EFFECTS OF CULTIVAR AND MATURITY OF ENSILED CORN PLANT FED WITH AND WITHOUT CONCENTRATES ON THE PERFORMANCE OF GROUP AND INDIVIDUALLY FED HEREFORD AND ANGUS STEERS

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Abstract
Field, feeding, and digestion experiments were conducted from 1966 to 1968 to determine the overall feeding value of corn (Zea mays L.) silages grown in an area where well-eared corn is not assured because of climatic conditions. The nutritive value of the silages was determined in 112-day feeding experiments with a total of 192 steer calves averaging 191 kg body weight. The variables in the 25 factorial experiment were early-maturing Pride 5 cultivar versus late-maturing Warwick 600, harvested on either September 6 or 26, fed with 0 or 1.5 kg concentrate/100 kg body weight daily, to Hereford or Angus steers penned in groups or fed individually. Mean green yields and crude protein and fiber contents were higher, and ear dry-matter (DM) yields, and DM and nitrogen-free extract contents were lower for Warwick 600 than those for corresponding Pride 5 silages. Differences in silage and total ration DM intakes, steer gains, and feed efficiency between cultivars and harvest dates were not statistically significant. Supplementation reduced silage DM intake (P < 0.01), and increased total ration DM intake (P < 0.01), body weight gain (P < 0.01), and feed efficiency (P < 0.01). DM intake was greater (P < 0.01) and gains slightly higher for Angus than for Hereford steers. DM, protein, and fiber digestion coefficients were greater for early-cut and less for late-cut Pride 5 than for corresponding Warwick 600 silages. Silages ranked Warwick 600 late-cut, Pride 5 late-cut, Pride 5 early-cut, and Warwick 600 early-cut, based on the calculated body weight gain per hectare of silage.