Effect of zernaol implantation daily gain and carcass quality of buffalo bulls

Abstract EN

Six buffalo bulls with an average body weight 311.3 0.74 kg were used in the experiment.

Bulls were divided randomly into two groups (3 bulls each) according to their live body weight.

The first group was served as a control whereas bulls of the second one were implanted with zeranol (36 mg) three times at 0,75 and 150 d at the base of the left ear.

Bulls were weighed every two weeks and slaughtered 150 days after the last implantation.

The overall slaughter body weight mean was 503.33 9.54 kg at 300 d.

Average body weights at 75d, the control and zeranol groups were not differed but at 150 and 225 d the zeranol group was highly differed and not significantly than control group by 0.38 % and 4.7 %, respectively.

The treated group had higher total daily gain at the end of fattening period by 14.9% than the control group.

Daily gain at 75 , 150 and 225 d of treated group, increased by 5.52 %, 16.49 % and 17.87 % than the control group, respectively.

Averages daily gain at different periods of implantation, from 1 to 75 d they were nearly equal.

Treated group had 0.852 0.076 vs.

0.822 0.108 kg at 75 d to 150 d and 0.669 0.039 vs 0.407 0.056 kg at 150 to 225 d periods with significant (P 0.05) increase at the last period by 64.37 %.

Dressing percentage either based on slaughter body weight (53.6 1.07 vs 53.47 1.64 %) or based on empty body weight (61.31 1.84 vs 62.63 1.08 %) was not significantly differed between the control and zeranol groups.

The edible and non-edible parts percentages were nearly close to each other between groups.

Only the total internal body fat (kidney and digestive tract fat) percentages were differed significantly (P 0.05), where the control group was 3.9 % and zeranol group had the lower percentage 1.64 %.

Also, the testes percentages of control and treated groups were the same 0.07 %, Choice meat cuts (round, sirloin and fillet) were 57.49 1.72 and 57.54 1.95 % for control and zeranol treated buffalo bulls, respectively.

Shoulder meat cut percentage (ratio of left side) of zeranol group was 19.71 0.15 % higher than control one (19.02 0.17 %).

Fillet meat cut of the control group was 1.97 0.18 % significantly higher (P 0.05) than treated group (1.50 0.03 %).

The Psoas major and minor muscles in control group (containing intramuscular fat) had higher significant (P 0.01) percentage 2.10 0.08 % than the zeranol treated animals (1.50 0.03 % ).

The Longisimus Doris muscle percentage (ratio if the left side and best rib cut) which had been dissected from the best ribs meat cut (9th–11th ribs) was significantly (P 0.05) higher for zeranol treated group 0.80 0.02 % and 28.42 2.08 % than the control one (0.59 0.07 & 21.

13 1.15 %).

Boneless tissues of retail meat cut percentages as a ratio of each retail meat cut.

Chilled best ribs joint percent was higher in control group (26.13 1.85 %) compared with zeranol group (24.89 1.14%).

Cooking losses percentages for the control group.

Differences were not significant between groups.

Lean meat of dissected best rib cut zeranol group was highly significant (P 0.01) than the control.

Bone percentages and intramuscular fat were higher in untreated group than treated one and these differences were not significant.

For the chemical analysis of Longissimus Doris muscle (dry matter, protein contents, and intramuscular fat and ash percentages), no significant differences between treated and non-treated groups were found.