This study evaluated the scope and trends in monthly estrus synchronization-artificial insemination ((ES-AI) services and calf drop per municipality in selected municipalities of Laguna and Cavite. From 1999 to 2003, a total of 4,309 buffalo females examined by rectal palpation, 1,017 buffaloes induced to come into estrus, 975 heat-induced buffaloes bred by AI and 1,249 natural-heat buffaloes bred by AI, was recorded in Laguna (Lumban, Magdalena, Pagsanjan, San Pablo City, and Santa Cruz) and Cavite (Dasmariiias, General Trias, Maragondon, Naic, and Tanza). Overall calving rate was 14.8%, with 330 buffalo calves born (160 males and 170 females). The monthly frequency of ES-AI services (i.e. number of female buffaloes examined, number of carabaos induced to estrus, number of carabaos bred by AI) were significantly different (P<.01) between municipalities, between years and between months of implementing the ES-AI program at the village level. The large number of monthly ES-AI services per municipality relative to the carabao inventory indicated wide participation and willingness of farmers in joining the ES-AI program. Differences in the number of ES-AI services between municipalities were due to the diverse production and environmental conditions in the municipalities. The reduction in number of ESAI services was attributed to the shift in workload of PCC at UPLB AI technicians with the establishment of new dairy cooperative modules and the implementation of the PCC-supervised bull loan program and the Unified National Artificial
Insemination Program (UNAIP). Differences in ES-AI services between months were associated to the seasonality of work required of carabaos in support of the major crop production on-farm. While calving rate should be emphasized as the practical measure of success at the municipal level, major improvement has to be done in the recording/reporting system to better monitor and evaluate individual calf drop.