Effect of various bale treatments on physical quality and chemical composition of rhodes grass (Chloris gayana) hay

Abstract

The effect of harvest season (winter vs. summer), moisture content at baling and bale mass on hay physical quality and chemical composition of two varieties of Rhodes grass (Chloris gayana) was studied during bale storage. Three moisture levels (15–20%, 20–25%, 25–30%) and three bale masses (13 kg, 18 kg, 24 kg, at an equal volume) were tested in varieties Pioneer and Alimba ‐ the most common cultivars in the Arabian Gulf region. Variety Alimba has a rougher texture with more stems and fewer leaves. This caused significantly higher water retention and consequently higher bale temperatures. In summer, bale temperatures of Alimba stored at 25–30% moisture content and 24 kg bale mass averaged 37.7°C compared with 28·2°C in variety Pioneer. Lowest dry‐matter (DM) content was 793 g kg−1 and was recorded in the winter cut of variety Alimba baled at the upper moisture level (25–30%), whereas the highest was that of variety Pioneer. Lowest crude protein content was that of variety Pioneer (61 g kg DM−1). Prolonged heat build‐up of some bales caused dark‐brown discoloration, and, although colour variations were significant, they were not large. There was no contribution of bale mass to changes in DM content, indicating that the selected levels of bale mass in the experiment were lower than those expected to cause significant effects on hay chemical composition and nutritive value. In general, it is recommended to store Rhodes grass hay at moistures up to 30% and even higher in the summer season in the case of variety Alimba. Higher moisture contents at baling could preserve hay quality by minimizing shattering of leaves excessively dried under the prevailing hay‐making conditions, especially in the variety Pioneer.