Effects of shortening the dry period of dairy cows on milk production, energy balance, health, and fertility: a systematic review

A dry period of 6-8 weeks for dairy cows is generally thought to maximise milk production in the next lactation. However, the value of such a long dry period is increasingly questioned. In particular, shortening the dry period shifts milk production from the critical period after calving to the weeks before calving. This shift in milk production could improve the energy balance (EB), health and fertility of dairy cows. The objective of this study was to systematically review the current knowledge on dry period length in relation to milk production, EB, fertility, and health of cows and calves. A meta-analysis was performed for variables where at least five studies were available. Overall, both shortening and omitting the dry period reduces milk production, increases milk protein percentage and tends to reduce the risk of ketosis in the next lactation. Individual studies reported an improvement of EB after a short or no dry period, compared with a conventional dry period. Shortening or omitting the dry period did not affect milk fat percentage and shortening the dry period did not alter the odds ratio for mastitis, metritis, or fertility measures in the next lactation. So, current evidence for an improvement of health and fertility of dairy cows is marginal and may be partly explained by the limited number of studies which have evaluated health and fertility in relation to dry period length, the limited number of animals in those studies and the variable responses reported.

Serum procalcitonin concentrations in transplant patients with acute rejection and bacterial infections

Procalcitonin (PCT) represents a new marker of systemic inflammatory reactions of the body to infections. PCT is selectively induced by severe bacterial infections leading to sepsis or multiorgan dysfunction syndrome. The aim of our study was to test PCT as a postoperative infection marker in heart and kidney transplant patients compared with healthy subjects and patients with localized lung-inflammatory processes without a manifest systemic response. PCT concentrations were measured by an immunoluminometric assay (ILMA) in a total of 419 serum samples. Normal serum levels were in the range of 0.08-0.6 ng/ml. Operative trauma associated with heart (not kidney) transplantation induced a transient increase in PCT levels to 7-10 ng/ml with a decline to normal levels within 2-3 days in most patients. Severe bacterial infections dramatically augmented serum PCT concentrations reaching values of 46-297 ng/ml in the most critical periods. Good response to antibiotic therapy was associated with a decline in serum PCT concentrations. Acute rejection or cytomegalovirus infections did not significantly increase the serum PCT levels. Localized pulmonary infections showed either no, or only a limited increase, in the serum PCT levels (max. 7 ng/ml). We conclude from our data that PCT can be used as a sensitive marker to differentiate systemic bacterial infections from other complications in organ transplantation.

[CD5-positive B lymphocytes and antinuclear antibodies]

BACKGROUND

The production of natural autoantibodies incl. antinuclear antibodies (ANA) is ascribed to lymphocytes which have a CD5 molecule on their surface. The role of CD5 positive B lymphocytes in the induction of autoimmunity is obscure so far. The authors focused their attention on the incidence of antinuclear antibodies (AA) in subjects with different diseases and sought a relationship with the ratio of CD5 positive B lymphocytes in the peripheral blood stream.

METHODS AND RESULTS

CD5 positive lymphocytes were assessed on a flow cytometer using monoclonal anti CD5 and anti CD19 antibodies. Antinuclear antibodies are detected by indirect fluorescence on a substrate of human leucocytes and HEP-2 cells. In a group of 134 subjects the authors did not provide evidence of a direct relationship between the relative number of CD5 positive B lymphocytes in the peripheral blood stream and the presence of ANA (IgG, IgA, IgM), not even in 33 patients with autoimmune diseases. In 86 patients the authors revealed that antinuclear antibodies type IgM predominate in patients with repeated respiratory infections. In systemic diseases the isotype IgG predominates (p = 0.01). After immunosuppressive treatment with a favourable clinical effect the ANA isotype IgG disappears and isotype IgM is found more frequently. The incidence of the ANA isotype IgM is significantly higher in healthy subjects aged over 60 years than in younger subjects (12.5%/6.1%, p = 0.06), and more frequent in women (p = 0.05).

CONCLUSIONS

The presence of antinuclear antibodies is not associated with the amount of CD5 positive B lymphocyte in the peripheral blood stream.