Development of the drought and supplementary feed calculator (DASFC) phone application

Abstract

Context Grazing cattle and sheep regularly suffer from feed shortfalls, which can be addressed by supplementary or drought feeding. Tools such as GrazFeed are often used in these circumstances. However, their use is mainly by consultants because they can be complex and time-consuming to use, thereby preventing their adoption by many producers. Aims To develop a simple to use phone application for iOS and Android systems for producers to estimate pasture intake and calculate the amount of supplement required for different classes of livestock. Methods The equations used to estimate pasture intake and animal feed requirements were adapted from the current Australian Feeding Standards for Ruminants and utilised in GrazFeed. A number of assumptions were made to simplify the inputs and complexity of calculations required. Equations were developed in the Microsoft Excel spreadsheet program and implemented by a commercial software developer. Validation and testing of the App was undertaken by user testing, comparison with existing models as well as against experimental data. Key results The prediction of intake as a percentage of maintenance energy requirements (MEm) was lower for the drought and supplementary feed calculator (DASFC) than for GrazFeed at low pasture availability (below 3 cm and 1000 kg DM ha−1) and higher for the DASFC at high pasture availability (above 8 cm and 2667 kg DM ha−1). Using an independent dataset for sheep and cattle, the relationship between observed and predicted intake was higher for the DASFC (sheep r2 = 0.58, cattle r2 = 0.82) than for GrazFeed (sheep r2 = 0.33, cattle r2 = 0.49) and the correlation between intakes predicted by both models was high (sheep r2 = 0.94, cattle r2 = 0.75). Conclusions The DASFC phone application required fewer inputs than many other models and predicted pasture intake and supplementation requirements equally well compared with other programs when compared with experimental data. Further developments are suggested to improve the accuracy and functionality of the App. Implications The DASFC is used by producers to estimate supplementary feed requirements for sheep and cattle of different classes. The DASFC phone application enables producers to make their own informed decisions, thereby improving the efficiency of feed provision and reducing overall costs.