west Sweden. Each farm was equipped with two pens with automatic milk-feeders and no possibility of direct contact between calves from different pens. The calves were housed individually until 3-35 (median, 12) days of age, and then were allocated to one of the two group pens by random-number lists. Altogether 892 calves were studied: 297 in the small- and 595 in the large-sized groups. The calves' heart girths were measured at birth and at 56 days of age. Blood samples for analysis of serum haptoglobin concentration (S-Hp) were collected once for each calf, at four to eight weeks of age. Diseases were recorded by the farmers and by a veterinarian, who visited the farms every third week and physically examined all the calves. The effects of group size on the risks of diarrhoea, clinical respiratory-tract disease and increased respiratory sounds, and on the growth rate and S-Hp were evaluated using multiple logistic- and linear-regression models with herd as fixed effect. Age at transfer to group pen, breed, immunoglobulin concentration of colostrum received, parity of the dam and presence of diarrhoea before transfer to the group pen, season, sex, year, and, in the analysis of growth rate, birth heart girth were extra explanatory variables. Calves in pens for 12-18 calves had a higher incidence of respiratory illness (OR: 1.4) and grew 0.022 cm/day less than calves housed in groups of 6-9 animals (equivalent to approximately 40 g/day). We detected no differences between calves kept in the small-sized versus the large-sized groups in terms of risk of diarrhoea or mean S-Hp. We concluded that housing calves in groups of under 10 calves is preferable from a health and growth perspective.

Dam-related effects on heart girth at birth, morbidity and growth rate from birth to 90 days of age in Swedish dairy calves.

We investigated the effects of dam-related factors (such as calving performance, milk leakage, diseases, milk production, and somatic-cell count (SCC)) on heart girth at birth and the incidence risk of diarrhoea and respiratory disease during the first 90 days in Swedish dairy calves. The effects of these dam-related factors and environmental and management-related (but not dietary) factors on the calves' growth rate during the first 90 days of life also were analysed. The study used nearly 3,000 heifer calves born in 1998 on 122 farms in the south-west of Sweden. Individual health records were kept by the farmers and visiting project veterinarians. The calf's heart girth was measured at birth and weaning. We used generalised linear mixed models for the size of the calf at birth and growth rate. Variables associated with the heart girth at birth were breed, calving performance, mastitis in the dam in the last 49 days before calving, milk production and parity. Variables associated with the growth rate were breed, calving performance, disease in the calf during its first 90 days of life, heart girth at birth, and housing of calves. The effect of the dam on the relative risk of diarrhoea and/or respiratory disease in the calf was evaluated by a generalised linear mixed model with a logit link. Morbidity in the dam during late pregnancy, retained placenta and SCC were associated with the relative risk of respiratory disease in the calf. None of the explanatory variables (other then breed) was associated with the relative risk of diarrhoea.

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.

Ultrasonography and determination of proteins and enzymes in blood for the diagnosis of liver abscesses in intensively fed beef cattle.

The concentrations of plasma proteins and the activities of liver enzymes were measured every 2 weeks from weaning to slaughter in 21 beef cattle, and their livers were examined ultrasonographically every 4 weeks. Eight of the 9 cases of single or multiple liver abscesses were detected by ultrasonography but some individual abscesses, particularly those in the left side of the liver, remained undetected. The time at which the abscesses were first detected ranged from 4 to 20 (mean 12.5) weeks. There were only slight variations in the blood constituents and they were of no significant value in the diagnosis of the liver abscesses.

[Glutaraldehyde test on whole blood of swine at slaughter--a preliminary report]. / Helblodstestning med glutaraldehyd vid svinslakt--en preliminär undersökning.

In an initial experiment the highest concentration of a glutaraldehyde solution that does not coagulate whole blood of fatteners without or with only slight pathological changes was established. Total protein, albumin, globulin, A/G ratio and electrophoretic protein pattern were at the same time determined in blood serum. A glutaraldehyde solution with the established highest concentration was used in a second experiment on whole blood to distinguish fatteners without or with only small pathological changes from those with severe processes such as abscesses and purulent arthritis. It is evident that the glutaraldehyde test gives a good idea of the immunoglobulin status of fatteners. There is reason to believe that systematized glutaraldehyde testing of whole blood taken at pig slaughter could improve the chances of detecting concealed inflammatory processes.

Studies on the synovia in healthy horses with particular reference to the protein composition.

Synovial fluid and blood were collected from 18 clinically healthy brood mares in resting conidition. The following parameters were analysed: total leucocytes, glucose, alkaline phosphatase (AP), lactate dehydrogenase (LDH), total protein, albumin, total globulin, albumin/globulin ratio and electrophoretic protein picture. The serum/synovia ratios were calculated for all parameters. It was considered to be of greater diagnostic value to compare these serum/synovia ratios rather than to look at the individual concentrations in synovia. The results obtained did not materially differ from those in the existing literature. In addition, this study confirmed that small protein molecules could more easily penetrate the synovial membrane than high-molecular proteins.