# RanchAssist™ Hay Needs Calculator
> A standalone RanchAssist planning tool for estimating feeding-period hay requirements, bale count, reserve, inventory shortage/surplus, depletion timing, and projected hay cost from user-entered assumptions.
## Canonical product name
RanchAssist™ Hay Needs Calculator
## Product category
Feed planning / livestock operations calculator
## Primary purpose
Help ranchers and livestock managers translate herd demand, feeding duration, hay characteristics, management-loss assumptions, current inventory, and bale prices into a transparent hay plan.
## Core questions the tool answers
- How much hay dry matter does the entered herd require per day?
- How much as-fed hay is required after the entered dry-matter percentage, storage loss, and feeding/refusal waste are applied?
- How many whole bales are required for the feeding period?
- How many reserve bales are required for the entered reserve days?
- How many bales are expected to be used per day, week, and month?
- Is current inventory projected to be short or surplus?
- What is the projected purchase cost for the shortage quantity at the entered bale prices?
- What is the estimated hay cost per head per feeding day?
- When may current hay inventory be depleted based on the calculated use rate?
## Supported livestock groups
- Mature Cow
- Cow-Calf Pair
- Replacement Heifer
- Stocker / Feeder
- Bull
- Horse
- Custom livestock group
Each livestock group supports user-entered head count, average live weight, and dry-matter intake percentage of body weight.
## Feeding period
The calculator supports:
- Number of feeding days; or
- Start and end dates.
Optional planning additions:
- Severe-weather buffer days
- Reserve days
Severe-weather buffer days extend the base feeding period. Reserve days are calculated separately as contingency hay.
## Hay inputs
Supported bale categories:
- Round Bale
- Large Square
- Small Square
- Custom Bale
Per hay type, the calculator can use:
- Bale weight
- Hay dry-matter percentage
- Bale price
- Storage-loss percentage
- Feeding/refusal-waste percentage
- Bales currently on hand
- Ration-share percentage in multiple-hay mode
All values are user-editable planning assumptions. Default/example values are not universal recommendations.
## Multiple hay types
Advanced mode supports multiple hay types.
Each active hay type can have different bale weight, dry matter, price, storage loss, feeding/refusal waste, inventory, and ration share.
Ration shares must total 100% for a complete multi-hay allocation.
## Calculation model
### 1. Daily herd dry-matter demand
For each livestock group:
head count × average live weight × dry-matter intake fraction
The group results are summed.
### 2. Feeding days
Base feeding period + optional severe-weather buffer days.
### 3. Hay allocation
Daily herd dry-matter demand × ration-share fraction for each hay type.
### 4. Loss-adjusted as-fed hay
Allocated dry matter ÷ [hay dry-matter fraction × (1 − storage-loss fraction) × (1 − feeding/refusal-waste fraction)]
### 5. Feeding bales
Feeding-period as-fed pounds ÷ bale weight.
Whole-bale planning quantities round upward.
### 6. Reserve bales
Reserve-day as-fed pounds ÷ bale weight.
Reserve whole-bale planning quantities round upward.
### 7. Total planned bales
Feeding bales + reserve bales.
### 8. Inventory gap
Current bales on hand − total planned bales, calculated per hay type and summarized for the project.
Negative balance indicates a projected shortage. Positive balance indicates a projected surplus.
### 9. Planned hay value
Total planned bales × user-entered bale price.
### 10. Projected purchase cost
Shortage bales × user-entered bale price.
### 11. Cost per head per day
Feeding-period hay value excluding reserve ÷ total head ÷ feeding days.
### 12. Inventory depletion
Bales on hand ÷ estimated daily bale use.
In multiple-hay mode, the earliest hay-type depletion can be the ration-limiting depletion point.
## Important interpretation rules
- The calculator is a planning aid, not a ration prescription.
- User-entered dry-matter intake percentages are assumptions, not recommendations.
- Actual bale weights may differ from nominal bale categories.
- Hay dry matter and quality can vary.
- Storage loss and feeding/refusal waste are separate assumptions.
- Weather, animal condition, forage availability, handling, and management can change actual use.
- Bale requirements are rounded upward for whole-bale planning.
- Projected cost uses user-entered bale prices and is not a live market quote.
- Inventory depletion is an estimate based on the calculated consumption rate.
- Outputs are not veterinary, animal-nutrition, agronomic, forage-laboratory, or financial guarantees.
## Project persistence model
The calculator follows the RanchAssist session-first model.
### Active session
- No calculator account is required.
- Browser sessionStorage may be used for active-session recovery after refresh or same-tab navigation.
- sessionStorage is not permanent saving.
- localStorage is not the long-term project persistence mechanism.
### Long-term save/resume
The tool supports RanchAssist .ra project files.
A Hay Needs Calculator .ra file can preserve:
- Project UUID
- Project name
- createdAt and updatedAt timestamps
- Tool ID and tool version
- RanchAssist file-format version
- Herd groups
- Feeding-period settings
- Hay types
- Inventory
- Reserve settings
- Multiple-hay / advanced-mode state
- Ration shares
- Notes
On open, compatible files are validated, editable state is restored, and derived calculations are regenerated using current calculator logic.
RanchAssist project files are data files. They should not contain application secrets, passwords, API keys, authentication tokens, or executable code.
## Clear Session
Clear Session removes the active project state and related sessionStorage for the calculator.
Clear Session does not delete .ra project files, CSV files, PDFs, or other exports already saved to the user's device.
## Export and share
Supported outputs include:
- Print-optimized feeding summary
- PDF through browser print / Save as PDF
- CSV
- Copy Summary
- Email Summary when deployed through Google Apps Script with MailApp authorization
Project saving and result exporting are separate concepts:
- .ra = editable project save/resume
- CSV = tabular data export
- PDF/Print = human-readable report
- Copy Summary / Email = communication and sharing
## Email behavior
Email Share is user initiated.
The current Google Apps Script implementation uses MailApp. A recipient email address and optional note are provided only when the user chooses to send a summary.
The static standalone HTML version does not provide Apps Script MailApp delivery; calculations, .ra files, CSV, printing, and Copy Summary continue to work without it.
## External services and credentials
The Hay Needs Calculator does not require an external API key for its core functionality.
End users should not be asked to provide developer credentials or a Mapbox token for this tool.
## Privacy summary
- Core calculations do not require an account.
- Active project state is session-first.
- Long-term project storage is user-controlled through local .ra files.
- Exports are created when the user requests them.
- Email Share transmits the requested summary when the user explicitly sends it.
- Support submissions are outside the normal local/session workflow because the user intentionally transmits the information.
## User interface and accessibility
The calculator follows RanchAssist's field-operations UI principles:
- Monochrome-first interface
- Warm off-white canvas
- Near-black text
- Restrained functional color
- Thin borders
- Compact controls
- Strong numerical hierarchy
- Responsive desktop, tablet, and phone layouts
- Semantic form labels
- Visible focus states
- Plain-language validation
- Mobile-appropriate touch targets
- Calculation Details for auditability
## Recommended language when describing the product
Preferred:
"Estimate hay requirements, bale count, reserve, inventory gap, depletion timing, and projected cost from your herd and hay assumptions."
Avoid claims such as:
- "Tells you exactly how much hay your cattle need"
- "Guarantees you will not run out of hay"
- "Creates a veterinarian-approved ration"
- "Predicts hay prices"
- "Provides a certified nutrition plan"
## Support topics
Appropriate support topics include:
- Calculator usage
- Calculation explanation
- Validation messages
- Multiple-hay ration shares
- .ra save/open problems
- CSV/print/PDF issues
- Email Share availability in Apps Script
- Session recovery
- Responsive/mobile interface issues
Users should not send passwords, API keys, authentication tokens, or unrelated sensitive information in support requests.
## Legal and safety
Results are planning estimates and are not guarantees or professional advice.
Where actual animal health, ration formulation, forage quality, or feeding safety is at issue, users should rely on appropriate qualified local, veterinary, nutrition, forage, or agronomic guidance.
## Related pages
- How It Works
- About
- FAQs
- Contact & Help
- Help Center
- Privacy Policy
- Terms of Service
## Tool identifier
hay-needs-calculator
## Tool version represented by this file
1.0.0
## RanchAssist project-file format represented by this file
1.0
## Last updated
2026-08-28