Insemination, pregnancy and abortion rates in a population of Glossina palpalis palpalis (robineau-desvoidy) at a relict forest in the Southern Guinea Savanna, Nigeria

Abstract

The female populations of Glossina palpalis palpalis were surveyed at the relict forest of River Kajim, Manchok, Nigeria with the objective of determining rates of fertility, types of reproductive losses and the constraints responsible for the reproductive losses. Nullipars constitutes 21.7% of the 272 females dissected. 80.2% of the 213 pars were at different stages of pregnancy; 32.5% had eggs and 20.3%, 17.5% 9.9% had 1^st, 2^nd and 3^rd-instar larvae in their uteri, while 42 pars had empty uteri. Mean monthly pregnancy rates were 70.2 ± 0.03% (57.1%-100%), highest in the peak wet season (34.5%) (July-September) and low in both warm wet (10.6%) (October) and hot dry (11.8%) (February-March) seasons. Virgin females were generally scarce. Abortion, insemination failure and ovular blockage were the common reproductive abnormalities in the population, totaling 9.9%. The results indicate that nutritional and physical stress were the likely constraints to optimum productivity.

Keywords: insemination, pregnancy, reproductive abnormality, G. p. palpalis, Southern Guinea Savanna

Tropical Veterinarian Vol. 23(1) 2005: 25-31