|LAWRENCE, RHEA - South Dakota State University|
|ANDERSON, JILL - South Dakota State University|
|MANTHEY, ANGELA - South Dakota State University|
Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/2016
Publication Date: 4/1/2017
Citation: Lawrence, R.D., Anderson, J.L., Manthey, A.K., Kalscheur, K.F. 2017. Growth performance and total tract nutrient digestion for Holstein heifers limit-fed diets high in distillers grains with different forage particle sizes. Professional Animal Scientist. 33:230-240.
Interpretive Summary: Feeds for dairy cattle are generally classified as forage or concentrate (feeds that are energy and/or protein dense such as grains or soybean meal). Dried distillers grains with solubles (DDGS), a byproduct of the ethanol industry, is an economical concentrate for dairy cattle and is used extensively in ruminant diets. The particle size of the forages being fed with concentrates has been shown to affect rumination, passage rate, and feed intake, and may affect how concentrates are utilized in the rumen. However, the particle size of forage in combination with DDGS has not been examined in depth for dairy heifers. Forage sources for dairy heifers usually include grass hay or corn silage without further processing. The objective of this study was to determine if ration particle size affects dairy heifer growth and total tract digestion in diets high in DDGS. Alfalfa hay was ground and pelleted to provide a smaller particle size compared to regular chopped alfalfa hay. Feeding DDGS in combination with pelleted or chopped alfalfa hay to growing dairy heifers resulted in similar growth performance. Total tract digestibility of nutrients was similar between treatments. This study demonstrates to dairy producers and nutritionists that forage processing, to achieve different diet particle size in diets, had minimal effects on utilization of DDGS by growing heifers.
Technical Abstract: This study evaluated dairy heifer growth performance and total tract nutrient digestion when fed diets high in dried distillers grains with solubles (DDGS) with different forage particle size. An 8-wk randomized complete block design study was conducted utilizing twenty-two Holstein heifers (123 ± 32 d of age; body weight (BW) of 140 ± 23.5 kg). Treatments were 15% chopped (CHOP) or 15% pelleted (PELL) alfalfa hay on a dry matter (DM) basis. Both diets also contained 30% DDGS, 53.8% corn silage, and 1.25% mineral mix and were limit-fed for dry matter intakes (DMI) at 2.3% of BW. Growth measurements were taken every 2 wk and jugular blood samples were taken every 4 wk. During wk 8, rumen samples were taken via esophageal tubing to evaluate fermentation and fecal grab samples were collected to determine total tract nutrient digestion. Heifer DMI increased when fed CHOP versus PELL, BW and ADG were similar. Gain to feed was less in the CHOP fed heifers. Frame measurements were similar, with the exceptions of paunch girth, heart girth, and hip width, which were greater for the CHOP. The CHOP fed heifers had less BCS than the PELL treatment. Rumen fermentation characteristics were similar, however, rumen pH was greater for PELL. Serum glucose and plasma cholesterol were similar between treatments, but plasma urea nitrogen tended to be greater in heifers fed CHOP. Total tract digestibility of nutrients was similar between treatments. Results indicate that different forage particle size minimally affects utilization of DDGS by heifers.