Ultrasound evaluation of ovarian response to photoperiodic control measures in Camelus dromedarius

Abstract

The present study was carried out with two objectives, (a) the use of ultrasound scanners to study the effect of 'mask on eyes' as a photoperiodic control measure for folliculogenesis in female camels. (b) Use of blood progesterone assays to monitor ovarian changes in camels. Fourteen female camels aged 7-11 years were used for the present experiment. Seven were studied for the effect of a mask over the eyes (for six hours daily) as a photoperiodic control measure on ovarian activity and the remaining seven were kept as controls. Ovaries were examined by ultrasound at weekly intervals for seven weeks during the non-breeding season. Camels were mated with virile stud when a follicle (≥0.9 cm diameter, ovulating size) was visible on either of the ovaries. Ovaries were monitored for ovulation up to 48 h post-mating by ultrasound at 12 hourly intervals and at 20, 30 and 40 days post mating to ascertain pregnancy. A commercially available RIA kit was used for serum progesterone assay on samples obtained at 0, 7, 15, 30 and 45 days of mating. No follicle was observed in camels before treatment and in treated (masked) or untreated camels during the first week of treatment. By the third week 100% camels in the treatment group evidenced measurable small follicles (0.5-0.89 cm, 6/7) or follicles of ovulating size (≥0.9 cm, 1/7). Follicles of ovulating size were observed in 28.6, 14.3, 14.3 and 14.3 percent camels by 4 th 5 th , 6 th and 7 th week of treatment. Fifty percent (3/6) of the camels became pregnant. The serum plasma progesterone level increased after ovulation and remained higher than 1.0 ng/mL in pregnant camels. In the control group one camel showed a follicle (0.6 cm diameter) at the 5 th week, which did not reach ovulating size. The results of the present study indicate that protecting eyes from sunlight one or two months ahead of the breeding season stimulates follicular growth in camels and pregnancy can occur in these camels when mated.