Effect of Implant Different Levels of Zeranol on Growth Performance, Carcass Trait and Body Composition of Awassi Lambs

Abstract

A total of 30 weaned Awassi lambs (3-4 months) with an average body weight of 28.10 ± o.64 kg were divided equally and randomly into 3 groups. The first was left intact, while the 2 nd and 3 rd groups were implanted with zeranol at the rate of 12 and 24 mg, respectively. Each group was kept in a separate pen and fed concentrate (15.067 % C.P. and 2950 kcal/kg) ad lib till they were slaughtered at 40 kg body weight. Results revealed that daily gain, dressing percentage based on body weight and rib eye area averaged 0.212 ± 0.007g, 50.17 ± 0.36 % and 12.88 ± 0.29 cm 2, respectively, and the differences among treatments were not significant. Fat thickness over L.dorsi muscle was significantly (p<0.05) thinner in lambs received 24 mg zeranol as compared with other treatments. Also, it appears that implanting lambs with zeranol resulted in a significant (p<0.01) increase in the percentage of lean and a reduction in fat percentage of the carcass. Intact lambs had significantly (p<0.05) higher total body fat (6.94 ± 0.22 kg) as compared with lambs implanted with 12 mg (6.15 ± 0.21 kg) and lambs implanted with 24 mg zeranol (5.94 ± 0.29 kg). This reduction was associated mainly with a reduction in carcass fat only.

Fatty Acid Composition of Longissimus Dorsi Muscle of Black Goats and Meriz Kids as Influenced by Castration and Slaughter Weight

“…Similarly, Gecgel et al (2015) and Tufekci and Olfaz (2021) found that about 90% of SFAs are (C16:0, C18:0 and C14) in L. dorsi muscle fat in various genotype of lambs. Alkass et al (2016) noticed that the predominant SFAs types was C16:0, C18:0 and C14:0 in Awassi and Karadi lambs. Such difference could be due to differences in age and body weight at slaughter and quality and quantity of feed consumed (Rajkumar et al,2015) Far as individual fatty acid is concerned, Linolic acid (C18:2) contributed the highest (22.45± 0.31) followed by Oleic (C18:1) (20.29± 0.32) and Palmatic (C16:0) (17.14± 0.28) (Table 2).…”

Effect of Implanting Zeranol on Growth and Carcass Characteristics of Awassi Lambs and Goat Kids Raised Under Commercial Condition

“…In previous experiments conducted by Alkass and Kak, (4) Alkass and Mahmood (5) and Alkass and Dosky (2) who found that implanting low dosage (12 mg/animal) of zeranol either in lambs or goat kids had no effect on average daily gain, total gain or final weight. These studies also concluded that the lower response of the zeranol may be due to the high ambiance temperature condition (5). (28) who found that the effect of hormone implantation reduced during summer as compared to the winter when they implement lambs with zeranol in Texas USA which has similar weather conditions to Iraq (4, 5).…”

“…DEFRA (9) reported that the price of soybean meal, rapeseed meal, maize gluten, brewers' grain, and silage have been increased by approximately 140, 80, 75, 100 and 50% respectively, from 2005 until 2014, and this has encouraged ruminant farmers to maximize feed efficiency in order to reduce animal production cost. Improving feed efficiency is considered as one of the most important factors that increase farmer's income (4). Many feed additives, growth promoters and/or drugs such as herbs, plant secondary compounds and hormones have been used to increase animal feed efficiency, hence, enhancing animal performance and increasing their production (30 and 1).…”