Providing mineral supplementation via water (Producer Demonstration Sites)

It cannot be argued that supplementation of extensively managed beef breeding herds is beneficial to overcome mineral deficiencies and improve animal performance, but it can also be costly. Supplementation decisions should be carefully considered to ensure that the benefits in terms of cattle performance exceed supplementation costs.

Supplementation via water medication is one of the cheaper methods and ensures that animals receive the appropriate amount of supplement for their body weight as it overcomes issues with shy feeding and gorging. Furthermore, providing consistent phosphorus (P) supplementation to cattle during the wet season, which can be challenging when paddocks are often inaccessible for long periods of time and many forms of P supplements need to be protected from rainfall.

Urea can also be supplemented through water medication when properly managed, allowing urea supplementation to continue during “shoulder seasons” when the protein content of pasture may be low but the chance of rain makes supplementing with urea loose licks and blocks risky. Delivery of supplement through water medication allows supplementation to continue year-round, more consistently and efficiently. Water medication technology is currently not widely used, however it provides an opportunity for the remote control of dose rates in quick response to changes in seasonal conditions, but does require a certain level of management and technical skills to maintain.

The Producer Demonstration Site (PDS) is investigating whether mineral supplements can be effectively provided through water medication systems and looks at the effectiveness of water medication through the wet season.

Little is understood about the water consumption behaviour of cattle that also have access to surface water, particularly after a rain event and how frequently they return to the water medicated trough or to consume other forms of supplement.

Objectives

• Demonstrate that year-round supplementation via water medication can be successfully implemented at a commercial scale without negatively impacting the productivity of breeders,
• Demonstrate that water medication is an effective method of addressing phosphorus deficiency during the wet season,
• Conduct a cost benefit analysis to determine the relative economic performance of automatic electronic water supplementation compared to the existing method of supplementation on individual properties,
• Use GPS livestock tracking equipment to compare the frequency of livestock access to medicated water troughs and lick blocks during the wet and dry season.
• Increase the awareness, knowledge and confidence of NT producers in water medication systems through various extension platforms and events.

Producer Demonstration Sites

In 2021, two MLA producer demonstration sites were established in collaboration with the Northern Territory Department of Industry, Tourism and Trade (the department) and DIT AgTech Ltd.

In the first year (up to the end of the 2021/22 wet season), there were some inconsistencies in data collection and in the data retrieved from the water medicators, which limited the accuracy of results. This was largely due to multiple handovers of the project with unforeseen staff changes, as well as the challenges associated with running trials on commercial properties.

In early 2022, the PDS was reviewed and ‘started over’ so that more accurate results could be gathered in the second year. Summaries of the PDS in each year are below:

Year 1 (2021/22)

At the Barkly region site, 166 breeders were assigned to a ‘water medicated’ group, and 166 assigned to the ‘control’ group, which were supplemented using the property’s usual practice (loose lick mineral supplementation). At the Katherine region site, 223 breeders were assigned to the ‘water medicated’ group and 149 assigned to the ‘control’ group.

When inducted into the trial, animals were weighed, body condition score (BCS) was recorded and a base phosphorus status was determined by collecting blood samples from 50 animals from each group to measure plasma inorganic phosphorus (PiP). Ten animals from each treatment group were fitted with GPS collars to record the proximity and frequency of visitation of animals to the water trough and or lick supplement. The amount and costs of supplement distributed to the water medicated treatment was provided in reports from DIT AgTech, and the amount and costs of dry lick distributed was recorded by the property.

Following the 2021 dry season and 2021/22 wet season, weights, BCS and PiP were recorded and analysed. Re-conception rates and weaning percentage was recorded for one property, but sufficient data was not available from the other property. GPS data was downloaded from the GPS collars that were able to be retrieved.

Year 2 (2022/23)

Two new paddocks were selected at the Barkly site for the water medicated treatment (1700 ha) and control/dry lick treatment (1500 ha). Both paddocks have two troughs, and water medicators were installed at both troughs in the water medicated treatment’s paddock. Supplement is directly injected into the trough line to ensure no other troughs are contributing to the intake data. Water medicators (uDOSE) are maintained by DIT AgTech and can be remotely monitored via an online dashboard (uHUB). Water flow meters were placed in the control paddock for comparison. Soil P tests and pasture assessments were conducted in both paddocks.

Two hundred PTIC first-calf heifers were inducted in May 2022, with 100 allocated to each treatment. Weights and BCS were recorded at entry, and 5 GPS collars placed on each treatment. Twenty blood samples from each treatment were collected for blood PiP testing. Faecal samples are being taken monthly for NIRS analysis of diets, including phosphorus, crude protein and digestibility. Following the 2022 dry season and 2022/23 wet season, GPS data, weights, BCS and PiP are being recorded and analysed.

Results so far:

Year 1 (2021/22)

While we cannot draw definite conclusions from the first year of data; it is important to report observations and the experience of setting up new water medication systems.

In the water medicated treatment, the water and supplement intake of the cattle was recorded by the water medicator (uDOSE). During the first year, the data could not be seen in real-time by the project management team, so updates on the water medicators were provided by DIT AgTech or from manual checking of the units. This increased the risk of faults within the medicator going un-noticed, and there were cases on both properties where that did happen (due to a range of challenges) meaning those cattle were not supplemented for significant periods of time. This hasn’t been a problem since, as all collaborators have access to the uHUB online dashboard and are able to see real-time intakes and uDOSE information and alarms. There was also evidence of lost satellite connection by the uDOSE in the data recorded from this first year, which DIT AgTech has addressed by incorporating internal memory into the uDOSE.

First year supplement intakes and costs of the medicated treatment were to be based on the water medicator reports, but because of the missing data we were not able to accurately compare costs and nutrient intakes between the water medicated and control treatment. It was also noticed that the condition of each paddock was quite different at the end of this first year. Hence why the PDS moved to new paddocks the following year.

The weight gain and blood PiP results reflected the possible absence of supplement in the water medicated treatment as the control treatments had a higher weight gain than the water medicated treatments on both properties, and higher average blood PiP. Initial results from the second year of this trial show the opposite, suggesting that these differences were probably due to the technical issues early-on and supplement was not being delivered to the water troughs and possibly due to differences in pasture quality for the water medicated treatment.

The GPS data from the first year appeared different for each property and paddock for the amount of time cattle would go without visiting a trough. One paddock in the Barkly showed periods of only 3-4 days with no trough visits by collared cattle, whereas one paddock in the Katherine region had periods of over 10 days at a time during the wet season where no collared cattle visited a trough. It is likely that these gaps in ‘visits’ were similar for how often the control treatment visited the dry lick supplement.

Year 2 (2022/23)

During the second year (2022-2023), the water medicators have been monitored remotely by project staff and data has been available in real-time. The few alerts from the water medicators that have been received as notifications were acted on very quickly with the help of the uHUB dashboard. The exception was an over-estimate of water intake from one uDOSE for one month. The medicator was still supplementing, but water intake per head appeared much higher than it was for this period. This may have been due to a water leak, and it was resolved easily by re-starting the uDOSE.

At the end of the 2022 dry season, blood PiP was significantly higher in the water medicated treatment than the control. All of the 20 sampled medicated cattle had above adequate levels of PiP, whereas 7 of the 20 control cattle sampled had marginal or deficient PiP. It should be noted that these cattle did not have PiP measured at the beginning of this second year, but they were allocated to treatments at random. There was no difference in BCS between each treatment. Dry season weight gain was not measured due to issues with the scales and unexpected rainfall limiting access.

GPS units were on 5 heifers in each treatment (only 4 were retrieved from the water medicated treatment) and they gave a picture of proximity to water over part of the dry season. Due to GPS batteries running out sooner than expected, we were unable to get data for the complete dry season. The GPS data will benefit from further statistical analysis, but initial observations can be reported. Table 1 summarises the average number of trough visits per day for each treatment, as well as the number of visits to the dry lick supplement in the control treatment (defined as being <20 m from the trough or supplement). There was no significant difference between treatments for the average daily visits to the trough, but quite a difference between visits to troughs and visits to dry lick.

Table 1. Summary of trough and supplement visits of GPS collared cattle between the 15/05/2022 and 10/07/2022

There were cases where a collared animal in the water medicated treatment did not visit the trough for up to six consecutive days and therefore did not consume supplement during this period. However, there was one individual collared animal in the control treatment that did not visit dry lick supplement for 11 consecutive days. Gaps in urea consumption can be detrimental to the rumen microbiology, so consistent intake is important. These periods of no visits occurred after rainfall in June/July, and further insight into the frequency of trough visits will be available after the wet season.

Final data for this PDS was collected in May 2023, and the final report will be available in early 2024. Keep an eye out for extension material relating to this PDS throughout the remainder of 2023, including a FutureBeef webinar.

If you would like more information, or would like to receive updates on results and extension of this PDS, please get in touch with Stacey Holzapfel, NT DITT Pastoral Extension Officer on (08) 8973 9730.

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