Studies with the Australian cashmere goat, 1. Growth and digestion in male and female goats given pelleted diets varying in protein content and energy level
1987
Ash, A.J. | Norton, B.W. (Queensland Univ., St Lucia (Australia). Dept. of Agriculture)
In the first experiment, weaner goats were given 3 ground and pelleted diets of varying protein content at 2 levels of intake. Growth rates were highest in males fed the high protein (HP) diet ad libitum and lowest in females consuming the low protein (LP) diet at restricted intakes. Increasing the protein content of the diet resulted in significantly greater liveweight gains, but this could be largely attributed to increased intake rather than to enhanced feed efficiency. Males grew faster, retained more nitrogen and used feed with greater efficiency than did females. A second experiment with fistulated goats fed the LP and HP diets from experiment 1 showed that organic matter (OM) digestion was greater in goats fed the LP diet. In contrast, the proportion of OM digestion which occurred in the stomach was greater for goats fed the HP diet. For both diets all starch escaped rumen digestion. Large losses of nitrogen across the rumen in goats given the HP diet resulted in reduced flows of non-ammonia nitrogen (NAN) to the small intestine. Digestion of NAN in the intestines was greater in animals consuming the LP diet. For both diets the ratio of protein to energy available was estimated to be in excess of maximum tissue requirements for growth.
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