Department of Animal Sciences and Industry, Kansas State University, Manhattan, KS.
Department of Animal Science, Oklahoma State University, Stillwater, OK.
J Anim Sci. 2018 Jul 28;96(8):3043-3054. doi: 10.1093/jas/sky209.
Water is an essential nutrient, but the effect it has on performance generally receives little attention. There are few systems and guidelines for collection of water intake (WI) phenotypes in beef cattle, which makes large-scale research on WI a challenge. The Beef Improvement Federation has established guidelines for feed intake (FI) and ADG tests, but no guidelines exist for WI. The goal of this study was to determine the test duration necessary for collection of accurate WI phenotypes. To facilitate this goal, individual daily WI and FI records were collected on 578 crossbred steers for a total of 70 d using an Insentec system at the Oklahoma State University Willard Sparks Beef Research Unit. Steers were fed in five groups and were individually weighed every 14 d. Within each group, steers were blocked by BW (low and high) and randomly assigned to one of four pens containing approximately 30 steers per pen. Each pen provided 103.0 m2 of shade and included an Insentec system containing six feed bunks and one water bunk. Steers were fed a constant diet across groups and DMI was calculated using the average of weekly percent DM within group. Average FI and WI for each animal were computed for increasingly large test durations (7, 14, 21, 28, 35, 42, 49, 56, 63, and 70 d), and ADG was calculated using a regression formed from BW taken every 14 d (0, 14, 28, 42, 56, and 70 d). Intervals for all traits were computed starting from both the beginning (day 0) and the end of the testing period (day 70). Pearson and Spearman correlations were computed for phenotypes from each shortened test period and for the full 70-d test. Minimum test duration was determined when the Pearson correlations were greater than 0.95 for each trait. Our results indicated that minimum test duration for WI, DMI, and ADG were 35, 42, and 70 d, respectively. No comparable studies exist for WI; however, our results for FI and ADG are consistent with those in the literature. Although further testing in other populations of cattle and areas of the country should take place, our results suggest that WI phenotypes can be collected concurrently with DMI, without extending test duration, even if following procedures for decoupled intake and gain tests.
水是一种必需的营养物质，但它对性能的影响通常很少受到关注。在肉牛中，很少有系统和准则可以收集水摄入量 (WI) 表型，这使得大规模研究 WI 成为一项挑战。牛肉改良联合会已经为采食量 (FI) 和 ADG 测试制定了准则，但没有为 WI 制定准则。本研究的目的是确定收集准确 WI 表型所需的测试持续时间。为了实现这一目标，在俄克拉荷马州立大学威拉德·斯帕克斯牛肉研究单位使用 Insentec 系统，对 578 头杂交阉牛进行了为期 70 天的个体每日 WI 和 FI 记录。牛群分为五组，每 14 天称重一次。在每组内，根据 BW（低和高）将阉牛分组，并随机分配到包含大约 30 头阉牛的四个围栏中的一个。每个围栏提供 103.0 m2 的遮荫面积，并包含一个 Insentec 系统，其中包含六个饲料仓和一个水仓。牛群在各组中均喂食相同的日粮，通过组内每周 DM 的平均百分比计算 DMI。为每个动物计算了越来越长的测试持续时间 (7、14、21、28、35、42、49、56、63 和 70 d) 的平均 FI 和 WI，并使用从每 14 天 BW 中得出的回归来计算 ADG（0、14、28、42、56 和 70 d）。从测试开始 (第 0 天) 和测试结束 (第 70 天) 开始计算所有性状的间隔。从每个缩短的测试期和完整的 70 天测试期的表型计算 Pearson 和 Spearman 相关系数。当每个性状的 Pearson 相关系数大于 0.95 时，确定最短测试持续时间。我们的结果表明，WI、DMI 和 ADG 的最短测试持续时间分别为 35、42 和 70 d。WI 没有可比的研究；然而，我们的 FI 和 ADG 结果与文献中的结果一致。尽管应该在其他牛群和国家的地区进行进一步的测试，但我们的结果表明，即使按照独立采食量和增重测试的程序进行，也可以在不延长测试持续时间的情况下，同时收集 WI 表型和 DMI。
