Effects Of Gestational Energy Source On Feedlot Performance Glucose Tolerance And Carcass Traits Of Progeny

Author : Amy E. Radunz
Publisher :
ISBN 13 :
Total Pages : 218 pages
Book Rating : 4.:/5 (68 download)

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Download or read book Effects of Prepartum Dam Energy Source on Progeny Growth, Glucose Tolerance, and Carcass Composition in Beef and Sheep written by Amy E. Radunz and published by . This book was released on 2009 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: A series of experiments were conducted in cattle and sheep to investigate the effects of prepartum dietary energy source during gestation on progeny growth, glucose tolerance, and carcass composition. The three dietary energy sources fed to dams at isoenergetic intakes were used for the experiments; hay or haylage (fiber, HAY); corn (starch, CORN); or dried distiller grains (fiber plus fat, DDGS). In the first experiment beef cows were used to determine the effects of late gestation dietary energy source on fetal growth and maternal nutrient supply. Cows fed HAY and CORN achieved the experimental objective of having similar body weight and body condition score change during late gestation, however, cows fed DDGS had greater body weight gain. Calves from cows fed CORN and DDGS had heavier birth weights than calves from cows fed HAY. Differences in progeny birth weight were still evident upon entry into the feedlot, as body weights were heavier for calves from cows fed CORN and DDGS than from those fed HAY. In contrast to arrival at the feedlot, carcass weights were lighter for calves from cows fed DDGS verses CORN or HAY. Growth rate was not different among treatments from birth to slaughter, but calves from dams fed CORN were slaughtered at a younger age than calves from cows fed HAY or DDGS. Measures of carcass yield were not affected by treatment, whereas intramuscular fat was greater in calves from dams fed DDGS or HAY than from those fed CORN. In addition, initial insulin secretion in response to a glucose tolerance test was greater in calves from dams fed HAY than calves from dams fed CORN or DDGS. In the second experiment, mature ewes were fed three dietary treatments in mid- to late-gestation similar to the first experiment. During mid-gestation ewe body weight gain and body condition score were similar among treatments and met the experimental objective. Lamb birth weights tended to be greater in lambs from ewes fed CORN and DDGS than in lambs from ewes fed HAY. Increased glucose and amino acid supply, as indicated by maternal metabolic status, could explain the increase in birth weight in lambs from ewes fed DDGS and CORN compared with that of lambs from ewes fed HAY. Overall growth rate from birth to slaughter was not different among treatments. Lambs from ewes fed DDGS vs. lambs from ewes fed CORN or HAY tended to have a greater initial insulin secretion due to glucose infusion in the glucose tolerance test. No difference was detected in HCW, fat thickness, proportion of seam fat, or intramuscular fat content among treatments. However, lambs from ewes fed DDGS vs. lambs from ewes fed CORN or HAY had a greater proportion of internal fat, less muscle, and lower calculated boneless trimmed retail cut percentage. In all experiments, prepartum energy source did not adversely affect postpartum cow or ewe performance. Together these results suggest prepartum energy sources, which may increase maternal glucose and amino acid supply to the fetus, impact fetal growth and alter postnatal insulin sensitivity and adipose tissue development.