Abstract :
Eleven goats belonging to Majorera breed were used during the early lactation to determine
the milk IgG, IgM and IgA concentration and the chitotriosidase (ChT) activity in milk
at three different milking frequencies. Goats were machine milked during 5 weeks; at week
1 and 5 once daily, at week 2 and 4 twice daily and at week 3, three times a day. Every week,
milk samples (50 ml) were collected from each goat after the morning milking. The samples
were aliquoted and storage at −80 ◦C until immunoglobulins concentration and ChT
activity were analyzed. To determine the IgG, IgM and IgA concentration a commercial goat
ELISA kit was used and ChT activity was measured using a fluorimetric assay. Milk IgG and
IgM concentration decreased as milking frequency increased, showing an enhance trend
when the milking frequency returned to milking once daily. IgA concentration increased
throughout the experimental period from 0.03 mg/ml (week 1) to 0.09 mg/ml (week 4). ChT
activity decreased from week 1 (782.90 nmol/ml/h) to week 5 (651.18 nmol/ml/h). In conclusion,
milking frequency affected the milk immune status, although different evolutions
have been observed. Findings in the present report might help in the discussion about the
susceptibility of mastitis when milking frequency is increased.
