Stanislaus County
University of California
Stanislaus County

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Photo of Jennifer Heguy
Jennifer Heguy 
Title: Farm Advisor
Specialty: Dairy - Merced, Stanislaus & San Joaquin Counties
University of California Cooperative Extension
3800 Cornucopia Way
Suite A
Modesto, CA 95358
Phone: (209) 525-6800 
Fax: (209) 525-6840

Jennifer Heguy is a native of California’s Central Valley.  She received her B.S. in Animal Science, with an emphasis in Livestock and Dairy, at the University of California, Davis.  In 2006, she received her M.S. degree at UC Davis, focusing on dairy nutrition.  Jennifer serves as the Dairy Farm Advisor in Merced, Stanislaus and San Joaquin Counties where milk is a major agricultural commodity.  The goal of the dairy program is to contribute to the continued success of the dairy industry in Merced, Stanislaus and San Joaquin Counties, and throughout California.

Corn Silage Management

Corn Silage Management Practices on California Dairies (Presentation, PDF), by Noelia Silva-del-Rio and Jennifer Heguy (2014) • Current silage management practices on California’s San Joaquin Valley dairies are described. Opportunities to optimize silage management are also presented and discussed.

Silage Management Practices on California Dairies (Poster Presentation, PDF), by Noelia Silva-del-Rio, Jennifer Heguy, and Alfonso Lago • Corn silage is a common ingredient of California dairy rations. In well managed corn silage, dry matter losses can be as low as 8 - 10%. However, when poor management practices are implemented dry matter losses can be as high as 20 - 40%.

Overview of Silage Management in California (Symposium Paper, PDF), by Jennifer Heguy (2010) • Current silage management practices on California dairies are described and discussed. Due to environmental pressures, Central Valley dairies are subject to stringent water and air regulations. Discussion of silage management in California is not complete without this regulatory component.

Silage Face Management (PDF), by Noelia Silva-del-Rio (2010) • The goal of silage face management is to minimize silage exposure to oxygen. This article discusses the importance of good face management practices to minimize dry matter losses and describes current silage management practices in California dairies based on a UCCE survey.

Dry Matter

Correcting for Dry Matter, Presentation (PDF), by Jennifer Heguy • Correcting for Dry Matter (DM) at Harvest; Determining Whole Field DM: Challenges and Proposed Solutions; Other monitoring: Length of cut, Kernel processing.

Correcting for Dry Matter, Article (PDF), by Jennifer Heguy • It’s important to remember that as corn matures (DM increases) and starch content increases, fiber quality declines. This trade-off between starch content and digestibility of forage will affect how the silage is incorporated into rations.

General Information

Snapshot of California’s Corn Silage Practices (PDF), by Jennifer Heguy and Noelia Silva-del-Rio for Progressive Dairyman (2015) • Corn silage is a valuable commodity. Dairy producers should invest time and effort to coordinate growers, pest control advisers, customharvesters and nutritionists to work toward the same goal: maximizing quality and quantity of the crop harvested and ensiled.

Corn Silage Audits: Lessons from Observing Harvest (PDF), by Jennifer Heguy (2014) • Dairies selected to participate in this study had previously taken part in a corn silage management survey in 2013; Corn silage harvest on 20 San Joaquin Valley dairies were evaluated in the summer of 2014.

2014 Corn Silage Audit (PDF), by Jennifer Heguy and Noelia Silva-del-Rio (2014) • In summer 2014, we visited twenty San Joaquin Valley dairies during corn silage harvest, and sampled and composited five, consecutive truckloads of corn silage for nutrient analysis.

California Dairy Newsletter

Those interested in keeping up to date about the dairy industry in the Stanislaus and San Joaquin County area.

Issue Articles Type Date Added
Volume 11, Issue 2, May 2019 (606KB)
  • CVDRMP Recommendations
  • NIR or Wet Chemistry?
  • By-Product Survey
  • Welcome Tim Hackmann
  • Waste Milk Quality
  • Antimicrobial Survey
  • Horn Removal Options
PDF 5/14/19
Volume 11, Issue 1, February 2019 (529KB)

In this Issue…

  • Almond Hull Usage
  • Western Dairy Management Conference
  • Research Opportunity
  • Semen Value Tool
  • Bacteria & Milk Shelf Life
PDF 2/14/19
Volume 10, Issue 4 December 2018 (729KB) PDF 1/10/19
Volume 10, Issue 3 September 2018 (1,221KB)

In this Issue…

  • Heat Stress Impact on Cows
  • Forage Nutrient Yields
  • Sorghum Characteristics
  • New Soils Advisor
  • Reducing Methane Emissions
  • Survey on Antibiotic Use
PDF 9/10/18
Volume 10, Issue 2 May 2018 (1,508KB)

In this Issue…

  • Next Generation of Carbon Management
  • Reducing Antimicrobial Resistance in Waste Milk
  • Heifer Operation Regulation
  • Gene Editing for Polled Trait into Elite Germplasm
  • Dairy Needs Assessment Results
PDF 5/21/18
Volume 10, Issue 1 February 2018 (356KB)

In this Issue…

  • De-Pooling of Milk                                                
  • Colostrum IgG                                                   
  • Manure Pipes and Struvite  
  • Calf Respiratory Disease    
  • Repro. Performance           
  • Golden State Dairy Management Conference     



PDF 2/23/18
Golden State Dairy Management Conference Brochure (930KB)

In this issue...

  • Brochure and Agenda for the Golden State Dairy Management Conference.
PDF 2/2/18
November 2017 (886KB)

In this issue...

  • Manure Management Money Available
  • Award of Distinction
  • Golden State Dairy Management Conference
  • Welcome R. Black
  • California Antibiotic Use
  • Testing Cooling Strategies
PDF 11/3/17
July Newsletter (1,027KB)

In this issue...

  • Forage Particle Length
  • Disbudding Calves
  • Managing Lagoons
  • Fresno/Madera Position Opening
PDF 8/7/17
April 2017 (487KB)

In this issue...

  • Needs assessment survey
  • Report of Salmonella in California cull cows
  • 2016 sorghum quality and survey results
  • Heat abatement strategies: tips and reminders
  • Understanding your annual report numbers
  • Spring sampling reminders
PDF 4/26/17
Sorghum Silage Meeting (256KB)

In this issue...

Two informative meetings coming up:

March 7, 2017 - Madera, CA & March 9, Tulare, CA

PDF 2/10/17
January 2017 (733KB)

In this issue...

  • Timed-AI Programs
  • TMR audits 
  • Sorghum field research
  • Sugar-cane aphid
  • BRD app
  • Winter storms
  • Meeting announcements
PDF 1/30/17
October 2016 (400KB)

In this issue...

  • Methane in the news
  • Welcome JP Martins
  • Silage structure options
  • Fresh pen milk yield
  • Research Roundup:
      * Sorghum
      * Greenhouse Gasses
PDF 11/18/16
August 2016 (391KB)

In this issue...

  • Dairy Biosecurity
  • Maximize Manure Nitrogen Value
  • Metritis Diagnosis Considerations
  • Announcements: Project Cooperators Needed & Position Opening
PDF 8/12/16
April 2016 (393KB)

In this issue...

  • California Dairy Conference
  • Silage Underlay, Part II
  • Sorghum Silage Project
  • In-crop Corn Management
  • IV Calcium & Subclinical Hypocalcemia
  • Raising Healthy Calves
  • C & N Management
PDF 4/25/16
January 2016 (603KB)

In this issue...

  • Gene Editing
  • Silage Underlay
  • Winter Reminders
  • Water Board Violations
  • Golden State Dairy Conference
PDF 1/20/16
2016 Golden State Management Conference (761KB)

In this issue...

  • 2016 Golden State Management Conference
PDF 1/6/16
Special Edition December 2015 (358KB)

In this issue...

  • Avoiding Drug Residues
  • Lameness -- Are Your Cows Stepping on Sharp Objects?
  • The Importance of Dry Matter: Tips for Feeders and Dairy Producers
PDF 12/11/15
October 2015 (459KB)

In this issue...

  • Preparing for El Nino
  • Managing Mud
  • Sharp Objects and Lame Cows
  • Pneumonia in Calves
  • CAHFS and Animal Disease
  • C Collar Retirement
  • Dairy Advisor Position Recruitments


PDF 10/16/15
July 2015 (319KB)

In this Issue…

Antibiotics on Dairies

Corn Silage Processing Scores of CA Silage

CDQAP Certification & Fee Reduction

Sorghum Tips

N. Peterson Retirement

PDF 8/11/15
UCCE Silage Day (216KB)


UCCE Silage Day

July 21, 2015

Harvest Hall, Stanislaus County Ag Center

3800 Cornucopia Way, Modesto, CA

PDF 6/19/15
April 2015 (410KB)
  • Monitoring DCAD
  • What is Dry Matter
  • Salmonella
  • Dairy Challenge in CA
  • Environmental Compliance Reminders
  • Announcements
PDF 4/15/15
January 2015 (255KB)
  • What is IVF?
  • Winter "To Do" List for Compliance
  • Western Dairy Management Conference, March 3-5, 2015
  • Meeting - Managing Cow Comfort in Hot Weather
    January 29, 2015, Tulare, CA
  • Meeting - California Dairy Management Seminars
    February 24, 2015 - Orland, CA
    February 25, 2015 - Modesto, CA
    February 26, 2015 - Tulare, CA
PDF 1/26/15
November 2014 (547KB)
  • Necropsy's Value
  • Pesticide Database
  • Managing Salts
  • BRD Management
  • Choosing a Lab
  • Announcements
  • Remembering Tom Schultz
PDF 11/5/14
July 2014 (954KB)
  • Correcting Silage DM
  • Silage DM Requirements
  • Managing Nutrients w/Drought
  • A. Castillo Retirement
  • What is Energy?
  • Soakers & Cow Cooling
  • Milk Pregnancy Test
PDF 7/30/14
UCCE Silage Day, Tuesday, July 8, 2014 (564KB) PDF 6/16/14
April 2014 (2,467KB)
  • Drought assistance
  • 100 years of UCCE
  • Managing nutrients without water
  • Sorghum for drought?
  • Avoiding antibiotic residues
  • Uterine infections
  • Aid for farmers with blackbirds
PDF 5/13/14
January 2014 (913KB)
  • Preventing Milk Fever
  • Promote Your Product
  • Voluntary Waiting Period
  • In Memoriam: Don Bath

Upcoming Meetings:

Heat Stress
April 4, Tulare, CA

Hoof Health Management Workshop
March 4, Tulare, CA
March 6, Merced, CA


PDF 1/16/14
November 2013 (242KB)
  • Changes to the WDR General Order
  • Meet the New Advisor
  • Silage Face Management
  • Calf Diarrhea Part 2
  • Dairy & Sustainablility
  • Upcoming Meetings
PDF 11/7/13
August 2013 (696KB)
  • Harvest Reminder, Kernel Processing

  • New AVMA Euthanasia Guidelines

  • Central Valley Regional Water Quality Control Board, General Order Reminders

  • Employee Heat Safety Reminders

  • Neonatal Calf Diarrhea

  • Sugar Beets as a Potential Starch Substitute

  • Dairy Surveys Underway

PDF 8/28/13
Silage Day 2013 (243KB) PDF 7/9/13
April 2013 (990KB)
  • Regulatory Reminders 

  • Forage NSC & NFC

  • Marvelous Improvement Device

  • Mineral Excretions

  • Silage Survey

  • Managing for Quality

PDF 4/17/13
March 2013 (342KB)
  • Labor Turnover
  • Feeding Calves
  • Forage NDF Digestibility
  • Position Announcement: Tulare & Kern Advisor
PDF 3/6/13
DairyNews Spanish Edition (363KB)

This is the annual Spanish Edition of the California Dairy Newsletter.  We've taken select articles from previous issues and translated them into Spanish in hopes that you will share the newsletter with your Spanish-speaking employees.  Articles are included in both English and Spanish. 

  • Time for a freestall check?
  • Antiobiotic residues in dairies.
  • Managing for more milk.
  • Identifying sick cows that need to be examined.
PDF 1/25/13
November 2012 (419KB)

This is a correction to the previously e-mailed Dairy Newsletter.  The link has been repaired and the newsletter is now accessible.  We appologize for the inconvenience.

In this issue:

  • Pistachio Shell Imapaction
  • Jejunal (Intestinal) Hematoma in Cattle
  • Back to Basics: The ABC’s of Forage Analysis
  • Western Dairy Management Conference
  • World Ag Expo Calls for Forage Challenge Entries
  • California Dairy Management Seminars
    - In English & Spanish-
    - Dec. 6th - Tulare 
    - Dec. 11th - Modesto 
    - Dec. 13th - Orland
PDF 11/16/12
August Dairy News (578KB)

* Dairies in the news
* Corn silage management
* Freestall check
* Calf diarrhea
* Rabies in ruminants
* By-product use
* Retirements & awards
* Announcements
* Silage Day


PDF 8/15/12
UCCE Silage Day (204KB)


**This is a correction to the previous email.  Silage samples will be analyzed for DM only.**

Silage Day will be held at the Stanislaus County Ag Center, Harvest Hall in Modesto, CA on Thursday, August 23, 2012.

Lots of helpful information regarding quality, value, production & animal health.

Bring in your silage samples for a FREE DM analysis using NIR technology!


PDF 8/2/12
May 2012 (350KB)

* Motivating employees
* Corn silage management
* Polio in cattle
* Schmallenberg Virus
* Cooling dry cows
* Dairy closures

PDF 5/11/12
Dairy Management Seminar - Registration Date Extended (78KB)

Registration extended for the Modesto Location!  Please register by Tuesday, March 20th to guarantee handouts and lunch.  Please click on the link below for details:

PDF 3/12/12
February 2012 (490KB)

In this issue:

* Mycotoxins

* TMR Mixing

* Calf Pneumonia

* Technology & Cows

* Announcements

PDF 2/27/12
Dairy News Spanish Edition, December, 2011 (653KB)

The purpose of the Spanish edition is to take select articles from past issues and translate them into Spanish. We hope that you will share the information with your Spanish-speaking employees.

PDF 12/16/11
November 2011 (394KB)

In this issue:

*Forage Dry Matter
*Milk Quality
*Research Update

PDF 11/8/11
September 2011 (294KB) PDF 9/9/11
June 2011 (421KB) PDF 7/12/11
February 2011 *To Our Readers *Silage Face Management *Milk Quality *WDR Reminders *Protected Amino Acids *Nutrient Efficiency PDF 2/19/08
2010 Spanish News Highlights of this year's Dairy News written in Spanish to help inform and update the Spanish speaking worker. PDF 12/23/10
November 2010 • The EU Challenge – 1 • Milking Procedure – 3 • Milk sampling – 4 • Irrigation – 5 • Update SJVAPCD – 7 • WDR Reminders – 8 • Announcements – 9 PDF 11/19/10
August 2010 *Heat Stress in Cattle *Timing Corn Harvest *Sampling Corn at Harvest *Milk Quality *Meet Dr. Rossow *Fly Management *WDR Reminders *Reproductive Short Course PDF 8/6/10
May 2010 *Carbon Footprints *Feeding for Animal Requirements *Training Videos *Milk Urea Nitrogen *When the Media Calls *Incinerators in CA? *Increasing Efficiency PDF 5/17/10
Dairy Business Education Forum Hedging and Risk Management in the Dairy Industry PDF 2/22/10
January 2010 •Dairy Wage Survey •Overfeeding Nutrients •Retained Placenta •Water Use by Cows •Crop Irrigation •Animal Welfare •Forage Seminar •Herdsman Course •Dairy Business Education Meeting •North Valley Dairy Day PDF 1/27/10
December 2009-Spanish Edition Highlights of 2009 in Spanish PDF 12/8/09
November 2009 * Language of Carbon Footprints * Employee Giftedness * Residue Violations * Johne's Disease * Tail Docking Update * UC Davis News * Nutrient Management * CDQAP Updates * Mycotoxins * Announcements PDF 11/3/09
July 2009 California Dairy Newsletter *Dairy Production Today *High LPC's? *Purchasing Forage? *Mineral Content in Feedstuffs *Know the Signs of Depression *Increase Cow Comfort *Concealing Animal Mortalities *Feeding Calves *Managing Irrigations *Reproductive Short Course *WDR Sampling PDF 7/16/09
May 2009 •Heat Stress Feeding Pg. 1 •Toxic Weeds Pg. 2 •Milk + Milk Replacer Powder? Pg. 2 •Culling Considerations Pg. 3 •Tail Docking Survey Pg. 3 •Tail Docking Practices Pg. 4 •UC Davis Teaching Prize Pg. 4 •Bulk Tank Milk Quality Pg. 5 •Educating Consumers Pg. 6 •Systems Management Pg. 6 •Feeding Gin Trash? Pg. 7 •Dairy Facility Options Pg. 8 PDF 5/11/09
January 2009 *Proposition 2 and Dairies *Ruminant Feed Ban *Feed Conversion Efficiency *WDR Deliverables, July 2009 *Tricolored Blackbirds *New Faculty at UC Davis *Pasteruized colostrum *Dairy Beef Quality Assurance *Top Notch Dairy Practices *Nutrient Tracking on Your Fields *Dairy Herdsman Shortcourse *Regional Water Quality Control Board Inspections PDF 1/23/09
August 2008 *Can You Afford to Feed Your Heifers? *Euthanasia Techniques Workshop *WDR News from California Dairy Quality Assurance Program *FDA Prohibits Extra-Label Use of Cephalosporins *Rice Straw in Free Choice Dairy Heifer Rations *Dairy Food Safety Laboratory – Bovine Mastitis Screening PDF 8/18/08
Meeting Notice Dairy Cattle Welfare Workshop, July 09, 2008 PDF 2/11/10
April, 2008 Introducing the new UCCE Dairy Advisor, Jennifer Heguy DOC 4/2/10
Commercial Goat Producers Workshop Workshop to be held at the Merced County Agricultural Center 2145 W. Wardrobe Ave., Merced, CA May 14-15 Pre-registration required DOC 5/5/08
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Stanislaus County
University of California Cooperative Extension
3800 Cornucopia Way, Ste. A
Modesto, CA 95358
Phone: (209) 525-6800
Fax: (209) 525-6840

Director: Roger Duncan
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