Effect of prolactin inhibition on thermoregulation, water and food intakes in heat-stressed fat-tailed male lambs

摘要: Two groups each of six lambs the fat-tailed Naeimi breed, well adapted to a semi-arid climate, were housed under semi-controlled temperature (43·2 43·8°C) with low relative humidity (<0·8). After 1-week adaptation period, first group (control) was injected subcutaneously 1 ml vehicle solution 40% ethanol in saline, twice daily at 08.00 and 17.00 hfor 11-day experimental period. In other group, lamb for 6 days 0·18 mg/kg per day prolactin inhibitor, 2 bromo-a-ergocryptine (CB154) dissolved solution. Treatment during next 5 as control animals. Rectal (RT), respiratory rate (RR), water food intakes recorded before injections. Daily average data used statistical analysis, except those 1st bromocryptine injection. Lambs able maintain their RT (39·5 (s.e. 0·04) °C) heat exposure, but treated could not (40·3 0·07) °C). However, latter continued respire more rapidly (P < 0·01) after cessation CB154 treatment, reducing body slightly (39·9 0·06) This shows that, following suppression, heat-stressed unable regulate despite RR. Water intake did change ratio dry-matter increase due lower consumption. These results suggest that might have an important role thermoregulation male sheep elevated ambient temperature.