Grass composition and distribution patterns as determinants of behavioral activities and weight accumulation of Nguni and Boran cattle post-relocation

Abstract

Grass biomass composition and distribution patterns within the paddock as determinants of behavioral activities and animal performance of Nguni (NG) and Boran (BR) cattle post-relocation to a novel environment were examined. Ten steers of each breed aged 9 months were bought from two different farms and sent to Honeydale research facilities, where they were reared on rangelands for 12 weeks. Identification and classification of grass species were done every sampling week before introducing cattle to each paddock. Direct visual observations and durations of behavior and paddock occupancy patterns were recorded every fortnight between 0500 and 1900 h every week. Individual animal weights and body condition scores (BCS) were recorded two times per week. Location within paddocks hugely affected (P < 0.0001) the composition of the vegetation as most grass species were found everywhere on pastures, near the watering points and along fencelines. However, the distribution patterns of the grass species significantly differed at different locations. Aristida congesta was dominant (P = 0.0014) everywhere in the pasture and along fenceline than in areas with a high density of trees. Except in shaded areas, Cynodon dactylon (P = 0.0003) and Eragrostis chloromelas (P = 0.0008) were highly abundant near the watering points, pastures, and along the fenceline. Themeda triandra (P < 0.0001) was only prevalent everywhere on pastures except in shade areas, near the water sites, and along fenceline. In terms of palatability and ecological groups, highly palatable species (P < 0.0001) and decreasers (P = 0.0010) were more frequent everywhere in the paddocks. From Weeks 1 to 3, NG spent more time walking (P < 0.0001), while the BR showed a significant decline in grazing activities (P < 0.0001) in spite of several differences in vegetation composition. Both breeds showed a significant decline in weight gain (P < 0.0001) and body condition score (P < 0.0001) in the first 3 weeks. However, the two cattle breeds quickly compensated for their behavioral activities and weight gain, and this shows a good ability to cope with stress caused by heterogeneous environmental conditions.

Keywords: beef cattle; climate change; foraging behavior; novel environment; rangelands.