Milk production and nutrient digestibility by dairy cows when fed exogenous amylase with coarsely ground dry corn
Department of Animal Sciences, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster 44691, USA. Journal of Dairy Science
(Impact Factor: 2.57).
05/2011; 94(5):2492-9. DOI: 10.3168/jds.2010-3766
The digestibility of starch provided by coarsely ground corn is often low, which reduces the digestible energy (DE) concentration of the diet. We hypothesized that adding exogenous amylase to diets based on coarsely ground dent corn would increase dietary DE resulting in greater milk production. Total-tract nutrient digestibility was measured in a partially replicated Latin square experiment (6 cows and 4 periods) with a 2 × 2 factorial arrangement of treatments. Diets had 26 or 31% starch with or without exogenous amylase (amylase was added to the concentrate mixes at the feed mill). In the low and high starch diets, coarsely ground dry corn (mean particle size=1.42 mm) provided 43 and 62% of total dietary starch (corn silage provided most of the remaining starch). No treatment interactions were observed. High starch diets had greater dry matter (DM), organic matter, and energy digestibility than low starch diets, and diets with amylase had greater neutral detergent fiber digestibility than diets without amylase. Digestibility of starch averaged 88% and was not affected by treatment. A long-term (98-d) lactation study with 48 Holstein cows (74 d in milk) was conducted using 3 of the diets (low starch diets with and without amylase and the high starch diet without amylase). Addition of amylase to a diet with 26% starch did not affect intake, milk yield, milk composition, body weight, or body condition. Cows fed the diet with 31% starch had greater DM and DE intakes; yields of milk, fat, and protein; and feed efficiency than those fed diets with 26% starch. Milk composition was not affected by starch concentration. Adding exogenous amylase to a lower starch diet did not make the diet nutritionally equivalent to a higher starch diet.
Available from: Diego P Morgavi
- "These values are in accordance with the expected values estimated from INRA (2007) feed tables. No effect of amylase supplementation was observed on ruminal and total-tract digestibility of NDF and ADF, which is in good agreement withHristov et al. (2008) andWeiss et al. (2011). In contrast, several studies in dairy cows (Gado et al., 2009;Klingerman et al., 2009;Gencoglu et al., 2010) and beef steers (DiLorenzo et al., 2011) reported a numerical increase in NDF total digestibility. "
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ABSTRACT: The objective of this study was to evaluate the effect of an exogenous amylase preparation on digestion of low- and high-starch diets in dairy cattle. Rumen and total-tract nutrient digestibility were measured in a 4 × 4 Latin square design with 28-d periods using 4 first-lactation cows cannulated at the rumen and duodenum. Corn silage-based diets had 20 or 30% starch, attained by changing the composition of concentrate, with or without addition of an exogenous amylase preparation. Effects of the enzyme additive were observed on ruminal digestibility but not at the total-tract level. Ruminal digestibility of starch increased from 75% in control to 81% with amylase supplementation. This difference in ruminal starch digestion was compensated postruminally, so that the total-tract digestibility of starch was almost complete and did not differ between treatments. The amylase supplement also increased the true ruminal digestibility of organic matter but did not affect microbial N flow to the duodenum. Amylase supplement reduced the proportion of acetate and butyrate and increased that of propionate, particularly in the high-starch diet, where it tended to increase the concentration of total volatile fatty acids in the rumen. Other effects were a higher amylase activity in the solid-associated microbial community and a tendency for lower numbers of protozoa. In contrast, we observed no changes in intake, production, dry matter and fiber (neutral detergent fiber and acid detergent fiber) digestibility, or ruminal digestion, and no or small changes on selected fibrolytic and amylolytic bacteria and on the microbial community in general. We conclude that the exogenous amylase improved starch digestion in the rumen in first-lactation cows with moderate intake and production levels.
Available from: German D Mendoza
- "Certain processes have been utilized to improve starch digestion, such as flaking or rolling, but those are expensive; thus, there are strategies to improve the ruminal digestibility of starch that include the addition of exogenous amylolytic enzymes (Rojo et al., 2005; Weiss et al., 2011). "
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ABSTRACT: The objective of this study was to evaluate the effects of the addition of glucoamylase and the reduction of the level of sorghum grain in a finishing diet on lamb performance (45 days) and on diet digestibility. The treatments evaluated were the following: a diet composed of 64% corn and sorghum grain mixture (64CSMG), a diet composed of 45% corn and sorghum grain mixture (45CSMG) and a diet composed of 45% corn and sorghum grain mixture plus added glucoamylase (1.5 ml of the enzyme protein/kg DM of grain; 45CSMG+E). In vivo DM digestibility showed differences (P<0.05) between treatments; the highest values were for the 64% grain diet (748 g/kg) and the 45% grain with enzyme diet (694 g/kg), and the lowest value was for the 45% grain without enzyme diet (740 g/kg). There were no differences (P> 0.05) in dry matter intake, average daily gain (ADG) and feed conversion even when the digestibility of the 45% grain ration with glucoamylase was improved.
Available from: Luiz Felipe Ferraretto
- "Partially replacing corn grain with nonforage fibrous byproducts increased total-tract starch digestibility (TTSD) in some (Pereira and Armentano, 2000; Gencoglu et al., 2010; Ferraretto et al., 2012), but not all, trials (Voelker and Allen, 2003b). Similarly, increasing dietary FNDF content either increased (Bal et al., 2000a), decreased (Agle et al., 2010b), or did not affect TTSD (Pereira and Armentano, 2000; Lechartier and Peyraud, 2010; Weiss et al., 2011b). "
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ABSTRACT: A meta-analysis was performed to determine the influence of cereal grain type and corn grain harvesting and processing methods, dietary starch, rumen-digestible starch, and forage NDF concentrations on intake, digestion, and lactation performance by dairy cows using a data set comprising 414 treatment means from 102 peer-reviewed journal reports from 2000 to 2011. Categories for corn processing were dry ground, cracked or rolled corn (DRY), high-moisture shelled or ear corn (ENS), and steam-flaked or -rolled corn (STM); categories for kernel mean particle size were 500 to 1,000, 1,000 to 1,500, 1,500 to 2,000, 3,000 to 3,500, and 3,500 to 4,000 µm for dry corn and <2,000 and ≥2,000 µm for ensiled corn. Dietary starch and forage NDF concentrations were used as continuous variables. Data were analyzed using PROC MIXED in SAS (SAS Institute Inc., Cary, NC), with treatment as fixed and trial as random effects. Total-tract starch digestibility was reduced and milk fat content was greater for DRY compared with ENS or STM. Total-tract digestibility of dietary starch was reduced for both DRY and ENS as particle size increased. Increased dietary starch concentrations increased milk yield and protein content, but decreased ruminal and total-tract NDF digestibilities and milk fat content. Dry matter intake, total-tract starch digestibility, and milk protein concentration decreased as forage NDF in the diet increased. Total-tract starch digestibility was positively related to ruminal (percentage of starch intake) and postruminal (percentage of duodenal flow) starch digestibilities.
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