The commencement of the wet season in Northern Australia is often greeted with relief by cattle producers. The start of the wet is a reset for grazing operations, with new growth and opportunities for stock to regain condition after an often-difficult dry season.

However, the wet season is not necessarily without its challenges. There are many considerations for breeding herds that have to be factored-in to management planning.

Importance of body condition

The CashCow project, continues to provide vital insights into the challenges faced by beef cattle producers in Northern Australia. One of the key findings from this research is that herds entering the wet season in poor body condition often struggle to regain sufficient nutritional status, even after the onset of rain.

This delayed recovery has a profound impact on reproductive performance, fertility rates, and overall herd productivity.

In Northern Australia, the wet season is a critical period for pasture growth, providing cattle with the essential nutrients needed to recover from the dry season and support reproductive processes.

However the CashCow project revealed that cows in poor condition at the start of the wet are often unable to fully capitalise on the nutritional benefits provided by the fresh forage. As a result, these cows face a prolonged period of nutritional stress, leading to delayed conception, reduced calving rates, and, ultimately, lower productivity.

Compromise

One of the primary reasons why herds struggle to catch up nutritionally, even once the wet season begins, is that cattle entering the wet in poor condition are often metabolically compromised. The extended dry season, characterised by low-quality forage and nutrient deficiencies, leaves cows in a weakened state. Their ability to digest and metabolise nutrients from the newly available pasture is significantly reduced.

Moreover, cattle in poor condition tend to have lower feed intake during the initial stages of the wet. This is because their digestive systems are not functioning at full capacity after the prolonged nutritional deprivation during the dry season.

Even though there is an abundance of high-quality forage, these cows are simply not consuming enough nutrients to rapidly regain body condition. This delay in recovery directly impacts their ability to conceive and support early pregnancies.

Another significant finding from the CashCow project is the relationship between poor body condition and the post-partum anoestrus interval – the period after calving during which cows do not cycle and are unable to conceive.

Cows in poor condition during the wet experience a longer anestrums period, which delays their ability to return to oestrus and conceive again. This results in longer intervals between calving, reducing the overall reproductive efficiency of the herd.

This extended anoestrus is particularly problematic for Northern Australian beef producers, as it disrupts compact calving patterns creating challenges for weaning, vaccination, and supplementation, as well as increasing the costs and labour associated with managing a spread-out calving season.

Importance of P

Even though the wet season provides an influx of new forage, key nutrients such as phosphorus and protein may still be lacking. The CashCow project emphasised the importance of phosphorus supplementation, as phosphorus is crucial for supporting reproductive processes. Cows deficient in phosphorus are less likely to conceive, even when other nutritional needs are met. Phosphorus deficiency is particularly common in Northern Australia, where the soils are often low in this essential nutrient.

Without supplementation, cows in poor condition at the start of the wet season are unable to fully recover, and their reproductive performance remains compromised. Protein supplementation is also critical, especially during the early wet season, when cows need additional nutrients to rebuild muscle mass and regain body condition.

Strategic Management Recommendations

The findings from the CashCow project highlight several important management strategies that producers can adopt to improve herd fertility and productivity during the wet season:

• Monitor Body Condition Throughout the Dry Season: Producers should regularly assess the body condition of their cattle during the dry season to ensure that they do not enter the wet season in a weakened state. Strategic supplementation with protein and phosphorus during the dry season can help maintain body condition and prepare cows for the nutritional demands of the wet.
• Provide Early Supplementation: Nutritional supplementation should begin as soon as the wet season starts, especially if the onset of rainfall is delayed. By providing protein and phosphorus supplements early, producers can support cows as they transition to a more nutrient-rich diet and reduce the negative effects of poor body condition.
• Focus on Compact Calving: To maximise reproductive efficiency, producers should aim for compact calving patterns by managing breeding seasons and ensuring that cows are in optimal condition at the start of the breeding season. This helps reduce extended calving intervals and improves overall herd management.
• Utilize Forecasting Tools: Climate forecasting tools, such as those based on the Southern Oscillation Index (SOI) and sea surface temperatures, can help producers predict the onset of the wet season and plan their supplementation and breeding strategies accordingly.

The CashCow project has provided valuable insights into the challenges that Northern Australian beef herds face when entering the wet season in poor condition.

Even with the onset of rainfall and improved forage availability, cows in poor condition struggle to regain their nutritional status, leading to delayed conception and reduced productivity.

By focusing on maintaining body condition throughout the dry season and providing early supplementation during the wet season, producers can improve reproductive performance and ensure the long-term sustainability of their herds.

Alastair Rayner is the General Manager of Extension & Operations with Cibo Labs and Principal of RaynerAg.  Alastair has over 28 years’ experience advising beef producers & graziers across Australia.   He can be contacted here or through his website www.raynerag.com.au