B.FLT.0244: Graded levels of woodchip during wet feedlot conditions

Abstract

This project was conceived to determine the production and management costs and benefits of providing woodchip bedding to feedlot cattle during wet feedlot conditions. A randomised block design using three treatments, each with ten replicate pens of ten cattle, was conducted over a 109 day experimental period during winter (May - September 2018). The project simulated wet winter conditions using an irrigation system that provided 74 mm of rainfall per 30 day period, applied over 16 rainfall days per period and which wetted the entire pen surface, all cattle and the feedbunk of each pen. The three experimental treatments were 1) no bedding (Control), 2) bedding provided at 54 kg/m², equivalent to a bedding cost of 30 c/head.day (W30) and 3) bedding provided at 108 kg/m², equivalent to a bedding cost of 60 c/head.day (W60). <br/> Provision of woodchip bedding at 54 kg/m² (W30) increased average daily gain (2.43 kg/hd.d, cf. 2.27 kg/hd.d for control, P = 0.003) and HSCW, yielding an additional 9.3 kg of HSCW (P = 0.001) compared to the control. There was no additional production benefit of providing double the amount of woodchip (W60). Provision of woodchip bedding had no effect on dry matter intake. As a result, conversion of gain from feed improved for W30 (0.205) and further for W60 (0.217) compared to control (0.197) (P = 0.012). There was no relationship between treatment and any other carcase attributes apart from HSCW and raw eye muscle area. It was concluded that there was no overall effect of treatment on behavioural signs of cattle welfare. However, there was a numerical effect of treatment on relative adrenal weight, such that W60 cattle were lower than W30, which were in turn lower than control cattle, indicating reduced chronic stress in woodchip bedded cattle. Woodchip bedding improved the pad score, but after week 10, the score of the pad in W30 also began to worsen, indicating that for medium and long-fed cattle, additional woodchip application may be required. <br/> There was a $74 increase in carcase value from applying woodchip bedding at W30 and W60 rates. Using the input costs of the experiment, there was a numerical net economic benefit from the W30 treatment over the unbedded cattle, but this was highly variable and sensitive to input costs. Future research is needed at commercial scale to fully understand the economic benefits of woodchip bedding in a range of production systems.