Reproductive status and synchronization of oestrus for predetermined insemination of Philippine carabaos (swamp buffalo) raised by smallholder farmers

There is an urgent need to improve size, and meat and milk productivity of the Philippine carabao, a swamp type of water buffalo (Bubalus bubalis), through crossbreeding with the riverine type. Studies were conducted to assess the reproductive status of carabaos raised by smallholder farmers, determine conception rates of buffaloes to artificial insemination (AI) through oestrus synchronization, and examine the patterns of plasma progesterone in cyclic and acyclic carabao heifers. Approximately 20% of carabaos raised by smallholder farmers were diagnosed pregnant by rectal palpation. This low pregnancy rate may be due to a combination of factors such as the failure to submit for examination carabaos exhibiting external signs of pregnancy, the deliberate postponement of breeding for working females, the inability of bulls to gain access to carabaos in oestrus which are tethered at night, or the high incidence of anoestrus or suboestrus. The reproductive problems in non-pregnant animals were cystic (19.5%), infantile (25.7%), and dormant ovaries (51.3%), and pathology of the uterus and cervix (3.5%). Both feeding and management practices in different locations influenced the nutritional status of female carabaos examined. Animals in good body condition were either cycling or pregnant. A 30-40% conception rate was achieved by synchronization of oestrus and insemination with frozen semen at 72 and 96 h later. Based on progesterone radioimmunoassay and rectal palpation of the ovaries, anoestrus in carabao heifers was due either to a failure of cycling animals to exhibit oestrus or those with inactive ovaries. (author)