A study assigning 1021 lactations of 313 Bulgarian Murrah buffalo cows with milk yield recorded on the farm of Agricultural Institute – Shumen during
the period 1967-2001 was initiated with the objective to estimate the effect of days open on the milk yield and the duration of the concurrent lactation. Using
linear LS-analyses, significant antagonistic effect of days open on 305-day milk yield and especially on complete days in milk was established. Service period of
three to five months is expected to be the most beneficial for the balance between reproductive efficiency and productive performance, at preferable lactation
duration.

Effects of days open on the milk yield and the duration of the concurrent lactation in Bulgarian Murrah buffaloes

P. Penchev, Y. Ilieva, Tz. Peeva