Aerial Spraying with Endosulfan against Glossina morsitans morsitans in the Okavango Delta area of Botswana

Abstract

Trials to determine if the costs of eradicating G. morsitans by aerial application of endosulfan (Park et al 1972) might be reduced, were carried out using lower quantities of the pesticide. Area dose rates were varied by altering; the swath width, the insecticide output per unit flying time and the insecticide concentration. The trials were judged by the reduction of the adult tsetse population after a single application. Results indicated that eradication of G. m. morsitans under the conditions prevailing in N.W. Botswana, is possible by the repeated application, at 21 day intervals, of 20% endosulfan at 3.0 //km² (0.6 kg a.i./km²). Applications should be made at a swath interval of 274m, using a single AU 3000 Britten-Norman Micronair unit to produce spray droplets mostly smaller than 40μm diam. The cost (1973) of each application (aircraft and insecticide only) was approximately US $13.00/km² for an area in excess of 1000 km².     

Efficacy of Long-Acting Formulations of Estradiol or Progesterone Plus Estradiol on Estrous Synchronization in Broodmares

A preliminary trial was performed to evaluate the ability of sustained release preparations of estradiol-17β or progesterone plus estradiol-17β to synchronize estrus in cyclic mares. Group 1 mares were treated with a 50 mg intramuscular (IM) injection of sustained release estradiol-17β, while group 2 mares were treated with estradiol plus 1.5 g of sustained release progesterone. All mares received an IM injection of 10 mg of prostaglandin-F₂α (PGF₂α) 10 days after steroid treatment. Mares were examined by transrectal ultrasonography on Days 1 and 10 of treatment and then at ≤2 day intervals to monitor follicle size. Once a follicle ≥30 mm diameter and uterine edema were detected, 0.5 mg of the GnRH analog histrelin was administered IM. Mares were examined daily thereafter to detect ovulation. Group 1 mares did not exhibit ovulation synchrony (ovulations occurred 12-22 days after steroid treatment), whereas ovulation synchrony was satisfactory in group 2 mares (interval to ovulation being 20.4 ± 1.5 days, range 17-22 days). Using sustained release preparations of progesterone plus estradiol-17β, with PGF₂α administered on Day 10, could eliminate the need for daily injections of steroid preparations in oil when synchronizing estrus and ovulation.     

Effect of intrauterine saline infusion during the late luteal phase on the estrous cycle and luteal function of the mare

The intrauterine infusion of 500 ml of warm sterile saline solution into mares on days 12, 13, or 14 after ovulation failed to alter the ovulatory interval, although intervals were shorter for days 12 and 13 (20.6 days) when compared with those in control mares (21.6 days). The IU fusion shortened luteal-life-span on days 12 (12.0 vs 13.8 days) and 13 (13.0 vs 14.4 days) (P is less than 0.05), but not day 14 (14.0 vs 13.5 days), when comparing the effects of IU infusion with an average of before and after base-line data. There was no effect on the interval from corpus luteum regression to ovulation, ie, the final follicular phases. The treatment average for days 12 and 13 combined was 7.7 days vs 7.3 days for controls. Also, no significant effect was observed for the duration of estrus in that the treatment average for days 12 and 13 was 5.1 days, and for controls, 6.0 days. The infusion of saline solution caused an immediate release of prostaglandin F(2alpha) within 5 minutes, with additional large releases occurring over the next 24 hours. Progestin concentrations decreased rapidly in relation to this prostaglandin release.