posted on 2023-05-26, 15:45authored byMalau-Aduli, AEO, Bruce, ID, Doonan, B, Lane, PA
This case study on improving grazing management skills was conducted over a 12-month period in 2007 utilizing 1200 beef cattle on two properties of 60 hectares each, subdivided into 24 paddocks. The objectives were to evaluate pasture utilisation, liveweight gains and profitability using a multi-faceted economic model. Leaf emergence rate, average pasture cover, pasture growth rate, pre-grazing pasture mass, post-grazing residual and cattle liveweight gain data were collected monthly. Data were analysed using mixed (PROC MIXED) and general linear (PROG GLM) models in SAS to test for the fixed effects of property, date of sampling, cattle type and their second order interactions, while age of cattle and paddocks were fitted as random effects. Relationships between livestock and pasture variables were tested in correlation analyses using PROC CORR and significance established using Bonferroni probabilities. Results demonstrated that significant improvement in grazing management led to an increase in total pasture utilisation per hectare of over 40%, significantly greater than the set target of 7000kgDM/Ha on both properties. Pasture utilised directly for liveweight gain was positively correlated with total pasture utilised (r = 0.8686, p<0.0001). Energy partitioning for animal maintenance was found to be negatively correlated with total pasture utilised (r = -0.5927, p<0.05), and pasture utilised for liveweight gain (r = -0.8112, p<0.0001) and related to the nutritive value and species composition of the pastures. Average daily liveweight gain was found to be positively correlated with total pasture utilisation (r = 0.7302, p<0.0001) and pasture utilised for liveweight gain (r = 0.9181, p<0.0001) and negatively correlated with energy partitioned for animal maintenance (r = -0.9263, p<0.0001). It was concluded that increased pasture utilisation per hectare allowed for stocking rate increases across each property resulting in significant increases of approximately 73% in beef produced per hectare, thus increasing profitability by an overwhelming average of 250% across both properties.