Dahmer Payton L, Zumbaugh Charles A, Reeb Macie E, Stafford Nicole B, Buessing Zachary T, Odde Kenneth G, Drouillard James S, Tarpoff A J, Jones Cassandra K
Kansas State University Department of Animal Sciences and Industry, Manhattan, KS 66506, USA.
Transl Anim Sci. 2022 Jun 21;6(3):txac085. doi: 10.1093/tas/txac085. eCollection 2022 Jul.
A total of 80 crossbred, high-risk heifers (initially 250 ± 4.2 kg BW), were transported from an Oklahoma City, Oklahoma sale barn to the Kansas State University Beef Cattle Research Center. Cattle were unloaded and randomly placed into one of four receiving pens and provided ad libitum hay and water. Each pen was randomly assigned to one of the four rest times before processing: (1) immediately upon arrival (0); (2) after a 6-h rest period (6); (3) after a 24-h rest period (24); and (4) after a 48-h rest period (48). After all cattle were processed, heifers were allotted into individual pens with ad libitum access to a receiving ration and water. Heifers were weighed individually on d 0, 7, 14, 21, 28, and 35 to calculate average daily gain (ADG). Feed added and refusals were measured daily to determine dry matter intake (DMI). A fecal egg count reduction test and analysis of blood serum metabolites were also conducted. All data were analyzed using the GLIMMIX procedure of SAS (v. 9.4, Cary, NC) with individual animal as the experimental unit. Processing time did not impact ( > 0.05) heifer BW or ADG. From d 0 to 35, DMI decreased linearly ( = 0.027) as rest time increased. The number of days for heifers to reach a DMI of 2.5% BW was linearly increased ( = 0.023) as rest time increased. There was no evidence of differences ( ≥ 0.703) among rest times for feed efficiency. While morbidity did not differ between treatments ( > 0.10), mortality increased linearly ( = 0.026) as the time of rest increased. A significant processing time × day interaction ( < 0.0001) was observed for the prevalence of fecal parasites, where the percentage of positive samples was significantly lower 14-d after anthelmintic treatment, regardless of the processing time. Serum IBR titer for heifers processed at either 0 or 6-h upon arrival was significantly higher ( < 0.01) on d 35 compared to d 0. Heifers processed after a 48-h rest period had significantly higher glucose values ( < 0.01) on d 0 compared to heifers processed at 0, 6, or 24-h. In summary, rest time prior to processing did not impact receiving calf growth performance. A 6-h rest period upon arrival appeared to be most beneficial to DMI. Anthelmintic treatment at processing reduced the parasitic load in heifers processed at all times. Vaccine titer did not increase after initial processing in heifers processed 24- or 48-h after arrival, indicating the seroconversion of IBR antibodies during the longer rest period.
总共80头杂交高风险小母牛（初始体重250±4.2千克）从俄克拉荷马州俄克拉荷马城的拍卖场被运至堪萨斯州立大学肉牛研究中心。牛只被卸下后随机放入四个接收栏之一，并提供自由采食的干草和水。每个栏在处理前被随机分配到四个休息时间之一：(1) 到达后立即（0小时）；(2) 休息6小时后（6小时）；(3) 休息24小时后（24小时）；(4) 休息48小时后（48小时）。所有牛只处理完毕后，小母牛被分配到单独的栏中，可自由采食接收日粮和饮水。在第0、7、14、21、28和35天分别对小母牛进行个体称重，以计算平均日增重（ADG）。每天测量添加的饲料量和剩料量，以确定干物质摄入量（DMI）。还进行了粪便虫卵计数减少试验和血清代谢物分析。所有数据使用SAS（版本9.4，北卡罗来纳州卡里）的GLIMMIX程序进行分析，以个体动物作为实验单位。处理时间对小母牛的体重或ADG没有影响（P＞0.05）。从第0天到第35天，随着休息时间的增加，DMI呈线性下降（P = 0.027）。小母牛达到DMI为体重2.5%的天数随着休息时间的增加呈线性增加（P = 0.023）。在不同休息时间之间，饲料效率没有差异（P≥0.703）。虽然不同处理之间的发病率没有差异（P＞0.10），但死亡率随着休息时间的增加呈线性增加（P = 0.026）。在粪便寄生虫患病率方面观察到显著的处理时间×天数交互作用（P＜0.0001），即无论处理时间如何，驱虫治疗后14天阳性样本的百分比显著降低。与第0天相比，到达后0或6小时处理的小母牛在第35天的血清IBR滴度显著更高（P＜0.01）。与0、6或24小时处理的小母牛相比，休息48小时后处理的小母牛在第0天的葡萄糖值显著更高（P＜0.01）。总之，处理前的休息时间不影响接收犊牛的生长性能。到达后6小时的休息期似乎对DMI最有益。处理时的驱虫治疗降低了所有时间处理的小母牛体内的寄生虫负荷。到达后24或48小时处理的小母牛在初次处理后疫苗滴度没有增加，表明在较长的休息期内IBR抗体发生了血清转化。
