Growth performance and meat characteristics of Awassi sheep that holds the Callipyge gene

• Published in: Journal of animal science Vol. 94; pp. 175 - 176
• Main Authors: Jawasreh, K I, Al-Amareen, A H, Abdullah, A Y
• Format: Journal Article
• Language: English
• Published: Champaign Oxford University Press 01.09.2016
• Subjects: Genes; Genotypes; Kidneys; Leg; Liver; Meat; Meat quality; Muscles; Ovis aries; Rams; Semen; Sheep; Slaughter
• ISSN: 0021-8812; 1525-3163

For improving meat quality and quantity of Awassi sheep, frozen semen of four Rambouillit rams (R, homozygous for the mutation of the Callipyge gene, CLPG) was imported from the United States (Utah University). The introgression of the CLPG into Awassi was started by producing the F1 by crossing R with Awassi (AW) ewes, while the first backcross (FBC; 75% AW and 25% R) was formed by using the F1 Callipyge carriers with AW ewes. To examine the performance of the FBC (heterozygous for CLPG) compared with the AW, a fattening trial was designed using 16 weaned male lambs (eight from each of AW and FBC lambs) kept in individual pens for 98 d. A well-balanced ration was offered, feed intake was recorded on a daily basis, and weights were monitored weekly. At the end of the fattening period, lambs were slaughtered to investigate the carcass cuts and meat characteristics. Callipyge carrier lambs (CAW) exceeded AW lambs in their slaughter weight (P = 0.0002) and the average daily gain for AW and CAW were 0.189 and 0.332 kg/d, respectively (P > 0.0001). Awassi lambs consumed 1.217 kg feed/kg live weight more than CAW (P = 0.0254). The slaughter weight of the CAW was higher than the AW (P = 0.0001); CAW weighed 50.9 kg at slaughter age (176.5 ± 1.34 d), while AW weighed 37.07 kg. The hot and cold carcass weights, dressing percentage, and shoulders, legs, rack, and loin weights were significantly higher in the CAW. Fat tail weight was nonsignificantly affected by the genotype. The heart, liver, kidney, and kidney fat weights were significantly higher in CAW. Longissimus, total leg muscle weight, intermuscular and subcutaneous fat, and total bone weights were higher in CAW compared with AW. The ratio of total muscle to leg weight and total bone to leg weight were higher in CAW, while the intermuscular fat/leg weight subcutaneous fat/leg weight were nonsignificantly affected by the genotype. Eye muscle area was 14.8099 in AW, while 25.3521 ± 1.4086 in CAW (P > 0.0001). CAW was higher than AW of about 0.168 kg in the eye muscle weight (P = 0.0003). Shearforce values were 7.2844 in CAW compared with 3.2187 in AW (P > 0.0002). Meat color nonsignificantly differs between CAW and AW. CLPG can be used for improving meat quantity and quality of AW.