The objective was to determine the effects of feeding soybean oil (SBO), an ingredient rich in n-6 polyunsaturated fatty acids (PUFA), to late gestation hair ewes on physiological responses, feedlot performance, and serum metabolite and electrolyte concentrations of their growing ewe lambs under outdoor heat stress conditions. Twenty-four Dorper × Pelibuey ewe lambs weaned (body weight = 21.5 ± 0.2 kg, age= 2 months, and multiple birth) born from ewes fed 0, 30, or 60 mg of SBO/kg dry matter (DM) during late gestation were selected (n = 8/treatment) to conduct a 30-day feeding trial during the summer season of a desert region (temperature = 34 °C and temperature-humidity index = 35 units). While rectal temperature was unaffected in any daytime, respiratory rate in the afternoon quadratically increased (P = 0.05) as the SBO levels increased from 0 to 60 mg/kg DM in the maternal diet. Final weight, average daily gain, and feed efficiency linearly increased (P = 0.04) with increasing levels of SBO. Body surface temperatures and serum concentration of glucose, cholesterol, triglyceride, total protein, urea, sodium, potassium, and chlorine did not vary by the SBO inclusion in the maternal diet. In conclusion, feeding late gestation hair ewes with source rich in n-6 PUFA appears to be an effective maternal nutritional strategy to improve post-weaning growth without compromising the thermoregulatory ability of their growing offspring under a heat stress environment.

目的是确定饲喂大豆油 (SBO)（一种富含 n-6 多不饱和脂肪酸 (PUFA) 的成分）对妊娠晚期毛母羊的生理反应、饲养场性能以及其生长过程中的血清代谢物和电解质浓度的影响。室外热应激条件下的母羊羔羊。24 头杜泊 × Pelibuey 母羊断奶（体重 = 21.5 ± 0.2 kg，年龄 = 2 个月，多胎），母羊在妊娠后期饲​​喂 0、30 或 60 mg SBO/kg 干物质 (DM)被选择（n = 8/处理）在沙漠地区的夏季（温度 = 34 °C 和温湿度指数 = 35 单位）进行 30 天的饲养试验。白天直肠温度不受影响，下午呼吸频率呈二次方增加（P= 0.05)，因为母体饮食中的 SBO 水平从 0 增加到 60 mg/kg DM。随着 SBO 水平的增加，最终体重、平均日增重和饲料效率线性增加（P = 0.04）。体表温度和葡萄糖、胆固醇、甘油三酯、总蛋白、尿素、钠、钾和氯的血清浓度不会因母体饮食中包含的 SBO 而变化。总之，用富含 n-6 多不饱和脂肪酸的来源喂养妊娠晚期毛母羊似乎是一种有效的母体营养策略，可改善断奶后的生长，同时不影响其在热应激环境下生长的后代的体温调节能力。