Calcium and phosphorus
Key minerals for a strong transition

Calcium and phosphorus are central to cow health at transition and early lactation. Calcium supports milk production, nerve and muscle function and prevents milk fever and down‑cow events. Phosphorus underpins appetite, rumen function, fertility, growth and claw health. Because both are largely stored in bone, the practical way to manage supply is to base supplementation on what’s actually in the feed, especially important on fodder beet or high‑sugar diets. Preload close‑up cows in autumn to reduce metabolic disease risk and protect spring performance.


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Timing and risk windows

Close-up (3 weeks before calving)

Main risks: Rising calcium demand as colostrum forms and mineral gaps from low‑phosphorus or low‑calcium feeds. Plan group‑level coverage now.

Calving day and first 48–72 hrs

Main risks: Acute milk fever (clinical hypocalcaemia) and calcium shock at onset of lactation. Rapid access to calcium treatment for affected cows is critical.

Early lactation (first 3 weeks after calving)

Main risks: Ongoing phosphorus shortfalls limiting appetite and production, and secondary metabolic disease (ketosis) if intake is low.

Winter fodder systems (fodder beet)

Main risk: Fodder beet is low in phosphorus, even with good energy, animals can develop phosphorus deficiency unless supplemented correctly.

Seasonal build‑up (autumn preload)

Main opportunity: Start supplementing transition cows well before calving to reduce spring metabolic losses and support fertility.

What to do this week

  • Record feed components for each mob (pasture %, silage, fodder beet, PKE, meal, straw) and estimate dietary calcium and phosphorus with your vet/nutritionist.
  • Flag high‑risk groups: older cows, low BCS, previous milk‑fever history, and mobs on fodder beet.
  • Select a delivery method you can control (free‑choice lick, dusting, water, in‑feed) and source product for close‑up groups.
  • Start autumn preloading for calvers, ensure fibre in the ration while adjusting mineral supply.
  • Check calving kits and emergency calcium supplies and brief staff on signs and response.

What to monitor

In the paddock

  • Appetite and clean‑up at feed outs, low intake is an early sign of phosphorus limitation.
  • Any cows showing weakness, muscle tremors, or inability to stand around calving.
  • Manure and rumen fill during step‑ups; poor fill suggests intake issues.

 

Onpaper 

  • BCS trend through the dry period and at calving by mob.
  • Incidence of milk fever, down cows, retained foetuses and early lactation illness.
  • Feed records and any lab results (blood calcium/ phosphorus or liver tests) used to refine rates.
  • Product usage logs and response after implementation.

Matching products to your system

Pick the delivery method you can manage reliably. Correct intake matters more than product choice.

Dusted on supplement (good when cows get a consistent daily supplement and you want even application)

  • CalciPhos Dusting Grade – Useful when cows are getting silage, straw or PKE daily and you need calcium and phosphorus coverage through supplement feeding.
  • CalciPhos Granular – Suited to systems where you want calcium and phosphorus added through daily supplement feeding with consistent intake.
  • Calsea – Can be used alongside your calcium and phosphorus strategy, where you also need support for rumen buffering and transition management.

 

Water-soluble (good when water lines to specific mobs are reliable and calibrated)

  • SoluPhos – Effective for targeted short-term phosphorus support or ongoing coverage where you can manage water delivery accurately.

 

Targeted options (good for individual high-risk or clinically affected cows, under vet guidance)

  • Boluses, drench, or injectable calcium – Use for individual high-risk or clinically affected cows, not as a replacement for herd-level planning.

 

Practical notes

  • Base rates on feed analysis and vet or nutritionist advice – Fodder beet systems often need extra phosphorus.
  • Combine calcium and phosphorus with broader transition management – Include magnesium, fibre, step-ups and BCS targets in the full plan.

 

FAQs

When should I start supplementing calcium and phosphorus?

A. Begin preloading springers in the winter (at least 3 weeks before expected calving) and maintain coverage through early lactation as required by diet.

A. Watch for reduced appetite, poor rumen fill, falling BCS, slow milk yield recovery and herd history on low-phosphorus feeds (fodder beet). Confirm with blood/liver testing.

A. The best method is the one you can manage consistently- free‑choice for grazing mobs, dusting for daily supplements, water for reliable water systems, and in‑feed for tight control.

A. Boluses can help individual high‑risk cows but are not a substitute for group‑level close‑up planning and diet management. Use under vet direction.

A. Yes, feed analysis and targeted blood or liver tests give the data your vet/nutritionist needs to set safe, effective calcium/ phosphorus rates and monitor response.

Recommended products

Have more questions or ready to order?

Your Agvance Consultant can help you set up a loose lick plan that matches your system and the time of year. Get in touch today. Ready to order? Simply head to My Account, log in or register, and complete your order online.

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