No abstract

No abstract

No abstract

No abstract

The relationship between stress responsiveness and beef quality of 40 Nguni, 30 Bonsmara and 30 Angus steers was determined. The L(∗) values, pHu, cooking loss (CL) and Warner-Bratzler shear force (WBSF) were determined. Catecholamine levels were determined from urine samples collected at slaughter. Bonsmara steers had the highest (P<0.05) levels of catecholamines with respective epinephrine, norepinephrine and dopamine concentrations of 10.8, 9.7 and 14.8nmol/mmol. Nguni steers had the lowest (P<0.05) levels of catecholamines, with respective catecholamine concentrations of 5.1, 4.3 and 4.0nmol/mmol. In the Nguni steers, there were significant (P<0.05) correlations between catecholamines and L(∗) and between dopamine and tenderness in meat aged for two days (WBSF2). In the Bonsmara, dopamine was correlated (P<0.05) pHu, WBSF2 and CL. No significant correlations were found in the Angus. Therefore the relationship between stress responsiveness and certain beef quality traits may not be similar in different breeds.

The objective of the current study was to compare tick loads, growth and carcass characteristics of dipped and non-dipped Nguni, Bonsmara and Angus steers raised on natural pasture. One hundred 7-month-old castrated weaners were kept at the University of Fort Hare Farm for 12 months. There were 30 weaners each of Angus and Bonsmara, and 40 weaners of the Nguni breed. Half the Bonsmara, Angus and 14 Nguni weaners were dipped every fortnight. The rest were not dipped. Monthly weights and tick counts under the tail, on scrotum, belly, sternum and ears of the steers were recorded. The dipped Nguni steers had lowest (P , 0.05) tick counts, and the non-dipped Angus steers had the highest (P , 0.05) tick counts. There were more ticks (P , 0.05) during the warm wet season than during the cool dry season. Ears had the highest (P , 0.05) tick infestation. Average daily gain (ADG) was similar (P . 0.05) among the three breeds. The non-dipped Bonsmara steers had the heaviest (P , 0.05) carcasses (142 6 5.4) while the non-dipped Nguni steers had the lightest (P , 0.05) carcasses (111 6 4.5 kg). The non-dipped Bonsmara had the highest (P , 0.05) eye muscle area (3996 6 120.8 mm 2 ) while the nondipped Angus had the smallest (P , 0.05) eye muscle area (3291 6 210.6 mm 2 ). The non-dipped Bonsmara also had the highest (P , 0.05) dressing percentage (53.8 6 1.01) while the non-dipped Nguni had the lowest (P , 0.05) dressing percentage (50.3 6 0.84). The current study has shown that while the non-dipped steers had higher (P , 0.05) tick loads than the dipped steers, their growth and carcass characteristics were similar (P . 0.05). The study has also shown that, despite being a smallframed breed, the Nguni steers had similar (P . 0.05) ADG to the large-framed Bonsmara and Angus steers. Therefore, the Nguni cattle have the potential to produce organic beef. However, a reasonable assessment of organic beef production potential of the Nguni requires an evaluation of its meat quality traits under natural pasture.

No abstract

No abstract