Different silage and concentrate rations for fattening beef cattle
Eighteen month old Africander steers were fed four basic rations viz. (l) silage ad lib., (2) silage ad lib. + maize meal at l% of live mass, (3) 5 kg silage+ maize meal ad lib.and (4)5kg silage+maize ear meal ad lib. In addition the four groups of steers received a daily protein supplement (1 kg/steer) consisting of 100 parts maize meal, 75 parts peanut oilcake meal, 25 parts fishmeal and 10 parts urea. The same four treatments were repeated with the difference that the protein supplement was changed to a daily mixture (1,8 kg/steer) of 96 parts lucerne meal and 4 parts urea. The silage in all cases was good quality maize silage. The highest DM intake occurred where steers were fed maize meal at l% of live mass. Mass gain, dressing percentage and carcass mass increased with an increase in the percentage concentrate in the ration. The largest increase (P <0,01) occurred up to a silage/concentrate ratio with the highest DM intake. In conjunction with this kg feed/kg carcass gain showed the greatest decrease up to the same silage/concentrate ratio. The pH of the rumen content did not decrease significantly as a result of maize meal addition to silage. Fat thickness was significantly (P <0,05) higher where maize meal was fed ad lib compared to silage ad lib. With the exception of a significant (P <0,05) greater ribeye area where maize meal ad lib was fed compared to maize ear meal ad lib no significant differences occurred among the various treatments for marbling score, carcass grade, ribeye area and length of carcass. The results indicate that any of the rations may be safely used for the fattening of eighteen month old beef cattle. The most efficient silage/concentrate ration may be influenced by factors like feed/meat price ratio, quality of silage, composition of concentrate, availability of feed and mass and condition of animals as well as breed of cattle. The feeding of maize ear meal resulted in a lower profit above feed costs compared to maize meal rations.