J. Anim Sci., doi: 10.2527/jas.2006-412
©Copyright, 2006, The American Society of Animal Science
Technical note: A method to estimate individual feed intake of group-fed pigs
M. D. Lindemann 1*
B. G. Kim 1
1 Department of Animal and Food Sciences, University of Kentucky, Lexington 40546
* To whom correspondence should be addressed. E-mail: mdlind1{at}uky.edu.
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Abstract |
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In most animal growth experiments, groups of animals are housed in a pen. Occasionally, an individual animal shows a very different growth rate than its pen mates or dies during the experiment. When this happens, if pen feed intake (PFI) cannot be re-estimated for the calculation of average daily feed intake and feed efficiency, an observation will be lost from the data set. Therefore, we propose a method to estimate individual feed intake (IFI) of pigs in group feeding with subsequent evaluation of the method using group feeding simulation studies. In the proposed method, the feed intake (FI) of each affected pen is partitioned into FI for maintenance (FIm) and FI for growth for each animal within that pen. First, individual pig FIm for the period is calculated using the 1998 National Research Council estimation of ME for maintenance. Then, FIm for all pigs in the pen is summed. The difference between the summed FIm and the total PFI is the FI that supported growth in the pen. Next, FI for growth (FIg) is calculated by apportioning the remaining feed equally to each unit of gain within the pen. Finally, the estimated IFI for the pig being removed from the pen is the sum of FIm and FIg for that pig; this FI estimate is subtracted from the original PFI to calculate the new PFI for the remaining pigs. The validity of the estimated IFI is dependent upon the accuracy of maintenance energy equation and energy analysis of feedstuffs. In simulation studies, we compared the accuracy of the proposed method with 2 other methods. In simulation study 1, the proposed method showed better accuracy than at least one of the other methods during all tested periods (P < 0.001). In simulation study 2, the higher accuracy of the proposed method compared with 2 other methods was demonstrated again. Because calculation of IFI is relatively cumbersome, we developed a Feed Intake Correction Spreadsheet (FICS) using a Microsoft Excel spreadsheet containing macros for FI correction. All the calculation procedures in the proposed method are included within FICS. The Microsoft Excel spreadsheet file and instructions are available at: http://www.uky.edu/Agriculture/AnimalSciences/swine/FICS.html.
Key Words:
feed intake, pigs, Microsoft Excel
