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Monday, September 22, 2003
FULL TEXT PAPER
Feeding to Increase Productive Life
by Michael Hutjens, Extension Dairy Specialist, University of Illinois, Urbana
Feeding to increase productive life by reducing culling rates, improving herd health status, maintaining fertility, reducing mastitis and somatic cell count, and increasing milk production are possible goals on dairy farms. This presentation will focus on three feeding aspects to increase productive life through feeding.
- Manipulating dry matter intake can increase milk production and components, minimize negative energy balance that can lead to ketosis, and improve reproductive performance by reaching positive energy balance earlier in lactation.
- Optimizing rumen fermentation can reduce acidosis while increasing microbial yield of volatile fatty acids and microbial protein to improve nutrient intake.
- Building transition cow feeding programs (three weeks before calving to three weeks after calving) will reduce culling and minimize metabolic disorders.
Dairy managers, veterinarians, and nutritionists can review the following outline of key points and nutrient guideline table for phase feeding.
Monitoring Dry Matter Intake (DMI)
- Maximizing DMI may not be the most efficient point or desirable target.
- Dairy or feed efficiency (kilograms of milk per kilogram of dry matter) should exceed 1.4 (one group TMR) with early lactation groups achieving 1.6 kg of 3.5% FCM per kg of dry matter or higher.
- Six kilograms of dry matter subtracted from total ration dry mater reflect available energy for productive function in Holstein cows.
- Current ration dry matter costs about 14 cents (U.S.) cents per kilograms in Illinois.
- Cows may consume 1.2 percent of their body weight at total NDF.
- If DMI violates these guidelines; evaluate feed particle size, look for periods of negative energy balance earlier, consider rumen acidosis, and determine if reformulation of the ration is needed (based on milk price, body condition score, feed costs, stage of lactation, and age of cows).
- Evaluate feed refusals as it impacts DMI and feed costs. Target 2 to 4 percent of the initial DMI as weigh back and evaluate particle size using the Penn State Box (less than +/- 10 percent of the initial TMR in each box).
Optimizing Rumen Fermentation
- Maintain rumen pH levels between 5.9 to 6.2.
- About 60 percent of amino acids and 80 percent of energy (via VFA) needs can be produced by rumen fermentation and microbial growth.
- Penn State Box TMR guidelines for optimal intake and fermentation include 10 to 15 in the top box, 40 to 50 percent in the second box, 30 to 35 percent in the third box, and 10 to 20 percent in the bottom box.
- Dry shelled corn should average 1100 microns with 33 percent above 1100 micron screen , 50 percent from 500 to 11000 micron screen, and less than 10 percent under 500 micron screen (about two thirds of dry shelled corn should passing though a flour sifter).
- Balancing carbohydrate and nitrogen fractions will optimize nitrogen capture of RDP (rumen degradable protein) and soluble protein as microbial protein. MUN (milk urea nitrogen) values from 11 to 16 can reflect this balance point.
Strategies with Transition Feeding Program
- A two-phase dry cow program (far off dry cow program for 30 days and 21 day close up dry cow program) and a fresh cow program (10 to 21 days) appear optimal. Nutrient guidelines for each of these phases are listed in Table 1.
- Minimizing metabolic disorders will improve productive life. The following guidelines can be used to evaluate individual farm status: milk fever < 3%, hypocalcemia < 15%, ketosis < 2%, displaced abomasums < 5%, retained placenta < 8%, and lameness < 10%.
- Strategic use of feed additives can be effective during the transition period. Feed additives can groups in three categories.
- Recommended category of feed additives for transition cows include yeast culture, organic trace minerals, propylene glycol, anionic products, and calcium propionate.
- Experimental additives (needing more controlled research before being recommended) include protected choline, methionine hydroxy analog, and probiotics.
- Evaluative additives (more research variation and should be evaluated on the farm) include niacin.
- Drenching can be a method that can rehydrate the cow with 30 to 40 liters of water, add electrolytes lost at calving (potassium, sodium, magnesium, chlorine, and calcium), and provide a source of glucose precursors (propylene glycol, calcium propionate, or glyercol).
Balancing and Meeting Nutrient Requirements
- Table 1 contains the recommended nutrient guidelines based on NRC 1989 for protein energy, protein, dry matter intake, and trace minerals guidelines.
- Phosphorous and vitamin E values reflect NRC 2001 values.
- Replacing one quarter to one third of zinc and copper with organic sources is recommended for transition and early lactating cows.
- While nutrient requirements are expressed as percent or parts per million, the cow’s needs are needed in pounds, grams, or international units. Actual dry matter intake dictates the nutrient level needed in rations.
Benchmarking Cow Performance
- Milk components can reflect nutrient form and level.
- Milk production guidelines by stage of lactation and lactation number reflect areas to investigate.
- Milk urea nitrogen values (MUN) are herd specific, can range from 10 to 16 mg/dl, and should be based on MUN valves averaged from 8 to 10 cows in each group to reflect actual values.
- Manure scores should range from 2.5 to 3.5 depending on the stage of lactation and gestation.
- Blood NEFA and ketone bodies, urine pH, and rumen pH using rumenocentesis can be measure nutrient balance and changes.
Table 1. Illinois nutrient recommendations for dairy cows in different stages of lactation and gestation.
||0 to 21d
||22 to 80d
||80 to 200d
||Cows 12 - 13
Heifers 14 - 15
|Metabolizable Protein (%)
|*RDP:% of CP (DM)
|RUP:% of CP (DM)
||40 ( 5)
|SIP:% of CP(DM)
|Ether Extract %
|*Ratio of NFC to DIP (%of DM) =3.5:1
|Major Minerals in % of DM
|*When anionic salts are used: mineral/anionic salts (%)
|Vitamins in IU per Day
a Trace minerals: iron (150 ppm), cobalt (0.1 ppm), copper (15 ppm), manganese (60 ppm), zinc (60 ppm), iodine (0.6 ppm), and selenium (0.3 ppm).
b Ratio of Minerals in Total Ration: zinc to copper 4:1, iron to copper 40:1, potassium to Mg 5:1, copper to molybdenum 6:1, potassium to sodium 3:1, nitrogen to sulfur 10:1
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