Residual feed intake and juvenile IGF-I
نویسندگان
چکیده
The efficiency of feed use is an important factor influencing costs of production. However, feed intake (FI) is generally difficult and costly to measure. In addition, feed intake per se is relatively meaningless unless taken in the context of prevailing environmental and physiological processes. For example, FI and its utilisation by animals is altered by climate, activity levels, disease and physiological status (maturity, lactation and reproductive status), dietary characteristics and delivery, along with individual animal live weight, efficiency of nutrient absorption, energetic efficiency of tissue growth and growth rate, body composition and metabolic rate. Thus, feed intake is rarely used alone; instead there are several measures of feed efficiency that combine feed intake with other measurements in an attempt to reflect production efficiency for a particular circumstance. These measures include (adapted from Archer et al, 1999; Arthur et al., 2004):
منابع مشابه
Selection to reduce residual feed intake in pigs produces a correlated response in juvenile insulin-like growth factor-I concentration.
Data from a selection experiment for residual feed intake (RFI) were used to estimate genetic correlations between measures of efficiency and performance traits with juvenile IGF-I, and to demonstrate direct and correlated responses to selection. The heritability of IGF-I was 0.28 +/- 0.06 and genetic correlations of IGF-I with feed intake (0.26 +/- 0.17), backfat (0.52 +/- 0.11), and feed conv...
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