ON FARM NORTHERN CATTLE NUTRITION Power of ‘P’ for profit Astudy at Victoria River phosphorus supplementation trial Tim said decreased mortality and Research Station, NT, is (ongoing since 2014) has shown increased pregnancy rates in mature producing compelling overwhelming returns on investment cows, heavier weaners and increased evidence of the benefits of (Table 1) – from 280% in three years, beef production per hectare were phosphorus (P) supplementation, 354% in four years and up to 402% some of the major benefits from (projected cumulative return after phosphorus supplementation. according to Northern Territory five years). Department of Primary Industries The 10%‑higher maiden heifer pregnancy and Resources (NTDPIR) “The reaction we’ve had from producers rate was less than expected given the researcher Tim Schatz. to this trial has been really exciting large difference in pre‑mating weight and we’ve seen practice changes and between treatments. He suspects the With only 20% of land in northern adoption as a direct result of producers results may have been confounded by Australia able to provide adequate coming and seeing the outcomes for another factor, such as disease. phosphorus to cattle through grazing, themselves,” he said. “There were actually quite a few of the there’s large scope for supplementation The trial started with two groups of heavier heifers in the P+ treatment to boost production and profitability in weaner heifers – one group was fed that didn’t get pregnant, and when we northern Australia. P supplement (+P) and the other was examined their ovaries by ultrasound, This research, along with other long‑term not (‑P). Paddocks were swapped each we found they were cycling,” he said. projects, is underpinning MLA work year to ensure the grazing experience “We think the 10% difference on encouraging producers to apply for each group was similar. probably underestimates the impact strategic supplementation to their herds. The key outcomes from the trial to date that phosphorus supplements Tim said the NTDPIR‑funded are shown in Tables 1 and 2. would normally have on maiden heifer pregnancy rates in Table 1: Preliminary economic assessment phosphorus‑deficient areas through Year Total weight Price ($/kg) Extra $ per Cost of extra Return on increasing pre‑mating weight.” of extra treatment supplement investment The first‑lactation heifer pregnancy calves (kg) rates were considerably different, with 2017 3,072 $3.50 $10,751 $3,839 280% phosphorus‑supplemented heifers 2018 2,806 $3.00 $8,417 NA NA achieving 30% compared to the control Total 5,878 $19,169 $5,529 347% group reaching 5%. – While Tim accepts phosphorus Table 2: Summary of results supplementation during the wet Outcome +P –P Difference season has its logistical challenges, he encouraged producers to think Maiden heifer avg. pre‑mating weight 392kg 327kg 65kg creatively about solutions. Maiden heifer pregnancy rate 70% 60% 10%NS 1st lacatation heifer avg. weight (WR1 2017) “There are a lot of different strategies 382kg 262kg 120kg that people use and we generally find Average P8 fat depth (WR1 2017) 3.9mm 0.1mm 3.8mm where there’s a will, there’s a way,” Calf loss (first calf) 20.6% 20.4% 0.2% NS he said. ■ 1st lactation heifer pregnancy rate 30% 5% 25% Tim Schatz Average weaner weight (WR1 2017) 173kg 139kg 34kg E: tim.schatz@nt.gov.au Total weight of weaners (WR1 2017) 8,616kg 5,544kg 3,072kg Download MLA’s Phosphorus Overall mortality rate to 3.5 year old 1% 8% 7% management for beef cattle at Wet cow pregnancy rate (WR1 2018) 57% 20% 37% futurebeef.com.au – search Average weaner weight (WR1 2018) 185kg 172kg 13kg ‘phosphorus management northern Australia’. Total weight of weaners (WR1 2018) 7,951kg 5,145kg 2,806kg NSNot significant; WR – weaning round. +P = fed P supplement; ‑P = not fed P supplement 27