• Effect of Burning and Mowing on Composition of Pineland Three Awn

      Kirk, W. G.; Davis, G. K.; Martin, F. G.; Hodges, E. M.; Easley, J. F. (Society for Range Management, 1974-11-01)
      The object of the experiment was to determine the effect of burning and mowing treatments on the composition of Pineland threeawn (Aristida stricta Michx) over a 5-year period. Treatments were control; burning annually; burning in alternate years; and mowing annually and in alternate years both with clippings removed or left on. Annual treatment dates varied from February 20 to March 6. Threeawn samples were analyzed for protein, ether extract, fiber, ash, calcium, magnesium, and phosphorus (P). The grass from all treatments improved in nutritional quality from March to June and decreased from July to the following March. There was a highly significant difference among collection dates in level of all seven nutritional factors, indicating strong seasonal trends. Effect on new growth was greater for protein than for the other factors. Samples collected from all plots 35 days after treatment averaged 5.9% protein, while grass collected 289 days after treatment had 3.8% protein, a reduction of 36%. Forage from threeawn plots either mowed or burned was higher in protein and lower in fiber and P than the control with no differences between the burned or mowed plots. Grass growth after burning approached the recommended minimum protein level for a nursing cow in only a few instances. Ash was lower in grass from the control than from the treated plots. Burning increased P compared to mowing. Threeawn from all treatments lacked sufficient P for good cattle production.
    • Effect of Pregnancy and Lactation on Liver Vitamin A of Beef Cows Grazing Pangolagrass

      Kirk, W. G.; Easley, J. F.; Shirley, R. L.; Hodges, E. M. (Society for Range Management, 1972-03-01)
      The effect of pregnancy and lactation on vitamin A and carotene in liver and plasma was determined for beef cows grazing pangolagrass. The cows averaged 13.4 years of age and had grazed pangolagrass continuously as the only source of nutrients for an average of 9.5 years. Calves were weaned August 29, 1965, and cows were slaughtered December 8, 1965. Ten cows, nursing calves in 1965 and pregnant when slaughtered, had an average of 12.3 million I. U. equivalent vitamin A in liver and plasma; seven cows, dry in 1965 and pregnant, had 20.9 million I. U.; three cows, nursing calves in 1965 and open, had 13.3 million I. U.; and one cow, dry in 1965 and open, had 24 million I. U. vitamin A. A well managed pangolagrass pasture in southcentral Florida furnished adequate carotene to meet the vitamin A needs of producing beef cows.
    • Vitamin A and B-carotene in Liver and Blood of Cows Grazing Pangolagrass

      Kirk, W. G.; Shirley, R. L.; Easley, J. F.; Peacock, F. M. (Society for Range Management, 1970-03-01)
      Mature grade Brahman cows grazing pangolagrass (Digitaria decumbens Stent.) from 3 to 17 years as the only source of nutrients other than common salt and red salt had an average of 2624 mcg vitamin A and 59 mcg B-carotene per gram dry liver and 46 mcg vitamin A and 1020 mcg B-carotene per 100 ml blood plasma. The liver of a 1168 pound cow had the equivalent of 16.3 million I. U. vitamin A. The cows had livers with approximately 28 times more vitamin A, and plasma 5.5 times more B-carotene than steers fed a finishing ration containing 10% yellow corn meal and 5% alfalfa meal for 140 days. Beef cows grazing well managed Florida improved pasture would obtain more than sufficient vitamin A for maintenance, reproduction, and milk production as indicated by their performance and storage of this vitamin.