Effect of The Inclusion of Thyme (Thymus schimperi. R.) Leaves as Feed Additives on Growth Performance, Carcass Characteristics, and Meat Quality of Hararghe Highland Sheep, and Consumers’ Perception of Hararghe Highland Sheep Mutton in Meta Woreda, East Hararghe Zone

Abstract

This study was conducted at Haramaya University, a goat farm, and Meta Woreda in the East Hararghe Zone to evaluate the effect of thyme (Thymus schimperi R.) leaves as feed additives on the growth performance, carcass characteristics, and meat quality of Hararghe Highland Sheep (HHS) and assess consumer perceptions of sheep mutton consumption trends in Meta Woreda. Eighteen finishing rams with an average initial body weight of 23.13 ± 0.02 kg were purchased from local markets. The experimental design utilized was a randomized complete block design (RCBD) with six replications, where the animals were blocked according to their initial body weight and randomly assigned to three dietary treatment groups: T1 (0 g thyme), T2 (100 g thyme), and T3 (200 g thyme). Each treatment consisted of concentrate mixtures formulated from wheat bran, noug seed cake, table salt, and vitamin and mineral premixes provided at 2.5% of the rams' body weight on a dry matter basis, with pasture grass hay offered ad libitum. The digestibility trial was carried out for 7 days, followed by a feeding trial of 60 days and carcass evaluation. The feed offered and refusals were recorded for each animal during both the digestion and feeding trials, whereas feces voided during the digestibility trial were recorded daily. The body weight changes of the animals during the feeding trial were recorded within a ten-day interval. Compared with those fed the control diet (T1), the rams fed diets containing 100 and 200 grams of dried thyme leaf (DTL) as a feed additive exhibited larger average DM, OM, CP, NDF, ADF, and ADL intakes. On the other hand, there was a significant difference (p<0.05) in the DM digestibility coefficient among the treatments, indicating that rams fed T2 had the highest digestible DM and OM coefficients (82.0 vs 80.4%) compared with those in T3 (79.9 vs 77.3%) and T1 (70.1 vs 67.3%), respectively. These findings suggest that the T2 diet is more effective at improving the digestibility of dry matter in the diet. Similarly, Hararghe Highland rams fed T2 (100 g DTL) supplemented with the concentrate mixture had shown the highest FBW, ADG, and FCE. The mean slaughter body weight (SBW), empty body weight (EBW), hot carcass weight (HCW), dressing percentage based on SBW and EBW, rib-eye muscle area, total edible proportion (TEP), and total usable products were significantly higher (P<0.05) for dried thyme leaf-supplemented rams than for the control diet. In addition, the inclusion of DTL as a natural feed additive in the diets of HH rams had enhanced meat color, water holding capacity, flavor, juiciness and tenderness, and chemical composition compared with those of the control diet. xviii Finally, the survey assessment conducted on perceptions of consuming sheep meat in Meta Woreda indicated that majority of the respondents (54.2% and 33.3%) said that they rarely eat mutton during religious holidays and wedding ceremonies, respectively. The major reason for the rare consumption of sheep meat was the bad smell of the meat (100%) due to the inherent excess fat content of the sheep (50%) and the feed source (33.3%). Moreover, the major mechanisms for alleviating its bad smell were washing live animal skin ahead of slaughtering (40.8%), hot carcass spicing (30.0%), and the application of a special cooking method (29.2%). Thus, from the results of this study, it was concluded that the inclusion of DTL at 100 g per day in the diet of finishing HH rams is optimal for enhancing feed intake, nutrient utilization efficiency, growth, carcass yield, and physical, chemical, and meat eating quality parameters. In addition, proper sheep feeding management and consumers’ perception improving training are essential to enhance sheep meat consumption habit in the study area.