Variations in the concentrations of the immunoglobulins IgG1, IgG2, IgM and IgA in sheep. 1. Changes in the blood serum and in the milk of sheep of different breeds and cross-breeds during lactation

A total of 103 ewes from the breeds Black mutt., Texel, Finn. L., Heidschnucke and the crossbreeds Texel x Finn. L. and Black. mutt. x Finn. L. was studied. Blood samples were drawn at days 1, 7, 21 and 42 and milk samples at the 4th, 12th, 24th and 72nd hour after the onset of lactation and subsequently on days 7, 21 and 42. The concentrations of the immunoglobulins IgG1, IgG2, IgM and IgA were assayed in serum and milk. The following results were obtained: 1. The total immunoglobulin contents in the serum was not significantly different between breeds. 2. All ewes showed a rise in serum immunoglobulin concentrations by about one third over the first six weeks of lactation. Between 50-60% of this increase were on the account of IgG1. 3. The serum concentration of IgG1 and IgG1 rose as of the third day, those of IgM as of day 21 after lambing. 4. The rise in serum immunoglobulin concentration continued after the weaning of the lambs. 5. The ratio of IgG1 to IgG1 in ewe serum was 2:1. 6. The immunoglobulin concentration in milk dropped sharply on the first day of lactation, followed by a continuous, more gradual decrease over the entire course of lactation. A terminal rise, as observed in sows, could not be detected. 7. The ratio of IgG1:IgG2 : IgM : IgA in the whey changed from 85 : 1 : 12 : 2 on day one to 70 : 7 : 12 : 11 on the last day of lactation. 8. While characteristic trends in immunoglobulin patterns in the sera of ewes over the course of lactation are clearly discernible, it is not possible to denote "normal" values.