PSIX-18 Effects of ascorbic acid and Artemisia absinthium supplementation on heat stress responses in Spanish goats during summer in Oklahoma.

Abstract This study evaluated the effects of ascorbic acid (ASC) and Artemisia absinthium (ART) in alleviating heat stress in Spanish goats during the summer in Oklahoma. Thirty-two adult female Spanish goats (4–5 years old, 48.8±8.1 kg body weight) were stratified by body weight and randomly assigned to four treatment groups (n=8 per group). The ASC group received 2 g of ASC per goat per day, the ART group received 2 g of ART powder in a gel capsule, and the ASC-ART group received a combination of 1 g ASC and 1 g ART, while the control group (CON) received no supplement. Treatments were administered orally each morning. Four paddocks with similar pasture types were used for grazing, and animals were regrouped into two larger groups (n=16 per group, 4 goats per treatment) and rotated between paddocks over six weeks. Ambient temperature and relative humidity (RH, %) were recorded hourly to calculate the temperature-humidity index (THI). Rectal temperature (RT, °C), respiratory rate (RR, breaths/min), and coat surface temperature (CST, °C) were measured weekly, while the coefficient of heat tolerance (CHT) and index of adaptability (IA) were calculated. Body weights (BW) were recorded biweekly. During the final five days, batches of 6–7 animals, representing all treatment groups, were sequentially moved to the calorimetry room for a one-day heat production measurement. The average THI was 26.5°C, with 28.3°C ambient temperature and 62.9% RH. RT was significantly influenced by treatment, ranking as follows: ASC-ART > CON, ASC, and ART (39.6, 39.6, 39.5, and 39.8°C for CON, ASC, ART, and ASC-ART, respectively; P< 0.017). The effect of treatment on CHT followed a similar pattern to RT (76.4, 76.9, 77.5, and 73.2 for CON, ASC, ART, and ASC-ART, respectively; P< 0.026). However, RR did not significantly differ (92.8, 104, 110, and 118 breaths/min for CON, ASC, ART, and ASC-ART, respectively; P >0.05). Similarly, BW, CST, and IA values were unaffected by treatment. Heat production (kJ/kg metabolic BW) was significantly lower in the ART group compared to the ASC-ART and CON groups (322, 298, 283, and 310 for CON, ASC, ART, and ASC-ART, respectively; P< 0.039). The study results indicate that supplementing goats with ascorbic acid, Artemisia absinthium, or their combination did not significantly reduce heat stress, as measured by physiological indicators, compared to non-supplemented groups. The relatively mild THI conditions during summer may have limited the potential benefits of supplementation.