Abstract

Mengistu Alemayehu, Zewdie Wondatir*, Yohannes Gojjam and Kassahun W/Gebriel

This study was intended to investigate the effect of cattle genotype and work stress on carcass characteristics of oxen maintained under slightly moderate management conditions. A total of 16 oxen representing two genotypes of the Ethiopian highland zebu (EHZ) and their contemporary Friesian x Boran (F x B) crossbred were used in the study conducted at on-station at Holetta Research Center where half numbers of each breed were put through work stress. The intrinsic heaviness of the crossbred oxen tended to yield more carcass (248.5±5.5Kg) than the genetically lighter zebu oxen (141.1±5.5Kg). Non-working F x B crossbred oxen appeared to put more weight than working oxen that were managed under similar conditions. The unadjusted rib eye area and fat thickness over the rib eye at the 12th rib were significantly greater for F x B crossbred (71.8±2.4 cm2 and 3.0±0.1mm, respectively) than for EHZ oxen (50.4±2.4cm2 and 2.2±0.1mm). Non-working F x B crossbred oxen had accumulated more adipose tissue (4.0±0.23mm) than the working contemporaries of the same genotype (2.0±0.16mm) that tended to partition extra energy for walking and work performance. Apparently, the EHZ oxen showed better feed conversion efficiency than their counterpart F x B crossbreds under solely roughage based feeding practice.