Two feeding trials were conducted to estimate the value of ammoniated rice hulls (ARH) as a roughage in barley-beef production.
In trial 1, six Holstein steers averaging 265 kg. were fed 80% barley ration for 238 days. This ration (Ration I) contained ground barley, ARH and premix; 80.0%, 14.4% and 5.6%, respectively. The steers were group-fed, twice daily, on an ad libitum basis. In trial 2, the steers were raised in stanchion stalls, immediately after trial 1, and were divided into two groups of three each on a basis of weight. The steers of one group were fed Ration I, and the other ones Ration II containing 80% ground corn, which was substituted for barley in Ration I. This trial was conducted to determine the feeding value and digestion coefficients of both rations.
A 28-day preliminary period to allow the steers to adjust to ground corn was followed by a 56-day experimental period. The rations were fed ad libitum with water available at all times by a water-cup.
The results collected were as follows:
1) Average weight gain and daily gain for 238 days were respectively 241 kg. and 1.01 kg. in trial 1.
2) Steers fed Ration I gained more than those fed Ration II, which elicited diarrhea. In spite of this, carcass weights were remarkedly similar in both steers fed Ration I and Ration II.
3) Digestion coefficients of Ration I and Ration II were respectively as follows: dry matter; 71.3%, 56.2%, crude protein; 77.4%, 50.6%, crude fat; 75.8%, 71.7%, crude fiber; 17.3%, 0%, NFE; 83.5%, 68.6%.
4) Fattening performance data of steers fed Ration I for 322 days through two trials were as follows: average final weight, daily gain and daily feed intake were respectively 584 kg., 1.00 kg. and 9.45 kg., and the amount of DCP and TDN per kg. of gain were respectively 0.86 kg. and 5.69 kg..
5) After fattening for a 22-week period, steers sometimes suffered from bloat, so that body weight gain and feed intake decreased. However, the tendency of compensatry growth was observed in all steers, after recovery from this digestive disturbance. Rumens of all steers were generally parakeratotic, however, no incidence of livers abscessation were found.
From the above results, it was found that dairy beef steers fed diet containing ground barley, ARH and premix reached successfully a final 584 kg. wt. with 1.00 kg. daily gain except for cases of bloat and rumenparakeratosis.
It is necessary to carry out still further experiments so as to find the means to prevent these digestive disturvances.