Jeffrey D. Oldham

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Theminimum-cost multicommodity ow problem involves simultaneously shipping multiple commodities through a single network so that the total ow obeys arc capacity constraints and has minimum cost. Multicommodity ow problems can be expressed as linear programs, and most theoretical and practical algorithms use linear-programming algorithms specialized for the(More)
We proposed an hypothesis that ruminants attempt to select a diet that promotes high levels of feed intake by maintaining optimal ruminal conditions. Three tests of the hypothesis considered whether the diet selection of sheep given either a choice of two high energy density (ED) feeds or a choice between a high and a low ED feed is affected by 1) sodium(More)
In dairy cows two distinct and important aspects of the interrelationship between protein and energy-yielding nutrients can be identified. First, a change of protein input can influence performance by changing overall plane of nutrition. To a large extent this results from changes of digestibility and associated intake of ration ingredients. Within this(More)
To determine the contribution of tissue protein reserves to lactational performance, multiparous female Sprague-Dawley rats were mated, caged individually and offered a diet high in protein (215 g crude protein (N x 6.25; CP)/kg dry matter (DM); H) ad lib. until day 12 of gestation. Subsequently half the rats continued to receive diet H while the remainder(More)
To test the proposition that sheep are able to select a diet that meets their crude protein (N x 6.25; CP) requirements, feeds L, A, B, C and H with the same energy content (11 MJ metabolizable energy/kg feed) but different CP contents (78, 109, 141, 172 and 235 g CP/kg fresh feed respectively) were formulated. In addition, feed U, which was feed L plus(More)
This experiment examined the effect of feed quality on the relationship between intake and stage of lactation in dairy cows. Two total mixed diets composed of grass silage and concentrate were formulated. The high concentrate total mixed diet was designed to meet energy requirements, and the low concentrate total mixed diet was designed to limit intake.(More)
Growing lambs (mean liveweight 22.4 kg) were used to test for the effects of long-term subclinical infection with Trichostrongylus colubriformis (2500 larvae per day) on the voluntary food intake (VFI), diet selection and performance of sheep given a choice between two foods of different protein content (low versus high). Sheep were either uninfected(More)
Variation in lactational performance comes about as a result of variation in the nature of the animal, its environment, or with time. Table 1 lists a variety of sources of variability, classified under broad headings of variation with the animal (species, breed and individual), with time and with various aspects of the environment. The list is probably not(More)