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

Abstract

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.

Dose dependent changes in inflammatory parameters in the milk of dairy cows after intramammary infusion of lipopolysaccharide

“…Albeit our results of EC showed maximal changes for all doses 12 hours after IM injection of LPS. Our findings of increasing EC levels after an IM infusion of LPS also agree with results of others (Kitchen, 1981;Nielen et al, 1992;Bruckmaier et al, 2004).…”

Effect of chronic oxytocin-treatment on the bovine mammary gland immune system

“…These findings might emphasize our hypothesis that high dosages of OT causes increased permeability of TJ. It was earlier suggested that open TJ are associated with this pattern of changes (Stelwagen et al, 1997;Nguyen and Neville, 1998;Bruckmaier et al, 2004). In contrast to these results we did not observe decreases in circulating WBC and PMN (this is the first time that you use PMN, need to define PMN in your introduction) in response to the OT treatment.…”

Carryover of aflatoxin from feed to milk in dairy cows with low or high somatic cell counts

“…The animal arrangement for the SCC content in our trial obtained groups (LY-LSCC, HY-LSCC) with average SCC below or slightly over 100 000/ml, which is considered a threshold value for a healthy udder (Walstra and Jenness, 1984;Steiner et al, 1990) and groups considerably higher in SCC (LY-HSCC, HY-HSCC) in which the integrity of tight junction was probably damaged allowing leaking of blood and milk components (Bruckmaier et al, 2004).…”