Plasma prolactin among superovulated prepuberal buffaloes (Bubalus bubalis)

Abstract

Eight Murrah buffalo heifers of 12 months of age wen: used to study the effect of synchronizing and superovulatory treatment of PGF₂a and PMSG combination on prolactin release. The GnRH (FertagyI) 200 µg was injected (i/v) in 4 heifers (experimental group) while saline (2 ml) was injected (i/v) in the remaining 4 heifers (control group) at induced estrus. Blood samples were collected through jugular catheter for prolactin estimation. The plasma prolactin level before first PGF₂a administration (basal value) was similar in both experimental (123.30 ± 17.41 ng/ml) and control ( 129.19 ± 7.55 ng/ml) groups. The level was elevated by 24 to 48 hr of PMSG injection and maintained at higher value on subsequent days during follicular phase among both experimental (195.16 ± 8.28 to 251.60 ± 33.73 ng/ml) and control (217.52 ± 36.58 to 225.51 ± 8.27 ng/ml) groups, The difference between plasma prolactin level recorded during oestrus among experimental ( 184.77 ± 6.97 to 260.81 ± 22.73 ng/ml) and control (218.68 + 20.33 to 250.93 ± 34.70 ng/ml) group heifers was not signiticant (P>0.05). However, a significant (P < 0.01) elevation of prolactin was maintained throughout the follicular phase after PMSG administration. GnRH injection at induced estrus did not have any influence per se at prolactin level.