Different heat treatments and sealing effect on the nutritive value of Lucerne hay

Abstract

This study investigated the comparative effects of conventional hot-air oven heating (CHO), microwave heating (MW) and sealing effect on the nutritive value of lucerne hay. Equivalent energy (125 J.g⁻¹) was applied with a 1.1 kW of MW oven for 60 seconds (s) or a 3.06 kW CHO oven for 350 s. The required equivalent energy level was measured based on a preliminary calibration trial. Two heating method (CHO and MW) and sealing condition (SC) applied as treatment factors in this study. A two-way analysis of variance (P < 0.05) was used to measure the effect of different factors on some properties of lucerne hay. The dry matter (DM) percentage of lucerne hay was increased when MW treatments were applied on both sealed and non-sealed lucerne hay compared with the control. Both heating method and their interaction with SC had negative effects on crude protein (CP) percentage. DM digestibility (DMD) and Digestible organic matter in the DM (DOMD) were decreased by 9% and 5%, respectively, in the sealed MW group, compared with the sealed control. Neutral detergent fibre % also increased by 6% in the sealed MW group, compared with the sealed control group. However, no differences in acid detergent fibre % due to any heating method and/or SC were observed in this study. The mechanisms behind these changes require further exploration.

Keywords:

• Microwave
• thermal heating
• hot-air heating
• legume
• forage digestibility

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

M. S. R. Shishir

Md Safiqur Rahaman Shishir is a final-year PhD student at the University of Melbourne, Faculty of Veterinary and Agricultural Sciences. He received a bachelor's degree in Animal Husbandry from Bangladesh Agricultural University (BAU), Bangladesh, and a master's degree in Animal Nutrition from the Department of Animal Nutrition from BAU. He is interested in the application of novel processing techniques on animal feed for improving quality.

K. Plessis-Fraissard

Kévin Plessis-Fraissard is an undergraduate engineering student at Agro Paris Tech, France and will be graduating in January 2021.

G. I. Brodie

Graham Brodie is an Associate Professor in the Faculty of Veterinary and Agricultural Sciences. He earned his electrical engineering degree from James Cook University and worked in the electrical power industry for some time before turning his hand to academia. Dr. Brodie's research interests include microwave heating of bio-materials; using microwaves for sensing and communication in agriculture and forestry; improving water use efficiency in agriculture; producing renewable energy on farms; on-farm animal waste management; and applications of Geographic Information System (GIS) and Remote Sensing technologies in agriculture and archaeology.

B. R. Cullen

Dr. Brendan Cullen is a Senior lecturer in Sustainable Agriculture (Pasture Systems) in the Faculty of Veterinary & Agricultural Sciences at the University of Melbourne. Over the last 15 years, Brendan has worked on a series of research projects with the dairy and red meat industries to understand the impacts of projected climate changes on livestock production businesses across Australia. The research aims to identify industry pathways that are adapted to a variable and changing climate, using farms systems modelling approaches. Brendan has published more than 40 peer reviewed scientific papers and currently supervisors 3 PhD students working in this field. He also teaches into the Bachelor and Masters coursework programs on pasture and livestock production, livestock production systems, dairy systems and climate change adaptation.

L. Cheng

Dr. Long Cheng graduated from Lincoln University (New Zealand's specialist land-based university), New Zealand, in 2008, with a Bachelor of Agricultural Science with Honours. In 2009 Dr. Cheng commenced his Ph.D., investigating the use of nitrogen isotopic fractionation as a biomarker to indicate nitrogen use efficiency of ruminants, graduating in 2013 from Lincoln University, New Zealand. Dr. Cheng's research interest includes energy and nitrogen metabolism, Precision agriculture, Nitrogen use efficiency in ruminant animals.