McBeth L J, Coffey K P, Coblentz W K, Turner J E, Scarbrough D A, Bailey C R, Stivarius M R
Department of Animal Science, University of Arkansas, Fayetteville 72701, USA.
J Anim Sci. 2001 Oct;79(10):2698-703. doi: 10.2527/2001.79102698x.
Spontaneous heating in stored alfalfa (Medicago sativa) has reduced forage quality and DM and N digestibility through microbial respiration and Maillard polymer formation. The impact of heating-degree-day (HDD) accumulation in stored bermudagrass (Cynodon dactylon [L.] Pers.) was evaluated for its effect on nutrient utilization by lambs. Twenty Rambouillet wether lambs (53.1 +/- 0.74 kg) were used in a completely randomized total collection experiment. The hays selected for this study had previously undergone spontaneous heating, producing either 5, 119, 201, 273, or 401 HDD (> 35 degrees C) during a 60-d storage period. Lambs were offered diets of these hays at 1.5% of BW. Dry matter intake did not differ (P = 0.59) among hays. Linear relationships were detected between HDD and apparent digestibilities of DM (y = 59.1 - 0.016x; P < 0.01; R2 = 0.37), OM (y = 59.3 - 0.017x; P < 0.01; R2 = 0.43), NDF (y = 66.4 - 0.012x; P = 0.01; R2 = 0.30), and hemicellulose (y = 74.0 - 0.012x; P = 0.02; R2 = 0.27). Similarly, significant regressions were observed for fecal N excretion (g/d; y = 4.70 + 0.004x; P < 0.01; R2 = 0.68), apparent N absorbed (g/d; y = 7.4 - 0.005x; P < 0.01; R2 = 0.50), apparent N absorption (%; y = 61.2 - 0.038x; P < 0.01; R2 = 0.71), apparent neutral detergent insoluble nitrogen digestibility (%; y = 85.8 - 0.026x; P = 0.01; R2 = 0.73), and apparent acid detergent insoluble nitrogen digestibility (%; y = 1.5 + 0.101x; P < 0.01; R2 = 0.62). Therefore, spontaneous heating during the storage of bermudagrass hay has a negative effect on dry matter and fiber digestion and nitrogen absorption by lambs.
储存苜蓿（紫花苜蓿）过程中的自燃会通过微生物呼吸和美拉德聚合物形成降低饲草质量以及干物质和氮的消化率。评估了储存狗牙根（狗牙根[L.] Pers.）过程中热积温（HDD）的累积对羔羊养分利用的影响。选用20只兰布列阉公羊（体重53.1±0.74千克）进行完全随机的全收粪试验。本研究选用的干草此前经历过自燃，在60天储存期内产生了5、119、201、273或401 HDD（>35℃）。以体重的1.5%给羔羊提供这些干草日粮。各干草间的干物质采食量无差异（P = 0.59）。检测到HDD与干物质（y = 59.1 - （0.016x）；P < 0.01；R2 = 0.37）、有机物（y = 59.3 - （0.017x）；P < 0.01；R2 = 0.43）、中性洗涤纤维（y = 66.4 - （0.012x）；P = 0.01；R2 = 0.30）和半纤维素（y = 74.0 - （0.012x）；P = 0.02；R2 = 0.27）的表观消化率之间存在线性关系。同样，在粪便氮排泄量（克/天；y = 4.70 + （0.004x）；P < 0.01；R2 = 0.68）、表观氮吸收量（克/天；y = 7.4 - （0.005x）；P < 0.01；R2 = 0.50）、表观氮吸收率（%；y = 61.2 - （0.038x）；P < 0.01；R2 = 0.71）、表观中性洗涤不溶性氮消化率（%；y = 85.8 - （0.026x）；P = 0.01；R2 = 0.73）和表观酸性洗涤不溶性氮消化率（%；y = 1.5 + （0.101x）；P < 0.01；R2 = 0.62）方面观察到显著回归关系。因此，狗牙根干草储存过程中的自燃对羔羊的干物质和纤维消化以及氮吸收有负面影响。
