Myometrial cytokines and their role in the onset of labour.

Human labour is an inflammatory event, physiologically driven by an interaction between hormonal and mechanical factors and pathologically associated with infection, bleeding and excessive uterine stretch. The initiation and communicators of inflammation is still not completely understood; however, a key role for cytokines has been implicated. We summarise the current understanding of the nature and role of cytokines, chemokines and hormones and their involvement in signalling within the myometrium particularly during labour.

Comparison of alternative methods of handling contemporary group effects in animal model prediction.

SUMMARY: Methods to associate animals between periods (grouping of records within a calving season into a 60-day interval starting from the date of the first calf born for 400-day weight analysis) within the contemporary group classification on sexmanagement group-date of weighing, using an animal model were compared. The data were derived from ten Angus herds. Assigning animals to more than one period and/or treating period as random or introducing days from start of calving period as a co-variate (linear and quadratic) did little to improve herd mean square error compared to the basic model where there were no associations between periods. The reduction in the standard errors of predictions were significant (p < 0.05) only when period within sex-management group-date of weighing was treated as random. However, the use of a similarity matrix S (which associates periods within the fixed contemporary group classification) in the mixed model equations reduced mean square error by as much as 7%. Using simulated observations for the ten herds, highest correlations between true breeding values and estimated breeding values were obtained only for the model using the similarity matrix. ZUSAMMENFASSUNG: Vergleich alternativer Methoden der Behandlung von Wirkungen kontemporärer Gruppen bei Tiermodellvoraussagen Methoden zur Verbindung zwischen Tieren verschiedener Perioden (Leistungsabschlüsse in 60-Tage-Intervallen einer Abkalbesaison für 400 Tagegewichte ab dem ersten geborenen Kalb) innerhalb kontemporärer Gruppenklassifikation und Geschlechts-Managementgruppen bei Tiermodellen wurden verglichen. Die Daten stammten von 10 Angusherden. Zuordnung von Tieren an mehr als eine Periode als zufällig oder Einbeziehung von Tagen von Beginn der Abkalbeperiode als Kovariable (linear und quadratisch) half wenig zur Verbesserung des Herdenfehlermittelquadrates im Vergleich zu dem Grundmodell, wo keine Verbindungen zwischen Perioden unterstellt wurden. Die Verminderung des Standardfehlers der Voraussage war signifikant (p < als 0,05) nur wenn Perioden innerhalb Geschlechts-Managementgruppen als zufällig betrachtet worden sind. Allerdings hat die Verwendung der Ähnlichkeitsmatrix S (welche Perioden innerhalb einer fixen kontemporären Gruppenklassifikation assoziiert) in der gemischten Modellgleichungen den Mittelquadratfehler um bis zu 7% reduziert. Unter Verwendung simulierter Beobachtungen für 10 Herden haben sich die höchsten Korrelationen zwischen wahren Zuchtwerten und geschätzten nur bei dem Modell ergeben, das die Ähnlichkeitsmatrix verwendet hat.

Haematologic and growth response to prepartum administration of vitamin A in calves.

Injectable vitamin A was given to six pregnant beef cows in their last third of pregnancy to study the effect of this vitamin in their calves. Average birth weight and growth rate of calves from the treated cows were higher than that of calves from the nontreated cows. Prepartum vitamin A injections also resulted in a significant increase (P less than 0.05) in the mean corpuscular volume (MCV), total serum protein and globulin fraction of serum protein in calves of treated cows.