Biomedical subjects

M J VandeHaar

Publications and source records attributed to M J VandeHaar.

3 recordsLinked to original sources

PubMed1991

Ration formulation using linear programming.

A combination spreadsheet-LP ration formulation program offers tremendous advantages for dairy nutritionists. The spreadsheet format provides the framework for flexibility in describing feeds and in formulating a realistic and practical ration. The LP module can solve for a complicated set of nutrient requirements to give a relatively well-balanced ration. This "first-cut" ration can then be reworked in the spreadsheet mode to meet the needs of the individual farm based on other biologic and management considerations.

Animal Feed↗

PubMed1991

Reduced serum concentrations of insulin-like growth factor-I (IGF-I) in protein-restricted growing rats are accompanied by reduced IGF-I mRNA levels in liver and skeletal muscle.

The serum concentration of insulin-like growth factor-I (IGF-I) is reduced in growing rats fed a low-protein diet, and this decrease is age-dependent, being more pronounced in younger animals. To determine whether this decrease in serum IGF-I is related to a decrease in IGF-I mRNA, growing female rats were given free access to either a 15% protein-sufficient or a 5% protein-deficient diet for 1 week. Protein restriction in 4-week-old rats decreased body weight gain by 44% (P less than 0.001 compared with 4-week controls), serum IGF-I concentration by 67% (P less than 0.001) and liver IGF-I mRNA abundance by 51% (P less than 0.001). During week 6, protein restriction for 1 week resulted in a 20% increase in food intake with no change in weight gain, a 38% reduction in serum IGF-I (P less than 0.001 compared with 6-week controls) and a 39% decrease in liver IGF-I mRNA (P less than 0.001). The serum IGF-I concentration was highly correlated (r = 0.80; P less than 0.001) with the hepatic IGF-I mRNA concentration. Skeletal muscle IGF-I mRNA abundance was also decreased significantly by protein restriction (37% at week 4, P less than 0.001, and 24% at week 6, P less than 0.01) and was closely correlated (r = 0.71; P less than 0.001) with body weight gain. Liver GH-binding protein and GH receptor mRNA abundance were reduced by 1 week of protein deprivation at week 6 but not at week 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Influence of alpha-ketoisocaproate on lamb growth, feed conversion, and carcass composition.

Four experiments were conducted to determine whether leucine's alpha-ketoacid, alpha-ketoisocaproate (KIC), would influence lamb growth, feed conversion, and carcass composition. In the first experiment, lambs were injected intraperitoneally with 3.5 g of Na-KIC per day. In the second experiment, KIC unprotected from rumen degradation was fed at a rate of 15 g per animal daily. In a third experiment, KIC, leucine, and isovalerate (IVA), protected from rumen degradation, were fed to growing lambs at a rate of 1 g per animal per day. Finally, a fourth experiment was conducted in which ruminally protected KIC was fed to growing lambs at a rate of 1 g per animal per day. Ketoisocaproate tended to increase ADG and decrease fat deposition in all four experiments. Ketoisocaproate increased ADG by 11 (P less than .09), 10 (P less than .05), 9, and 13% in 1 through 4, respectively, and feed efficiency improved 5, 9 (P less than .02), 5, and 5%, respectively. Fat thickness over the 12th rib decreased 28 (P less than .06), 11, 17 (P less than .04), and 5% in Exp. 1 through 4, and the perirenal fat depot also decreased 13, 5, 18, and 3%, respectively. In contrast, neither ruminally protected leucine nor IVA affected the growth of young lambs. Together these studies indicate that administration of KIC to growing lambs can increase weight gain and muscle growth while decreasing fat deposition.

Adipose Tissue↗