Milk progesterone determination in buffaloes post-insemination

Abstract

Milk progesterone levels were studied in 17 buffaloes between post-insemination and 30 days thereafter. Six animals were confirmed pregnant. Seven of 10 animals took > 24 days to return to oestrus and the pattern of change of progesterone levels indicated a steady increase from 1 ng/ml on day 2 to 20 ng/ml on day 14 post-insemination, falling subsequently to about 5 ng/ml, 2 days prior to oestrus. In pregnant buffaloes, the milk progesterone levels showed a continuous increase up to 20 days post-insemination but did not decline thereafter. In individual buffaloes returning to oestrus, a cut-off milk progesterone level of > 10 ng/ml was considered for pregnancy diagnosis, 20, 22 and 24 days post-insemination. The test was 60, 75 and 75% accurate for detection of pregnancy on days 20, 22 and 24 respectively and 100% for non-pregnancy diagnosis on all three days. Individual animals showed a highly variable oestrous cycle length, which has been suggested as a contributory factor for false pregnancy diagnosis by milk progesterone test in this species. Milk progesterone assay may also identify silent heats, and clinical disorders.