The mineral minefield- what do livestock require for optimal performance? - Final Report

Key considerations

•  By combining forage mineral reports with a full audit of all mineral inputs, the farm was able to implement highly targeted diagnostics with the veterinary practice. The resulting blood tests were crucial, revealing specific cases of both under-supply and potentially detrimental over-supply of various elements.
• The data also highlighted that certain supplements previously utilised were ineffective and failed to meet the livestock's requirements. This confirms that understanding the animals' actual mineral status through monitoring is vital before investing in supplementation.
• Moving beyond the animal and the feed, a holistic strategy must consider the soil. Correcting soil pH and improving overall soil health is fundamental, as this optimises the natural transfer and availability of minerals from the soil into the growing plants, thereby improving forage quality at its source.

Background

The role of mineral nutrition in livestock farming must not be underestimated, as it can directly impact productivity and production of livestock. In an effort to meet their livestock's mineral requirements, Roger and Dyddanwy of Crickie Farm have, in recent years, trialled a variety of mineral supplementation methods, including boluses, drenches, buckets, and bagged loose minerals. These strategies have yielded variable degrees of success while simultaneously adding a significant cost to the business. While previous forage analysis has indicated the presence of certain mineral deficiencies, a thorough audit of all available feeds, forages, and water sources provided to the livestock had not been conducted.

Purpose of the work 

The project aims were to:-

• monitor performance and review the mineral status of the farm.
• address concerns connected to the supply of macro and micro elements which have historically been used to supplement the stock.
• improve animal performance against investment made.

What we did

1.  A full mineral audit was undertaken at Crickie which involved assessing the level of macro & micro minerals in consumed crops, forages (grazed or conserved), livestock drinking water and purchased feeds.
2. Blood samples were also taken from 4 animals in each livestock group (lambs, ewes, calves, heifer and cows) to look for deficiencies, with these animals treated to any deficiencies that were highlighted from the results.
3. Forage and blood testing were repeated in the Autumn to measure quality of forage/grazing and effectiveness of supplements and efficacy.
4. Following the sampling results, various considerations and options were looked at by the farm. 

Outcomes

Forage status

Table 1. Traditional leys & Herbal Ley Mineral Content

*CAB = Cation Anion Balance. This equation uses the cations of sodium (Na) + potassium (K) and the anions of chloride (CI) & sulphur (S) stated as mEq/Kg. 

As detailed in Table 1, the forage mineral data highlights several key nutritional imbalances:

• Magnesium (Mg): Levels were reported as low, potentially inhibiting livestock from achieving adequate intake. It was advised that supplementary magnesium be made available to stock, particularly during grazing periods. Intake may require increasing during periods of high grass growth.
• Sodium (Na): Forage analysis indicated low sodium levels. Sodium is crucial for maintaining nutritional balance, playing a key indirect role in magnesium uptake. Furthermore, sodium is vital for crop palatability, saliva production, and promoting rumen stability.
  •  Consideration: The application of agricultural salt was briefly considered to address the deficiency. However, due to the need for agronomic consultation and the risk of grass scorch if spread during dry periods, the decision was deferred pending future monitoring.
• Sulphur (S): Elevated sulphur levels were recorded. High sulphur intake poses a risk to animal health by potentially binding with, and consequently inhibiting, the uptake of essential trace elements, specifically selenium, copper, and cobalt.
  • Action & Advice: Historically, the farm utilised a sulphur-enriched fertiliser that supported strong grass production. However, due to the documented risk to livestock trace element status, it was strongly advised that the farm reduce its usage of sulphur-enriched products and conduct an annual review of its overall fertiliser strategy. While sulphur is a vital nutrient for soil and plant health, excessive intake carries significant adverse effects for livestock.

Livestock blood status

Referring to Table 1, the confirmed status of the increased level of sulphur and concerns related to finishing lambs, blood samples were taken on two occasions. One to establish animal status before any recommendations were made and a second to monitor livestock blood status versus livestock production gains.

Table 2. Blood sample results for the different livestock groups
 

As shown in Table 2, the iodine status in both the sheep and cattle groups was low, despite the inclusion of iodine in purchased supplements and commercial feeds. Following the ineffective use of an iodine bolus (indicated by no post-application rise in blood iodine levels), a revised treatment strategy was implemented:

• Cattle received iodine as a single-element pour-on.
• Sheep were administered a Flexidine injection.

Subsequent sampling confirmed a resultant increase in iodine status, leading the farm to adopt this treatment protocol moving forward. 

For cobalt levels in lambs, the farm's current practice of providing a monthly multi-drench will continue. Going forward, Crickie Farm has established an annual monitoring protocol with their farm vet, involving post-weaning blood testing to assess both iodine and cobalt status, with treatment administered as necessary.

Copper Antagonism

The livestock also exhibited copper-related issues. This was not due to a primary copper deficiency but rather to conditioned copper deficiency resulting from elevated levels of sulphur, iron, and molybdenum present in grazed crops and conserved forages.To mitigate this antagonism, it was recommended that the farm reduce its sulphur application, targeting a forage sulphur content of 0.20 – 0.25%. 

How to apply on your farm

• Conduct a full mineral audit: Analyse the mineral status of all feed inputs, including grazed grass, conserved forages (silage/hay), purchased feeds, and the water supply.
•  Establish baseline livestock status: Complement feed analysis with targeted blood testing of livestock (in collaboration with the farm vet) to accurately determine the animals' current mineral status.
• Targeted supplementation: Crucially, understand the exact mineral values of your forage and the established status of your livestock before administering supplements. This approach shifts supplementation from guesswork to a specific, targeted intervention, ensuring cost-effective and appropriate dosing while avoiding unnecessary over-supply.
• Embrace a holistic approach: When applying fertiliser to grassland, it is vital to understand the complete range of possible outcomes. What benefits the plant may not necessarily be optimal for the animal. For example, maximising grass yield may inadvertently cause mineral imbalances in the resulting forage.
• Performance Monitoring: Regularly monitor stock performance and identify any unexplained production or health issues. This ongoing assessment is the final check on the efficacy of the mineral management.