Determination of oxytocin in milk of cows administered oxytocin

To address people's concerns of exogenous oxytocin (OT) administration to lactating bovines, a studywas undertaken to (a) establish an enzyme immunoassay (EIA) for OT determination in milk, (b) quantify OT in milk of cows administered OT, and (c) study influence of pasteurization on OT stability in milk. A sensitive EIA validated according to the criteria of EuropeanUnion---Decision 2002/657/ECwas developed for OT in skim milk in an analytical range of 10--250pgmL$-$1 with a decision limit (CC*) of30pgmL$-$1 and detection capability (CC*) of41.5pgmL$-$1. Milk samples collected from cows (n=38) administered either 25 or 50IU OT prior to milking were investigated for the presence of OT. There was no significant difference among both groups with the mean concentrations of OT being 15.8 and 14.9pgmL$-$1 for cows subjected to 25 and 50IU OT administration, respectively. The OT levels in skim milk of control cows (n=30; untreated) were basal (around 10pgmL$-$1). All the analyzed milk samples were below the CC value of30pgmL$-$1.Pasteurization ofOTspikedmilksamples at differenttemperatureandsampleholding conditions reducedtheimmunologicalactivity ofOTto43%at110◦C.However,nofurther declineoccurred in the immunological activity with increased pasteurization temperature and time. Itwas concluded that the milk OT concentrations after OT administrations were minimal and below the assay decision limit. However, OTwas quite stable to pasteurization in OT spiked milk.     «

To address people's concerns of exogenous oxytocin (OT) administration to lactating bovines, a studywas undertaken to (a) establish an enzyme immunoassay (EIA) for OT determination in milk, (b) quantify OT in milk of cows administered OT, and (c) study influence of pasteurization on OT stability in milk. A sensitive EIA validated according to the criteria of EuropeanUnion---Decision 2002/657/ECwas developed for OT in skim milk in an analytical range of 10--250pgmL$-$1 with a decision limit (CC*)...     »