|ANDERSON, JILL - South Dakota State University|
|CLAPPER, JEFFREY - South Dakota State University|
|PERRY, GEORGE - South Dakota State University|
|KEISLER, DUANE - University Of Missouri|
|GARCIA, ALVARO - South Dakota State University|
|SCHINGOETHE, DAVID - South Dakota State University|
Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/28/2015
Publication Date: 8/1/2015
Citation: Anderson, J.L., Kalscheur, K., Clapper, J.A., Perry, G.A., Keisler, D.H., Garcia, A.D., Schingoethe, D.J. 2015. Feeding fat from distillers dried grains with solubles to dairy heifers: II. Effect on metabolic profile. Journal of Dairy Science. 98:5709-5719.
Interpretive Summary: Distillers dried grains with solubles (DDGS), a byproduct of the ethanol industry, is an economic feed source for dairy cattle and is used extensively in ruminant diets. But there have been questions about feeding it to dairy heifers, with one concern being that the high fat level might negatively affect the metabolic profile and onset of puberty. In this study, for 24 weeks Holstein heifers were fed three different diets containing: 1) soybean products with ground corn; 2) low-fat DDGS with ground corn; or 3) high-fat traditional DDGS. Most metabolites and metabolic hormones were similar, but plasma cholesterol and total fatty acids were increased by feeding fat from DDGS. Not all heifers reached puberty by the end of the feeding period, but the limited results indicate that feeding fat from DDGS may have decreased the age at which puberty was reached. More definitive results would require further research.
Technical Abstract: The objective of this study was to determine if increased dietary fat from dried distillers grains with solubles (DDGS) in diets of growing heifers affected metabolic profile, plasma fatty acid profile, and reproductive maturation. Thirty-three Holstein heifers (133 ± 18 d old) were used in a 24-week randomized complete block design with three treatment diets. Treatment diets were: 1) control (CON) containing ground corn (15.9% of DM) and soybean products (17.9%); 2) low-fat (LFDG) containing low-fat DDGS (21.9%) and ground corn (11.9%); or 3) high-fat (HFDG) with traditional DDGS (33.8%). Diets were isonitrogenous and isocaloric, but the HFDG diet was formulated to contain 4.8% fat compared to 2.8% in the CON and LFDG diets. All three diets were precision fed to 2.45% of BW on a DM basis. Every 4 weeks, jugular blood was collected for analysis of metabolites and metabolic hormones. During week 20 of the feeding period, blood samples were collected for analysis of plasma fatty acid profiles. While heifers weighed between 200 and 300 Kg of BW, coccygeal blood samples were taken twice weekly for analysis of progesterone to determine if puberty had been reached. Plasma concentrations of NEFA were similar among treatments and consistent over the duration of the study. Plasma concentrations of BHBA, insulin, IGF-1 and leptin were similar among heifers fed each treatment diet, but increased over the duration of the feeding period. Serum concentrations of glucose tended to be lower in heifers fed HFDG compared to heifers fed the CON diet. Glucose concentrations fluctuated throughout the feeding period, but there were no treatment by time interactions. Plasma urea nitrogen concentrations were lower in LFDG-fed heifers compared to heifers fed HFDG and CON diets. The concentrations of PUN increased over the duration of the feeding period, with no treatment by week interaction. Plasma total cholesterol was greater in heifers fed HFDG compared to the CON and LFDG diets and there was a significant week effect and a week by time interaction. Fatty acid profiles also differed among treatments, based on the supply of fatty acids from the diet. Progesterone analysis indicated that heifers fed HFDG were pubertal at a younger age than heifers on LFDG or CON. These results demonstrate that dietary fat from DDGS can be used in rations for growing heifers and still maintain metabolic energy status compared to starch from corn, but alters the concentrations of different blood lipids.