MEASURE OF GROWTH
The mostly growth measure by live weight. The live weight recording is most widely used technique in experimental field and day to day record to determine growth rate in animals.
The advantage of this technique - it is easy, less time consuming and less expensive. But care must be taken in respect of - precision of weighing machine and human error.The growth rate may be expressed as absolute gain in weight in unite time, by formula- w2-w1 / t2-t1, where w1 and w2 are initial and final body weight and t1 and t2 are initial and final time.
The relative growth calculated by w2-w1 / w1, where w1 and w2 are initial and final body weight. The relative growth rate is also very much misleading when final weight is more than the initial weight. Brody has suggested alternative formula W-Ae Kt.
Where, w = the natural logarithm of weight of the animal at time t
e = natural logarithm of W when
t = 0 and K is the constant relative growth rate. This value when multiplied by 100 gives the percentage growth rate.
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