The use of radioimmunoassay technique for early diagnosis of non-pregnancy and establishment of reproductive performance of cattle in Burkina Faso

A survey was conducted in 14 farms, mainly in the peri-urban areas of Ouagadougou. A total of 407 artificial inseminations (AI) done by six technicians were monitored, comprising 106 done after natural oestrus and 301 done after synchronization of oestrus by use of a progestagen ear implant. Samples of milk or plasma (n=1132) were collected on days 0, 10-12 and 21-24 after AI and progesterone was measured by radioimmunoassay (RIA). The results from the three samples showed that only 26% of the animals conceived and 42.6% were anoestrous or acyclic at the time of AI. The overall conception rate (OCR) was 31.4%. It was significantly higher (p <0.005) when AI was done after a natural oestrus (51.8%) than after a synchronized oestrus (26.2%), with the mean number of services per conception being 1.9 and 3.8 for these two groups, respectively. The OCR was significantly higher (p <0.01) in crossbreds (52%) than in Zebus (31.2%) or local taurines (28%). Overall, the mean intervals from calving to first service and calving to conception were 141.1 ± 62.3 days and 145.6 ± 57.7 days. The interval from calving to conception was influenced by the system of feeding on different types of farms, being significantly longer (180.4 ± 79.3 days) in cows provided grazing only, compared with those provided grazing and supplementary feeding (134.6 ± 44.4 days, p <0.05). This interval was shorter in crossbreds (116 ± 32.4 days) and Zebus (122.4 ± 40.6 days) than that in local taurines (169.5 ± 59.6 days), but this difference was not significant. Calvings from December to February were followed by shorter intervals. The level of education of AI technicians had a significant effect (p <0.03) on OCR, but the length of experience had no effect. Self employed technicians achieved a higher OCR (39.2%) in comparison to government technicians (29.6%). The cost of assaying one milk sample for progesterone was estimated to be Euro 3.14. The revenue forgone when a cow fails to conceive to an AI, resulting in an unproductive period of one cycle length (i.e. 24 extra days open), was estimated to be Euro 47.36 in extensive farms and Euro 100.64 in intensive farms. It was concluded that monitoring reproduction through RIA of progesterone was cost- effective in improving reproductive efficiency. (author)