Serum amyloid A and TNF alpha in serum and milk during experimental endotoxin mastitis

A cross-over study was conducted to investigate the effect of intramammarily infused lipopolysaccharide (LPS) on the acute phase reaction in early (EL) and in late (LL) lactation. Nine cows received intramammary injections of 100 microg of Escherichia coli 0111:B4 LPS during EL and LL. The severity of each cows systemic and local signs and change in milk appearance were recorded and scored throughout the experiment. Systemic and local signs were found to be more serious in EL cows. Tumor necrosis factor alpha (TNF alpha) was detected in milk but not in serum. Serum amyloid A (SAA) concentrations increased both in serum and in milk. The milk TNF alpha concentrations peaked at 8 h post-challenge (PC). SAA concentrations started to increase at 8 h PC, and peak concentrations were seen at 32 and 48 h PC in milk and serum, respectively. The milk TNF alpha and SAA seemed to be correlated, being on average higher in EL. Serum SAA concentration was not correlated with milk TNF alpha or SAA, nor with the severity of local or systemic signs, but was correlated with changes in milk appearance.     

Disposition kinetics of lactoferrin in milk after intramammary administration

Disposition kinetics of lactoferrin (Lf) purified from cheese whey was studied in the milk of Finnish Ayrshire cows after intramammary administration of 1 g of Lf into one udder quarter. Intramammary administration of 1 g of Lf increased Lf concentration in milk for several hours. Mean elimination half-life of Lf was 2.2 h and a mean maximum concentration of 6.3 g/L was reached between 1 and 4 h. After 8 h of administration, Lf concentrations in milk decreased to almost the same level as before the infusion. Forty-eight hours postinfusion, the mean Lf concentration was again higher than in the milk samples taken before the infusion of Lf, being on average 1.5 g/L. Lactoferrin caused some local tissue irritation in the udder quarter. Severity of the irritation reactions varied between cows. The udder quarters of primiparous cows reacted faster than those of multiparous cows, but irritation reactions decreased more rapidly in the older cows than in primiparous cows. The cows had no general signs such as fever or anorexia. The somatic cell count returned to baseline level 4 days after the administration.     

Efficacy and pharmacokinetics of enrofloxacin and flunixin meglumine for treatment of cows with experimentally induced Escherichia coli mastitis

The efficacy of flunixin alone and together with enrofloxacin in treatment of experimental Escherichia coli mastitis was compared using six cows. The cross-over study design was used. Pharmacokinetics of flunixin and enrofloxacin were also studied in these diseased cows. The response of each cow was similar after the first and second challenge and the individual reaction seemed to explain the severity of clinical signs. The most important predictive factor for outcome of E. coli mastitis was a heavy drop in milk yield. Treatment with enrofloxacin and flunixin enhanced elimination of bacteria, but the difference from those receiving flunixin alone was not significant. Two cows, which had received no antimicrobial treatment (Group 1), were killed on day 4 postchallenge. One cow was killed after the first and the other after the second challenge. Cows receiving combination therapy produced 0.9 L more milk per day during the study period than cows which had only received flunixin (P < 0.05). Based on our findings, antimicrobial treatment might be beneficial in the treatment of high-yielding cows in early lactation. The absorption of enrofloxacin was delayed after subcutaneous administration, the mean apparent elimination half-life being about 23 h, whereas after i.v. administration elimination t(1/2) was only 1.5 h. The majority of the antimicrobial activity in milk originated from the active metabolite, ciprofloxacin, which could be measured throughout the 120-h follow-up period after the last subcutaneous administration. No differences were present in the pharmacokinetic parameters of flunixin between treatment groups: mean elimination half-life was 5.7-6.2 h, volume of distribution 0.43-0.49 L/kg and clearance 0.13-0.14 L h/kg. No flunixin or merely traces were detected in milk: one of the three cows had a concentration of 0.019 mg/L 8 h after administration.     

Acute phase response in two consecutive experimentally induced E. coli intramammary infections in dairy cows

Background

Acute phase proteins haptoglobin (Hp), serum amyloid A (SAA) and lipopolysaccharide binding protein (LBP) have suggested to be suitable inflammatory markers for bovine mastitis. The aim of the study was to investigate acute phase markers along with clinical parameters in two consecutive intramammary challenges with Escherichia coli and to evaluate the possible carry-over effect when same animals are used in an experimental model.

Methods

Mastitis was induced with a dose of 1500 cfu of E. coli in one quarter of six cows and inoculation repeated in another quarter after an interval of 14 days. Concentrations of acute phase proteins haptoglobin (Hp), serum amyloid A (SAA) and lipopolysaccharide binding protein (LBP) were determined in serum and milk.

Results

In both challenges all cows became infected and developed clinical mastitis within 12 hours of inoculation. Clinical disease and acute phase response was generally milder in the second challenge. Concentrations of SAA in milk started to increase 12 hours after inoculation and peaked at 60 hours after the first challenge and at 44 hours after the second challenge. Concentrations of SAA in serum increased more slowly and peaked at the same times as in milk; concentrations in serum were about one third of those in milk. Hp started to increase in milk similarly and peaked at 36–44 hours. In serum, the concentration of Hp peaked at 60–68 hours and was twice as high as in milk. LBP concentrations in milk and serum started to increase after 12 hours and peaked at 36 hours, being higher in milk. The concentrations of acute phase proteins in serum and milk in the E. coli infection model were much higher than those recorded in experiments using Gram-positive pathogens, indicating the severe inflammation induced by E. coli.

Conclusion

Acute phase proteins would be useful parameters as mastitis indicators and to assess the severity of mastitis. If repeated experimental intramammary induction of the same animals with E. coli is used in cross-over studies, the interval between challenges should be longer than 2 weeks, due to the carry-over effect from the first infection.     

Physiological responses to continuous swimming in wild salmon (Salmo salar L.) parr and smolt

Wild salmon (Salmo salar) parr and smolt were forced to swim against constant flow (50 cm.s^–1) for 8 hours. Physiological properties describing the hormonal status, the energy metabolism and the ionic and osmotic balance of fish were measured from the fish prior to and at the end of the swimming test.Plasma cortisol levels were elevated in response to enforced swimming; the response of the smolt was clearly greater than that of the parr. Plasma thyroxine concentration increased in the parr but stayed at the initial level in the smolts. The parr consumed much of their coelomic fat, but the glycogen stores stayed nearly constant. The smolts had very low fat stores, and the glycogen stores were depleted in the test. The ionic and osmotic balance of the parr was stable in the test, but in smolts, the plasma Cl^–1 and osmotic concentrations decreased and muscle moisture increased.The results indicate that downstream migration smolts have markedly lower physiological capacity for continuous swimming than parr.     

Measurement of wind-induced motion of crop canopies from digital video images

We present a new measurement technique based on image correlation to capture the wind-induced motions of crop canopies. Tests were carried out on an alfalfa field submitted to natural wind. The motion is video-recorded from the side of the field and we take advantage of the natural periodicity of the crop to correct the distortion due to perspective. The computation of the canopy motions between successive images is based on Particle Image Velocimetry (PIV), and takes advantage of the natural small-scale heterogeneities of the canopy. It provides the two-dimensionnal spatio-temporal velocity field of the crop top surface with high spatial and temporal resolution. The Bi-Orthogonal Decomposition (BOD) of the velocity field then reveals large coherent propagating structures that scale with typical wavelength of wind fluctuation over canopies.     

Using optimization for fitting individual-tree growth models for uneven-aged stands

A convenient model type for simulating the dynamics of uneven-aged and uneven-sized stands of Finland is individual-tree model. This is because the stand structures are complex due to the presence of several tree species and irregular size distributions of trees. The required minimum set of models in this approach consists of species-specific individual-tree diameter increment models, individual-tree survival models, and ingrowth models. The development of these models needs data in which the diameter and survival of each tree of the sample plots is known for at least two time points. For this, the trees need to be numbered, which is tedious in uneven-aged forests due to the great number of small trees and the continuous ingrowth process. This study proposes a modelling approach that fits the above models but requires only the diameter distributions of the plots in the beginning and at the end of the measurement interval. The method uses non-linear optimization to derive such values for model parameters that, when the models are applied to the initial diameter distribution, the simulated stand development results in a diameter distribution which agrees with the measured ending distribution. The study showed that the method produces similar models and model parameters as regression analysis. Since the method is less demanding in terms of modelling data, it brings new data sets available for modelling the dynamics of uneven-aged stands and reduces the cost of collecting new data. The models fitted by the proposed optimization method were rather similar to the models developed earlier for Finnish uneven-aged forests.     

Indicators of inflammation in the diagnosis of mastitis

Mastitis affects the quality of milk and is a potential health risk for the other cows. In a well managed dairy herd, in addition to clinical mastitis, subclinical mastitis should be efficiently detected. Bacteriological sampling is not feasible as a routine test to identify subclinical mastitis, and indirect tests of mastitis are more suitable for selecting cows with intramammary infections for subsequent bacteriological sampling. Mastitis affects the composition of milk, and the degree of changes depends on the infecting agent and the inflammatory response. Indicators of inflammation in the milk which can be determined using rapid, reliable and easy routine techniques, can be used for the early detection of mastitis. The measuring of the somatic cell count in milk is the standard method, but the analysis technique is problematic for routine use in herds. The most promising parameters for monitoring subclinical mastitis are milk N-acetyl-beta-D-glucosaminidase activity, lactose, and electrical conductivity along with some other indicators such as optical and milk flow measurements, preferably with an inter-quarter evaluation included in the test. Acute phase proteins, haptoglobin and serum amyloid A, are also potential candidates for mastitis monitoring. New mastitis detection systems which can be adapted into on-line use are urgently needed, since dairy units are growing bigger and automatic milking systems are being taken into use.