Efficiency of two timed artificial insemination protocols in Murrah buffaloes managed under a semi-intensive system in the tropics.

The objective of the study was to determine the efficiency of ovsynch (OV) versus presynch-ovsynch (P-OV) protocol for synchronization of ovulation and timed artificial insemination (TAI) in female buffaloes. The OV group (n = 40) received gonadotrophin-releasing hormone (GnRH) on day 0 (random day of the estrous cycle), prostaglandin PGF2α on day 7 and a second GnRH administration on day 9 followed by a single artificial insemination (AI) 16-20 h later. The P-OV group (n = 40) received two PGF2α injections 14 days apart, with the second injection administered 14 days before starting the OV protocol. Progesterone (P(4)) was measured at the time of PGF2α administration (within the OV protocol) and AI. Neither ovulation rate ((24 h after TAI) OV 90%-36/40 vs. P-OV 85%-34/40) nor pregnancy rates ((day 60 after TAI) OV 35%-14/40 vs. P-OV 45%-18/40) differed between the two protocols. Pregnant buffaloes had lower concentrations of P(4) at AI compared with non-pregnant animals in the OV group (0.7 +/- 0.1 vs. 1.1 +/- 0.1 ng/ml); but in the P-OV group, differences did not reach statistical significance (0.8 +/- 0.1 vs. 1.0 +/- 0.1 ng/ml). This apparent trend reached statistical significance when the analysis was carried out in animals from both protocols (0.7 +/- 0.1 (pregnant) vs. 1.1 +/- 0.1 (non-pregnant) ng/ml). In conclusion, both protocols synchronize ovulation effectively with no significant differences in conception rates. High concentrations of P(4) at AI seem to be detrimental for the establishment of pregnancy in lactating buffalo cows.

Expression of granulocyte-macrophage colony stimulating factor (GM-CSF) in male germ cells: GM-CSF enhances sperm motility.

The granulocyte-macrophage colony stimulating factor (GM-CSF) is a pleiotropic cytokine capable of stimulating proliferation, maturation and function of hematopoietic cells. Receptors for this cytokine are composed of two subunits, alpha and beta, and are expressed on myeloid progenitors and mature mononuclear phagocytes, monocytes, eosinophils and neutrophils, as well as in other nonhematopietic cells. We have recently demonstrated that bull spermatozoa express functional GM-CSF receptors that signal for increased glucose and Vitamin C uptake. In this study, we analyzed the expression of GM-CSF in bovine and human germ cells and its influence in bovine sperm motility. Reverse transcription-polymerase chain reaction (RT-PCR), in situ hybridization and immunoblotting analysis demonstrated that adult bovine and human testes expressed GM-CSF. In addition, immunolocalization studies confirmed the presence of GM-CSF in the germ cell line in bovine and human testes. Computer-assisted evaluation of patterns of sperm motility demonstrated that the addition of GM-CSF enhances several parameters of sperm motility in the presence of glucose or fructose substrates.