Dale Bauman - Academia.edu (original) (raw)

Papers by Dale Bauman

Journal of Lipid Research, Jul 1, 2008

Journal of Dairy Science, Nov 1, 1985

Tissue-specific effects of bovine growth hormone on lactating dairy cows were examined by analysi... more Tissue-specific effects of bovine growth hormone on lactating dairy cows were examined by analysis of milk composition. Milk samples were from 6 cows that received subcutaneous injections of 0, 5, 10, 25, 50, and 100 IU/d of growth hormone in a Latin-square design. Samples from the last 5 d of each 10-d treatment period were pooled for analyses of milk components. Concentration of alpha-lactalbumin in milk increased progressively across the treatment range up to 32% above controls (1.30 mg/nl) at the 100 IU dose. Specific alpha-lactalbumin synthesis (expressed as a percent of total milk protein) was also increased. Secretion of de novo synthesized fatty acids (short and medium chain length) in milk was increased, but response plateaued between the 50 and 100 IU/d. Secretion of preformed (long-chain) fatty acids progressively increased across the entire dose range. Thus, the percentage of long-chain fatty acids in milk increased at the highest doses of hormone. Changes in fatty acid composition of milk were apparently related to energy status; the milk response to 50 and 100 IU/d of growth hormone caused cows to be in or near negative energy balance. Exogenous growth hormone did not affect the concentration of calcium, phosphorus, sodium, iron, copper, and manganese in milk. Results are consistent with growth hormone functioning in homeorhesis to coordinate the partitioning of all nutrients to support the increased secretion of milk and milk components.

Journal of Animal Science, May 1, 2002

The FASEB Journal, Apr 1, 2009

In Vitro Cellular & Developmental Biology – Animal, 2001

Journal of Animal Science, Sep 1, 1991

Journal of Dairy Science, 1989

The utilization of energy, carbon, and nitrogen, and irreversible loss rates of nonesterified fat... more The utilization of energy, carbon, and nitrogen, and irreversible loss rates of nonesterified fatty acids were examined in lactating cows during treatment with bovine somatotropin. Six multiparous Holstein cows at approximately 62 d postpartum received daily intramuscular injections of somatotropin (29.4 mg/d) or excipient during two 21-d treatment periods in a crossover experimental design. Milk yield was increased 11% (37.1 versus 41.3 kg/d), whereas intake and digestibility of DM, energy, nitrogen, and carbon were not affected. Cows remained near zero net energy balance during both treatments (1.31 versus -1.52 Mcal/d for control and somatotropin, respectively). The major effect of somatotropin was to partition net energy into milk while tissue energy accretion was reduced. Postabsorptive use of nitrogen and carbon was altered by somatotropin as reflected by greater secretion in milk. Urinary losses of nitrogen and tissue use of carbon were reduced. Plasma concentrations and irreversible loss rates of nonesterified fatty acids did not differ between treatments. Somatotropin treatment of lactating cows results in partitioning of nutrients away from tissue deposition toward milk synthesis. The extent to which different metabolic processes are altered depends upon the energy balance of the somatotropin-treated animal.

Journal of Nutrition, Oct 1, 2004

Journal of Dairy Science, Apr 1, 1983

Journal of Nutrition, Sep 1, 1981

Bovine growth hormone (bGH) was administered to high-yielding Holstein cows fed a complete mixed ... more Bovine growth hormone (bGH) was administered to high-yielding Holstein cows fed a complete mixed ration ad libitum. Commencing on day 74 of lactation, 10 cows averaging 34.4 kg milk per day were divided into two groups and received a daily subcutaneous injection of bGH (51.5 IU/day) or a placebo. Injections were continued for an 11-day period and differences in lactational performance, nitrogen balance and estimated energy balance between the two groups were compared for the last 5 days of the preinjection and injection periods. Growth hormone resulted in increases of 9.5% in milk yield, 22.7% in milk fat yield, 14.5% in milk lactose yield and a 17.1% increase in milk energy secretion. Feed intake was slightly reduced (-4.3%, nonsignificant) while milk protein secretion and nitrogen balance were unchanged. Serum growth hormone levels in the bGH group were maintained at the higher concentrations of the normal physiological range during the injection period. By 48 hours following the last injection, declining bGH concentrations approached control values, and milk production decreased to preinjection values. Serum prolactin levels and plasma concentrations of free-fatty acids were slightly increased during the injection period in the bGH group. Growth hormone clearly enhances milk synthesis in the high-yielding dairy cow.

American Journal of Physiology-endocrinology and Metabolism, Apr 1, 1990

The dose dependence of plasma nonesterified fatty acids (NEFA) and glycerol responses to epinephr... more The dose dependence of plasma nonesterified fatty acids (NEFA) and glycerol responses to epinephrine was determined in lactating cows treated with bovine somatotropin (bST). Also, the effects of insulin on lipolysis and glucose clearance were examined. Lactating cows (190 +/- 24 days postpartum) received daily subcutaneous injections of methionyl bST (40 mg) or excipient during two 12-day treatment periods. Epinephrine challenges (0.1, 0.2, 0.4, 0.8, 1.2, and 1.6 micrograms/kg body wt) were administered intravenously on days 6-11 and an insulin challenge (1 microgram/kg) on day 12. Milk energy secretion increased 55% without any change in voluntary feed intake during bST treatment. Circulating concentrations of NEFA were chronically elevated and reciprocally paralleled changes in net energy balance. Maximal response of plasma NEFA and glycerol to epinephrine was markedly increased during bST treatment, whereas the dose of signal-producing half-maximal response (ED50) was unchanged. Antilipolytic effects of insulin were also enhanced, whereas the effect of insulin on the fractional rate of glucose change was reduced. Thus bST alters tissue response to homeostatic signals to allow more nutrients to be partitioned for milk synthesis. Furthermore, the alterations in response to epinephrine and insulin appear to predominantly occur at a postreceptor level.