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Rupert M Bruckmaier

Publications and source records attributed to Rupert M Bruckmaier.

12 recordsLinked to original sources
PubMed2006

Use and relevance of a bovine mammary gland explant model to study infection responses in bovine mammary tissue.

Our aim was to develop an explant model to define more precisely the early response of bovine mammary epithelial cells to infection. Therefore we investigated the mRNA expression encoding for some soluble immunological factors in lipopolysaccharide (LPS)-treated bovine mammary gland explants. Explants were taken out from the mammary gland of eight lactating cows after slaughter then incubated with LPS (10 mug/ml) for 6 h. The mRNA expression of alpha-lactalbumin (alpha-la), various cytokines, tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, IL-8, and two immunoglobulin receptors, the neonatal Fc receptor (FcRn) and polymeric immunoglobulin receptor (pIGR), were assessed with qPCR before and after 3 h and 6 h of LPS challenge. Both immunoglobulin receptors and alpha-la increased at 3 h then recovered their initial level at 6 h whereas IL-1beta, IL-6 and IL-8 increased only after 6 h (P<0.05). Surprisingly, TNF-alpha transcripts did not show any regulation in response to the LPS treatment. We nevertheless concluded that our model was valid to examine the short-term response of mammary epithelial cell challenged with LPS.

Animals↗
PubMed2006

Hypertonic NaCl infusions affect milk composition in goats.

The capability of goats to maintain milk production during water deprivation is remarkable and not yet fully understood. The aim of the present study was to investigate whether intravenous infusions of hypertonic NaCl cause release of both vasopressin and oxytocin and whether the peptides, in combination with the hyperosmolality, affect milk flow and milk composition. Six Swedish domestic landrace goats in their first to third lactation were milked every 30 min during experiments. Hypertonic NaCl (HNaCl) or isotonic NaCl (IsoNaCl) were infused for 90 min. Goats were not allowed to drink during infusions. Plasma vasopressin concentration increased during HNaCl infusions, and did not change in response to IsoNaCl infusions. Plasma oxytocin concentration did not change during either infusion. Milk flow was maintained during the infusions. Milk fat concentration decreased in the three samples taken before onset of the infusions, but then increased gradually during HNaCl infusions, while it continued to fall during the IsoNaCl infusions. Milk osmolality followed the rise in plasma osmolality during the HNaCl infusions and did not change in IsoNaCl experiments. Milk lactose concentration increased throughout both series of experiments, the concentration being higher during HNaCl infusions. Milk protein concentration did not change during HNaCl infusions, but fell in the IsoNaCl experiments. It is concluded that the hyperosmolality in combination with elevated plasma vasopressin levels did not disturb the secretory activity of the mammary cells, but rather facilitated emptying of the alveolar milk. Such a mechanism may help to explain the sustained milk production in water deprived goats.

Animals↗
PubMed2006

Oxytocin release and lactation performance in Syrian Shami cattle milked with and without suckling.

Oxytocin (OT) release and lactation performance in primiparous Syrian Shami cows were evaluated in response to two different machine milking regimes. Six cows were milked in the presence of the calves (PC) and subsequently suckled, whereas six cows were exclusively machine milked without the presence of their calves (WC) until day 91 post partum. Milk yield and milk constituents were determined weekly. The degree of udder evacuation was determined by the succeeding removal of residual milk. PC released OT during the milking process, whereas in WC no OT release was detected throughout the milking process. Consequently, the residual milk fraction was much lower in PC than in WC (11% v. 58%, P<0.05) and daily milk yield until day 91 post partum was higher in PC than in WC (12.6+/-0.3 v. 7.1+/-0.4 kg, P<0.05). In conclusion, Syrian Shami cattle are not suitable to be exclusively machine milked without the presence of their calves.

Animals↗
PubMed2005

Effect of different milking routines on milking-related release of the hormones oxytocin, prolactin and cortisol, and on milk yield and milking performance in Murrah buffaloes.

Milking-related release of oxytocin, prolactin, and cortisol was studied following three premilking treatments. Six Murrah buffaloes were treated with direct application of milking cluster (O), a 1-min pre-stimulation (M), and combined feeding and pre-stimulation (MF). Machine milk yield, stripping yield and milk composition were recorded. Milk ejection occurred significantly earlier with MF than M and O (P<0.05; 2.50, 5.10 and 6.33 min, respectively). In all treatments, milk ejection occurred with small increases >3-5 ng/l in oxytocin concentration. Increase in oxytocin concentration over a threshold level and milk ejection occurred simultaneously and were closely correlated (r=0.83, P<0.05). There was a positive correlation between total time oxytocin concentration remained elevated over threshold levels and machine yield (r=0.86, P<0.05). For treatment O, milk ejection was inhibited during machine milking, while a marked increase in oxytocin occurred during hand stripping (6 and 16 ng/l, respectively). For treatment M, mean oxytocin concentrations remained unchanged during prestimulation but increased during subsequent machine milking and hand stripping (6.38, 18.06 and 12.36 ng/l, respectively). For treatment MF, although there was a 3.6-fold increase during pre-stimulation, oxytocin increased by 10-fold and 3-fold during machine milking and hand stripping, and was significant for machine milking (P<0.05, 17.32, 47.86, 18.13 ng/l, respectively). Milk-ejection-related cortisol release was visible only in treatment MF. For treatments O and M, prolactin concentration increased prior to the increase in oxytocin. The stripping yield was higher, and fat content in the stripping yield significantly lower, for treatment O indicating incomplete milking. Thus buffaloes are easily disturbed even by small changes in milking routines.

Animals↗
PubMed2005

Gene expression of factors related to the immune reaction in response to intramammary Escherichia coli lipopolysaccharide challenge.

Pathogenic microorganisms invading the mammary gland induce an inflammatory reaction which includes an increase of somatic cells in milk and activation of bacteriostatic enzymes and proteins in milk. During spontaneously occurring subclinical mastitis the somatic milk cells, mainly macrophages, secrete cytokines, eicosanoids, acute phase proteins and other immunomediators. In contrast, the bacteriostatic protein lactoferrin is mainly secreted by mammary epithelial tissue, while major milk proteins like alpha-lactalbumin and kappa-casein are down-regulated already during subclinical infection. Changes of the mRNA expression of various immunomediators in the mammary tissue of cows during 12 h after induction of mastitis via intramammary administration of lipopolysaccharide (LPS) in several studies are reported. Six healthy lactating cows were injected in one quarter with 100 microg Escherichia coli-LPS (O26: B6) and the contralateral quarter with saline (9 g/l) serving as control. mRNA expression in mammary biopsy samples of various inflammatory factors and milk proteins at 0, 3, 6, 9 and 12 h after LPS administration was quantified by real-time reverse transcription-PCR. In LPS-challenged quarters tumour necrosis factor alpha and cyclooxygenase-2 mRNA expression increased to their highest values (P<0.05) at 3 h after LPS-challenge. Expression of lactoferrin, lysozyme, inducible nitric oxide synthase, and of the apoptotic factors caspase-3, caspase-7 and FAS was elevated (P<0.05) and peaked at 6 h after challenge. No significant increase in mRNA expression of platelet-activating factor acethylhydrolase, 5-lipoxygenase, and insulin-like growth factor 1 was found. None of the parameters tested did change significantly in the control quarters. mRNA expression of major milk proteins did not change significantly in response to the LPS challenge (alphaS1-casein, alphaS2-CN, beta-CN and beta-lactoglobulin) except for alpha-lactalbumin which decreased (P<0.05) in LPS-treated and control quarters and for kappa-CN which decreased in the LPS-treated quarters. In conclusion, mRNA expression of the majority albeit not all inflammatory factors changed within hours of LPS challenge. Decreased gene expression of alpha-lactalbumin and kappa-CN may reduce milk yield and suitability for cheese production.

Animals↗
PubMed2005

Distribution of leucocyte populations, and milk composition, in milk fractions of healthy quarters in dairy cows.

The goal of the study was to evaluate the composition of leucocyte populations in different milk fractions as a basis on which to judge their possible role in the immune response in different compartments of the udder. The milk of one healthy quarter of nine dairy cows (SCC/quarter <or=125,000/ml; bacteriologically negative) was removed separately and during the course of milking divided into: cisternal milk (C), alveolar milk 0-25%, 25-50%, 50-75%, 75-100% (A25; A50; A75; A100, respectively) and residual milk (R). Each fraction was analysed for the main constituents, SCC and distribution of leucocyte populations and their viability. The content of fat increased steadily during milking and reached highest values in R. Protein and lactose increased from C to A25, decreased from A25 to A100 and reached their minimum in R. Na and Cl ion levels diminished from C to A25 and thereafter increased from A50 to R. Electrical Conductivity (EC) also decreased from C to A25 but remained similar within the alveolar samples and reached a minimum in R. SCC decreased from C to a minimum in A25 and increased subsequently to a significant maximum in R. Somatic cell viability increased throughout consecutive fractions with a maximum value in R. The ratio of cell populations in the various milk fractions showed a reverse trend of macrophages (M) and polymorphonuclear neutrophils (PMN). M values were highest in C while PMN levels increased to their maximum in the R fraction. The lymphocyte (L) fraction remained similar in C, A25, A50, A75 and R but was higher in A100. Proportions of L, PMN and M were, respectively, 9.3%, 38.2%, 52.3% in C, 10.9%, 64%, 25.1% in A25-A100 and 10.2%, 64.9%, 24.8% in R. Numbers of L, PMN and M in milk showed a similar pattern for all three cell types: high levels in C decreased to a minimum at A25 and increased steadily thereafter to their maxima in R. It is concluded that, for healthy quarters, M, the predominant cell type in C, are located near the teat canal, the main entrance of pathogens. Obviously they are the first immunological barriers for invading pathogens. In contrast, PMN are the most important population in the alveolar compartment. However, each leucocyte fraction had a higher concentration in C than in early alveolar fractions, thus indicating the crucial role of immune defence in the cisternal compartment.

Animals↗
PubMed2004

Mammary cisternal size, cisternal milk and milk ejection in Murrah buffaloes.

The internal arrangement of the mammary gland cavity system, cisternal and alveolar milk fractions and the characteristics of milk ejection were investigated in buffaloes. Twenty-four Murrah buffaloes in three different stages of lactation and of two age groups were used. Continuous ultrasound cross-sections during milk ejection induced by exogenous oxytocin were performed to record the latency period of milk ejection. Buffaloes had small cisterns and the cavity area in the teat and gland regions were not significantly different (P > 0.05). The animals had long teat canals (3.1 +/- 0.1 cm), longer in the hind than fore quarters. Cisternal milk yield was low (0.17 +/- 0.01 kg) and cisternal fraction was only 4.9 +/- 0.1% of the total milk. The cisternal area (cm2) was 69.6 +/- 4.6, 51.61 +/- 4.8 and 26.01 +/- 4.8 while the cisternal yield (kg) was 0.32 +/- 0.05, 0.18 +/- 0.05 and 0.05 +/- 0.05 in early, mid and late lactation, respectively. A close correlation (r = 0.87, P < 0.05) existed between the ultrasound cisternal area and cisternal milk yield. The latency period of induced milk ejection was similar to that reported for cows (25 +/- 1 s) and was negatively correlated with milk yield (r = -0.75, P < 0.05). Milk ejection occurred shortly after elevated oxytocin concentrations were present. Delayed milk ejection reported earlier in this species must therefore be due to the absence of cisternal milk and delayed oxytocin release. An increase in teat length and circumference at milk ejection was also evident in the ultrasound cross sections.

Aging↗
PubMed2004

Changes of physicochemical indicators during mastitis and the effects of milk ejection on their sensitivity.

We examined the relationship between physicochemical indicators and somatic cells in the milk of dairy cows during experimentally induced mastitis and their significance as indicators for use in controlling udder health. We were concerned particularly with the effect of alveolar milk ejection on the sensitivity of these indicators. In Expt 1, Escherichia coli lipopolysaccharide (Esch. coli LPS) was injected into the left rear quarter to induce an inflammatory reaction in one quarter in each of six cows. The contralateral control quarter was injected with a solution of NaCl (9 g/l). Nine milk samples were taken from both quarters until 60 h after injection. In Expt 2, repeated milk samples were taken every 20 s from one quarter during a 120-s teat stimulation in 20 cows with different somatic cell counts (SCC). Quarters were clustered for low (<5.0 log cells/ml), mid (5.0-5.7 log cells/ml) and high (>5.7 log cells/ml) SCC of the sample taken at t=0 s. Samples were analysed for SCC, electrical conductivity (EC) and Na+ and Cl- concentrations. During the experimental inflammation SCC, EC, Na+ and Cl- peaked at 12 h from LPS administration and values in treated quarters (T) at this time were elevated to 7900, 157, 501 and 169% of the values in untreated quarters, respectively. In Expt 2, SCC, EC, Na+ and Cl- in high SCC quarters were 2520, 121, 283 and 141% of low SCC quarters at the start of stimulation (t=0 s), respectively. Highly significant (P<0.001) differences in EC, Na+ and Cl- between high and low SCC quarters disappeared owing to the onset of alveolar milk ejection 100 s after the first contact with the teat. In conclusion, SCC in cows' milk provided the strongest amplitude in the case of an intramammary inflammation. EC, Na+ or Cl- were useful tools only if the measurements were performed in cisternal milk before the start of alveolar milk ejection.

Animals↗
PubMed2003

Effects of alpha- and beta-adrenergic receptor stimulation and oxytocin receptor blockade on milking characteristics in dairy cows before and after removal of the teat sphincter.

Alpha (alpha)- and beta (beta)-adrenergic receptors in the bovine mammary gland are mainly present in the teat muscles and in the region where large milk ducts reach the cisternal cavities. The aim of the study was to test the hypothesis that the region of the large mammary ducts is the most important location of alpha- and beta-adrenergic receptor stimulation affecting milk ejection and milk removal. Effects of alpha- and beta-adrenergic receptor stimulation and of oxytocin (OT) receptor blockade on milking characteristics were tested in six cows. Milk flow was measured before and after the distal part of one teat, including the teat canal and teat sphincter, had been partly amputated. Before the operation, milk yield and peak flow rate decreased during alpha-adrenergic receptor stimulation and during the OT receptor blockade, and increased during beta-adrenergic stimulation. After removal of the teat tip, relations of milk yield and peak flow rates after administration of alpha- and beta-agonists and after application of an OT receptor blocking agent were similar to those before operation. Only total milk yield had decreased in the teat-amputated quarter owing to unhindered flow of cisternal milk before cluster attachment. Since responses to alpha- and beta-adrenergic receptor stimulation as well as to OT receptor blockade do not differ with or without the teat sphincter, it is concluded that milk flow is mainly influenced by the muscle tone of the large mammary ducts.

Adrenergic alpha-Agonists↗
PubMed2002

Inhibition of oxytocin release during repeated milking in unfamiliar surroundings: the importance of opioids and adrenal cortex sensitivity.

The aim of this study was to test if the opioid antagonist naloxone has a beneficial effect on normalization of oxytocin (OT) release during repeated milking of cows in unfamiliar surroundings. One control milking without naloxone treatment in all cows was performed in the familiar parlour. For four successive evening milkings, cows were transported to, and milked in, the operating theatre of the research station without (control group) or with naloxone administration (1 mg/kg BW) (naloxone group) before milking. After cessation of spontaneous milk flow, but not before 3 min of milking, vaginal stimulation was applied for 2 min. After milk flow ceased again, 10 IU of OT was injected intravenously to remove the remaining milk including residual milk. Milk flow was recorded continuously and blood samples were collected via a jugular vein cannula at 1-min intervals from 1 min before the start of milking until i.v. injection of OT. The inhibition of milk ejection and its normalization during repeated milking in unfamiliar surroundings was not influenced by naloxone treatment. Concentrations of cortisol and beta-endorphin during control milking and all relocations were similar in the naloxone and control groups, although their concentrations were higher after relocations than in the control. Therefore, a role of endogenous opioids in the inhibition of milk ejection in unfamiliar surroundings could not be demonstrated. In addition, the effect of exogenous ACTH1-24 (8 IU, i.v.) on the release of cortisol related to the response of cows milked in unfamiliar surroundings was studied. Cows with totally inhibited milk ejection in response to vaginal stimulation during milking after first relocation had numerically, but not significantly lower cortisol levels (8.8+/-3.4 ng/ml; AUC/min) in response to ACTH than did cows with at least partial milk ejection (38.7+/-12.9 ng/ml). Thus animals with a higher adrenal response to ACTH seemed to have less severe inhibition of milk ejection.

Adrenal Cortex↗