Suppr超能文献

一项研究运输时间和运输时年龄对过剩奶牛犊牛影响的随机对照试验:第一部分。对健康和生长的影响。

A randomized controlled trial investigating the effect of transport duration and age at transport on surplus dairy calves: Part I. Impact on health and growth.

机构信息

Department of Population Medicine, University of Guelph, Guelph, ON, Canada N1G 2W1.

Department of Animal and Food Science, University of Wisconsin-River Falls 54022.

出版信息

J Dairy Sci. 2023 Apr;106(4):2784-2799. doi: 10.3168/jds.2022-22366. Epub 2023 Feb 14.

Abstract

Calves arriving to veal and dairy-beef facilities in poor condition are at risk of future health challenges and reduced growth rates, and limited knowledge is available on how time in transit affects subsequent health and growth of these animals. The objective of this randomized controlled trial was to understand the effects of transport duration on diarrhea, respiratory disease, and growth of surplus calves destined for veal production following 6, 12, or 16 h of continuous road transport. Surplus dairy calves (n = 175; 7 transport cohorts) from 5 commercial dairy farms in Ontario, Canada, were enrolled on the day of birth. These calves were clinically examined daily on the source farms until the day before transport and on a daily basis for the first 14 d at the veal farm. On the day of transport, they were randomly assigned to 6, 12, or 16 h of transport to a veal farm. A blood sample was collected between 24 and 48 h of birth to assess transfer of passive immunity status. Calves were weighed at birth, before and immediately after transport, as well as 24, 48, and 72 h after unloading. Calves were also weighed 14 and 50 d after transport. Health exams were conducted daily at the source farm, immediately before and after transport, and once daily for 14 d thereafter to evaluate clinical signs of diarrhea, respiratory disease, dehydration, and navel inflammation. Mixed effects Poisson regression models were used to evaluate variables associated with the number of days with abnormal respiratory and fecal scores, whereas mixed logistic regression models with repeated measures were built to assess the probability of a calf having abnormal respiratory scores, abnormal fecal scores, or dehydration by day after arrival to the facility. A mixed model with repeated measures was used to evaluate calf weight at each time point at which body weight was measured after transport, whereas a mixed linear regression model was used to evaluate factors associated with average daily gain (ADG) in the 50 d after transport. Calves transported for 16 h had greater incidence of abnormal fecal scores compared with 6 h in the 14 d after transport. In addition, an interaction between age and duration of transport on the number of days with abnormal respiratory scores was identified, where calves older than 7 d of age had reduced incidence of abnormal respiratory score compared with calves 2 to 6 d old, even when transported for 16 h. As for growth, age at transport was positively associated with ADG in the 50 d of observation; however, no differences were observed between transport duration groups. These findings highlight that transporting calves for a longer duration negatively affects subsequent health, and calves greater than 1 wk of age experience improved health and growth after transport compared with their younger counterparts.

摘要

到达小牛肉和奶牛牛肉设施的小牛状况不佳,未来面临健康挑战和生长速度降低的风险,而对于运输时间如何影响这些动物的后续健康和生长,目前知之甚少。本随机对照试验的目的是了解运输持续时间对腹泻、呼吸道疾病和运往小牛肉生产的过剩小牛生长的影响,这些小牛在连续道路运输 6、12 或 16 小时后到达。来自加拿大安大略省 5 个商业奶牛场的多余奶牛(n = 175;6 个运输队列)在出生当天被纳入研究。这些小牛在源农场每天进行临床检查,直到运输前一天,并在小牛肉农场的头 14 天内每天进行检查。在运输当天,他们被随机分配到小牛肉农场进行 6、12 或 16 小时的运输。在出生后 24 至 48 小时内采集血样,以评估被动免疫状态的转移情况。小牛在出生时、运输前和运输后立即称重,以及在卸货后 24、48 和 72 小时称重。运输后 14 天和 50 天再次称重。在源农场、运输前后以及此后每天进行健康检查,以评估腹泻、呼吸道疾病、脱水和脐炎的临床症状。使用混合效应泊松回归模型评估与异常呼吸和粪便评分天数相关的变量,而使用具有重复测量的混合逻辑回归模型评估小牛到达设施后第几天出现异常呼吸评分、异常粪便评分或脱水的概率。使用具有重复测量的混合模型评估运输后每次测量体重时的小牛体重,而使用混合线性回归模型评估运输后 50 天内平均日增重(ADG)的相关因素。与 6 小时相比,运输 16 小时的小牛在运输后 14 天内异常粪便评分的发生率更高。此外,还发现年龄和运输持续时间对异常呼吸评分天数的相互作用,即 7 日龄以上的小牛与 2 至 6 日龄的小牛相比,异常呼吸评分的发生率降低,即使运输 16 小时也是如此。至于生长,运输时的年龄与观察 50 天内的 ADG 呈正相关;然而,在运输持续时间组之间未观察到差异。这些发现强调了运输小牛的时间延长会对随后的健康产生负面影响,并且 1 周以上的小牛在运输后比年幼的小牛更健康、生长更快。

文献AI研究员

20分钟写一篇综述,助力文献阅读效率提升50倍。

立即体验

用中文搜PubMed

大模型驱动的PubMed中文搜索引擎

马上搜索

文档翻译

学术文献翻译模型,支持多种主流文档格式。

立即体验