Veterinary Entomology Research Laboratory, New Mexico State University, Las Cruces, NM 80003, USA.
Department of Animal and Range Sciences, New Mexico State University, Las Cruces, NM 80003, USA.
J Econ Entomol. 2022 Feb 9;115(1):365-370. doi: 10.1093/jee/toab208.
Seven mature Angus × Hereford crossbreed cows (544 ± 23.2 kg of body weight) fitted with duodenal and ruminal cannulas were used in a crossover design to evaluate the effects of horn fly (Haematobia irritans) (L.) infestation on horn fly-induced defensive behaviors, feed and water intake, as well as digestion characteristics of beef cows. Cows were randomly assigned to one of two treatment groups: 1) a horn fly infested (1,000 flies per cow) or 2) a noninfested control group. All cows were housed in individual screened pens. Fly counts and infestations were performed daily to maintain consistent populations throughout the study. Sudan hay (11.4 % crude protein, dry matter basis) was selected to mimic forage quality that range cattle frequently graze in the southwest region. Horn fly-induced host defensive behaviors were greater (P ≤ 0.0002) for horn fly infested cattle. Intake of water, dry matter, organic matter, crude protein, and neutral detergent fiber were similar (P ≥ 0.4765) among infested and noninfested cows. However, total volatile fatty acid concentration tended to increase (P = 0.0967) when horn flies were present. Dry matter fecal excretion and total tract digestion were not affected (P ≥ 0.2602) by horn fly infestation. These data indicate that horn fly infestations do not affect forage intake or digestion characteristics of beef cattle (Bos taurus) in confinement settings.
七头成熟的安格斯牛与海弗牛杂交（体重 544±23.2 千克），通过十二指肠和瘤胃插管，采用交叉设计，评估角蝇（Haematobia irritans）（L.）侵扰对角蝇诱导的防御行为、饲料和水摄入以及肉牛消化特性的影响。牛被随机分配到两个处理组之一：1）角蝇侵扰（每头牛 1000 只苍蝇）或 2）非侵扰对照组。所有牛均被安置在单独的有筛网的围栏中。每天进行苍蝇计数和侵扰，以维持整个研究过程中的稳定种群。苏丹干草（粗蛋白 11.4%，干物质基础）被选择来模拟牛在西南部地区经常放牧的饲草质量。角蝇诱导的宿主防御行为对角蝇侵扰的牛更大（P≤0.0002）。水、干物质、有机物、粗蛋白和中性洗涤剂纤维的摄入量在侵扰和非侵扰牛之间相似（P≥0.4765）。然而，当角蝇存在时，总挥发性脂肪酸浓度有增加的趋势（P=0.0967）。干物质粪便排泄和全肠道消化不受角蝇侵扰的影响（P≥0.2602）。这些数据表明，在封闭环境中，角蝇侵扰不会影响肉牛（Bos taurus）的饲料摄入或消化特性。
