Cole N A, Phillips W A, Hutcheson D P
J Anim Sci. 1986 Jun;62(6):1719-31. doi: 10.2527/jas1986.6261719x.
Two trials were conducted to determine the effects of transport stress and pre-transport diet on N losses, blood chemistry and ruminal variables of steers. In each trial, 16 crossbred steers (261 kg avg weight) were assigned to four groups in a 2 X 2 factorial arrangement of treatments. Treatments consisted of either transported or non-transported groups and two pre-transport dietary regimens (alfalfa hay or a 50% concentrate diet fed for 3 d before fasting). The alfalfa hay contained 14.6% crude protein (CP) and had a calculated metabolizable energy (ME) content of 1.92 mcal/kg. The 50% concentrate diet contained 15.5% CP and had a calculated ME content of 2.23 mcal/kg. Steers in the transport group were transported for 13 h in trial 1 and 46 h in trial 2, while the remaining steers were not transported. Both groups were withheld from feed and water during the observation periods. Urine and feces were collected and blood samples were obtained at intervals during the observation periods. Transport increased (P less than .05) urinary and total N excretion and nonevaporative water losses compared with fasting alone. Calves fed the 50% concentrate diet had lower N and nonevaporative water losses than calves fed hay, probably due to lower pre-fast N and water intakes. Ruminal total volatile fatty acid (VFA) concentrations and molar proportions of propionate and butyrate declined (P less than .05) with time in all groups, while molar proportions of acetate and minor VFA increased. Results of these trials indicate transportation stress can cause a significant increase in total N excretion and nonevaporative water loss compared with feed and water deprivation alone. Losses of N and water were lower in calves fed a 50% concentrate diet rather than hay for 3 d before the fasting period, probably because of lower pre-fast N and water intakes.
进行了两项试验，以确定运输应激和运输前日粮对阉牛氮损失、血液生化指标和瘤胃变量的影响。在每项试验中，16头杂种阉牛（平均体重261千克）按照2×2析因设计处理方案被分为四组。处理包括运输组和非运输组，以及两种运输前日粮方案（苜蓿干草或禁食前3天饲喂的50%精料日粮）。苜蓿干草含有14.6%的粗蛋白（CP），计算得出的代谢能（ME）含量为1.92兆卡/千克。50%精料日粮含有15.5%的CP，计算得出的ME含量为2.23兆卡/千克。试验1中运输组的阉牛运输13小时，试验2中运输46小时，其余阉牛不运输。在观察期内，两组阉牛均不给饲料和水。在观察期内定期收集尿液和粪便，并采集血样。与仅禁食相比，运输增加了（P<0.05）尿液和总氮排泄以及非蒸发水损失。饲喂50%精料日粮的犊牛的氮和非蒸发水损失低于饲喂干草的犊牛，这可能是由于禁食前的氮和水摄入量较低。所有组的瘤胃总挥发性脂肪酸（VFA）浓度以及丙酸和丁酸的摩尔比例均随时间下降（P<0.05），而乙酸和微量VFA的摩尔比例增加。这些试验结果表明，与仅剥夺饲料和水相比，运输应激可导致总氮排泄和非蒸发水损失显著增加。在禁食期前3天饲喂50%精料日粮而非干草的犊牛的氮和水损失较低，这可能是因为禁食前的氮和水摄入量较低。
