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Biomedical subjects

G K MacLeod

Publications and source records attributed to G K MacLeod.

At least 19 recordsLinked to original sources
PubMed1990

Digesta kinetics in sheep and cattle fed diets with different forage to concentrate ratios at high and low intakes.

Effect of maintenance and ad libitum intakes on digesta kinetics was studied with six ruminally fistulated cows and six ruminally fistulated wethers to validate the use of sheep as a model of cattle. Complete diets were made up of ratios of alfalfa:cracked corn and soybean meal of 80:20, 55:45, and 30:70. The rate of passage of Cr-mordanted alfalfa and soybean meal in the reticulorumen was negatively related to percentage of concentrate in the diet in both species at low intakes. Passage values of particulate and liquid markers were faster at high than at low intakes in both species for all diets. Rumen liquid volume increased with intake only in the cows on the low and intermediate concentrate diets. No substantial differences were found in particulate passage values between sheep and cattle. However, liquid passage rates from the rumen and the differentials between liquid and particulate dilution rates were higher in cows than in sheep for all diets at both intakes. These results together with those for digestibility data reported in a previous communication suggest that caution should be exercised when extrapolating results from one species to the other.

Animal Feed↗
PubMed1990

Overall efficacy of chronically administered recombinant bovine somatotropin to lactating dairy cows.

Recombinant bST at daily dosages of 0, 10.3, 20.6, and 41.2 mg/d were injected for 266 d into 8, 10, 9, and 9 Holstein cows, respectively. Treatment effects of recombinant bST were assessed for milk production traits, BW, blood components, and health and reproductive variables. Data reported compare controls to all bST-treated cows. There was an average increase of 18% in 3.5% FCM for bST versus control cows. This increase resulted in enhanced feed efficiency for bST cows, as their DM intakes were not elevated above those of the control cows. Recovery of BW was similar between control and bST groups. Milk composition was unaffected except for a slight decrease in protein percentage during the first 9 wk of treatment, and an elevated SCC between wk 19 and 28. Blood parameters were not different between control and bST cows, except for hematocrit, which decreased with bST treatment. The only health and reproductive parameters affected by bST were mastitis and days open, which were increased in the highest dosage groups.

Animals↗
PubMed1987

An attitudinal assessment of faculty practice plans.

An awareness of potential conflict between medical schools and private practice prompted an attitudinal assessment of faculty practice plans (FPPs). A representative sample of eight medical school FPPs in seven different communities was selected for study. For each FPP, a sample of health care leaders, stratified at different levels of administrative responsibility, was selected from academic medical centers and from community settings. Topics for FPP assessment were chosen for their relevance to physician and lay administrators involved with academic and community practice. Questions were answered on a yes-no basis and were graded by intensity of response. Although only two of the questions revealed statistical disparity on a simple yes-no basis, the intensity of response differed significantly in eight of the 14 questions asked. This study gives consideration to the strategic implications of FPPs for universities, medical schools, and organized medicine.

Administrative Personnel↗
PubMed1986

Faculty practice plans. Profile and critique.

In 1910, the Flexner report signaled the end of commercialism in American medical schools, only to have it reappear in 1931. Between 1960 and 1985, access to federal, state, and private-sector funds paid to medical service plans in all 127 medical schools led to almost a 20-fold increase in faculty practice plan (FPPs)--from six to 118. All 127 US medical schools were surveyed. Wide swings in federal funding policies left medical schools with a defective management model, particularly for FPPs. Disposition of collected revenues, the role of for-profit FPPs, the personally lucrative nature of FPPs, an unwieldy number of fairly autonomous departments, ineffective governance, and hostile opposition from other parts of the university have raised questions of conflict of interest and accountability. Some 75 years after the Flexner report, a thorough evaluation of the effects of commercialism on medical education once again appears to be warranted.

Academic Medical Centers↗
PubMed1986

Effect of prepartum energy, body condition, and sodium bicarbonate on production of cows in early lactation.

In trial 1, the effects of dietary energy (102, 131 or 162% of requirement) in the dry period and of sodium bicarbonate (0 or .75% of diet dry matter) in early lactation were assessed with 31 cows in a 3 X 2 factorial arrangement of treatments. Body condition and weight increased linearly with prepartum energy. Dry matter intake and milk yield were similar across treatments through 12 wk postpartum. Sodium bicarbonate increased milk fat content only in the 131% group, an effect apparently related to greater mobilization of fat in that group. In trial 2, energy treatments imposed in late lactation (145 to 55 d prepartum) and in the dry period (55 to 0 d) were 1) cows fed to requirement in both periods, 2) cows overfed in the first and underfed in the second period, 3) cows fed to requirement in the first and overfed in the second period, and 4) cows overfed in both periods. Cows in treatments 1 and 2 (normal) calved in a thinner state than those in 3 or 4 (fat). In the first 12 wk postpartum, intake did not differ, but cows in groups 3 and 4 produced more milk. Sodium bicarbonate imposed factorially postpartum increased milk fat content. Overconsumption of energy prepartum did not impair production when high energy total mixed rations were fed postpartum.

Animals↗
PubMed1975

Glucose metabolism in cows fed low- and high-roughage diets.

Six lactating first-calf Holstein cows were used to test the effect of dietary roughage on glucose metabolism. Cows were fed either a low-roughage or high-roughage diet at isocaloric digestible energy intakes in a double changeover design experiment. Mean values (plus or minus standard deviation) for milk yield (kg/day), fat (%), lactose (%), and protein (%) for cows fed low-roughage were 19.0 plus or minus 4.4, 3.11 plus or minus .78, 5.19 plus or minus .27, 3.44 plus or minus .48; values for cows fed high-roughage were 17.5 plus or minus 5.1, 3.99 plus or minus .58, 4.94 plus or minus .25, and 2.78 plus or minus .33. One hour post-feeding on the 20th day of each period 2 mCi of tritiated glucose were administered to each cow by single injection to measure glucose kinetics. Mean values (plus or minus standard deviation) for plasma concentration (mg/100 ml) pool size (mg/kg), half-time (min), and utilization rate (mg/kg--75 per min) of glucose, and plasma insulin concentration (muU/ml) for cows fed low-roughage were 63.1 plus or minus 3.9, 17.9 plus or minus 3.4, 30.4 plus or minus 5.2, 8.55 plus or minus 2.44, and 22.0 plus or minus 3.9; for cows fed high-roughage values were 54.9 plus or minus 2.2, 114.5 plus or minus 17.2, 40.0 plus or minus 2.2, 4.06 plus or minus .38, and 16.2 plus or minus 2.4. A glucose load was administered intravenously to each cow on the last day of each period. Glucose half-times and mean plasma insulin following the clearance test were not affected by diet. Compared to high-roughage, low-roughage diets greatly affect metabolism in lactating cows when isocaloric intakes of each are fed. Fat depression, however, may or may not occur simultaneously.

Animal Feed↗