Assessment of Growth Performance, Ultrasound Measurements, Carcass Merits and Meat Quality of Barki Lambs at Different Weaning Weights

Abstract

Weaning weight is considered one of pre-weaning traits which influence the post-weaning growth performance. In addition, ultrasound technique is commonly used in the livestock sector, such as a diagnostic tool and a tool in animal science and veterinary research. So, the present study was performed to study the effect of different weaning weights on growth performance, ultrasound measurements, carcass characteristics and meat quality of Barki ramlambs. Moreover, this investigation aimed to examine the relationship among ultrasound measurements, body measurements, carcass characteristics and meat quality of Barki lambs. Twenty-three Barki lambs were divided into three groups according to their weaning weights: seven lambs in a low weaning weight group (G1), nine lambs in a medium weaning weight group (G2), seven lambs in a high weaning weight group (G3) (17.5±1.1, 22.7±1.0 and 28.4±1.1 kg, respectively), and raised for around seven months in an individual housing system. Subcutaneous fat thickness, muscle depth, muscle width, and muscle area at the 12 th thoracic vertebrae were measured two times using the ultrasound scan. Body weight and measurements were recorded. All Barki lambs were slaughtered (one year of age approximately), and their carcass traits, and meat quality were evaluated. All growth performance traits showed significant (p<0.01) differences among the three groups, except birth weight and age. Dressing % (based on slaughter body weight) was higher (p <0.05) in G3 than G1 and G2 groups. The lowest (p <0.05) percentage of offal's was observed in G3 compared to G1 and G2 groups. Meat protein % was higher (p <0.05) in G3 than G1 group. Meat of the G3 group was less (p <0.05) tender than other two groups. The ultrasound Longissimus dorsi muscle area (ULDMA) and ultrasound fat thickness have a positive significant (p <0.05) correlation with carcass back fat and carcass Longissimus dorsi muscle area. The hot carcass weight could be predicted using the ULDMA and slaughter body weight, where the model R 2 reached 95%. Our results confirmed that the weaning weight has an influence on the post-weaning growth traits, carcass merits and some meat quality parameters. Also the obtained results clearly indicated that the ultrasound technique could be used for the accurate prediction of carcass characteristics in Barki lambs.