Corn silage digestibility
Last month, we focused on the obvious relationship between forage NDF digestibility and performance based upon a summary by Oba and Allen at Michigan State University. Dr. Bill Stone from the PRO-Dairy group at Cornell summarized in vitro (30 hour) NDF digestibility data provided by Paul Sirois of DairyOne Labs, and these data indicate a wide variation in NDF digestibility that does not seem to be correlated with the NDF content of the forage.
These data have tremendous implications for ration formulation for dairy cows. We can diligently analyze our forages, but factors beyond chemical composition also determine the dynamics of that forage in the rumen.
Peter Van Soest presented an equation at the 1998 Cornell Nutrition Conference that related corn silage digestibility to weather data. This makes sense, given that both temperature and water will affect plant physiology, particularly extent of lignification. The equation takes into account the rainfall that the crop received and the temperature in terms of growing degree days (GDD).
Dry Matter Digestibility = 106 – 0.87 water – 0.0135 GDD, where water equals inches of rainfall from planting to harvest and GDD equals growing degree days, base 50, from planting to harvest.
To calculate growing degree days for a single day, base 50, simply subtract the low temperature for the day from the high temperature for the day. If the low temperature is below 50, then use 50 for the low temperature value. Add the single-day GDD values together to calculate the total GDD for your timeframe of interest.
This equation seems to work fairly well in the Northeast, but further data and validation are required before it can be reliably used in other regions. Furthermore, the wacky weather patterns from the current growing season should be enough to convince us that we need to use data from the actual farm of interest as opposed to regional weather data.
T. R. Overton
Digestibility of BT Corn
We continue to receive questions regarding the nutritional quality of BT corn. The data below were provided by Kurt Ruppel from Pioneer Hi-Bred.
| Hybrid | Number of |
Yield |
In-vitro digestibility |
| 3394 | 16 | 22.3 | 71.8 |
| 33V08(BT) | 16 | 25.2(+2.9) | 72.4 |
| 37M81 | 37 | 22.9 | 72.9 |
| 37R71(BT) | 37 | 23.3(+0.4) | 73.2 |
| 3893 | 34 | 20.9 | 72.1 |
| 38W36(BT) | 34 | 23.3(+1.4) | 72.3 |
The differences in this study do not indicate any negative digestibility effects of the BT gene in corn.
L. E. Chase
1999 Cornell Nutrition Conference
Below are the program and registration form for the 1999 Cornell Nutrition Conference. We are excited about this year’s program, including the preconference symposium sponsored by Cornell. The single-page registration form can be printed below for your convenience. Please contact Dee Brothers (dab2@cornell.edu) or Larry Chase (lec7@cornell.edu) for additional information
| Tuesday,, October 19 | ||
| 11:00 - 4:00 | Registration | |
Pre-Conference Symposium |
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| 1:00-1:10 | Welcome | L. Chase |
1:10-1:50 |
Milk composition in the cow | J. Kennelly |
| 1:50-2:30 | How does the new milk component pricing system work? | C. Alexander |
| 2:30-3:00 | Trends in milk composition and analysis in NY | D. Barbano |
| 3:00-3:30 | Break | |
| 3:30-3:55 | The effect of subclinical rumen acidosis on milk components | W. Stone |
| 3:55-4:45 | What role does genetics play? Are there limits to nutritional manipulation? | R. Everett |
| 4:45-5:30 | A model for the control of milk composition | J. Cant |
| 5:30 | Cash Bar/Appetizers | |
| Wednesday, October 20, 1999 | ||
| 7:00-8:00 | Zinpro Breakfast Trace Mineral Nutrition for the Modern Dairy -M. Socha |
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| 8:30-9:00 | Selenium and prostate health in the dog model | D. Waters |
| 9:00-9:20 | Using transgenic mice to study selenium nutrition | X. Lei |
| 9:20-9:40 | How will environmental regulations change animal management strategies? | L. Chas |
| 9:40-10:10 | Phosphorus nutrition of dairy cattle – What’s new? | L. Satter |
| 10:10-10:40 | Break | |
| 10:40-11:00 | Phytase for poultry diets | K. Keshavarz |
| 11:00-12:00 | Antibiotics in animal feeds | J. Coffman |
| 11:45-1:00 | Lunch | |
| 1:00-1:30 | An update on conjugated linoleic acid | Y. Chouinard |
| 1:30-2:00 | CLA, metabolism and health | M. Cook |
| 2:00-2:30 | bST and test day model | R. Everett |
| 2:30-3:00 | Molds, mycotoxins and animal feeds | L. Thompson |
| 3:00-3:30 | Break | |
| 3:30-3:50 | Liver metabolism and the transition cow | T. Overton |
| 3:50-4:20 | Johnes Disease Update | C. Elrod |
| 4:20-5:30 | NYS Cattle Health Assurance Program | J. Huntley |
| 5:30-6:30 | Cash Bar/Appetizers | |
| 6:30-8:00 | Dinner | |
| Thursday, October 21, 1999 | ||
| 7:00-8:00 | Biotechnology in the feed industry: "Looking Back to move forward into the next millennium | P. Lyons |
| 8:00-8:30 | Fiber source and digestibility for sheep | M. Thonney |
| 8:30-9:00 | High moisture corn in dairy rations: Digestion, metabolism and milk production | K. Knowlton |
| 9:00-9:20 | Performance and meat quality of beef steers fed corn or bakery-waste based diets | P. Guiroy |
| 9:20-9:40 | Soluble fiber content of ruminant feeds | M. Van Amburgh |
| 9:40-10:20 | Equine Nutrition | J. Pagan |
| 10:20-10:45 | Break | |
| 10:45-11:15 | Promise and limitations of herbal anthelmentics | J. Ketzis |
| 11:15-11:45 | Energy prediction equations for ruminant feeds | B. Weiss |
| 11:45-12:15 | Feeding forages for optimum performance and pasture sustainability | D. Cherney |
| 12:15 | Adjourn - Have a Safe Trip Home | |
Conference registration postmarked on or before October 1, 1999 is $75. Registration postmarked after October 1, 1999 , or taken at the door is $100. MasterCard and Visa are accepted. Checks must be drawn on a U.S. bank; international money orders are also accepted. Registration will not be acknowledged in advance of the conference. There is no partial registration fee. The fee includes one lunch, refreshment breaks, hors d’oeuvres, one dinner and a copy of the conference proceedings. Extra copies of the conference proceedings are also available. You must register for the Zinpro and Alltech breakfasts separately.
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Name*__________________________________________ Affiliation*______________________________________ (*As you would like it to appear on your nametag) |
___Check here if new address |
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Address_________________________________________ _______________________________________________ |
Where to send this form: Cornell Nutrition Conference PO Box 105 Ithaca NY 14851-0105 |
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City, State,Zip____________________________________ |
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Entrée choice: ____Prime Rib ____Baked Orange Roughy no substitutions) |
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Country_________________________________________ |
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Daytime phone_(_____)____________________________ |
____I will not be joining the group for dinner |
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Fax_(___)_______________________________________ |
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E-mail___________________________________________ |
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Please check all that apply Registration:___Pre-Conference Symposium (no charge for symposium only) ___Registration postmarked before 10/1 - $75 ___Registration postmarked after 10/1 - $100 Proceedings: ____I cannot attend the conference but would like to purchase ___ copy (ies) of the proceedings at $10 (US/Canada) or $20(All other destinations). Payment must accompany order. _____Format: _____Softcover _____CD-ROM |
Method of payment (Please see our refund policy below.) ___My check/money order, payable to Cornell University in the amount of $________ is enclosed. (U.S. bank checks or international money orders.) ___Please charge my credit card $______. Circle one below and complete the information. Your credit card will be charged on the day your registration is received. Mastercard Visa Credit card number___________________________________________ Expiration date ___________________ Signature ____________________________ |
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Refund Policy: Requests for refunds must be postmarked by October 1, 1999. |
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Email notification
Please email Tom Overton at tro2@cornell.edu to be added to our list of subscribers for notification of new issues.