Cattle Feeding Experiment and Chopping Device Parameter Determination for Mechanized Harvesting of Forage Rape Crop

HighlightsForage rape crop could effectively alleviate the lack of green forage for livestock in winter.With the growth of forage rape crop, stem lignification was exacerbated and its palatability degenerated.The relationship between particle length and palatability was explored in a cattle feeding experiment.Optimal working parameters of the chopping device were obtained for harvesting the crop in different stages.Abstract. Forage rape crop, which uses the immature plant leaf and stem of a hybrid rape crop (Brassica napus L.) with low erucic acid and glucosinolate to feed livestock, is an innovative fresh-fed feed material with the advantages of high yield, low cost, rich nutrients, and vigorous growth in winter. In this work, a systematic study was carried out on the relationships among the characteristics of forage rape crop stems, chopping device parameters of the harvester, feeding performance, and chopped particle length (PL) in different growth stages. The results of the stem characteristics tests indicated that stem lignification occurred and increased with growth of the crop from the bolting stage to the silique stage, leading to degeneration of its palatability. The cattle feeding experiment showed that when the bolting rape crop was used, the average feed intake of the cattle fed the chopped rape crop increased by 33.35%, compared to feeding the whole crop without chopping, while the average feeding time decreased by 35.44%. Further experiments on the effects of PL after chopping on feeding performance in different growth stages showed that the optimal PL values in the bolting, flowering, and silique stages were 80, 60, and 30 mm, respectively. Finally, the corresponding cutterhead rotational speeds of the chopping device were calculated as 450, 510, and 1200 r min-1, respectively. This study provides a reference for the development and application of harvesting equipment for forage rape crop. Keywords: Agricultural mechanization, Cattle feeding, Forage palatability, Harvester, Parameter matching.