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

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.