New research highlights benefits of Phosphorus supplementation

Researchers say new results shows why Phosphorus is 'king in the North'

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First lactation heifers in the P+ treatment. This mob did recieve P supplementation.

First lactation heifers in the P+ treatment. This mob did recieve P supplementation.

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NT Department of Primary Industry and Resources officers say new research has proven the benefits of wet season P supplementation.

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Beef extension officers and supplement manufacturers have been talking about the benefits of wet season Phosphorus (P) supplementation of breeders in northern Australia for many years but despite a concerted push, adoption has remained as low as about 10 per cent. 

Sales figures show that P supplementation is not happening at anywhere near the level that might be expected for the amount of P deficient country in northern Australia (see figure 1).

So it seems likely that the case for P supplementation has not been compelling enough for many northern producers to spend money on it.

Tim Schatz is a principal livestock research officer with the Northern Territory Department of Primary Industry and Resources.

Mr Schatz said one of the contributing factors behind the lack of adoption is that there are currently no published scientific studies showing significant increases in pregnancy rates specifically from P supplementation in northern Australia.

Map showing Phosphorus deficiency across northern Australia.

Map showing Phosphorus deficiency across northern Australia.

As a result extension officers and supplement manufacturers have had to give estimates of what sort of benefit producers might expect without hard data to back them up.

The low rate of adoption suggests that this has not been convincing enough for many northern producers, but exciting new results from research at Kidman Springs (Victoria River Research Station) in the Northern Territory may change all that.

Mr Schatz said the research trial had shown massive benefits from P supplementation. This was highlighted when pregnancy rates from maiden joining at two years old were 10pc higher in the P+ treatment.

But the most exciting data, he said, was around the first time calf heifers.

Mr Schatz said that was because this was the point at which large volumes of P leaves the body in milk.

The research found that first lactation heifers that were supplemented with P were 120kg heavier on average than heifers not supplemented when their first calves were weaned.

It also found the average weaning weight of calves weaned from the two treatments was 34kg heavier mob that were supplemented and re-conception rates were 25pc higher.

Also the total mortality rate over the three years from weaning until after the heifer’s first calf was weaned was 7pc lower in the supplemented mob.

“All this adds up to a lot more beef produced per heifer mated in the P+ treatment,” Mr Schatz said. 

“We still need to do a proper economic analysis and hope to publish the results in more detail shortly, but the early indications are that the return on investment for money spent on P supplementation was looking very good.

First lactation heifers in the P- treatment. This mob were not supplemented with P.

First lactation heifers in the P- treatment. This mob were not supplemented with P.

“By spending an extra $41 per head on supplement over the first three years the P plus treatment has produced about $300 per head more so far.

“If the heavier weight of the females retained is also included then it works out to be around $513 more per head”.

Mr Schatz did provide a word of caution though, saying that the response would differ depending on the level of P deficiency and noting that benefits of this scale may not be seen where P deficiency is not as severe.

The trial in detail 

The trial is being conducted at Victoria River Research Station about 220km south west of Katherine, NT.

The cattle graze in two adjoining paddocks of native pasture that are acutely P deficient.

The treatments swap paddocks each year to minimise paddock effects.

The two treatment groups (P+ or P-) have been managed in exactly the same way since weaning except that their mineral loose lick supplement either contains P (P+) or does not (P-).

The lick is fed year round in troughs under supplement sheds.

The composition of the lick fed to each treatment is shown in Table 1.The trial is on-going and will study the benefits of P supplementation over several years.

Table 1.

Table 1.

- Edited by Penelope Arthur 

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