Influence of Protein Level and Quality on the Growth and Development of Yearling Foals3

Publisher Website
Google Scholar
Abstract
Sixty-eight Thoroughbred and Quarter Horse yearlings were used in three trials in consecutive years to study the influence of protein intake and quality on growth and development. Weight and body measurements were taken at the start of the experiments and at 28-day intervals. The yearlings were housed in drylots, individually fed concentrates to appetite twice daily and group fed Coastal Bermudagrass hay at a rate of 1% of body weight (BW). Yearlings consuming a concentrate that contained 17.7% crude protein (CP) and .77% lysince on a dry matter basis consumed more feed (P<.05) than yearlings consuming a concentrate that contained 14.8% CP and .58% lysine. This increased feed intake was accompanied by small but nonsignificant increases in weight, height and girth. Blood cell counts and hemoglobin were not influenced by protein intake. Replacing oats and most of the soybean meal (SBM) with brewers dried grains (BDG) did not alter feed or protein intake but decreased weight (P<.05), height (P<.05), girth (P<.05) and length (P<.10) gains. Supplementation of concentrates containing BDG with lysine resulted in increased weight gain and feed efficiency (P<.05) after 140 days on the experiment. These responses were still apparent by the end of the trial (217 days) but differences were not significant (P>.05). The SBM-fed foals had greater height gains at 112 and 168 days (P<.05) of the trial. This advantage was still evident at the end of the trial but differences were not significant (P>.05). Results of these trials suggest that Thoroughbred and Quarter Horse yearlings that consumed 2.54 to 2.64 kg of air dry feed per 100 kg BW and 3 g CP/kg BW/day gained at near maximum rates if the protein provided at least 38 to 40 g of lysine per day. Copyright © 1979. American Society of Animal Science . Copyright 1979 by American Society of Animal Science.

This publication has 1 reference indexed in Scilit: