Arthur P F, Barchia I M, Giles L R
New South Wales Department of Primary Industries, Elizabeth Macarthur Agricultural Institute, Camden, NSW 2570, Australia.
J Anim Sci. 2008 May;86(5):1096-105. doi: 10.2527/jas.2007-0627. Epub 2008 Jan 11.
The optimum duration of test for the measurement of ADG, ADFI, feed:gain ratio [which is the reciprocal of the efficiency of gain (G:F) and therefore increases as the efficiency of gain decrease and vice versa], and residual feed intake was examined in growing pigs. Data from 144 hybrid (mainly Large White x Landrace) pigs involved in a longitudinal (n = 54) and serial slaughter (n = 90) experiment were used. The pigs were housed in individual pens from 70 +/- 1 d of age (mean +/- SD) and fed ad libitum a pelleted commercial diet. Feed intake and BW data on pigs that had a minimum of 10-wk records were partitioned into a 14-d adjustment and a 56-d test period. Phenotypic correlations among weekly measurements were used to examine the repeatability of each trait. Changes in phenotypic residual variance and correlation using shortened (7-, 14-, 21-, 28-, 35-, 42-, and 49-d) tests compared with the full-length 56-d test were used as criteria to assess the optimum test duration. The results of the phenotypic correlations among weekly measurements indicated that ADFI, which was characterized by moderate to high correlations (0.41 to 0.81), was more repeatable than ADG, which was characterized by low correlations (0.00 to 0.43). Mean gut fill (n = 107) was 4.2% of BW but was characterized by large variation among the pigs (SD = 1.8; CV = 42.2%). This variation in gut fill was a major contributor to the low repeatability of the measurement of ADG. These repeatability results indicated that ADG, rather than ADFI, will determine the optimum duration of test for the feed efficiency traits. The results of the shortened relative to the full-length test indicate that for growing pigs under good nutrition and ad libitum feeding, a 28-d test was adequate for the measurement of feed intake, whereas a 35-d test was required to measure ADG, feed:gain ratio, and residual feed intake without compromising the accuracy of measurement.
研究了生长猪中用于测量平均日增重（ADG）、平均日采食量（ADFI）、饲料转化率[它是增重效率（G:F）的倒数，因此随着增重效率降低而增加，反之亦然]和剩余采食量的最佳测试持续时间。使用了来自144头杂种猪（主要是大白猪×长白猪）的数据，这些猪参与了一项纵向（n = 54）和连续屠宰（n = 90）实验。这些猪从70±1日龄（平均值±标准差）开始单独饲养，并自由采食颗粒状商业日粮。对至少有10周记录的猪的采食量和体重数据进行划分，分为14天的适应期和56天的测试期。利用每周测量值之间的表型相关性来检验每个性状的重复性。与全长56天测试相比，使用缩短的（7、14、21、28、35、42和49天）测试时表型残差方差和相关性的变化被用作评估最佳测试持续时间的标准。每周测量值之间的表型相关性结果表明，ADFI的相关性为中度到高度（0.41至0.81），比ADG更具重复性，ADG的相关性较低（0.00至0.43）。平均肠道充盈度（n = 107）为体重的4.2%，但猪之间差异很大（标准差 = 1.8；变异系数 = 42.2%）。肠道充盈度的这种差异是ADG测量重复性低的主要原因。这些重复性结果表明，对于饲料效率性状，ADG而非ADFI将决定最佳测试持续时间。缩短测试相对于全长测试的结果表明，对于营养良好且自由采食的生长猪，28天的测试足以测量采食量，而测量ADG、饲料转化率和剩余采食量则需要35天的测试，且不会影响测量的准确性。
