Influences of parity, age and mineral and trace element mixture on lysozyme activity in mare’s milk during early lactation period

The aim of this study was to elucidate the influences of parity, age and mineral and trace elementmixture-supplementation on the course of lysozyme activity in mare’s milk during early lactation period. The interrelationship between equine milk lysozyme activity and calcium content was also tested. Lysozyme activity was measured by the modified turbidimetric method using Micrococcus lysodeiktikus as an indicator germ. Calcium content in mare’s milk was assayed using the atomic absorption method. Lysozyme activity averaged 66500 ± 12814 U/ml with a range of from 3800 to 115500 U/ml in milk of 24 trotter mares during the period from the 6th to 60th day postpartum. Multiparous and old (10-14 years) mares showed significantly (P<0.05) higher mean values compared with their primiparous and young counterparts. Mares supplemented with mineral and trace elementmixture and not conceived during foal-heat, manifested significantly (P<0.05) higher initial lysozyme activities than controls. Lysozyme activity and calcium content in mare’s milk was found to be strongly correlated (r = 0.6072). These data suggest that very high lysozyme activity in milk can, above all, be considered as a protective factor for new-borns. Moreover, high concentration of lysozyme in milk can certainly be a considerable factor for the low udder infections susceptibility. The strong correlation between lysozyme activity and calcium content can be attributed to a particular stability and enhanced activity of equine milk lysozyme.