Why is phosphorus so important for your dairy cattle?

Phosphorus is an essential mineral that cows need for overall  condition, optimal claw health and fertility. Creating a good understanding of the level of phosphorus intake from their feed and the excretion of phosphorus in the milk produced is therefore very important. In this article, we will tell you more about it. 

A cow needs phosphorus for her resistance, physical growth, fetal development and for optimal milk production. The majority of phosphorus is needed in milk production. In addition, phosphorus is important for rumen function, microbial protein formation and enzyme production.

Optimal phosphorus levels lead to improved fertility, better feed intake, increased milk production and healthy bones. In growing animals, sufficient phosphorus can prevent skeletal deformation and ensures optimal feed efficiency. This is particularly essential for heifers and second-calf cows: after all, they produce a lot of milk while also having to grow and have limited feed intake capacity. To maintain animal health and therefore milk production and growth, it is important to consider phosphorus levels. 

When and how much phosphorus does a cow need?

Research by the Dutch Animal Health Service (2020) shows that phosphorus content in milk varies widely between individual cows and dairy farms. The amount of phosphorus excreted through the milk determines the amount of phosphorus needed in the diet for optimal herd health.

Advice on phosphate varies considerably. Jan Dijkstra, associate professor of cattle nutrition at Wageningen University reports that the current standardization has a wide safety margin. A feed ration with an average of 2.5 grams of phosphorus per kilo of dry matter is sufficient for a lactating cow producing 400 kgs of milk solids. Previously, the standards were kept too low, resulting in unconscious shortages. The following standards (P) can be adhered to, according to him: 

• Small calves 3.4 g/kg dry matter
• Older calves and heifers 2.3 g/kg dry matter
• Dry cows 2.0 g/kg dry matter
• Dairy animals (lactating) need more: at 1.5-2 kg MS/day 2.5 g/kg dry matter, at 3-4 kg MS 3.3 g/kg dry matter and for animals with >4 kg MS/day the norm is 3.5 g/kg dry matter

After calving, phosphorus is most important

Due to high milk production at the beginning of lactation, phosphorus requirement is at its highest. At the end of a lactation, the cow can replenish its phosphorus reserves. An optimal dry matter intake, including good rumination activity, is important. The better the rumination activity, the more favorable this is for phosphorus recycling in the body. Saliva contains a lot of phosphorus and ensures that it flows back into the rumen. Optimal rumen activity means more phosphorus recycling in the body. This has positive consequences for the P requirement.

In general,  1/3 of the phosphorus intake is needed for maintenance. The rest is excreted through milk production. When a cow excretes more phosphorus through milk than it takes in, it draws on its limited bone reserves to compensate for deficiencies. It is therefore always good to pay attention to phosphorus levels. 

Proactive approach to optimal phosphorus levels

To maintain phosphorus levels, it is important to take measures around calving. Around calving, the cow’s body is already asking for extra energy and this will only increase at the beginning of lactation because of the milk yield peak (see graph 1).

What is the advice from the AHV Specialist? 

The advice from the AHV Territory Managers is to administer the AHV Milk Start Bolus as soon as possible after calving (if possible, prior to calving). This way you ensure that the cow gets through these 24 hours better. After all, she receives the necessary substances that ensure that her energy needs can be met. Something that is important for both cow and calf. 

If you also have challenges with the afterbirth not coming off, this is often due to a lack of calcium as well as a lack of phosphorus. This is because cows with an abnormal energy balance have often already taken in too little feed in the dry period, creating challenges. To prevent this challenge, it is best to administer AHV Opti Bolus and AHV Milk Start Paste immediately after calving. The AHV Opti Bolus ensures that the afterbirth comes off faster and the uterus is cleaned up. With the AHV Milk Start  Paste, you quickly provide the cow with sufficient magnesium, calcium and phosphorus again. In addition, the paste gives the cow an energy boost, making her feed faster and more often and getting the mineral and energy mobilization processes going again. Health challenges will be reduced post calving if you administer these products immediately after calving.

By deploying these solutions, you significantly reduce the risk of challenges, and with just 5 kgs of extra milk solids delivered (AHV, 2022), you will already have earned back the investment. Not to mention the positive consequences for the further lactation, start-up of the calves, fertility and costs you would otherwise have incurred for buying restorative products.

Optimising your animal health?

AHV International develops and produces innovative animal health solutions, based on quorum sensing science. Would you like more information or make an appointment with a Territory Manager in your area? Click here and take a look at our programs. 

Contact our Territory Managers directly? You can! Click here and visit our specialists in the field or fill in the form below. www.ahvint.co.nz; email newzealand@ahvint.com; phone 0800 4 248 69