Timing of testing critical when determining the phosphorus (P) status of beef cattle in northern Australia

Abstract

Phosphorous (P) deficiency in northern Australia can significantly impact the productivity and profitability of beef cattle businesses due to reduced cattle growth rates, reproductive performance, and increased mortality (Bowen et al. 2019). Plasma inorganic P (PiP) in conjunction with estimates of diet quality from faecal analyses is the best method of diagnosing P status in cattle (Dixon et al. 2020). Testing should be undertaken at the end of the rainy season when protein and energy are above maintenance in the animal’s diet. Appropriate timing can be challenging on extensive properties as it is most practical to undertake sampling when cattle are mustered for routine husbandry practices. Timing of testing is also more challenging in regions such as south west Queensland with highly variable and less summer dominant rainfall than the seasonally dry tropics. The Mulga Lands of south west Queensland are considered P deficient, and common industry practice is to have two musters per year (Bowen and Chudleigh 2021). Therefore, the objective of this work was to determine if P status testing at a routine muster in June, was appropriate to determine the P status of cattle on a Mulga Lands property.