Fattening Lambs with Small Fat Tail Dimensions and Comparing Them with Larger Fat Tail on the Growth Performance and Carcass Traits of Lambs of Lori Sheep Breeds

Subject Areas : Journal of Animal Biology

Behrouz Yarahmadi ¹ , Mohsen Mohamadisaei ² , Mir Hassan Beiranvand ³ , Amin Kazemi Zadeh ⁴

1 - Department of Animal Sciences, Lorestan Agricultural and Natural Resources Research and Education Center, AREEO, Iran
2 - Department of Animal Sciences, Lorestan Agricultural and Natural Resources Research and Education Center, AREEO, Iran
3 - Department of Animal Sciences, Lorestan Agricultural and Natural Resources Research and Education Center, AREEO, Iran
4 - Department of Animal Sciences, Lorestan Agricultural and Natural Resources Research and Education Center, AREEO, Iran

Received: 2024-06-18 Accepted : 2024-10-21 Published : 2025-01-12

Keywords: Fattening characteristics, Carcass traits, Feed conversion ratio, Lori lambs, Small fat-tail. ,

Abstract :

This study was conducted with the aim of fattening lambs with small fat-tail compared to lambs with large fat-tail on growth performance and carcass traits of lambs of the Lori breed. In order to carry out this project, 30 male lambs were selected based on the size of the tail. The lambs weighing about 30 kg and three months old of weaning were selected and divided into two groups of 15. The experimental group lambs included lambs whose fat-tail width was between 15.5-19.5 cm and fat-tail length 17-22 cm, and the control group included all lambs with tails with widths greater than 19.5 cm and tail length greater than 22 cm.. Finally, daily weight gain (ADG), feed intake (FI), and feed conversion ratio (FCR) were measured. At the end of the 90-day fattening phase, 8 lambs from each small-tailed and large-tailed group were weighed and slaughtered, and carcass traits were measured. The two groups were compared using an independent t-test.The results showed that the highest ADG in lambs with small fat-tail and 90 days of fattening was 210 grams per day and the lowest ADG was related to lambs with larger fat-tail of 182 g/d.The FCR was better in lambs with small fat-tail compared to lambs with larger fat-tail (7.21 vs. 8.35). The highest carcass  yield, cold and hot carcass weight, percentage of carcass parts, and percentage of lean meat were in small-tailed lambs. In terms of total carcass fat, there was a significant difference between the two groups and small tail lambs had the lowest total carcass fat with 17.29% and large tail lambs had the highest total carcass fat with 23.63%. There was a significant difference between small-tailed lambs and control lambs in terms of lean meat percentage (p < 0.05) and carcass length, bone percentage and rectus muscle cross-sectional area were not significant (p > 0.05). he results showed that the cost per kilogram of weight gain per feed consumed for small-tailed lambs was 13.65% cheaper than that of larger-tailed lambs, and in this respect, they had a higher economic value. Based on the results obtained, lambs with small tail size are recommended for fattening due to their appropriate feed conversion ratio, higher daily weight gain and more suitable carcass traits along with lower production cost per kilogram of weight gain and carcass.

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