Browsing by Author "McClure, William H."

Now showing 1 - 3 of 3
  • Thumbnail Image
    Corn performance tests in Virginia in 1966
    Genter, Clarence F.; Alexander, Morris W.; Camper, Houston M.; Sears, R. D.; Carter, Millard T.; Jones, G. D.; McClaugherty, F. S.; McClure, William H. (Virginia Polytechnic Institute. Research Division, 1967-01)
    Analyzed results of varietal trials of corn hybrids being sold or designed for sale in Virginia
  • Thumbnail Image
    The effect of stage of maturity on the biological availability of magnesuim from wheat and orchardgrass fed to sheep
    Stager, Cynthia Lee (Virginia Tech, 1976-12-05)
    Wheat, a tetany prone forage, and orchardgrass, a non-tetany prone forage, were cut at three stages of maturity to determine the magnesium availability in these forages for lambs. The forages were dried in forced air ovens and ground through a 2.5 cm screen. The nitrogen contents of the forages were not significantly different between forages but decreased quadratically with maturity in wheat (P < .Ol) and linearly in orchardgrass (P < .Ol). Nonprotein nitrogen was significantly higher in wheat than in orchardgrass. The magnesium content of the wheat was lower (P < .O1) than orchardgrass (.14 vs .21%). Magnesium content in wheat was similar at all maturities but decreased with maturity in orchardgrass. Potassium, calcium and phosphorous levels in the forages were similar between wheat and orchardgrass but decreased with advancing maturity in both forages. In two metabolism trials with 18 wether lambs, the biological availability of magnesium was determined for the two forages cut at three stages of maturity. The biological availability of magnesium for lambs fed wheat was slightly lower than for those fed orchardgrass. It increased linearly with increasing maturity in wheat (P < .O1) and tended to decrease with maturity in orchardgrass. In the first two maturities of wheat, the biological availability of magnesium was approximately 22% and for the third maturity it approached 39%. In orchardgrass, it was 36, 34 and 28% for maturities l, 2 and 3, respectively.
  • Thumbnail Image
    Heterosis from crosses among British breeds of beef cattle : straightbred versus crossbred cows
    Gaines, James A.; Hill, C.; McClure, William H. (Virginia Agricultural Experiment Station, 1985)
    The second phase of a long-term beef cattle crossbreeding experiment involving the Angus, Hereford and Shorthorn breeds was conducted at the Shenandoah Valley Research Station, Steeles Tavern, Virginia. Records of 604 matings and 567 births from 120 cows were collected over five successive calf crops. Comparisons were made between crossbred and straightbred dams, backcross and three-breed cross calves, three breeds of straightbred cows, six kinds of crossbred cows, various combinations within the backcross and three-breed cross calves, and the general combining abilities of the three breeds. Calves from crossbred cows were heavier at birth and weaning, and had higher weaning grades. Crossbred cows were 31.9 kg heavier than straightbred cows. There were 2.0% more calves born, but 0.2% fewer calves weaned from the crossbred cows. Crossbred cows weaned more kg of calf per year, but fewer units of calf per 100 units of cow, and fewer units of calf per 100 units of cow per cow year. There were increases of three-breed cross over backcross calves for all measures of growth, leading to the conclusion that three-breed crossing would increase production over backcrossing. Differences existed among the three breeds of cows for every calf performance trait, and for cow weight. Differences were found among the kinds of crossbred cows for all calf traits. Crossbred cows out of Hereford dams excelled over the reciprocal matings. The breeds did not differ in general combining ability.