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Unformatted text preview: J. Dairy Sci. 89:4376–4386 © American Dairy Science Association, 2006. Effects of Supplementing Concentrates Differing in Carbohydrate Composition in Veal Calf Diets: II. Rumen Development 1 B. J. Sua ´rez,* 2 C. G. Van Reenen,† W. J. J. Gerrits,* N. Stockhofe,† A. M. van Vuuren,† and J. Dijkstra* *Animal Nutrition Group, Wageningen UR, P.O. Box 338, 6700 AH Wageningen, The Netherlands †Animal Science Group, Wageningen UR, P.O. Box 65, 8200 AB Lelystad, The Netherlands ABSTRACT The objective of this experiment was to examine the effects of concentrates in feed, differing in carbohy- drate source, on the rumen development of veal calves. For this purpose, 160 male Holstein Friesian × Dutch Friesian crossbred calves were used in a complete ran- domized block design with a 5 × 2 factorial arrange- ment. Dietary treatments consisted of 1) a milk re- placer control, 2) a pectin-based concentrate, 3) a neu- tral detergent fiber-based concentrate, 4) a starch- based concentrate, and 5) a mixed concentrate (equal amounts of the concentrates in treatments 2, 3, and 4). Concentrate diets were provided as pellets in addi- tion to a commercial milk replacer. Calves were eu- thanized at either 8 or 12 wk of age. Plasma acetate and β-hydroxybutyrate (BHBA) were measured as in- dicators of rumen development. Empty rumen weight was determined, and wall samples were taken at slaughter. In most calves, a poorly developed rumen mucosa was observed. Coalescing rumen papillae with embedded hair, feed particles, and cell debris were found in all calves fed the concentrate diets. Calves fed concentrates had significantly heavier rumens than calves fed the control diet. In the dorsal location of the rumen, calves fed concentrate diets showed an in- creased ratio of mucosa to serosa length compared with calves fed the control diet, whereas in the ventral loca- tion only, calves fed the pectin and mixed diets showed larger ratios of mucosa to serosa length. Mucosa thick- ness and muscle thickness were greater in the ventral and dorsal locations of the rumen, respectively. In both locations, the NDF diet resulted numerically in the lowest mucosa thickness and highest muscle thickness among the concentrate treatments. At 8 wk, calves fed the concentrate diets had higher plasma acetate concentrations than calves on the control treatment. However, at 12 wk, only NDF-fed calves showed sig- Received December 23, 2005. Accepted June 20, 2006. 1 This study was partially supported by The Dutch Product Board Animal Feed and The Dutch Ministry of Agriculture. 2 Corresponding author: [email protected] 4376 nificantly higher plasma acetate concentrations. The plasma BHBA concentrations of calves at 8 wk of age fed the pectin and mixed diets were higher than those of the control diet-fed calves. At 12 wk, no differences in BHBA concentrations were observed among treat- ments. Results of a principal component analysis indi- cated that, in addition to rumen volatile fatty acid...
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This note was uploaded on 09/19/2011 for the course ANS 5446 taught by Professor Brown during the Spring '08 term at University of Florida.
- Spring '08